ovs-vswitchd.conf.db(5) Open vSwitch Manual ovs-vswitchd.conf.db(5) NAME ovs-vswitchd.conf.db - Open_vSwitch database schema A database with this schema holds the configuration for one Open vSwitch daemon. The top-level configuration for the daemon is the Open_vSwitch table, which must have exactly one record. Records in other tables are significant only when they can be reached directly or indirectly from the Open_vSwitch table. Records that are not reachable from the Open_vSwitch table are automatically deleted from the data‐ base, except for records in a few distinguished ``root set’’ tables. Common Columns Most tables contain two special columns, named other_config and exter‐ nal_ids. These columns have the same form and purpose each place that they appear, so we describe them here to save space later. other_config: map of string-string pairs Key-value pairs for configuring rarely used features. Supported keys, along with the forms taken by their val‐ ues, are documented individually for each table. A few tables do not have other_config columns because no key-value pairs have yet been defined for them. external_ids: map of string-string pairs Key-value pairs for use by external frameworks that inte‐ grate with Open vSwitch, rather than by Open vSwitch it‐ self. System integrators should either use the Open vSwitch development mailing list to coordinate on common key-value definitions, or choose key names that are likely to be unique. In some cases, where key-value pairs have been defined that are likely to be widely useful, they are documented individually for each table. TABLE SUMMARY The following list summarizes the purpose of each of the tables in the Open_vSwitch database. Each table is described in more detail on a later page. Table Purpose Open_vSwitch Open vSwitch configuration. Bridge Bridge configuration. Port Port configuration. Interface One physical network device in a Port. Flow_Table OpenFlow table configuration QoS Quality of Service configuration Queue QoS output queue. Mirror Port mirroring. Controller OpenFlow controller configuration. Manager OVSDB management connection. NetFlow NetFlow configuration. Datapath Datapath configuration. CT_Zone CT_Zone configuration. CT_Timeout_Policy CT_Timeout_Policy configuration. SSL SSL configuration. sFlow sFlow configuration. IPFIX IPFIX configuration. Flow_Sample_Collector_Set Flow_Sample_Collector_Set configuration. AutoAttach AutoAttach configuration. Open_vSwitch TABLE Configuration for an Open vSwitch daemon. There must be exactly one record in the Open_vSwitch table. Summary: Configuration: datapaths map of string-Datapath pairs bridges set of Bridges ssl optional SSL external_ids : system-id optional string external_ids : hostname optional string external_ids : rundir optional string other_config : stats-update-interval optional string, containing an integer, at least 5,000 other_config : flow-restore-wait optional string, either true or false other_config : flow-limit optional string, containing an integer, at least 0 other_config : max-idle optional string, containing an integer, at least 500 other_config : max-revalidator optional string, containing an integer, at least 100 other_config : min-revalidate-pps optional string, containing an integer, at least 0 other_config : offloaded-stats-delay optional string, containing an integer, at least 0 other_config : hw-offload optional string, either true or false other_config : n-offload-threads optional string, containing an integer, in range 1 to 10 other_config : tc-policy optional string, one of none, skip_hw, or skip_sw other_config : dpdk-init optional string, one of false, true, or try other_config : dpdk-lcore-mask optional string, containing an integer, at least 1 other_config : pmd-cpu-mask optional string other_config : dpdk-alloc-mem optional string, containing an integer, at least 0 other_config : dpdk-socket-mem optional string other_config : dpdk-socket-limit optional string other_config : dpdk-hugepage-dir optional string other_config : dpdk-extra optional string other_config : vhost-sock-dir optional string other_config : vhost-iommu-support optional string, either true or false other_config : vhost-postcopy-support optional string, either true or false other_config : per-port-memory optional string, either true or false other_config : shared-mempool-config optional string other_config : tx-flush-interval optional string, containing an integer, in range 0 to 1,000,000 other_config : pmd-perf-metrics optional string, either true or false other_config : smc-enable optional string, either true or false other_config : pmd-rxq-assign optional string, one of cycles, group, or roundrobin other_config : pmd-rxq-isolate optional string, either true or false other_config : n-handler-threads optional string, containing an integer, at least 1 other_config : n-revalidator-threads optional string, containing an integer, at least 1 other_config : emc-insert-inv-prob optional string, containing an integer, in range 0 to 4,294,967,295 other_config : vlan-limit optional string, containing an integer, at least 0 other_config : bundle-idle-timeout optional string, containing an integer, at least 1 other_config : offload-rebalance optional string, either true or false other_config : pmd-auto-lb optional string, either true or false other_config : pmd-auto-lb-rebal-interval optional string, containing an integer, in range 0 to 20,000 other_config : pmd-auto-lb-load-threshold optional string, containing an integer, in range 0 to 100 other_config : pmd-auto-lb-improvement-threshold optional string, containing an integer, in range 0 to 100 other_config : pmd-sleep-max optional string other_config : userspace-tso-enable optional string, either true or false Status: next_cfg integer cur_cfg integer dpdk_initialized boolean Statistics: other_config : enable-statistics optional string, either true or false statistics : cpu optional string, containing an integer, at least 1 statistics : load_average optional string statistics : memory optional string statistics : process_NAME optional string statistics : file_systems optional string Version Reporting: ovs_version optional string db_version optional string system_type optional string system_version optional string dpdk_version optional string Capabilities: datapath_types set of strings iface_types set of strings Database Configuration: manager_options set of Managers IPsec: other_config : private_key optional string other_config : certificate optional string other_config : ca_cert optional string Plaintext Tunnel Policy: other_config : ipsec_skb_mark optional string Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: Configuration: datapaths: map of string-Datapath pairs Map of datapath types to datapaths. The datapath_type column of the Bridge table is used as a key for this map. The value points to a row in the Datapath table. bridges: set of Bridges Set of bridges managed by the daemon. ssl: optional SSL SSL used globally by the daemon. external_ids : system-id: optional string A unique identifier for the Open vSwitch’s physical host. The form of the identifier depends on the type of the host. external_ids : hostname: optional string The hostname for the host running Open vSwitch. This is a fully qualified domain name since version 2.6.2. external_ids : rundir: optional string In Open vSwitch 2.8 and later, the run directory of the running Open vSwitch daemon. This directory is used for runtime state such as control and management sockets. The value of other_con‐ fig:vhost-sock-dir is relative to this directory. other_config : stats-update-interval: optional string, containing an integer, at least 5,000 Interval for updating statistics to the database, in millisec‐ onds. This option will affect the update of the statistics col‐ umn in the following tables: Port, Interface , Mirror. Default value is 5000 ms. Getting statistics more frequently can be achieved via OpenFlow. other_config : flow-restore-wait: optional string, either true or false When ovs-vswitchd starts up, it has an empty flow table and therefore it handles all arriving packets in its default fashion according to its configuration, by dropping them or sending them to an OpenFlow controller or switching them as a standalone switch. This behavior is ordinarily desirable. However, if ovs-vswitchd is restarting as part of a ``hot-upgrade,’’ then this leads to a relatively long period during which packets are mishandled. This option allows for improvement. When ovs-vswitchd starts with this value set as true, it will neither flush or expire previously set datapath flows nor will it send and receive any packets to or from the datapath. When this value is later set to false, ovs-vswitchd will start receiving packets from the data‐ path and re-setup the flows. Additionally, ovs-vswitchd is prevented from connecting to con‐ trollers when this value is set to true. This prevents con‐ trollers from making changes to the flow table in the middle of flow restoration, which could result in undesirable intermediate states. Once this value has been set to false and the desired flow state has been restored, ovs-vswitchd will be able to re‐ connect to controllers and process any new flow table modifica‐ tions. Thus, with this option, the procedure for a hot-upgrade of ovs-vswitchd becomes roughly the following: 1. Stop ovs-vswitchd. 2. Set other_config:flow-restore-wait to true. 3. Start ovs-vswitchd. 4. Use ovs-ofctl (or some other program, such as an OpenFlow controller) to restore the OpenFlow flow table to the de‐ sired state. 5. Set other_config:flow-restore-wait to false (or remove it entirely from the database). The ovs-ctl’s ``restart’’ and ``force-reload-kmod’’ functions use the above config option during hot upgrades. other_config : flow-limit: optional string, containing an integer, at least 0 The maximum number of flows allowed in the datapath flow table. Internally OVS will choose a flow limit which will likely be lower than this number, based on real time network conditions. Tweaking this value is discouraged unless you know exactly what you’re doing. The default is 200000. other_config : max-idle: optional string, containing an integer, at least 500 The maximum time (in ms) that idle flows will remain cached in the datapath. Internally OVS will check the validity and activ‐ ity for datapath flows regularly and may expire flows quicker than this number, based on real time network conditions. Tweak‐ ing this value is discouraged unless you know exactly what you’re doing. The default is 10000. other_config : max-revalidator: optional string, containing an integer, at least 100 The maximum time (in ms) that revalidator threads will wait be‐ fore executing flow revalidation. Note that this is maximum al‐ lowed value. Actual timeout used by OVS is minimum of max-idle and max-revalidator values. Tweaking this value is discouraged unless you know exactly what you’re doing. The default is 500. other_config : min-revalidate-pps: optional string, containing an inte‐ ger, at least 0 Set minimum pps that flow must have in order to be revalidated when revalidation duration exceeds half of max-revalidator con‐ fig variable. Setting to 0 means always revalidate flows regard‐ less of pps. The default is 5. other_config : offloaded-stats-delay: optional string, containing an integer, at least 0 Set worst case delay (in ms) it might take before statistics of offloaded flows are updated. Offloaded flows younger than this delay will always be revalidated regardless of other_config:min- revalidate-pps. The default is 2000. other_config : hw-offload: optional string, either true or false Set this value to true to enable netdev flow offload. The default value is false. Changing this value requires restarting the daemon Currently Open vSwitch supports hardware offloading on Linux systems. On other systems, this value is ignored. This function‐ ality is considered ’experimental’. Depending on which OpenFlow matches and actions are configured, which kernel version is used, and what hardware is available, Open vSwitch may not be able to offload functionality to hardware. In order to dump HW offloaded flows use ovs-appctl dpctl/dump-flows, ovs-dpctl doesn’t support this functionality. See ovs-vswitchd(8) for details. other_config : n-offload-threads: optional string, containing an inte‐ ger, in range 1 to 10 Set this value to the number of threads created to manage hard‐ ware offloads. The default value is 1. Changing this value requires restarting the daemon. This is only relevant for userspace datapath and only if other_config:hw-offload is enabled. other_config : tc-policy: optional string, one of none, skip_hw, or skip_sw Specified the policy used with HW offloading. Options: none Add software rule and offload rule to HW. skip_sw Offload rule to HW only. skip_hw Add software rule without offloading rule to HW. This is only relevant if other_config:hw-offload is enabled. The default value is none. other_config : dpdk-init: optional string, one of false, true, or try Set this value to true or try to enable runtime support for DPDK ports. The vswitch must have compile-time support for DPDK as well. A value of true will cause the ovs-vswitchd process to abort if DPDK cannot be initialized. A value of try will allow the ovs- vswitchd process to continue running even if DPDK cannot be ini‐ tialized. The default value is false. Changing this value requires restarting the daemon If this value is false at startup, any dpdk ports which are con‐ figured in the bridge will fail due to memory errors. other_config : dpdk-lcore-mask: optional string, containing an integer, at least 1 Specifies the CPU cores where dpdk lcore threads should be spawned. The DPDK lcore threads are used for DPDK library tasks, such as library internal message processing, logging, etc. Value should be in the form of a hex string (so ’0x123’) similar to the ’taskset’ mask input. The lowest order bit corresponds to the first CPU core. A set bit means the corresponding core is available and an lcore thread will be created and pinned to it. If the input does not cover all cores, those uncovered cores are considered not set. For performance reasons, it is best to set this to a single core on the system, rather than allow lcore threads to float. If not specified, the value will be determined by choosing the lowest CPU core from initial cpu affinity list. Otherwise, the value will be passed directly to the DPDK library. other_config : pmd-cpu-mask: optional string Specifies CPU mask for setting the cpu affinity of PMD (Poll Mode Driver) threads. Value should be in the form of hex string, similar to the dpdk EAL ’-c COREMASK’ option input or the ’taskset’ mask input. The lowest order bit corresponds to the first CPU core. A set bit means the corresponding core is available and a pmd thread will be created and pinned to it. If the input does not cover all cores, those uncovered cores are considered not set. If not specified, one pmd thread will be created for each numa node and pinned to any available core on the numa node by de‐ fault. other_config : dpdk-alloc-mem: optional string, containing an integer, at least 0 Specifies the amount of memory to preallocate from the hugepage pool, regardless of socket. It is recommended that dpdk-socket- mem is used instead. other_config : dpdk-socket-mem: optional string Specifies the amount of memory to preallocate from the hugepage pool, on a per-socket basis. The specifier is a comma-separated string, in ascending order of CPU socket. E.g. On a four socket system 1024,0,2048 would set socket 0 to preallocate 1024MB, socket 1 to preallocate 0MB, socket 2 to preallocate 2048MB and socket 3 (no value given) to preallocate 0MB. If other_config:dpdk-socket-mem and other_config:dpdk-alloc-mem are not specified, neither will be used and there will be no de‐ fault value for each numa node. DPDK defaults will be used in‐ stead. If other_config:dpdk-socket-mem and other_config:dpdk-al‐ loc-mem are specified at the same time, other_config:dpdk- socket-mem will be used as default. Changing this value requires restarting the daemon. other_config : dpdk-socket-limit: optional string Limits the maximum amount of memory that can be used from the hugepage pool, on a per-socket basis. The specifier is a comma-separated list of memory limits per socket. 0 will disable the limit for a particular socket. If not specified, OVS will not configure limits by default. Changing this value requires restarting the daemon. other_config : dpdk-hugepage-dir: optional string Specifies the path to the hugetlbfs mount point. If not specified, this will be guessed by the DPDK library (de‐ fault is /dev/hugepages). Changing this value requires restart‐ ing the daemon. other_config : dpdk-extra: optional string Specifies additional eal command line arguments for DPDK. The default is empty. Changing this value requires restarting the daemon other_config : vhost-sock-dir: optional string Specifies a relative path from external_ids:rundir to the vhost- user unix domain socket files. If this value is unset, the sock‐ ets are put directly in external_ids:rundir. Changing this value requires restarting the daemon. other_config : vhost-iommu-support: optional string, either true or false vHost IOMMU is a security feature, which restricts the vhost memory that a virtio device may access. vHost IOMMU support is disabled by default, due to a bug in QEMU implementations of the vhost REPLY_ACK protocol, (on which vHost IOMMU relies) prior to v2.9.1. Setting this value to true enables vHost IOMMU support for vHost User Client ports in OvS-DPDK, starting from DPDK v17.11. Changing this value requires restarting the daemon. other_config : vhost-postcopy-support: optional string, either true or false vHost post-copy is a feature which allows switching live migra‐ tion of VM attached to dpdkvhostuserclient port to post-copy mode if default pre-copy migration can not be converged or takes too long to converge. Setting this value to true enables vHost post-copy support for all dpdkvhostuserclient ports. Available starting from DPDK v18.11 and QEMU 2.12. Changing this value requires restarting the daemon. other_config : per-port-memory: optional string, either true or false By default OVS DPDK uses a shared memory model wherein devices that have the same MTU and socket values can share the same mem‐ pool. Setting this value to true changes this behaviour. Per port memory allow DPDK devices to use private memory per device. This can provide greater transparency as regards memory usage but potentially at the cost of greater memory requirements. Changing this value requires restarting the daemon if dpdk-init has already been set to true. other_config : shared-mempool-config: optional string Specifies dpdk shared mempool config. Value should be set in the following form: other_config:shared-mempool-config=< user-shared-mem‐ pool-mtu-list> where • ::= NULL | ::= | , ::= | ::= ::= : Changing this value requires restarting the daemon if dpdk-init has already been set to true. other_config : tx-flush-interval: optional string, containing an inte‐ ger, in range 0 to 1,000,000 Specifies the time in microseconds that a packet can wait in output batch for sending i.e. amount of time that packet can spend in an intermediate output queue before sending to netdev. This option can be used to configure balance between throughput and latency. Lower values decreases latency while higher values may be useful to achieve higher performance. Defaults to 0 i.e. instant packet sending (latency optimized). other_config : pmd-perf-metrics: optional string, either true or false Enables recording of detailed PMD performance metrics for analy‐ sis and trouble-shooting. This can have a performance impact in the order of 1%. Defaults to false but can be changed at any time. other_config : smc-enable: optional string, either true or false Signature match cache or SMC is a cache between EMC and megaflow cache. It does not store the full key of the flow, so it is more memory efficient comparing to EMC cache. SMC is especially use‐ ful when flow count is larger than EMC capacity. Defaults to false but can be changed at any time. other_config : pmd-rxq-assign: optional string, one of cycles, group, or roundrobin Specifies how RX queues will be automatically assigned to CPU cores. Options: cycles Rxqs will be sorted by order of measured processing cy‐ cles before being assigned to CPU cores. roundrobin Rxqs will be round-robined across CPU cores. group Rxqs will be sorted by order of measured processing cy‐ cles before being assigned to CPU cores with lowest esti‐ mated load. The default value is cycles. Changing this value will affect an automatic re-assignment of Rxqs to CPUs. Note: Rxqs mapped to CPU cores with pmd-rxq-affin‐ ity are unaffected. other_config : pmd-rxq-isolate: optional string, either true or false Specifies if a CPU core will be isolated after being pinned with an Rx queue. Set this value to false to non-isolate a CPU core after it is pinned with an Rxq using pmd-rxq-affinity. This will allow OVS to assign other Rxqs to that CPU core. The default value is true. This can only be false when pmd-rxq-assign is set to group. other_config : n-handler-threads: optional string, containing an inte‐ ger, at least 1 Attempts to specify the number of threads for software datapaths to use for handling new flows. Some datapaths may choose to ig‐ nore this and it will be set to a sensible option for the data‐ path type. This configuration is per datapath. If you have more than one software datapath (e.g. some system bridges and some netdev bridges), then the total number of threads is n-handler-threads times the number of software datapaths. other_config : n-revalidator-threads: optional string, containing an integer, at least 1 Attempts to specify the number of threads for software datapaths to use for revalidating flows in the datapath. Some datapaths may choose to ignore this and will set to a sensible option for the datapath type. Typically, there is a direct correlation between the number of revalidator threads, and the number of flows allowed in the datapath. The default is the number of cpu cores divided by four plus one. If n-handler-threads is set, the default changes to the number of cpu cores minus the number of handler threads. This configuration is per datapath. If you have more than one software datapath (e.g. some system bridges and some netdev bridges), then the total number of threads is n-handler-threads times the number of software datapaths. other_config : emc-insert-inv-prob: optional string, containing an in‐ teger, in range 0 to 4,294,967,295 Specifies the inverse probability (1/emc-insert-inv-prob) of a flow being inserted into the Exact Match Cache (EMC). On average one in every emc-insert-inv-prob packets that generate a unique flow will cause an insertion into the EMC. A value of 1 will re‐ sult in an insertion for every flow (1/1 = 100%) whereas a value of zero will result in no insertions and essentially disable the EMC. Defaults to 100 ie. there is (1/100 =) 1% chance of EMC inser‐ tion. other_config : vlan-limit: optional string, containing an integer, at least 0 Limits the number of VLAN headers that can be matched to the specified number. Further VLAN headers will be treated as pay‐ load, e.g. a packet with more 802.1q headers will match Ethernet type 0x8100. Open vSwitch userspace currently supports at most 2 VLANs, and each datapath has its own limit. If vlan-limit is nonzero, it acts as a further limit. If this value is absent, the default is currently 1. This main‐ tains backward compatibility with controllers that were designed for use with Open vSwitch versions earlier than 2.8, which only supported one VLAN. other_config : bundle-idle-timeout: optional string, containing an in‐ teger, at least 1 The maximum time (in seconds) that idle bundles will wait to be expired since it was either opened, modified or closed. OpenFlow specification mandates the timeout to be at least one second. The default is 10 seconds. other_config : offload-rebalance: optional string, either true or false Configures HW offload rebalancing, that allows to dynamically offload and un-offload flows while an offload-device is out of resources (OOR). This policy allows flows to be selected for of‐ floading based on the packets-per-second (pps) rate of flows. Set this value to true to enable this option. The default value is false. Changing this value requires restarting the daemon. This is only relevant if HW offloading is enabled (hw-offload). When this policy is enabled, it also requires ’tc-policy’ to be set to ’skip_sw’. other_config : pmd-auto-lb: optional string, either true or false Configures PMD Auto Load Balancing that allows automatic assign‐ ment of RX queues to PMDs if any of PMDs is overloaded (i.e. a processing cycles > other_config:pmd-auto-lb-load-threshold). It uses current scheme of cycle based assignment of RX queues that are not statically pinned to PMDs. The default value is false. Set this value to true to enable this option. It is currently disabled by default and an experimental feature. This only comes in effect if cycle based assignment is enabled and there are more than one non-isolated PMDs present and at least one of it polls more than one queue. other_config : pmd-auto-lb-rebal-interval: optional string, containing an integer, in range 0 to 20,000 The minimum time (in minutes) 2 consecutive PMD Auto Load Bal‐ ancing iterations. The default value is 1 min. If configured to 0 then it would be converted to default value i.e. 1 min This option can be configured to avoid frequent trigger of auto load balancing of PMDs. For e.g. set the value (in min) such that it occurs once in few hours or a day or a week. other_config : pmd-auto-lb-load-threshold: optional string, containing an integer, in range 0 to 100 Specifies the minimum PMD thread load threshold (% of used cy‐ cles) of any non-isolated PMD threads when a PMD Auto Load Bal‐ ance may be triggered. The default value is 95%. other_config : pmd-auto-lb-improvement-threshold: optional string, con‐ taining an integer, in range 0 to 100 Specifies the minimum evaluated % improvement in load distribu‐ tion across the non-isolated PMD threads that will allow a PMD Auto Load Balance to occur. Note, setting this parameter to 0 will always allow an auto load balance to occur regardless of estimated improvement or not. The default value is 25%. other_config : pmd-sleep-max: optional string Specifies the maximum sleep time that will be requested in mi‐ croseconds per iteration for a PMD thread which has received zero or a small amount of packets from the Rx queues it is polling. The actual sleep time requested is based on the load of the Rx queues that the PMD polls and may be less than the maximum value. The default value is 0 microseconds, which means that the PMD will not sleep regardless of the load from the Rx queues that it polls. The maximum value is 10000 microseconds. other_config:pmd-sleep-max= where • ::= NULL | ::= | , ::= | ::= ::= : other_config : userspace-tso-enable: optional string, either true or false Set this value to true to enable userspace support for TCP Seg‐ mentation Offloading (TSO). When it is enabled, the interfaces can provide an oversized TCP segment to the datapath and the datapath will offload the TCP segmentation and checksum calcula‐ tion to the interfaces when necessary. The default value is false. Changing this value requires restarting the daemon. The feature only works if Open vSwitch is built with DPDK sup‐ port. The feature is considered experimental. Status: next_cfg: integer Sequence number for client to increment. When a client modifies any part of the database configuration and wishes to wait for Open vSwitch to finish applying the changes, it may increment this sequence number. cur_cfg: integer Sequence number that Open vSwitch sets to the current value of next_cfg after it finishes applying a set of configuration changes. dpdk_initialized: boolean True if other_config:dpdk-init is set to true and the DPDK li‐ brary is successfully initialized. Statistics: The statistics column contains key-value pairs that report statistics about a system running an Open vSwitch. These are updated periodically (currently, every 5 seconds). Key-value pairs that cannot be determined or that do not apply to a platform are omitted. other_config : enable-statistics: optional string, either true or false Statistics are disabled by default to avoid overhead in the com‐ mon case when statistics gathering is not useful. Set this value to true to enable populating the statistics column or to false to explicitly disable it. statistics : cpu: optional string, containing an integer, at least 1 Number of CPU processors, threads, or cores currently online and available to the operating system on which Open vSwitch is run‐ ning, as an integer. This may be less than the number installed, if some are not online or if they are not available to the oper‐ ating system. Open vSwitch userspace processes are not multithreaded, but the Linux kernel-based datapath is. statistics : load_average: optional string A comma-separated list of three floating-point numbers, repre‐ senting the system load average over the last 1, 5, and 15 min‐ utes, respectively. statistics : memory: optional string A comma-separated list of integers, each of which represents a quantity of memory in kilobytes that describes the operating system on which Open vSwitch is running. In respective order, these values are: 1. Total amount of RAM allocated to the OS. 2. RAM allocated to the OS that is in use. 3. RAM that can be flushed out to disk or otherwise discarded if that space is needed for another purpose. This number is necessarily less than or equal to the previous value. 4. Total disk space allocated for swap. 5. Swap space currently in use. On Linux, all five values can be determined and are included. On other operating systems, only the first two values can be deter‐ mined, so the list will only have two values. statistics : process_NAME: optional string One such key-value pair, with NAME replaced by a process name, will exist for each running Open vSwitch daemon process, with name replaced by the daemon’s name (e.g. process_ovs-vswitchd). The value is a comma-separated list of integers. The integers represent the following, with memory measured in kilobytes and durations in milliseconds: 1. The process’s virtual memory size. 2. The process’s resident set size. 3. The amount of user and system CPU time consumed by the process. 4. The number of times that the process has crashed and been automatically restarted by the monitor. 5. The duration since the process was started. 6. The duration for which the process has been running. The interpretation of some of these values depends on whether the process was started with the --monitor. If it was not, then the crash count will always be 0 and the two durations will al‐ ways be the same. If --monitor was given, then the crash count may be positive; if it is, the latter duration is the amount of time since the most recent crash and restart. There will be one key-value pair for each file in Open vSwitch’s ``run directory’’ (usually /var/run/openvswitch) whose name ends in .pid, whose contents are a process ID, and which is locked by a running process. The name is taken from the pidfile’s name. Currently Open vSwitch is only able to obtain all of the above detail on Linux systems. On other systems, the same key-value pairs will be present but the values will always be the empty string. statistics : file_systems: optional string A space-separated list of information on local, writable file systems. Each item in the list describes one file system and consists in turn of a comma-separated list of the following: 1. Mount point, e.g. / or /var/log. Any spaces or commas in the mount point are replaced by underscores. 2. Total size, in kilobytes, as an integer. 3. Amount of storage in use, in kilobytes, as an integer. This key-value pair is omitted if there are no local, writable file systems or if Open vSwitch cannot obtain the needed infor‐ mation. Version Reporting: These columns report the types and versions of the hardware and soft‐ ware running Open vSwitch. We recommend in general that software should test whether specific features are supported instead of relying on ver‐ sion number checks. These values are primarily intended for reporting to human administrators. ovs_version: optional string The Open vSwitch version number, e.g. 1.1.0. db_version: optional string The database schema version number, e.g. 1.2.3. See ovsdb- tool(1) for an explanation of the numbering scheme. The schema version is part of the database schema, so it can also be retrieved by fetching the schema using the Open vSwitch database protocol. system_type: optional string An identifier for the type of system on top of which Open vSwitch runs, e.g. KVM. System integrators are responsible for choosing and setting an appropriate value for this column. system_version: optional string The version of the system identified by system_type, e.g. 4.18.0-372.19.1.el8_6 on RHEL 8.6 with kernel 4.18.0-372.19.1. System integrators are responsible for choosing and setting an appropriate value for this column. dpdk_version: optional string The version of the linked DPDK library. Capabilities: These columns report capabilities of the Open vSwitch instance. datapath_types: set of strings This column reports the different dpifs registered with the sys‐ tem. These are the values that this instance supports in the datapath_type column of the Bridge table. iface_types: set of strings This column reports the different netdevs registered with the system. These are the values that this instance supports in the type column of the Interface table. Database Configuration: These columns primarily configure the Open vSwitch database (ovsdb-server), not the Open vSwitch switch (ovs-vswitchd). The OVSDB database also uses the ssl settings. The Open vSwitch switch does read the database configuration to deter‐ mine remote IP addresses to which in-band control should apply. manager_options: set of Managers Database clients to which the Open vSwitch database server should connect or to which it should listen, along with options for how these connections should be configured. See the Manager table for more information. For this column to serve its purpose, ovsdb-server must be con‐ figured to honor it. The easiest way to do this is to invoke ovsdb-server with the option --re‐ mote=db:Open_vSwitch,Open_vSwitch,manager_options The startup scripts that accompany Open vSwitch do this by default. IPsec: These settings control the global configuration of IPsec tunnels. The options column of the Interface table configures IPsec for individual tunnels. The options column also allows for custom options prefixed with ipsec_ to be passed to the individual connections. OVS IPsec supports the following three forms of authentication. Cur‐ rently, all IPsec tunnels must use the same form: 1. Pre-shared keys: Omit the global settings. On each tunnel, set options:psk. 2. Self-signed certificates: Set the private_key and certifi‐ cate global settings. On each tunnel, set options:re‐ mote_cert. The remote certificate can be self-signed. 3. CA-signed certificates: Set all of the global settings. On each tunnel, set options:remote_name to the common name (CN) of the remote certificate. The remote certificate must be signed by the CA. other_config : private_key: optional string Name of a PEM file containing the private key used as the switch’s identity for IPsec tunnels. other_config : certificate: optional string Name of a PEM file containing a certificate that certifies the switch’s private key, and identifies a trustworthy switch for IPsec tunnels. The certificate must be x.509 version 3 and with the string in common name (CN) also set in the subject alterna‐ tive name (SAN). other_config : ca_cert: optional string Name of a PEM file containing the CA certificate used to verify that a remote switch of the IPsec tunnel is trustworthy. Plaintext Tunnel Policy: When an IPsec tunnel is configured in this database, multiple indepen‐ dent components take responsibility for implementing it. ovs-vswitchd and its datapath handle packet forwarding to the tunnel and a separate daemon pushes the tunnel’s IPsec policy configuration to the kernel or other entity that implements it. There is a race: if the former config‐ uration completes before the latter, then packets sent by the local host over the tunnel can be transmitted in plaintext. Using this set‐ ting, OVS users can avoid this undesirable situation. other_config : ipsec_skb_mark: optional string This setting takes the form value/mask. If it is specified, then the skb_mark field in every outgoing tunneled packet sent in plaintext is compared against it and, if it matches, the packet is dropped. This is a global setting that is applied to every tunneled packet, regardless of whether IPsec encryption is en‐ abled for the tunnel, the type of tunnel, or whether OVS is in‐ volved. Example policies: 1/1 Drop all unencrypted tunneled packets in which the least- significant bit of skb_mark is 1. This would be a useful policy given an OpenFlow flow table that sets skb_mark to 1 for traffic that should be encrypted. The default skb_mark is 0, so this would not affect other traffic. 0/1 Drop all unencrypted tunneled packets in which the least- significant bit of skb_mark is 0. This would be a useful policy if no unencrypted tunneled traffic should exit the system without being specially permitted by setting skb_mark to 1. (empty) If this setting is empty or unset, then all unencrypted tunneled packets are transmitted in the usual way. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Bridge TABLE Configuration for a bridge within an Open_vSwitch. A Bridge record represents an Ethernet switch with one or more ``ports,’’ which are the Port records pointed to by the Bridge’s ports column. Summary: Core Features: name immutable string (must be unique within table) ports set of Ports mirrors set of Mirrors netflow optional NetFlow sflow optional sFlow ipfix optional IPFIX flood_vlans set of up to 4,096 integers, in range 0 to 4,095 auto_attach optional AutoAttach OpenFlow Configuration: controller set of Controllers flow_tables map of integer-Flow_Table pairs, key in range 0 to 254 fail_mode optional string, either secure or stand‐ alone datapath_id optional string datapath_version string other_config : datapath-id optional string other_config : dp-desc optional string other_config : dp-sn optional string other_config : disable-in-band optional string, either true or false other_config : in-band-queue optional string, containing an integer, in range 0 to 4,294,967,295 other_config : controller-queue-size optional string, containing an integer, in range 1 to 512 protocols set of strings, one of OpenFlow10, Open‐ Flow11, OpenFlow12, OpenFlow13, Open‐ Flow14, or OpenFlow15 Spanning Tree Configuration: STP Configuration: stp_enable boolean other_config : stp-system-id optional string other_config : stp-priority optional string, containing an integer, in range 0 to 65,535 other_config : stp-hello-time optional string, containing an integer, in range 1 to 10 other_config : stp-max-age optional string, containing an integer, in range 6 to 40 other_config : stp-forward-delay optional string, containing an integer, in range 4 to 30 other_config : mcast-snooping-aging-time optional string, containing an integer, at least 1 other_config : mcast-snooping-table-size optional string, containing an integer, at least 1 other_config : mcast-snooping-disable-flood-unregistered optional string, either true or false STP Status: status : stp_bridge_id optional string status : stp_designated_root optional string status : stp_root_path_cost optional string Rapid Spanning Tree: RSTP Configuration: rstp_enable boolean other_config : rstp-address optional string other_config : rstp-priority optional string, containing an integer, in range 0 to 61,440 other_config : rstp-ageing-time optional string, containing an integer, in range 10 to 1,000,000 other_config : rstp-force-protocol-version optional string, containing an integer other_config : rstp-max-age optional string, containing an integer, in range 6 to 40 other_config : rstp-forward-delay optional string, containing an integer, in range 4 to 30 other_config : rstp-transmit-hold-count optional string, containing an integer, in range 1 to 10 RSTP Status: rstp_status : rstp_bridge_id optional string rstp_status : rstp_root_id optional string rstp_status : rstp_root_path_cost optional string, containing an integer, at least 0 rstp_status : rstp_designated_id optional string rstp_status : rstp_designated_port_id optional string rstp_status : rstp_bridge_port_id optional string Multicast Snooping Configuration: mcast_snooping_enable boolean Other Features: datapath_type string external_ids : bridge-id optional string other_config : hwaddr optional string other_config : forward-bpdu optional string, either true or false other_config : mac-aging-time optional string, containing an integer, at least 1 other_config : mac-table-size optional string, containing an integer, at least 1 Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: Core Features: name: immutable string (must be unique within table) Bridge identifier. Must be unique among the names of ports, in‐ terfaces, and bridges on a host. The name must be alphanumeric and must not contain forward or backward slashes. The name of a bridge is also the name of an Interface (and a Port) within the bridge, so the restrictions on the name column in the Interface table, particularly on length, also apply to bridge names. Refer to the documentation for In‐ terface names for details. ports: set of Ports Ports included in the bridge. mirrors: set of Mirrors Port mirroring configuration. netflow: optional NetFlow NetFlow configuration. sflow: optional sFlow sFlow(R) configuration. ipfix: optional IPFIX IPFIX configuration. flood_vlans: set of up to 4,096 integers, in range 0 to 4,095 VLAN IDs of VLANs on which MAC address learning should be dis‐ abled, so that packets are flooded instead of being sent to spe‐ cific ports that are believed to contain packets’ destination MACs. This should ordinarily be used to disable MAC learning on VLANs used for mirroring (RSPAN VLANs). It may also be useful for debugging. SLB bonding (see the bond_mode column in the Port table) is in‐ compatible with flood_vlans. Consider using another bonding mode or a different type of mirror instead. auto_attach: optional AutoAttach Auto Attach configuration. OpenFlow Configuration: controller: set of Controllers OpenFlow controller set. If unset, then no OpenFlow controllers will be used. If there are primary controllers, removing all of them clears the OpenFlow flow tables, group table, and meter table. If there are no primary controllers, adding one also clears these tables. Other changes to the set of controllers, such as adding or re‐ moving a service controller, adding another primary controller to supplement an existing primary controller, or removing only one of two primary controllers, have no effect on these tables. flow_tables: map of integer-Flow_Table pairs, key in range 0 to 254 Configuration for OpenFlow tables. Each pair maps from an Open‐ Flow table ID to configuration for that table. fail_mode: optional string, either secure or standalone When a controller is configured, it is, ordinarily, responsible for setting up all flows on the switch. Thus, if the connection to the controller fails, no new network connections can be set up. If the connection to the controller stays down long enough, no packets can pass through the switch at all. This setting de‐ termines the switch’s response to such a situation. It may be set to one of the following: standalone If no message is received from the controller for three times the inactivity probe interval (see inactiv‐ ity_probe), then Open vSwitch will take over responsibil‐ ity for setting up flows. In this mode, Open vSwitch causes the bridge to act like an ordinary MAC-learning switch. Open vSwitch will continue to retry connecting to the controller in the background and, when the connection succeeds, it will discontinue its standalone behavior. secure Open vSwitch will not set up flows on its own when the controller connection fails or when no controllers are defined. The bridge will continue to retry connecting to any defined controllers forever. The default is standalone if the value is unset, but future ver‐ sions of Open vSwitch may change the default. The standalone mode can create forwarding loops on a bridge that has more than one uplink port unless STP is enabled. To avoid loops on such a bridge, configure secure mode or enable STP (see stp_enable). The fail_mode setting applies only to primary controllers. When more than one primary controller is configured, fail_mode is considered only when none of the configured controllers can be contacted. Changing fail_mode when no primary controllers are configured clears the OpenFlow flow tables, group table, and meter table. datapath_id: optional string Reports the OpenFlow datapath ID in use. Exactly 16 hex digits. (Setting this column has no useful effect. Set other-con‐ fig:datapath-id instead.) datapath_version: string Reports the datapath version. This column is maintained for backwards compatibility. The preferred locatation is the data‐ path_id column of the Datapath table. The full documentation for this column is there. other_config : datapath-id: optional string Overrides the default OpenFlow datapath ID, setting it to the specified value specified in hex. The value must either have a 0x prefix or be exactly 16 hex digits long. May not be all-zero. other_config : dp-desc: optional string Human readable description of datapath. It is a maximum 256 byte-long free-form string to describe the datapath for debug‐ ging purposes, e.g. switch3 in room 3120. The value is returned by the switch as a part of reply to OFPMP_DESC request (ofp_desc). The OpenFlow specification (e.g. 1.3.5) describes the ofp_desc structure to contaion "NULL terminated ASCII strings". For the compatibility reasons no more than 255 ASCII characters should be used. other_config : dp-sn: optional string Serial number. It is a maximum 32 byte-long free-form string to provide an additional switch identification. The value is re‐ turned by the switch as a part of reply to OFPMP_DESC request (ofp_desc). Same as mentioned in the description of other-con‐ fig:dp-desc, the string should be no more than 31 ASCII charac‐ ters for the compatibility. other_config : disable-in-band: optional string, either true or false If set to true, disable in-band control on the bridge regardless of controller and manager settings. other_config : in-band-queue: optional string, containing an integer, in range 0 to 4,294,967,295 A queue ID as a nonnegative integer. This sets the OpenFlow queue ID that will be used by flows set up by in-band control on this bridge. If unset, or if the port used by an in-band control flow does not have QoS configured, or if the port does not have a queue with the specified ID, the default queue is used in‐ stead. other_config : controller-queue-size: optional string, containing an integer, in range 1 to 512 This sets the maximum size of the queue of packets that need to be sent to the OpenFlow management controller. The value must be less than 512. If not specified the queue size is limited to 100 packets by default. Note: increasing the queue size might have a negative impact on latency. protocols: set of strings, one of OpenFlow10, OpenFlow11, OpenFlow12, OpenFlow13, OpenFlow14, or OpenFlow15 List of OpenFlow protocols that may be used when negotiating a connection with a controller. OpenFlow 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 are enabled by default if this column is empty. Spanning Tree Configuration: The IEEE 802.1D Spanning Tree Protocol (STP) is a network protocol that ensures loop-free topologies. It allows redundant links to be included in the network to provide automatic backup paths if the active links fails. These settings configure the slower-to-converge but still widely sup‐ ported version of Spanning Tree Protocol, sometimes known as 802.1D-1998. Open vSwitch also supports the newer Rapid Spanning Tree Protocol (RSTP), documented later in the section titled Rapid Spanning Tree Configuration. STP Configuration: stp_enable: boolean Enable spanning tree on the bridge. By default, STP is disabled on bridges. Bond, internal, and mirror ports are not supported and will not participate in the spanning tree. STP and RSTP are mutually exclusive. If both are enabled, RSTP will be used. other_config : stp-system-id: optional string The bridge’s STP identifier (the lower 48 bits of the bridge-id) in the form xx:xx:xx:xx:xx:xx. By default, the identifier is the MAC address of the bridge. other_config : stp-priority: optional string, containing an integer, in range 0 to 65,535 The bridge’s relative priority value for determining the root bridge (the upper 16 bits of the bridge-id). A bridge with the lowest bridge-id is elected the root. By default, the priority is 0x8000. other_config : stp-hello-time: optional string, containing an integer, in range 1 to 10 The interval between transmissions of hello messages by desig‐ nated ports, in seconds. By default the hello interval is 2 sec‐ onds. other_config : stp-max-age: optional string, containing an integer, in range 6 to 40 The maximum age of the information transmitted by the bridge when it is the root bridge, in seconds. By default, the maximum age is 20 seconds. other_config : stp-forward-delay: optional string, containing an inte‐ ger, in range 4 to 30 The delay to wait between transitioning root and designated ports to forwarding, in seconds. By default, the forwarding de‐ lay is 15 seconds. other_config : mcast-snooping-aging-time: optional string, containing an integer, at least 1 The maximum number of seconds to retain a multicast snooping en‐ try for which no packets have been seen. The default is cur‐ rently 300 seconds (5 minutes). The value, if specified, is forced into a reasonable range, currently 15 to 3600 seconds. other_config : mcast-snooping-table-size: optional string, containing an integer, at least 1 The maximum number of multicast snooping addresses to learn. The default is currently 2048. The value, if specified, is forced into a reasonable range, currently 10 to 1,000,000. other_config : mcast-snooping-disable-flood-unregistered: optional string, either true or false If set to false, unregistered multicast packets are forwarded to all ports. If set to true, unregistered multicast packets are forwarded to ports connected to multicast routers. STP Status: These key-value pairs report the status of 802.1D-1998. They are present only if STP is enabled (via the stp_enable column). status : stp_bridge_id: optional string The bridge ID used in spanning tree advertisements, in the form xxxx.yyyyyyyyyyyy where the xs are the STP priority, the ys are the STP system ID, and each x and y is a hex digit. status : stp_designated_root: optional string The designated root for this spanning tree, in the same form as status:stp_bridge_id. If this bridge is the root, this will have the same value as status:stp_bridge_id, otherwise it will dif‐ fer. status : stp_root_path_cost: optional string The path cost of reaching the designated bridge. A lower number is better. The value is 0 if this bridge is the root, otherwise it is higher. Rapid Spanning Tree: Rapid Spanning Tree Protocol (RSTP), like STP, is a network protocol that ensures loop-free topologies. RSTP superseded STP with the publi‐ cation of 802.1D-2004. Compared to STP, RSTP converges more quickly and recovers more quickly from failures. RSTP Configuration: rstp_enable: boolean Enable Rapid Spanning Tree on the bridge. By default, RSTP is disabled on bridges. Bond, internal, and mirror ports are not supported and will not participate in the spanning tree. STP and RSTP are mutually exclusive. If both are enabled, RSTP will be used. other_config : rstp-address: optional string The bridge’s RSTP address (the lower 48 bits of the bridge-id) in the form xx:xx:xx:xx:xx:xx. By default, the address is the MAC address of the bridge. other_config : rstp-priority: optional string, containing an integer, in range 0 to 61,440 The bridge’s relative priority value for determining the root bridge (the upper 16 bits of the bridge-id). A bridge with the lowest bridge-id is elected the root. By default, the priority is 0x8000 (32768). This value needs to be a multiple of 4096, otherwise it’s rounded to the nearest inferior one. other_config : rstp-ageing-time: optional string, containing an inte‐ ger, in range 10 to 1,000,000 The Ageing Time parameter for the Bridge. The default value is 300 seconds. other_config : rstp-force-protocol-version: optional string, containing an integer The Force Protocol Version parameter for the Bridge. This can take the value 0 (STP Compatibility mode) or 2 (the default, normal operation). other_config : rstp-max-age: optional string, containing an integer, in range 6 to 40 The maximum age of the information transmitted by the Bridge when it is the Root Bridge. The default value is 20. other_config : rstp-forward-delay: optional string, containing an inte‐ ger, in range 4 to 30 The delay used by STP Bridges to transition Root and Designated Ports to Forwarding. The default value is 15. other_config : rstp-transmit-hold-count: optional string, containing an integer, in range 1 to 10 The Transmit Hold Count used by the Port Transmit state machine to limit transmission rate. The default value is 6. RSTP Status: These key-value pairs report the status of 802.1D-2004. They are present only if RSTP is enabled (via the rstp_enable column). rstp_status : rstp_bridge_id: optional string The bridge ID used in rapid spanning tree advertisements, in the form x.yyy.zzzzzzzzzzzz where x is the RSTP priority, the ys are a locally assigned system ID extension, the zs are the STP sys‐ tem ID, and each x, y, or z is a hex digit. rstp_status : rstp_root_id: optional string The root of this spanning tree, in the same form as rstp_sta‐ tus:rstp_bridge_id. If this bridge is the root, this will have the same value as rstp_status:rstp_bridge_id, otherwise it will differ. rstp_status : rstp_root_path_cost: optional string, containing an inte‐ ger, at least 0 The path cost of reaching the root. A lower number is better. The value is 0 if this bridge is the root, otherwise it is higher. rstp_status : rstp_designated_id: optional string The RSTP designated ID, in the same form as rstp_sta‐ tus:rstp_bridge_id. rstp_status : rstp_designated_port_id: optional string The RSTP designated port ID, as a 4-digit hex number. rstp_status : rstp_bridge_port_id: optional string The RSTP bridge port ID, as a 4-digit hex number. Multicast Snooping Configuration: Multicast snooping (RFC 4541) monitors the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery traffic between hosts and multicast routers. The switch uses what IGMP and MLD snooping learns to forward multicast traffic only to interfaces that are con‐ nected to interested receivers. Currently it supports IGMPv1, IGMPv2, IGMPv3, MLDv1 and MLDv2 protocols. mcast_snooping_enable: boolean Enable multicast snooping on the bridge. For now, the default is disabled. Other Features: datapath_type: string Name of datapath provider. The kernel datapath has type system. The userspace datapath has type netdev. A manager may refer to the datapath_types column of the Open_vSwitch table for a list of the types accepted by this Open vSwitch instance. external_ids : bridge-id: optional string A unique identifier of the bridge. other_config : hwaddr: optional string An Ethernet address in the form xx:xx:xx:xx:xx:xx to set the hardware address of the local port and influence the datapath ID. other_config : forward-bpdu: optional string, either true or false Controls forwarding of BPDUs and other network control frames when NORMAL action is invoked. When this option is false or un‐ set, frames with reserved Ethernet addresses (see table below) will not be forwarded. When this option is true, such frames will not be treated specially. The above general rule has the following exceptions: • If STP is enabled on the bridge (see the stp_enable col‐ umn in the Bridge table), the bridge processes all re‐ ceived STP packets and never passes them to OpenFlow or forwards them. This is true even if STP is disabled on an individual port. • If LLDP is enabled on an interface (see the lldp column in the Interface table), the interface processes received LLDP packets and never passes them to OpenFlow or for‐ wards them. Set this option to true if the Open vSwitch bridge connects dif‐ ferent Ethernet networks and is not configured to participate in STP. This option affects packets with the following destination MAC addresses: 01:80:c2:00:00:00 IEEE 802.1D Spanning Tree Protocol (STP). 01:80:c2:00:00:01 IEEE Pause frame. 01:80:c2:00:00:0x Other reserved protocols. 00:e0:2b:00:00:00 Extreme Discovery Protocol (EDP). 00:e0:2b:00:00:04 and 00:e0:2b:00:00:06 Ethernet Automatic Protection Switching (EAPS). 01:00:0c:cc:cc:cc Cisco Discovery Protocol (CDP), VLAN Trunking Protocol (VTP), Dynamic Trunking Protocol (DTP), Port Aggregation Protocol (PAgP), and others. 01:00:0c:cc:cc:cd Cisco Shared Spanning Tree Protocol PVSTP+. 01:00:0c:cd:cd:cd Cisco STP Uplink Fast. 01:00:0c:00:00:00 Cisco Inter Switch Link. 01:00:0c:cc:cc:cx Cisco CFM. other_config : mac-aging-time: optional string, containing an integer, at least 1 The maximum number of seconds to retain a MAC learning entry for which no packets have been seen. The default is currently 300 seconds (5 minutes). The value, if specified, is forced into a reasonable range, currently 15 to 3600 seconds. A short MAC aging time allows a network to more quickly detect that a host is no longer connected to a switch port. However, it also makes it more likely that packets will be flooded unneces‐ sarily, when they are addressed to a connected host that rarely transmits packets. To reduce the incidence of unnecessary flood‐ ing, use a MAC aging time longer than the maximum interval at which a host will ordinarily transmit packets. other_config : mac-table-size: optional string, containing an integer, at least 1 The maximum number of MAC addresses to learn. The default is currently 8192. The value, if specified, is forced into a rea‐ sonable range, currently 10 to 1,000,000. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Port TABLE A port within a Bridge. Most commonly, a port has exactly one ``interface,’’ pointed to by its interfaces column. Such a port logically corresponds to a port on a physical Ethernet switch. A port with more than one interface is a ``bonded port’’ (see Bonding Configuration). Some properties that one might think as belonging to a port are actu‐ ally part of the port’s Interface members. Summary: name immutable string (must be unique within table) interfaces set of 1 or more Interfaces VLAN Configuration: vlan_mode optional string, one of access, dot1q-tunnel, native-tagged, native-un‐ tagged, or trunk tag optional integer, in range 0 to 4,095 trunks set of up to 4,096 integers, in range 0 to 4,095 cvlans set of up to 4,096 integers, in range 0 to 4,095 other_config : qinq-ethtype optional string, either 802.1ad or 802.1q other_config : priority-tags optional string, one of always, if-non‐ zero, or never Bonding Configuration: bond_mode optional string, one of active-backup, balance-slb, or balance-tcp other_config : bond-hash-basis optional string, containing an integer other_config : lb-output-action optional string, either true or false other_config : bond-primary optional string other_config : all-members-active optional string, either true or false Link Failure Detection: other_config : bond-detect-mode optional string, either carrier or miimon other_config : bond-miimon-interval optional string, containing an integer bond_updelay integer bond_downdelay integer LACP Configuration: lacp optional string, one of active, off, or passive other_config : lacp-system-id optional string other_config : lacp-system-priority optional string, containing an integer, in range 1 to 65,535 other_config : lacp-time optional string, either fast or slow other_config : lacp-fallback-ab optional string, either true or false Rebalancing Configuration: other_config : bond-rebalance-interval optional string, containing an integer, in range 0 to 2,147,483,647 bond_fake_iface boolean Spanning Tree Protocol: STP Configuration: other_config : stp-enable optional string, either true or false other_config : stp-port-num optional string, containing an integer, in range 1 to 255 other_config : stp-port-priority optional string, containing an integer, in range 0 to 255 other_config : stp-path-cost optional string, containing an integer, in range 0 to 65,535 STP Status: status : stp_port_id optional string status : stp_state optional string, one of blocking, dis‐ abled, forwarding, learning, or listening status : stp_sec_in_state optional string, containing an integer, at least 0 status : stp_role optional string, one of alternate, desig‐ nated, or root Rapid Spanning Tree Protocol: RSTP Configuration: other_config : rstp-enable optional string, either true or false other_config : rstp-port-priority optional string, containing an integer, in range 0 to 240 other_config : rstp-port-num optional string, containing an integer, in range 1 to 4,095 other_config : rstp-path-cost optional string, containing an integer other_config : rstp-port-admin-edge optional string, either true or false other_config : rstp-port-auto-edge optional string, either true or false other_config : rstp-port-mcheck optional string, either true or false RSTP Status: rstp_status : rstp_port_id optional string rstp_status : rstp_port_role optional string, one of Alternate, Backup, Designated, Disabled, or Root rstp_status : rstp_port_state optional string, one of Disabled, Dis‐ carding, Forwarding, or Learning rstp_status : rstp_designated_bridge_id optional string rstp_status : rstp_designated_port_id optional string rstp_status : rstp_designated_path_cost optional string, containing an integer RSTP Statistics: rstp_statistics : rstp_tx_count optional integer rstp_statistics : rstp_rx_count optional integer rstp_statistics : rstp_error_count optional integer rstp_statistics : rstp_uptime optional integer Multicast Snooping: other_config : mcast-snooping-flood optional string, either true or false other_config : mcast-snooping-flood-reports optional string, either true or false Other Features: qos optional QoS mac optional string fake_bridge boolean protected boolean external_ids : fake-bridge-* optional string other_config : transient optional string, either true or false bond_active_slave optional string Port Statistics: Statistics: STP transmit and receive counters: statistics : stp_tx_count optional integer statistics : stp_rx_count optional integer statistics : stp_error_count optional integer Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: name: immutable string (must be unique within table) Port name. For a non-bonded port, this should be the same as its interface’s name. Port names must otherwise be unique among the names of ports, interfaces, and bridges on a host. Because port and interfaces names are usually the same, the restrictions on the name column in the Interface table, particularly on length, also apply to port names. Refer to the documentation for Inter‐ face names for details. interfaces: set of 1 or more Interfaces The port’s interfaces. If there is more than one, this is a bonded Port. VLAN Configuration: In short, a VLAN (short for ``virtual LAN’’) is a way to partition a single switch into multiple switches. VLANs can be confusing, so for an introduction, please refer to the question ``What’s a VLAN?’’ in the Open vSwitch FAQ. A VLAN is sometimes encoded into a packet using a 802.1Q or 802.1ad VLAN header, but every packet is part of some VLAN whether or not it is encoded in the packet. (A packet that appears to have no VLAN is part of VLAN 0, by default.) As a result, it’s useful to think of a VLAN as a metadata property of a packet, separate from how the VLAN is encoded. For a given port, this column determines how the encoding of a packet that ingresses or egresses the port maps to the packet’s VLAN. When a packet enters the switch, its VLAN is determined based on its setting in this column and its VLAN headers, if any, and then, conceptually, the VLAN headers are then stripped off. Conversely, when a packet exits the switch, its VLAN and the settings in this column determine what VLAN headers, if any, are pushed onto the packet before it egresses the port. The VLAN configuration in this column affects Open vSwitch only when it is doing ``normal switching.’’ It does not affect flows set up by an OpenFlow controller, outside of the OpenFlow ``normal action.’’ Bridge ports support the following types of VLAN configuration: trunk A trunk port carries packets on one or more specified VLANs specified in the trunks column (often, on every VLAN). A packet that ingresses on a trunk port is in the VLAN specified in its 802.1Q header, or VLAN 0 if the packet has no 802.1Q header. A packet that egresses through a trunk port will have an 802.1Q header if it has a nonzero VLAN ID. Any packet that ingresses on a trunk port tagged with a VLAN that the port does not trunk is dropped. access An access port carries packets on exactly one VLAN speci‐ fied in the tag column. Packets egressing on an access port have no 802.1Q header. Any packet with an 802.1Q header with a nonzero VLAN ID that ingresses on an access port is dropped, regardless of whether the VLAN ID in the header is the access port’s VLAN ID. native-tagged A native-tagged port resembles a trunk port, with the ex‐ ception that a packet without an 802.1Q header that in‐ gresses on a native-tagged port is in the ``native VLAN’’ (specified in the tag column). native-untagged A native-untagged port resembles a native-tagged port, with the exception that a packet that egresses on a na‐ tive-untagged port in the native VLAN will not have an 802.1Q header. dot1q-tunnel A dot1q-tunnel port is somewhat like an access port. Like an access port, it carries packets on the single VLAN specified in the tag column and this VLAN, called the service VLAN, does not appear in an 802.1Q header for packets that ingress or egress on the port. The main dif‐ ference lies in the behavior when packets that include a 802.1Q header ingress on the port. Whereas an access port drops such packets, a dot1q-tunnel port treats these as double-tagged with the outer service VLAN tag and the in‐ ner customer VLAN taken from the 802.1Q header. Corre‐ spondingly, to egress on the port, a packet outer VLAN (or only VLAN) must be tag, which is removed before egress, which exposes the inner (customer) VLAN if one is present. If cvlans is set, only allows packets in the specified customer VLANs. A packet will only egress through bridge ports that carry the VLAN of the packet, as described by the rules above. vlan_mode: optional string, one of access, dot1q-tunnel, native-tagged, native-untagged, or trunk The VLAN mode of the port, as described above. When this column is empty, a default mode is selected as follows: • If tag contains a value, the port is an access port. The trunks column should be empty. • Otherwise, the port is a trunk port. The trunks column value is honored if it is present. tag: optional integer, in range 0 to 4,095 For an access port, the port’s implicitly tagged VLAN. For a na‐ tive-tagged or native-untagged port, the port’s native VLAN. Must be empty if this is a trunk port. trunks: set of up to 4,096 integers, in range 0 to 4,095 For a trunk, native-tagged, or native-untagged port, the 802.1Q VLAN or VLANs that this port trunks; if it is empty, then the port trunks all VLANs. Must be empty if this is an access port. A native-tagged or native-untagged port always trunks its native VLAN, regardless of whether trunks includes that VLAN. cvlans: set of up to 4,096 integers, in range 0 to 4,095 For a dot1q-tunnel port, the customer VLANs that this port in‐ cludes. If this is empty, the port includes all customer VLANs. For other kinds of ports, this setting is ignored. other_config : qinq-ethtype: optional string, either 802.1ad or 802.1q For a dot1q-tunnel port, this is the TPID for the service tag, that is, for the 802.1Q header that contains the service VLAN ID. Because packets that actually ingress and egress a dot1q- tunnel port do not include an 802.1Q header for the service VLAN, this does not affect packets on the dot1q-tunnel port it‐ self. Rather, it determines the service VLAN for a packet that ingresses on a dot1q-tunnel port and egresses on a trunk port. The value 802.1ad specifies TPID 0x88a8, which is also the de‐ fault if the setting is omitted. The value 802.1q specifies TPID 0x8100. For other kinds of ports, this setting is ignored. other_config : priority-tags: optional string, one of always, if-non‐ zero, or never An 802.1Q header contains two important pieces of information: a VLAN ID and a priority. A frame with a zero VLAN ID, called a ``priority-tagged’’ frame, is supposed to be treated the same way as a frame without an 802.1Q header at all (except for the priority). However, some network elements ignore any frame that has 802.1Q header at all, even when the VLAN ID is zero. Therefore, by de‐ fault Open vSwitch does not output priority-tagged frames, in‐ stead omitting the 802.1Q header entirely if the VLAN ID is zero. Set this key to if-nonzero to enable priority-tagged frames on a port. For if-nonzero Open vSwitch omits the 802.1Q header on output if both the VLAN ID and priority would be zero. Set to always to retain the 802.1Q header in such frames as well. All frames output to native-tagged ports have a nonzero VLAN ID, so this setting is not meaningful on native-tagged ports. Bonding Configuration: A port that has more than one interface is a ``bonded port.’’ Bonding allows for load balancing and fail-over. The following types of bonding will work with any kind of upstream switch. On the upstream switch, do not configure the interfaces as a bond: balance-slb Balances flows among members based on source MAC address and output VLAN, with periodic rebalancing as traffic patterns change. active-backup Assigns all flows to one member, failing over to a backup member when the active member is disabled. This is the only bonding mode in which interfaces may be plugged into different upstream switches. The following modes require the upstream switch to support 802.3ad with successful LACP negotiation. If LACP negotiation fails and other-con‐ fig:lacp-fallback-ab is true, then active-backup mode is used: balance-tcp Balances flows among members based on L3 and L4 protocol information such as IP addresses and TCP/UDP ports. These columns apply only to bonded ports. Their values are otherwise ignored. bond_mode: optional string, one of active-backup, balance-slb, or bal‐ ance-tcp The type of bonding used for a bonded port. Defaults to ac‐ tive-backup if unset. other_config : bond-hash-basis: optional string, containing an integer An integer hashed along with flows when choosing output members in load balanced bonds. When changed, all flows will be assigned different hash values possibly causing member selection deci‐ sions to change. Does not affect bonding modes which do not em‐ ploy load balancing such as active-backup. other_config : lb-output-action: optional string, either true or false Enable/disable usage of optimized lb_output action for balancing flows among output members in load balanced bonds in bal‐ ance-tcp. When enabled, it uses optimized path for balance-tcp mode by using rss hash and avoids recirculation. This knob does not affect other balancing modes. other_config : bond-primary: optional string If a slave interface with this name exists in the bond and is up, it will be made active. Relevant only when other_con‐ fig:bond_mode is active-backup or if balance-tcp falls back to active-backup (e.g., LACP negotiation fails and other_con‐ fig:lacp-fallback-ab is true). other_config : all-members-active: optional string, either true or false Enable/Disable delivery of broadcast/multicast packets on sec‐ ondary interface of a balance-slb bond. Relevant only when lacp is off. This parameter is identical to all_slaves_active for Linux ker‐ nel bonds. Disabled by default as it is not a desirable configu‐ ration for most users. Link Failure Detection: An important part of link bonding is detecting that links are down so that they may be disabled. These settings determine how Open vSwitch detects link failure. other_config : bond-detect-mode: optional string, either carrier or mi‐ imon The means used to detect link failures. Defaults to carrier which uses each interface’s carrier to detect failures. When set to miimon, will check for failures by polling each interface’s MII. other_config : bond-miimon-interval: optional string, containing an in‐ teger The interval, in milliseconds, between successive attempts to poll each interface’s MII. Relevant only when other_config:bond- detect-mode is miimon. bond_updelay: integer The number of milliseconds for which the link must stay up on an interface before the interface is considered to be up. Specify 0 to enable the interface immediately. This setting is honored only when at least one bonded interface is already enabled. When no interfaces are enabled, then the first bond interface to come up is enabled immediately. bond_downdelay: integer The number of milliseconds for which the link must stay down on an interface before the interface is considered to be down. Specify 0 to disable the interface immediately. LACP Configuration: LACP, the Link Aggregation Control Protocol, is an IEEE standard that allows switches to automatically detect that they are connected by mul‐ tiple links and aggregate across those links. These settings control LACP behavior. lacp: optional string, one of active, off, or passive Configures LACP on this port. LACP allows directly connected switches to negotiate which links may be bonded. LACP may be en‐ abled on non-bonded ports for the benefit of any switches they may be connected to. active ports are allowed to initiate LACP negotiations. passive ports are allowed to participate in LACP negotiations initiated by a remote switch, but not allowed to initiate such negotiations themselves. If LACP is enabled on a port whose partner switch does not support LACP, the bond will be disabled, unless other-config:lacp-fallback-ab is set to true. Defaults to off if unset. other_config : lacp-system-id: optional string The LACP system ID of this Port. The system ID of a LACP bond is used to identify itself to its partners. Must be a nonzero MAC address. Defaults to the bridge Ethernet address if unset. other_config : lacp-system-priority: optional string, containing an in‐ teger, in range 1 to 65,535 The LACP system priority of this Port. In LACP negotiations, link status decisions are made by the system with the numeri‐ cally lower priority. other_config : lacp-time: optional string, either fast or slow The LACP timing which should be used on this Port. By default slow is used. When configured to be fast LACP heartbeats are re‐ quested at a rate of once per second causing connectivity prob‐ lems to be detected more quickly. In slow mode, heartbeats are requested at a rate of once every 30 seconds. other_config : lacp-fallback-ab: optional string, either true or false Determines the behavior of openvswitch bond in LACP mode. If the partner switch does not support LACP, setting this option to true allows openvswitch to fallback to active-backup. If the op‐ tion is set to false, the bond will be disabled. In both the cases, once the partner switch is configured to LACP mode, the bond will use LACP. Rebalancing Configuration: These settings control behavior when a bond is in balance-slb or bal‐ ance-tcp mode. other_config : bond-rebalance-interval: optional string, containing an integer, in range 0 to 2,147,483,647 For a load balanced bonded port, the number of milliseconds be‐ tween successive attempts to rebalance the bond, that is, to move flows from one interface on the bond to another in an at‐ tempt to keep usage of each interface roughly equal. If zero, load balancing is disabled on the bond (link failure still cause flows to move). If less than 1000ms, the rebalance interval will be 1000ms. bond_fake_iface: boolean For a bonded port, whether to create a fake internal interface with the name of the port. Use only for compatibility with legacy software that requires this. Spanning Tree Protocol: The configuration here is only meaningful, and the status is only popu‐ lated, when 802.1D-1998 Spanning Tree Protocol is enabled on the port’s Bridge with its stp_enable column. STP Configuration: other_config : stp-enable: optional string, either true or false When STP is enabled on a bridge, it is enabled by default on all of the bridge’s ports except bond, internal, and mirror ports (which do not work with STP). If this column’s value is false, STP is disabled on the port. other_config : stp-port-num: optional string, containing an integer, in range 1 to 255 The port number used for the lower 8 bits of the port-id. By de‐ fault, the numbers will be assigned automatically. If any port’s number is manually configured on a bridge, then they must all be. other_config : stp-port-priority: optional string, containing an inte‐ ger, in range 0 to 255 The port’s relative priority value for determining the root port (the upper 8 bits of the port-id). A port with a lower port-id will be chosen as the root port. By default, the priority is 0x80. other_config : stp-path-cost: optional string, containing an integer, in range 0 to 65,535 Spanning tree path cost for the port. A lower number indicates a faster link. By default, the cost is based on the maximum speed of the link. STP Status: status : stp_port_id: optional string The port ID used in spanning tree advertisements for this port, as 4 hex digits. Configuring the port ID is described in the stp-port-num and stp-port-priority keys of the other_config sec‐ tion earlier. status : stp_state: optional string, one of blocking, disabled, for‐ warding, learning, or listening STP state of the port. status : stp_sec_in_state: optional string, containing an integer, at least 0 The amount of time this port has been in the current STP state, in seconds. status : stp_role: optional string, one of alternate, designated, or root STP role of the port. Rapid Spanning Tree Protocol: The configuration here is only meaningful, and the status and statis‐ tics are only populated, when 802.1D-1998 Spanning Tree Protocol is en‐ abled on the port’s Bridge with its stp_enable column. RSTP Configuration: other_config : rstp-enable: optional string, either true or false When RSTP is enabled on a bridge, it is enabled by default on all of the bridge’s ports except bond, internal, and mirror ports (which do not work with RSTP). If this column’s value is false, RSTP is disabled on the port. other_config : rstp-port-priority: optional string, containing an inte‐ ger, in range 0 to 240 The port’s relative priority value for determining the root port, in multiples of 16. By default, the port priority is 0x80 (128). Any value in the lower 4 bits is rounded off. The signif‐ icant upper 4 bits become the upper 4 bits of the port-id. A port with the lowest port-id is elected as the root. other_config : rstp-port-num: optional string, containing an integer, in range 1 to 4,095 The local RSTP port number, used as the lower 12 bits of the port-id. By default the port numbers are assigned automatically, and typically may not correspond to the OpenFlow port numbers. A port with the lowest port-id is elected as the root. other_config : rstp-path-cost: optional string, containing an integer The port path cost. The Port’s contribution, when it is the Root Port, to the Root Path Cost for the Bridge. By default the cost is automatically calculated from the port’s speed. other_config : rstp-port-admin-edge: optional string, either true or false The admin edge port parameter for the Port. Default is false. other_config : rstp-port-auto-edge: optional string, either true or false The auto edge port parameter for the Port. Default is true. other_config : rstp-port-mcheck: optional string, either true or false The mcheck port parameter for the Port. Default is false. May be set to force the Port Protocol Migration state machine to trans‐ mit RST BPDUs for a MigrateTime period, to test whether all STP Bridges on the attached LAN have been removed and the Port can continue to transmit RSTP BPDUs. Setting mcheck has no effect if the Bridge is operating in STP Compatibility mode. Changing the value from true to false has no effect, but needs to be done if this behavior is to be triggered again by subse‐ quently changing the value from false to true. RSTP Status: rstp_status : rstp_port_id: optional string The port ID used in spanning tree advertisements for this port, as 4 hex digits. Configuring the port ID is described in the rstp-port-num and rstp-port-priority keys of the other_config section earlier. rstp_status : rstp_port_role: optional string, one of Alternate, Backup, Designated, Disabled, or Root RSTP role of the port. rstp_status : rstp_port_state: optional string, one of Disabled, Dis‐ carding, Forwarding, or Learning RSTP state of the port. rstp_status : rstp_designated_bridge_id: optional string The port’s RSTP designated bridge ID, in the same form as rstp_status:rstp_bridge_id in the Bridge table. rstp_status : rstp_designated_port_id: optional string The port’s RSTP designated port ID, as 4 hex digits. rstp_status : rstp_designated_path_cost: optional string, containing an integer The port’s RSTP designated path cost. Lower is better. RSTP Statistics: rstp_statistics : rstp_tx_count: optional integer Number of RSTP BPDUs transmitted through this port. rstp_statistics : rstp_rx_count: optional integer Number of valid RSTP BPDUs received by this port. rstp_statistics : rstp_error_count: optional integer Number of invalid RSTP BPDUs received by this port. rstp_statistics : rstp_uptime: optional integer The duration covered by the other RSTP statistics, in seconds. Multicast Snooping: other_config : mcast-snooping-flood: optional string, either true or false If set to true, multicast packets (except Reports) are uncondi‐ tionally forwarded to the specific port. other_config : mcast-snooping-flood-reports: optional string, either true or false If set to true, multicast Reports are unconditionally forwarded to the specific port. Other Features: qos: optional QoS Quality of Service configuration for this port. mac: optional string The MAC address to use for this port for the purpose of choosing the bridge’s MAC address. This column does not necessarily re‐ flect the port’s actual MAC address, nor will setting it change the port’s actual MAC address. fake_bridge: boolean Does this port represent a sub-bridge for its tagged VLAN within the Bridge? See ovs-vsctl(8) for more information. protected: boolean The protected ports feature allows certain ports to be desig‐ nated as protected. Traffic between protected ports is blocked. Protected ports can send traffic to unprotected ports. Unpro‐ tected ports can send traffic to any port. Default is false. external_ids : fake-bridge-*: optional string External IDs for a fake bridge (see the fake_bridge column) are defined by prefixing a Bridge external_ids key with fake-bridge-, e.g. fake-bridge-bridge-id. other_config : transient: optional string, either true or false If set to true, the port will be removed when ovs-ctl start --delete-transient-ports is used. bond_active_slave: optional string For a bonded port, record the MAC address of the current active member. Port Statistics: Key-value pairs that report port statistics. The update period is con‐ trolled by other_config:stats-update-interval in the Open_vSwitch ta‐ ble. Statistics: STP transmit and receive counters: statistics : stp_tx_count: optional integer Number of STP BPDUs sent on this port by the spanning tree li‐ brary. statistics : stp_rx_count: optional integer Number of STP BPDUs received on this port and accepted by the spanning tree library. statistics : stp_error_count: optional integer Number of bad STP BPDUs received on this port. Bad BPDUs include runt packets and those with an unexpected protocol ID. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Interface TABLE An interface within a Port. Summary: Core Features: name immutable string (must be unique within table) ifindex optional integer, in range 0 to 4,294,967,295 mac_in_use optional string mac optional string error optional string OpenFlow Port Number: ofport optional integer ofport_request optional integer, in range 1 to 65,279 System-Specific Details: type string Tunnel Options: options : remote_ip optional string options : local_ip optional string options : in_key optional string options : out_key optional string options : dst_port optional string options : key optional string options : tos optional string options : ttl optional string options : df_default optional string, either true or false options : egress_pkt_mark optional string Tunnel Options: lisp only: options : packet_type optional string, either legacy_l3 or ptap Tunnel Options: vxlan only: options : exts optional string options : packet_type optional string, one of legacy_l2, legacy_l3, or ptap Tunnel Options: gre only: options : packet_type optional string, one of legacy_l2, legacy_l3, or ptap options : seq optional string, either true or false Tunnel Options: gre, ip6gre, geneve, bareudp and vxlan: options : csum optional string, either true or false Tunnel Options: IPsec: options : psk optional string options : remote_cert optional string options : remote_name optional string Tunnel Options: erspan only: options : erspan_idx optional string options : erspan_ver optional string options : erspan_dir optional string options : erspan_hwid optional string Tunnel Options: Bareudp only: options : payload_type optional string Tunnel Options: srv6 only: options : srv6_segs optional string options : srv6_flowlabel optional string, one of compute, copy, or zero Patch Options: options : peer optional string PMD (Poll Mode Driver) Options: options : n_rxq optional string, containing an integer, at least 1 options : dpdk-devargs optional string other_config : pmd-rxq-affinity optional string options : xdp-mode optional string, one of best-effort, generic, native-with-zerocopy, or native options : use-need-wakeup optional string, either true or false options : vhost-server-path optional string options : tx-retries-max optional string, containing an integer, in range 0 to 32 options : n_rxq_desc optional string, containing an integer, in range 1 to 4,096 options : n_txq_desc optional string, containing an integer, in range 1 to 4,096 options : dpdk-vf-mac optional string options : rx-steering optional string, either rss+lacp or rss other_config : tx-steering optional string, either hash or thread EMC (Exact Match Cache) Configuration: other_config : emc-enable optional string, either true or false MTU: mtu optional integer mtu_request optional integer, at least 1 Interface Status: admin_state optional string, either down or up link_state optional string, either down or up link_resets optional integer link_speed optional integer duplex optional string, either full or half lacp_current optional boolean status map of string-string pairs status : driver_name optional string status : driver_version optional string status : firmware_version optional string status : source_ip optional string status : tunnel_egress_iface optional string status : tunnel_egress_iface_carrier optional string, either down or up dpdk: status : port_no optional string status : numa_id optional string status : min_rx_bufsize optional string status : max_rx_pktlen optional string status : max_rx_queues optional string status : max_tx_queues optional string status : max_mac_addrs optional string status : max_hash_mac_addrs optional string status : max_vfs optional string status : max_vmdq_pools optional string status : n_rxq optional string status : n_txq optional string status : rx_csum_offload optional string status : if_type optional string status : if_descr optional string status : bus_info optional string status : dpdk-vf-mac optional string status : rx-steering optional string status : rx_steering_queue optional string status : rss_queues optional string dpdkvhostuser: status : mode optional string status : features optional string status : num_of_vrings optional string status : numa optional string status : socket optional string status : status optional string status : vring_n_size optional string status : userspace-tso optional string afxdp: status : xdp-mode optional string Statistics: Statistics: Successful transmit and receive counters: statistics : rx_packets optional integer statistics : rx_bytes optional integer statistics : tx_packets optional integer statistics : tx_bytes optional integer Statistics: Receive errors: statistics : rx_dropped optional integer statistics : rx_frame_err optional integer statistics : rx_over_err optional integer statistics : rx_crc_err optional integer statistics : rx_errors optional integer Statistics: Transmit errors: statistics : tx_dropped optional integer statistics : collisions optional integer statistics : tx_errors optional integer Ingress Policing: ingress_policing_rate integer, at least 0 ingress_policing_kpkts_rate integer, at least 0 ingress_policing_burst integer, at least 0 ingress_policing_kpkts_burst integer, at least 0 Bidirectional Forwarding Detection (BFD): BFD Configuration: bfd : enable optional string, either true or false bfd : min_rx optional string, containing an integer, at least 1 bfd : min_tx optional string, containing an integer, at least 1 bfd : decay_min_rx optional string, containing an integer bfd : forwarding_if_rx optional string, either true or false bfd : cpath_down optional string, either true or false bfd : check_tnl_key optional string, either true or false bfd : bfd_local_src_mac optional string bfd : bfd_local_dst_mac optional string bfd : bfd_remote_dst_mac optional string bfd : bfd_src_ip optional string bfd : bfd_dst_ip optional string bfd : oam optional string bfd : mult optional string, containing an integer, in range 1 to 255 BFD Status: bfd_status : state optional string, one of admin_down, down, init, or up bfd_status : forwarding optional string, either true or false bfd_status : diagnostic optional string bfd_status : remote_state optional string, one of admin_down, down, init, or up bfd_status : remote_diagnostic optional string bfd_status : flap_count optional string, containing an integer, at least 0 Connectivity Fault Management: cfm_mpid optional integer cfm_flap_count optional integer cfm_fault optional boolean cfm_fault_status : recv none cfm_fault_status : rdi none cfm_fault_status : maid none cfm_fault_status : loopback none cfm_fault_status : overflow none cfm_fault_status : override none cfm_fault_status : interval none cfm_remote_opstate optional string, either down or up cfm_health optional integer, in range 0 to 100 cfm_remote_mpids set of integers other_config : cfm_interval optional string, containing an integer other_config : cfm_extended optional string, either true or false other_config : cfm_demand optional string, either true or false other_config : cfm_opstate optional string, either down or up other_config : cfm_ccm_vlan optional string, containing an integer, in range 1 to 4,095 other_config : cfm_ccm_pcp optional string, containing an integer, in range 1 to 7 Bonding Configuration: other_config : lacp-port-id optional string, containing an integer, in range 1 to 65,535 other_config : lacp-port-priority optional string, containing an integer, in range 1 to 65,535 other_config : lacp-aggregation-key optional string, containing an integer, in range 1 to 65,535 Virtual Machine Identifiers: external_ids : attached-mac optional string external_ids : iface-id optional string external_ids : iface-status optional string, either active or inac‐ tive external_ids : vm-id optional string Auto Attach Configuration: lldp : enable optional string, either true or false Flow control Configuration: options : rx-flow-ctrl optional string, either true or false options : tx-flow-ctrl optional string, either true or false options : flow-ctrl-autoneg optional string, either true or false Link State Change detection mode: options : dpdk-lsc-interrupt optional string, either true or false Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: Core Features: name: immutable string (must be unique within table) Interface name. Should be alphanumeric. For non-bonded port, this should be the same as the port name. It must otherwise be unique among the names of ports, interfaces, and bridges on a host. The maximum length of an interface name depends on the underly‐ ing datapath: • The names of interfaces implemented as Linux and BSD net‐ work devices, including interfaces with type internal, tap, or system plus the different types of tunnel ports, are limited to 15 bytes. Windows limits these names to 255 bytes. • The names of patch ports are not used in the underlying datapath, so operating system restrictions do not apply. Thus, they may have arbitrary length. Regardless of other restrictions, OpenFlow only supports 15-byte names, which means that ovs-ofctl and OpenFlow controllers will show names truncated to 15 bytes. ifindex: optional integer, in range 0 to 4,294,967,295 A positive interface index as defined for SNMP MIB-II in RFCs 1213 and 2863, if the interface has one, otherwise 0. The ifindex is useful for seamless integration with protocols such as SNMP and sFlow. mac_in_use: optional string The MAC address in use by this interface. mac: optional string Ethernet address to set for this interface. If unset then the default MAC address is used: • For the local interface, the default is the lowest-num‐ bered MAC address among the other bridge ports, either the value of the mac in its Port record, if set, or its actual MAC (for bonded ports, the MAC of its member whose name is first in alphabetical order). Internal ports and bridge ports that are used as port mirroring destinations (see the Mirror table) are ignored. • For other internal interfaces, the default MAC is ran‐ domly generated. • External interfaces typically have a MAC address associ‐ ated with their hardware. Some interfaces may not have a software-controllable MAC ad‐ dress. This option only affects internal ports. For other type ports, you can change the MAC address outside Open vSwitch, us‐ ing ip command. error: optional string If the configuration of the port failed, as indicated by -1 in ofport, Open vSwitch sets this column to an error description in human readable form. Otherwise, Open vSwitch clears this column. OpenFlow Port Number: When a client adds a new interface, Open vSwitch chooses an OpenFlow port number for the new port. If the client that adds the port fills in ofport_request, then Open vSwitch tries to use its value as the Open‐ Flow port number. Otherwise, or if the requested port number is already in use or cannot be used for another reason, Open vSwitch automatically assigns a free port number. Regardless of how the port number was ob‐ tained, Open vSwitch then reports in ofport the port number actually assigned. Open vSwitch limits the port numbers that it automatically assigns to the range 1 through 32,767, inclusive. Controllers therefore have free use of ports 32,768 and up. ofport: optional integer OpenFlow port number for this interface. Open vSwitch sets this column’s value, so other clients should treat it as read-only. The OpenFlow ``local’’ port (OFPP_LOCAL) is 65,534. The other valid port numbers are in the range 1 to 65,279, inclusive. Value -1 indicates an error adding the interface. ofport_request: optional integer, in range 1 to 65,279 Requested OpenFlow port number for this interface. A client should ideally set this column’s value in the same database transaction that it uses to create the interface. Open vSwitch version 2.1 and later will honor a later request for a specific port number, althuogh it might confuse some con‐ trollers: OpenFlow does not have a way to announce a port number change, so Open vSwitch represents it over OpenFlow as a port deletion followed immediately by a port addition. If ofport_request is set or changed to some other port’s auto‐ matically assigned port number, Open vSwitch chooses a new port number for the latter port. System-Specific Details: type: string The interface type. The types supported by a particular instance of Open vSwitch are listed in the iface_types column in the Open_vSwitch table. The following types are defined: system An ordinary network device, e.g. eth0 on Linux. Sometimes referred to as ``external interfaces’’ since they are generally connected to hardware external to that on which the Open vSwitch is running. The empty string is a syn‐ onym for system. internal A simulated network device that sends and receives traf‐ fic. An internal interface whose name is the same as its bridge’s name is called the ``local interface.’’ It does not make sense to bond an internal interface, so the terms ``port’’ and ``interface’’ are often used impre‐ cisely for internal interfaces. tap A TUN/TAP device managed by Open vSwitch. Open vSwitch checks the interface state before send pack‐ ets to the device. When it is down, the packets are dropped and the tx_dropped statistic is updated accord‐ ingly. Older versions of Open vSwitch did not check the interface state and then the tx_packets was incremented along with tx_dropped. geneve An Ethernet over Geneve (http://tools.ietf.org/html/draft-ietf-nvo3-geneve) IPv4/IPv6 tunnel. A description of how to match and set Geneve options can be found in the ovs-ofctl manual page. gre Generic Routing Encapsulation (GRE) over IPv4 tunnel, configurable to encapsulate layer 2 or layer 3 traffic. ip6gre Generic Routing Encapsulation (GRE) over IPv6 tunnel, en‐ capsulate layer 2 traffic. vxlan An Ethernet tunnel over the UDP-based VXLAN protocol de‐ scribed in RFC 7348. Open vSwitch uses IANA-assigned UDP destination port 4789. The source port used for VXLAN traffic varies on a per-flow basis and is in the ephemeral port range. lisp A layer 3 tunnel over the experimental, UDP-based Loca‐ tor/ID Separation Protocol (RFC 6830). Only IPv4 and IPv6 packets are supported by the protocol, and they are sent and received without an Ethernet header. Traffic to/from LISP ports is expected to be con‐ figured explicitly, and the ports are not intended to participate in learning based switching. As such, they are always excluded from packet flooding. stt The Stateless TCP Tunnel (STT) is particularly useful when tunnel endpoints are in end-systems, as it utilizes the capabilities of standard network interface cards to improve performance. STT utilizes a TCP-like header in‐ side the IP header. It is stateless, i.e., there is no TCP connection state of any kind associated with the tun‐ nel. The TCP-like header is used to leverage the capabil‐ ities of existing network interface cards, but should not be interpreted as implying any sort of connection state between endpoints. Since the STT protocol does not engage in the usual TCP 3-way handshake, so it will have diffi‐ culty traversing stateful firewalls. The protocol is doc‐ umented at https://tools.ietf.org/html/draft-davie-stt All traffic uses a default destination port of 7471. patch A pair of virtual devices that act as a patch cable. gtpu GPRS Tunneling Protocol (GTP) is a group of IP-based com‐ munications protocols used to carry general packet radio service (GPRS) within GSM, UMTS and LTE networks. GTP-U is used for carrying user data within the GPRS core net‐ work and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats. The protocol is documented at http://www.3gpp.org/DynaRe‐ port/29281.htm Open vSwitch uses UDP destination port 2152. The source port used for GTP traffic varies on a per-flow basis and is in the ephemeral port range. Bareudp The Bareudp tunnel provides a generic L3 encapsulation support for tunnelling different L3 protocols like MPLS, IP, NSH etc. inside a UDP tunnel. srv6 Segment Routing IPv6 (SRv6) tunnel encapsulates L3 traf‐ fic as "IPv6 in IPv6" or "IPv4 in IPv6" with Segment Routing Header (SRH) defined in RFC 8754. The segment list in SRH can be set using a SRv6 specific option. Tunnel Options: These options apply to interfaces with type of geneve, bareudp, gre, ip6gre, vxlan, lisp, stt and srv6. Each tunnel must be uniquely identified by the combination of type, op‐ tions:remote_ip, options:local_ip, and options:in_key. If two ports are defined that are the same except one has an optional identifier and the other does not, the more specific one is matched first. options:in_key is considered more specific than options:local_ip if a port defines one and another port defines the other. options:in_key is not applicable for bareudp and srv6 tunnels. Hence it is not considered while identi‐ fying bareudp or srv6 tunnels. options : remote_ip: optional string Required. The remote tunnel endpoint, one of: • An IPv4 or IPv6 address (not a DNS name), e.g. 192.168.0.123. Only unicast endpoints are supported. • The word flow. The tunnel accepts packets from any remote tunnel endpoint. To process only packets from a specific remote tunnel endpoint, the flow entries may match on the tun_src or tun_ipv6_srcfield. When sending packets to a remote_ip=flow tunnel, the flow actions must explicitly set the tun_dst or tun_ipv6_dst field to the IP address of the desired remote tunnel endpoint, e.g. with a set_field action. The remote tunnel endpoint for any packet received from a tunnel is available in the tun_src field for matching in the flow ta‐ ble. options : local_ip: optional string Optional. The tunnel destination IP that received packets must match. Default is to match all addresses. If specified, may be one of: • An IPv4/IPv6 address (not a DNS name), e.g. 192.168.12.3. • The word flow. The tunnel accepts packets sent to any of the local IP addresses of the system running OVS. To process only packets sent to a specific IP address, the flow entries may match on the tun_dst or tun_ipv6_dst field. When sending packets to a local_ip=flow tunnel, the flow actions may explicitly set the tun_src or tun_ipv6_src field to the desired IP address, e.g. with a set_field action. However, while routing the tunneled packet out, the local system may override the specified address with the local IP address configured for the out‐ going system interface. This option is valid only for tunnels also configured with the remote_ip=flow option. The tunnel destination IP address for any packet received from a tunnel is available in the tun_dst or tun_ipv6_dst field for matching in the flow table. options : in_key: optional string Optional, not applicable for bareudp and srv6. The key that re‐ ceived packets must contain, one of: • 0. The tunnel receives packets with no key or with a key of 0. This is equivalent to specifying no options:in_key at all. • A positive 24-bit (for Geneve, VXLAN, and LISP), 32-bit (for GRE) or 64-bit (for STT) number. The tunnel receives only packets with the specified key. • The word flow. The tunnel accepts packets with any key. The key will be placed in the tun_id field for matching in the flow table. The ovs-fields(7) manual page contains additional information about matching fields in OpenFlow flows. options : out_key: optional string Optional, not applicable for bareudp and srv6. The key to be set on outgoing packets, one of: • 0. Packets sent through the tunnel will have no key. This is equivalent to specifying no options:out_key at all. • A positive 24-bit (for Geneve, VXLAN and LISP), 32-bit (for GRE) or 64-bit (for STT) number. Packets sent through the tunnel will have the specified key. • The word flow. Packets sent through the tunnel will have the key set using the set_tunnel Nicira OpenFlow vendor extension (0 is used in the absence of an action). The ovs-fields(7) manual page contains additional information about the Nicira OpenFlow vendor extensions. options : dst_port: optional string Optional. The tunnel transport layer destination port, for UDP and TCP based tunnel protocols (Geneve, VXLAN, LISP, and STT). options : key: optional string Optional. Shorthand to set in_key and out_key at the same time. options : tos: optional string Optional. The value of the ToS bits to be set on the encapsulat‐ ing packet. ToS is interpreted as DSCP and ECN bits, ECN part must be zero. It may also be the word inherit, in which case the ToS will be copied from the inner packet if it is IPv4 or IPv6 (otherwise it will be 0). The ECN fields are always inherited. Default is 0. options : ttl: optional string Optional. The TTL to be set on the encapsulating packet. It may also be the word inherit, in which case the TTL will be copied from the inner packet if it is IPv4 or IPv6 (otherwise it will be the system default, typically 64). Default is the system de‐ fault TTL. options : df_default: optional string, either true or false Optional. If enabled, the Don’t Fragment bit will be set on tun‐ nel outer headers to allow path MTU discovery. Default is en‐ abled; set to false to disable. options : egress_pkt_mark: optional string Optional. The pkt_mark to be set on the encapsulating packet. This option sets packet mark for the tunnel endpoint for all tunnel packets including tunnel monitoring. Tunnel Options: lisp only: options : packet_type: optional string, either legacy_l3 or ptap A LISP tunnel sends and receives only IPv4 and IPv6 packets. This option controls what how the tunnel represents the packets that it sends and receives: • By default, or if this option is legacy_l3, the tunnel represents packets as Ethernet frames for compatibility with legacy OpenFlow controllers that expect this behav‐ ior. • If this option is ptap, the tunnel represents packets us‐ ing the packet_type mechanism introduced in OpenFlow 1.5. Tunnel Options: vxlan only: options : exts: optional string Optional. Comma separated list of optional VXLAN extensions to enable. The following extensions are supported: • gbp: VXLAN-GBP allows to transport the group policy con‐ text of a packet across the VXLAN tunnel to other network peers. See the description of tun_gbp_id and tun_gbp_flags in ovs-fields(7) for additional informa‐ tion. (https://tools.ietf.org/html/draft-smith-vxlan-group-pol‐ icy) • gpe: Support for Generic Protocol Encapsulation in accor‐ dance with IETF draft https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe. Without this option, a VXLAN packet always encapsulates an Ethernet frame. With this option, an VXLAN packet may also encapsulate an IPv4, IPv6, NSH, or MPLS packet. options : packet_type: optional string, one of legacy_l2, legacy_l3, or ptap This option controls what types of packets the tunnel sends and receives and how it represents them: • By default, or if this option is legacy_l2, the tunnel sends and receives only Ethernet frames. • If this option is legacy_l3, the tunnel sends and re‐ ceives only non-Ethernet (L3) packet, but the packets are represented as Ethernet frames for compatibility with legacy OpenFlow controllers that expect this behavior. This requires enabling gpe in options:exts. • If this option is ptap, Open vSwitch represents packets in the tunnel using the packet_type mechanism introduced in OpenFlow 1.5. This mechanism supports any kind of packet, but actually sending and receiving non-Ethernet packets requires additionally enabling gpe in op‐ tions:exts. Tunnel Options: gre only: gre interfaces support these options. options : packet_type: optional string, one of legacy_l2, legacy_l3, or ptap This option controls what types of packets the tunnel sends and receives and how it represents them: • By default, or if this option is legacy_l2, the tunnel sends and receives only Ethernet frames. • If this option is legacy_l3, the tunnel sends and re‐ ceives only non-Ethernet (L3) packet, but the packets are represented as Ethernet frames for compatibility with legacy OpenFlow controllers that expect this behavior. • The legacy_l3 option is only available via the user space datapath. The OVS kernel datapath does not support de‐ vices of type ARPHRD_IPGRE which is the requirement for legacy_l3 type packets. • If this option is ptap, the tunnel sends and receives any kind of packet. Open vSwitch represents packets in the tunnel using the packet_type mechanism introduced in OpenFlow 1.5. options : seq: optional string, either true or false Optional. A 4-byte sequence number field for GRE tunnel only. Default is disabled, set to true to enable. Sequence number is incremented by one on each outgoing packet. Tunnel Options: gre, ip6gre, geneve, bareudp and vxlan: gre, ip6gre, geneve, bareudp and vxlan interfaces support these op‐ tions. options : csum: optional string, either true or false Optional. Compute encapsulation header (either GRE or UDP) checksums on outgoing packets. Default is disabled, set to true to enable. Checksums present on incoming packets will be vali‐ dated regardless of this setting. When using the upstream Linux kernel module, computation of checksums for geneve and vxlan requires Linux kernel version 4.0 or higher. gre and ip6gre support checksums for all versions of Open vSwitch that support GRE. The out of tree kernel module distributed as part of OVS can compute all tunnel checksums on any kernel version that it is compatible with. Tunnel Options: IPsec: Setting any of these options enables IPsec support for a given tunnel. gre, geneve, vxlan and stt interfaces support these options. See the IPsec section in the Open_vSwitch table for a description of each mode. options : psk: optional string In PSK mode only, the preshared secret to negotiate tunnel. This value must match on both tunnel ends. options : remote_cert: optional string In self-signed certificate mode only, name of a PEM file con‐ taining a certificate of the remote switch. The certificate must be x.509 version 3 and with the string in common name (CN) also set in the subject alternative name (SAN). options : remote_name: optional string In CA-signed certificate mode only, common name (CN) of the re‐ mote certificate. Tunnel Options: erspan only: Only erspan interfaces support these options. options : erspan_idx: optional string 20 bit index/port number associated with the ERSPAN traffic’s source port and direction (ingress/egress). This field is plat‐ form dependent. options : erspan_ver: optional string ERSPAN version: 1 for version 1 (type II) or 2 for version 2 (type III). options : erspan_dir: optional string Specifies the ERSPAN v2 mirrored traffic’s direction. 1 for egress traffic, and 0 for ingress traffic. options : erspan_hwid: optional string ERSPAN hardware ID is a 6-bit unique identifier of an ERSPAN v2 engine within a system. Tunnel Options: Bareudp only: options : payload_type: optional string Specifies the ethertype of the l3 protocol the bareudp device is tunnelling. For the tunnels which supports multiple ethertypes of a l3 protocol (IP, MPLS) this field specifies the protocol name as a string. Tunnel Options: srv6 only: options : srv6_segs: optional string Specifies the segment list in Segment Routing Header (SRH). It consists of a comma-separated list of segments represented in IPv6 format, e.g. "fc00:100::1,fc00:200::1,fc00:300::1". Note that the first segment must be the same as options:remote_ip. options : srv6_flowlabel: optional string, one of compute, copy, or zero Optional. This option controls how flowlabel in outer IPv6 header is configured. It gives the benefit of IPv6 flow label based load balancing, which is supported by some popular vendor appliances. Like net.ipv6.seg6_flowlabel sysconfig, it is one of the three values below: • By default, or if this option is copy, copy the flowlabel of inner IPv6 header to the flowlabel of outer IPv6 header. If inner header is not IPv6, it is set to 0. • If this option is zero, simply set flowlabel to 0. • If this option is compute, set flowlabel to a hash over the L3/L4 fields of the inner packet. Patch Options: These options apply only to patch ports, that is, interfaces whose type column is patch. Patch ports are mainly a way to connect otherwise in‐ dependent bridges to one another, similar to how one might plug an Eth‐ ernet cable (a ``patch cable’’) into two physical switches to connect those switches. The effect of plugging a patch port into two switches is conceptually similar to that of plugging the two ends of a Linux veth device into those switches, but the implementation of patch ports makes them much more efficient. Patch ports may connect two different bridges (the usual case) or the same bridge. In the latter case, take special care to avoid loops, e.g. by programming appropriate flows with OpenFlow. Patch ports do not work if its ends are attached to bridges on different datapaths, e.g. to connect bridges in system and netdev datapaths. The following command creates and connects patch ports p0 and p1 and adds them to bridges br0 and br1, respectively: ovs-vsctl add-port br0 p0 -- set Interface p0 type=patch options:peer=p1 \ -- add-port br1 p1 -- set Interface p1 type=patch options:peer=p0 options : peer: optional string The name of the Interface for the other side of the patch. The named Interface’s own peer option must specify this Interface’s name. That is, the two patch interfaces must have reversed name and peer values. PMD (Poll Mode Driver) Options: Only PMD netdevs support these options. options : n_rxq: optional string, containing an integer, at least 1 Specifies the maximum number of rx queues to be created for PMD netdev. If not specified or specified to 0, one rx queue will be created by default. Not supported by DPDK vHost interfaces. options : dpdk-devargs: optional string Specifies the PCI address associated with the port for physical devices, or the virtual driver to be used for the port when a virtual PMD is intended to be used. For the latter, the argument string typically takes the form of eth_driver_namex, where driver_name is a valid virtual DPDK PMD driver name and x is a unique identifier of your choice for the given port. Only sup‐ ported by the dpdk port type. other_config : pmd-rxq-affinity: optional string Specifies mapping of RX queues of this interface to CPU cores. Value should be set in the following form: other_config:pmd-rxq-affinity= where • ::= NULL | ::= | , ::= : options : xdp-mode: optional string, one of best-effort, generic, na‐ tive-with-zerocopy, or native Specifies the operational mode of the XDP program. In native-with-zerocopy mode the XDP program is loaded into the device driver with zero-copy RX and TX enabled. This mode re‐ quires device driver support and has the best performance be‐ cause there should be no copying of packets. native is the same as native-with-zerocopy, but without zero- copy capability. This requires at least one copy between kernel and the userspace. This mode also requires support from device driver. In generic case the XDP program in kernel works after skb allo‐ cation on early stages of packet processing inside the network stack. This mode doesn’t require driver support, but has much lower performance. best-effort tries to detect and choose the best (fastest) from the available modes for current interface. Note that this option is specific to netdev-afxdp. Defaults to best-effort mode. options : use-need-wakeup: optional string, either true or false Specifies whether to use need_wakeup feature in afxdp netdev. If enabled, OVS explicitly wakes up the kernel RX, using poll() syscall and wakes up TX, using sendto() syscall. For physical devices, this feature improves the performance by avoiding un‐ necessary sendto syscalls. Defaults to true if supported by libbpf. options : vhost-server-path: optional string The value specifies the path to the socket associated with a vHost User client mode device that has been or will be created by QEMU. Only supported by dpdkvhostuserclient interfaces. options : tx-retries-max: optional string, containing an integer, in range 0 to 32 The value specifies the maximum amount of vhost tx retries that can be made while trying to send a batch of packets to an inter‐ face. Only supported by dpdkvhostuserclient interfaces. Default value is 8. options : n_rxq_desc: optional string, containing an integer, in range 1 to 4,096 Specifies the rx queue size (number rx descriptors) for dpdk ports. The value must be a power of 2, less than 4096 and sup‐ ported by the hardware of the device being configured. If not specified or an incorrect value is specified, 2048 rx descrip‐ tors will be used by default. options : n_txq_desc: optional string, containing an integer, in range 1 to 4,096 Specifies the tx queue size (number tx descriptors) for dpdk ports. The value must be a power of 2, less than 4096 and sup‐ ported by the hardware of the device being configured. If not specified or an incorrect value is specified, 2048 tx descrip‐ tors will be used by default. options : dpdk-vf-mac: optional string Ethernet address to set for this VF interface. If unset then the default MAC address is used: • For most drivers, the default MAC address assigned by their hardware. • For bifurcated drivers, the MAC currently used by the kernel netdevice. This option may only be used with dpdk VF representors. options : rx-steering: optional string, either rss+lacp or rss Configure hardware Rx queue steering policy. This option takes one of the following values: rss Distribution of ingress packets in all Rx queues accord‐ ing to the RSS algorithm. This is the default behaviour. rss+lacp Distribution of ingress packets according to the RSS al‐ gorithm on all but the last Rx queue. An extra Rx queue is allocated for LACP packets. If the user has already configured multiple options:n_rxq on the port, an additional one will be allocated for the specified pro‐ tocols. Even if the hardware cannot satisfy the requested number of requested Rx queues, the last Rx queue will be used. If only one Rx queue is available or if the hardware does not support the rte_flow matchers/actions required to redirect the selected protocols, custom rx-steering will fall back to default rss mode. This feature is mutually exclusive with other_config:hw-offload as it may conflict with the offloaded flows. If both are en‐ abled, rx-steering will fall back to default rss mode. This option is only applicable to interfaces with type dpdk. other_config : tx-steering: optional string, either hash or thread Specifies the Tx steering mode for the interface. thread enables static (1:1) thread-to-txq mapping when the num‐ ber of Tx queues is greater than number of PMD threads, and dy‐ namic (N:1) mapping if equal or lower. In this mode a single thread can not use more than 1 transmit queue of a given port. hash enables hash-based Tx steering, which distributes the pack‐ ets on all the transmit queues based on their 5-tuples hashes. Defaults to thread. EMC (Exact Match Cache) Configuration: These settings controls behaviour of EMC lookups/insertions for packets received from the interface. other_config : emc-enable: optional string, either true or false Specifies if Exact Match Cache (EMC) should be used while pro‐ cessing packets received from this interface. If true, other_config:emc-insert-inv-prob will have effect on this inter‐ face. Defaults to true. MTU: The MTU (maximum transmission unit) is the largest amount of data that can fit into a single Ethernet frame. The standard Ethernet MTU is 1500 bytes. Some physical media and many kinds of virtual interfaces can be configured with higher MTUs. A client may change an interface MTU by filling in mtu_request. Open vSwitch then reports in mtu the currently configured value. mtu: optional integer The currently configured MTU for the interface. This column will be empty for an interface that does not have an MTU as, for example, some kinds of tunnels do not. Open vSwitch sets this column’s value, so other clients should treat it as read-only. mtu_request: optional integer, at least 1 Requested MTU (Maximum Transmission Unit) for the interface. A client can fill this column to change the MTU of an interface. RFC 791 requires every internet module to be able to forward a datagram of 68 octets without further fragmentation. The maximum size of an IP packet is 65535 bytes. If this is not set and if the interface has internal type, Open vSwitch will change the MTU to match the minimum of the other interfaces in the bridge. Interface Status: Status information about interfaces attached to bridges, updated every 5 seconds. Not all interfaces have all of these properties; virtual in‐ terfaces don’t have a link speed, for example. Non-applicable columns will have empty values. admin_state: optional string, either down or up The administrative state of the physical network link. link_state: optional string, either down or up The observed state of the physical network link. This is ordi‐ narily the link’s carrier status. If the interface’s Port is a bond configured for miimon monitoring, it is instead the network link’s miimon status. link_resets: optional integer The number of times Open vSwitch has observed the link_state of this Interface change. link_speed: optional integer The negotiated speed of the physical network link. Valid values are positive integers greater than 0. duplex: optional string, either full or half The duplex mode of the physical network link. lacp_current: optional boolean Boolean value indicating LACP status for this interface. If true, this interface has current LACP information about its LACP partner. This information may be used to monitor the health of interfaces in a LACP enabled port. This column will be empty if LACP is not enabled. status: map of string-string pairs Key-value pairs that report port status. Supported status values are type-dependent; some interfaces may not have a valid sta‐ tus:driver_name, for example. status : driver_name: optional string The name of the device driver controlling the network adapter. status : driver_version: optional string The version string of the device driver controlling the network adapter. status : firmware_version: optional string The version string of the network adapter’s firmware, if avail‐ able. status : source_ip: optional string The source IP address used for an IPv4/IPv6 tunnel end-point, such as gre. status : tunnel_egress_iface: optional string Egress interface for tunnels. Currently only relevant for tun‐ nels on Linux systems, this column will show the name of the in‐ terface which is responsible for routing traffic destined for the configured options:remote_ip. This could be an internal in‐ terface such as a bridge port. status : tunnel_egress_iface_carrier: optional string, either down or up Whether carrier is detected on status:tunnel_egress_iface. dpdk: DPDK specific interface status options. status : port_no: optional string DPDK port ID. status : numa_id: optional string NUMA socket ID to which an Ethernet device is connected. status : min_rx_bufsize: optional string Minimum size of RX buffer. status : max_rx_pktlen: optional string Maximum configurable length of RX pkt. status : max_rx_queues: optional string Maximum number of RX queues. status : max_tx_queues: optional string Maximum number of TX queues. status : max_mac_addrs: optional string Maximum number of MAC addresses. status : max_hash_mac_addrs: optional string Maximum number of hash MAC addresses for MTA and UTA. status : max_vfs: optional string Maximum number of hash MAC addresses for MTA and UTA. Maximum number of VFs. status : max_vmdq_pools: optional string Maximum number of VMDq pools. status : n_rxq: optional string Number of Rx queues. status : n_txq: optional string Number of Tx queues. status : rx_csum_offload: optional string Whether Rx Checksum offload is enabled or not. status : if_type: optional string Interface type ID according to IANA ifTYPE MIB definitions. status : if_descr: optional string Interface description string. status : bus_info: optional string Bus name and bus info such as Vendor ID and Device ID of PCI de‐ vice. status : dpdk-vf-mac: optional string Ethernet address set for this VF interface. Only reported for dpdk VF representors. status : rx-steering: optional string Hardware Rx queue steering policy in use. status : rx_steering_queue: optional string ID of rx steering queue. Only reported if rx-steering is sup‐ ported by hardware. status : rss_queues: optional string IDs of rss queues. Only reported if rx-steering is supported by hardware. dpdkvhostuser: dpdkvhostuser and dpdkvhostuserclient netdev specific interface status information. status : mode: optional string client (connecting) or server (listening) in the socket communi‐ cation. status : features: optional string virtio features bitmap as per virtio specification. status : num_of_vrings: optional string The number of available virtqueues. status : numa: optional string The numa id of the device and guest memory. status : socket: optional string The path to the socket used for communication. status : status: optional string Status of connection to the device. status : vring_n_size: optional string Each virtqueue will have it’s size reported, where n is the virtqueue number from 0..(num_of_vrings-1). status : userspace-tso: optional string Whether userspace-tso is enabled or disabled. afxdp: AF_XDP specific interface status options. status : xdp-mode: optional string XDP mode currently in use. See options:xdp-mode for description of possible values. Statistics: Key-value pairs that report interface statistics. The current implemen‐ tation updates these counters periodically. The update period is con‐ trolled by other_config:stats-update-interval in the Open_vSwitch ta‐ ble. Future implementations may update them when an interface is cre‐ ated, when they are queried (e.g. using an OVSDB select operation), and just before an interface is deleted due to virtual interface hot-unplug or VM shutdown, and perhaps at other times, but not on any regular pe‐ riodic basis. These are the same statistics reported by OpenFlow in its struct ofp_port_stats structure. If an interface does not support a given statistic, then that pair is omitted. Statistics: Successful transmit and receive counters: statistics : rx_packets: optional integer Number of received packets. statistics : rx_bytes: optional integer Number of received bytes. statistics : tx_packets: optional integer Number of transmitted packets. statistics : tx_bytes: optional integer Number of transmitted bytes. Statistics: Receive errors: statistics : rx_dropped: optional integer Number of packets dropped by RX. statistics : rx_frame_err: optional integer Number of frame alignment errors. statistics : rx_over_err: optional integer Number of packets with RX overrun. statistics : rx_crc_err: optional integer Number of CRC errors. statistics : rx_errors: optional integer Total number of receive errors, greater than or equal to the sum of the above. Statistics: Transmit errors: statistics : tx_dropped: optional integer Number of packets dropped by TX. statistics : collisions: optional integer Number of collisions. statistics : tx_errors: optional integer Total number of transmit errors, greater than or equal to the sum of the above. Ingress Policing: These settings control ingress policing for packets received on this interface. On a physical interface, this limits the rate at which traf‐ fic is allowed into the system from the outside; on a virtual interface (one connected to a virtual machine), this limits the rate at which the VM is able to transmit. Policing is a simple form of quality-of-service that simply drops pack‐ ets received in excess of the configured rate. Due to its simplicity, policing is usually less accurate and less effective than egress QoS (which is configured using the QoS and Queue tables). Policing settings can be set with byte rate or packet rate, and they can be configured together, in which case they take effect together, that means the smaller speed limit of them is in effect. Currently, byte rate policing is implemented on Linux and OVS with DPDK, while packet rate policing is only implemented on Linux. Both Linux and OVS DPDK implementations use a simple ``token bucket’’ ap‐ proach. Byte rate policing: • The size of the bucket corresponds to ingress_polic‐ ing_burst. Initially the bucket is full. • Whenever a packet is received, its size (converted to to‐ kens) is compared to the number of tokens currently in the bucket. If the required number of tokens are avail‐ able, they are removed and the packet is forwarded. Oth‐ erwise, the packet is dropped. • Whenever it is not full, the bucket is refilled with to‐ kens at the rate specified by ingress_policing_rate. Packet rate policing: • The size of the bucket corresponds to ingress_polic‐ ing_kpkts_burst. Initially the bucket is full. • Whenever a packet is received, it will consume one token from the current bucket. If the token is available in the bucket, it’s removed and the packet is forwarded. Other‐ wise, the packet is dropped. • Whenever it is not full, the bucket is refilled with to‐ kens at the rate specified by ingress_policing_kp‐ kts_rate. Policing interacts badly with some network protocols, and especially with fragmented IP packets. Suppose that there is enough network activ‐ ity to keep the bucket nearly empty all the time. Then this token bucket algorithm will forward a single packet every so often, with the period depending on packet size and on the configured rate. All of the fragments of an IP packets are normally transmitted back-to-back, as a group. In such a situation, therefore, only one of these fragments will be forwarded and the rest will be dropped. IP does not provide any way for the intended recipient to ask for only the remaining fragments. In such a case there are two likely possibilities for what will happen next: either all of the fragments will eventually be retransmitted (as TCP will do), in which case the same problem will recur, or the sender will not realize that its packet has been dropped and data will simply be lost (as some UDP-based protocols will do). Either way, it is possi‐ ble that no forward progress will ever occur. ingress_policing_rate: integer, at least 0 Maximum rate for data received on this interface, in kbps. Data received faster than this rate is dropped. Set to 0 (the de‐ fault) to disable policing. ingress_policing_kpkts_rate: integer, at least 0 Maximum rate for data received on this interface, in kpps (1 kpps is 1000 pps). Data received faster than this rate is dropped. Set to 0 (the default) to disable policing. ingress_policing_burst: integer, at least 0 Maximum burst size for data received on this interface, in kb. The default burst size if set to 0 is 8000 kbit. This value has no effect if ingress_policing_rate is 0. Specifying a larger burst size lets the algorithm be more for‐ giving, which is important for protocols like TCP that react se‐ verely to dropped packets. The burst size should be at least the size of the interface’s MTU. Specifying a value that is numeri‐ cally at least as large as 80% of ingress_policing_rate helps TCP come closer to achieving the full rate. ingress_policing_kpkts_burst: integer, at least 0 Maximum burst size for data received on this interface, in kpkts (1 kpkts is 1000 packets). The default burst size if set to 0 is 16 kpkts. This value has no effect if ingress_policing_kp‐ kts_rate is 0. Specifying a larger burst size lets the algorithm be more for‐ giving, which is important for protocols like TCP that react se‐ verely to dropped packets. Specifying a value that is numeri‐ cally at least as large as 80% of ingress_policing_kpkts_rate helps TCP come closer to achieving the full rate. Bidirectional Forwarding Detection (BFD): BFD, defined in RFC 5880 and RFC 5881, allows point-to-point detection of connectivity failures by occasional transmission of BFD control mes‐ sages. Open vSwitch implements BFD to serve as a more popular and stan‐ dards compliant alternative to CFM. BFD operates by regularly transmitting BFD control messages at a rate negotiated independently in each direction. Each endpoint specifies the rate at which it expects to receive control messages, and the rate at which it is willing to transmit them. By default, Open vSwitch uses a detection multiplier of three, meaning that an endpoint signals a con‐ nectivity fault if three consecutive BFD control messages fail to ar‐ rive. In the case of a unidirectional connectivity issue, the system not receiving BFD control messages signals the problem to its peer in the messages it transmits. The Open vSwitch implementation of BFD aims to comply faithfully with RFC 5880 requirements. Open vSwitch does not implement the optional Au‐ thentication or ``Echo Mode’’ features. OVS 2.13 and earlier intercepted and processed all BFD packets. OVS 2.14 and later only intercept and process BFD packets destined to a configured BFD instance, and other BFD packets are made available to the OVS flow table for forwarding. BFD Configuration: A controller sets up key-value pairs in the bfd column to enable and configure BFD. bfd : enable: optional string, either true or false True to enable BFD on this Interface. If not specified, BFD will not be enabled by default. bfd : min_rx: optional string, containing an integer, at least 1 The shortest interval, in milliseconds, at which this BFD ses‐ sion offers to receive BFD control messages. The remote endpoint may choose to send messages at a slower rate. Defaults to 1000. bfd : min_tx: optional string, containing an integer, at least 1 The shortest interval, in milliseconds, at which this BFD ses‐ sion is willing to transmit BFD control messages. Messages will actually be transmitted at a slower rate if the remote endpoint is not willing to receive as quickly as specified. Defaults to 100. bfd : decay_min_rx: optional string, containing an integer An alternate receive interval, in milliseconds, that must be greater than or equal to bfd:min_rx. The implementation switches from bfd:min_rx to bfd:decay_min_rx when there is no obvious in‐ coming data traffic at the interface, to reduce the CPU and bandwidth cost of monitoring an idle interface. This feature may be disabled by setting a value of 0. This feature is reset when‐ ever bfd:decay_min_rx or bfd:min_rx changes. bfd : forwarding_if_rx: optional string, either true or false When true, traffic received on the Interface is used to indicate the capability of packet I/O. BFD control packets are still transmitted and received. At least one BFD control packet must be received every 100 * bfd:min_rx amount of time. Otherwise, even if traffic are received, the bfd:forwarding will be false. bfd : cpath_down: optional string, either true or false Set to true to notify the remote endpoint that traffic should not be forwarded to this system for some reason other than a connectivty failure on the interface being monitored. The typi‐ cal underlying reason is ``concatenated path down,’’ that is, that connectivity beyond the local system is down. Defaults to false. bfd : check_tnl_key: optional string, either true or false Set to true to make BFD accept only control messages with a tun‐ nel key of zero. By default, BFD accepts control messages with any tunnel key. bfd : bfd_local_src_mac: optional string Set to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set the MAC used as source for transmitted BFD packets. The default is the mac address of the BFD enabled interface. bfd : bfd_local_dst_mac: optional string Set to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set the MAC used as destination for transmitted BFD packets. The de‐ fault is 00:23:20:00:00:01. bfd : bfd_remote_dst_mac: optional string Set to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set the MAC used for checking the destination of received BFD pack‐ ets. Packets with different destination MAC will not be consid‐ ered as BFD packets. If not specified the destination MAC ad‐ dress of received BFD packets are not checked. bfd : bfd_src_ip: optional string Set to an IPv4 address to set the IP address used as source for transmitted BFD packets. The default is 169.254.1.1. bfd : bfd_dst_ip: optional string Set to an IPv4 address to set the IP address used as destination for transmitted BFD packets. The default is 169.254.1.0. bfd : oam: optional string Some tunnel protocols (such as Geneve) include a bit in the header to indicate that the encapsulated packet is an OAM frame. By setting this to true, BFD packets will be marked as OAM if encapsulated in one of these tunnels. bfd : mult: optional string, containing an integer, in range 1 to 255 The BFD detection multiplier, which defaults to 3. An endpoint signals a connectivity fault if the given number of consecutive BFD control messages fail to arrive. BFD Status: The switch sets key-value pairs in the bfd_status column to report the status of BFD on this interface. When BFD is not enabled, with bfd:en‐ able, the switch clears all key-value pairs from bfd_status. bfd_status : state: optional string, one of admin_down, down, init, or up Reports the state of the BFD session. The BFD session is fully healthy and negotiated if UP. bfd_status : forwarding: optional string, either true or false Reports whether the BFD session believes this Interface may be used to forward traffic. Typically this means the local session is signaling UP, and the remote system isn’t signaling a problem such as concatenated path down. bfd_status : diagnostic: optional string A diagnostic code specifying the local system’s reason for the last change in session state. The error messages are defined in section 4.1 of [RFC 5880]. bfd_status : remote_state: optional string, one of admin_down, down, init, or up Reports the state of the remote endpoint’s BFD session. bfd_status : remote_diagnostic: optional string A diagnostic code specifying the remote system’s reason for the last change in session state. The error messages are defined in section 4.1 of [RFC 5880]. bfd_status : flap_count: optional string, containing an integer, at least 0 Counts the number of bfd_status:forwarding flaps since start. A flap is considered as a change of the bfd_status:forwarding value. Connectivity Fault Management: 802.1ag Connectivity Fault Management (CFM) allows a group of Mainte‐ nance Points (MPs) called a Maintenance Association (MA) to detect con‐ nectivity problems with each other. MPs within a MA should have com‐ plete and exclusive interconnectivity. This is verified by occasionally broadcasting Continuity Check Messages (CCMs) at a configurable trans‐ mission interval. According to the 802.1ag specification, each Maintenance Point should be configured out-of-band with a list of Remote Maintenance Points it should have connectivity to. Open vSwitch differs from the specifica‐ tion in this area. It simply assumes the link is faulted if no Remote Maintenance Points are reachable, and considers it not faulted other‐ wise. When operating over tunnels which have no in_key, or an in_key of flow. CFM will only accept CCMs with a tunnel key of zero. cfm_mpid: optional integer A Maintenance Point ID (MPID) uniquely identifies each endpoint within a Maintenance Association. The MPID is used to identify this endpoint to other Maintenance Points in the MA. Each end of a link being monitored should have a different MPID. Must be configured to enable CFM on this Interface. According to the 802.1ag specification, MPIDs can only range be‐ tween [1, 8191]. However, extended mode (see other_con‐ fig:cfm_extended) supports eight byte MPIDs. cfm_flap_count: optional integer Counts the number of cfm fault flapps since boot. A flap is con‐ sidered to be a change of the cfm_fault value. cfm_fault: optional boolean Indicates a connectivity fault triggered by an inability to re‐ ceive heartbeats from any remote endpoint. When a fault is trig‐ gered on Interfaces participating in bonds, they will be dis‐ abled. Faults can be triggered for several reasons. Most importantly they are triggered when no CCMs are received for a period of 3.5 times the transmission interval. Faults are also triggered when any CCMs indicate that a Remote Maintenance Point is not receiv‐ ing CCMs but able to send them. Finally, a fault is triggered if a CCM is received which indicates unexpected configuration. No‐ tably, this case arises when a CCM is received which advertises the local MPID. cfm_fault_status : recv: none Indicates a CFM fault was triggered due to a lack of CCMs re‐ ceived on the Interface. cfm_fault_status : rdi: none Indicates a CFM fault was triggered due to the reception of a CCM with the RDI bit flagged. Endpoints set the RDI bit in their CCMs when they are not receiving CCMs themselves. This typically indicates a unidirectional connectivity failure. cfm_fault_status : maid: none Indicates a CFM fault was triggered due to the reception of a CCM with a MAID other than the one Open vSwitch uses. CFM broad‐ casts are tagged with an identification number in addition to the MPID called the MAID. Open vSwitch only supports receiving CCM broadcasts tagged with the MAID it uses internally. cfm_fault_status : loopback: none Indicates a CFM fault was triggered due to the reception of a CCM advertising the same MPID configured in the cfm_mpid column of this Interface. This may indicate a loop in the network. cfm_fault_status : overflow: none Indicates a CFM fault was triggered because the CFM module re‐ ceived CCMs from more remote endpoints than it can keep track of. cfm_fault_status : override: none Indicates a CFM fault was manually triggered by an administrator using an ovs-appctl command. cfm_fault_status : interval: none Indicates a CFM fault was triggered due to the reception of a CCM frame having an invalid interval. cfm_remote_opstate: optional string, either down or up When in extended mode, indicates the operational state of the remote endpoint as either up or down. See other_config:cfm_op‐ state. cfm_health: optional integer, in range 0 to 100 Indicates the health of the interface as a percentage of CCM frames received over 21 other_config:cfm_intervals. The health of an interface is undefined if it is communicating with more than one cfm_remote_mpids. It reduces if healthy heartbeats are not received at the expected rate, and gradually improves as healthy heartbeats are received at the desired rate. Every 21 other_config:cfm_intervals, the health of the interface is re‐ freshed. As mentioned above, the faults can be triggered for several rea‐ sons. The link health will deteriorate even if heartbeats are received but they are reported to be unhealthy. An unhealthy heartbeat in this context is a heartbeat for which either some fault is set or is out of sequence. The interface health can be 100 only on receiving healthy heartbeats at the desired rate. cfm_remote_mpids: set of integers When CFM is properly configured, Open vSwitch will occasionally receive CCM broadcasts. These broadcasts contain the MPID of the sending Maintenance Point. The list of MPIDs from which this In‐ terface is receiving broadcasts from is regularly collected and written to this column. other_config : cfm_interval: optional string, containing an integer The interval, in milliseconds, between transmissions of CFM heartbeats. Three missed heartbeat receptions indicate a connec‐ tivity fault. In standard operation only intervals of 3, 10, 100, 1,000, 10,000, 60,000, or 600,000 ms are supported. Other values will be rounded down to the nearest value on the list. Extended mode (see other_config:cfm_extended) supports any interval up to 65,535 ms. In either mode, the default is 1000 ms. We do not recommend using intervals less than 100 ms. other_config : cfm_extended: optional string, either true or false When true, the CFM module operates in extended mode. This causes it to use a nonstandard destination address to avoid conflicting with compliant implementations which may be running concurrently on the network. Furthermore, extended mode increases the accu‐ racy of the cfm_interval configuration parameter by breaking wire compatibility with 802.1ag compliant implementations. And extended mode allows eight byte MPIDs. Defaults to false. other_config : cfm_demand: optional string, either true or false When true, and other_config:cfm_extended is true, the CFM module operates in demand mode. When in demand mode, traffic received on the Interface is used to indicate liveness. CCMs are still transmitted and received. At least one CCM must be received ev‐ ery 100 * other_config:cfm_interval amount of time. Otherwise, even if traffic are received, the CFM module will raise the con‐ nectivity fault. Demand mode has a couple of caveats: • To ensure that ovs-vswitchd has enough time to pull sta‐ tistics from the datapath, the fault detection interval is set to 3.5 * MAX(other_config:cfm_interval, 500) ms. • To avoid ambiguity, demand mode disables itself when there are multiple remote maintenance points. • If the Interface is heavily congested, CCMs containing the other_config:cfm_opstate status may be dropped caus‐ ing changes in the operational state to be delayed. Simi‐ larly, if CCMs containing the RDI bit are not received, unidirectional link failures may not be detected. other_config : cfm_opstate: optional string, either down or up When down, the CFM module marks all CCMs it generates as opera‐ tionally down without triggering a fault. This allows remote maintenance points to choose not to forward traffic to the In‐ terface on which this CFM module is running. Currently, in Open vSwitch, the opdown bit of CCMs affects Interfaces participating in bonds, and the bundle OpenFlow action. This setting is ig‐ nored when CFM is not in extended mode. Defaults to up. other_config : cfm_ccm_vlan: optional string, containing an integer, in range 1 to 4,095 When set, the CFM module will apply a VLAN tag to all CCMs it generates with the given value. May be the string random in which case each CCM will be tagged with a different randomly generated VLAN. other_config : cfm_ccm_pcp: optional string, containing an integer, in range 1 to 7 When set, the CFM module will apply a VLAN tag to all CCMs it generates with the given PCP value, the VLAN ID of the tag is governed by the value of other_config:cfm_ccm_vlan. If other_config:cfm_ccm_vlan is unset, a VLAN ID of zero is used. Bonding Configuration: other_config : lacp-port-id: optional string, containing an integer, in range 1 to 65,535 The LACP port ID of this Interface. Port IDs are used in LACP negotiations to identify individual ports participating in a bond. other_config : lacp-port-priority: optional string, containing an inte‐ ger, in range 1 to 65,535 The LACP port priority of this Interface. In LACP negotiations Interfaces with numerically lower priorities are preferred for aggregation. other_config : lacp-aggregation-key: optional string, containing an in‐ teger, in range 1 to 65,535 The LACP aggregation key of this Interface. Interfaces with dif‐ ferent aggregation keys may not be active within a given Port at the same time. Virtual Machine Identifiers: These key-value pairs specifically apply to an interface that repre‐ sents a virtual Ethernet interface connected to a virtual machine. These key-value pairs should not be present for other types of inter‐ faces. Keys whose names end in -uuid have values that uniquely identify the entity in question. external_ids : attached-mac: optional string The MAC address programmed into the ``virtual hardware’’ for this interface, in the form xx:xx:xx:xx:xx:xx. external_ids : iface-id: optional string A system-unique identifier for the interface. external_ids : iface-status: optional string, either active or inactive Hypervisors may sometimes have more than one interface associ‐ ated with a given external_ids:iface-id, only one of which is actually in use at a given time. For example, in some circum‐ stances hypervisor may have both a ``tap’’ and a ``vif’’ inter‐ face for a single external_ids:iface-id, but only uses one of them at a time. A hypervisor that behaves this way must mark the currently in use interface active and the others inactive. A hy‐ pervisor that never has more than one interface for a given ex‐ ternal_ids:iface-id may mark that interface active or omit ex‐ ternal_ids:iface-status entirely. During VM migration, a given external_ids:iface-id might tran‐ siently be marked active on two different hypervisors. That is, active means that this external_ids:iface-id is the active in‐ stance within a single hypervisor, not in a broader scope. There is one exception: some hypervisors support ``migration’’ from a given hypervisor to itself (most often for test purposes). Dur‐ ing such a ``migration,’’ two instances of a single exter‐ nal_ids:iface-id might both be briefly marked active on a single hypervisor. external_ids : vm-id: optional string The VM to which this interface belongs. Auto Attach Configuration: Auto Attach configuration for a particular interface. lldp : enable: optional string, either true or false True to enable LLDP on this Interface. If not specified, LLDP will be disabled by default. Flow control Configuration: Ethernet flow control defined in IEEE 802.1Qbb provides link level flow control using MAC pause frames. Implemented only for interfaces with type dpdk. options : rx-flow-ctrl: optional string, either true or false Set to true to enable Rx flow control on physical ports. By de‐ fault, Rx flow control is disabled. options : tx-flow-ctrl: optional string, either true or false Set to true to enable Tx flow control on physical ports. By de‐ fault, Tx flow control is disabled. options : flow-ctrl-autoneg: optional string, either true or false Set to true to enable flow control auto negotiation on physical ports. By default, auto-neg is disabled. Link State Change detection mode: options : dpdk-lsc-interrupt: optional string, either true or false Set this value to true to configure interrupt mode for Link State Change (LSC) detection instead of poll mode for the DPDK interface. If this value is not set, poll mode is configured. This parameter has an effect only on netdev dpdk interfaces. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Flow_Table TABLE Configuration for a particular OpenFlow table. Summary: name optional string Eviction Policy: flow_limit optional integer, at least 0 overflow_policy optional string, either evict or refuse groups set of strings Classifier Optimization: prefixes set of up to 3 strings Common Columns: external_ids map of string-string pairs Details: name: optional string The table’s name. Set this column to change the name that con‐ trollers will receive when they request table statistics, e.g. ovs-ofctl dump-tables. The name does not affect switch behavior. Eviction Policy: Open vSwitch supports limiting the number of flows that may be in‐ stalled in a flow table, via the flow_limit column. When adding a flow would exceed this limit, by default Open vSwitch reports an error, but there are two ways to configure Open vSwitch to instead delete (``evict’’) a flow to make room for the new one: • Set the overflow_policy column to evict. • Send an OpenFlow 1.4+ ``table mod request’’ to enable eviction for the flow table (e.g. ovs-ofctl -O OpenFlow14 mod-table br0 0 evict to enable eviction on flow table 0 of bridge br0). When a flow must be evicted due to overflow, the flow to evict is cho‐ sen through an approximation of the following algorithm. This algorithm is used regardless of how eviction was enabled: 1. Divide the flows in the table into groups based on the val‐ ues of the fields or subfields specified in the groups col‐ umn, so that all of the flows in a given group have the same values for those fields. If a flow does not specify a given field, that field’s value is treated as 0. If groups is empty, then all of the flows in the flow table are treated as a single group. 2. Consider the flows in the largest group, that is, the group that contains the greatest number of flows. If two or more groups all have the same largest number of flows, consider the flows in all of those groups. 3. If the flows under consideration have different importance values, eliminate from consideration any flows except those with the lowest importance. (``Importance,’’ a 16-bit inte‐ ger value attached to each flow, was introduced in OpenFlow 1.4. Flows inserted with older versions of OpenFlow always have an importance of 0.) 4. Among the flows under consideration, choose the flow that expires soonest for eviction. The eviction process only considers flows that have an idle timeout or a hard timeout. That is, eviction never deletes permanent flows. (Per‐ manent flows do count against flow_limit.) flow_limit: optional integer, at least 0 If set, limits the number of flows that may be added to the ta‐ ble. Open vSwitch may limit the number of flows in a table for other reasons, e.g. due to hardware limitations or for resource availability or performance reasons. overflow_policy: optional string, either evict or refuse Controls the switch’s behavior when an OpenFlow flow table modi‐ fication request would add flows in excess of flow_limit. The supported values are: refuse Refuse to add the flow or flows. This is also the default policy when overflow_policy is unset. evict Delete a flow chosen according to the algorithm described above. groups: set of strings When overflow_policy is evict, this controls how flows are cho‐ sen for eviction when the flow table would otherwise exceed flow_limit flows. Its value is a set of NXM fields or sub- fields, each of which takes one of the forms field[] or field[start..end], e.g. NXM_OF_IN_PORT[]. Please see meta-flow.h for a complete list of NXM field names. Open vSwitch ignores any invalid or unknown field specifica‐ tions. When eviction is not enabled, via overflow_policy or an OpenFlow 1.4+ ``table mod,’’ this column has no effect. Classifier Optimization: prefixes: set of up to 3 strings This string set specifies which fields should be used for ad‐ dress prefix tracking. Prefix tracking allows the classifier to skip rules with longer than necessary prefixes, resulting in better wildcarding for datapath flows. Prefix tracking may be beneficial when a flow table contains matches on IP address fields with different prefix lengths. For example, when a flow table contains IP address matches on both full addresses and proper prefixes, the full address matches will typically cause the datapath flow to un-wildcard the whole address field (depending on flow entry priorities). In this case each packet with a different address gets handed to the userspace for flow processing and generates its own datapath flow. With prefix tracking enabled for the address field in question packets with addresses matching shorter prefixes would generate datapath flows where the irrelevant address bits are wildcarded, allowing the same datapath flow to handle all the packets within the prefix in question. In this case many userspace upcalls can be avoided and the overall performance can be better. This is a performance optimization only, so packets will receive the same treatment with or without prefix tracking. The supported fields are: tun_id, tun_src, tun_dst, tun_ipv6_src, tun_ipv6_dst, nw_src, nw_dst (or aliases ip_src and ip_dst), ipv6_src, and ipv6_dst. (Using this feature for tun_id would only make sense if the tunnel IDs have prefix structure similar to IP addresses.) By default, the prefixes=ip_dst,ip_src are used on each flow ta‐ ble. This instructs the flow classifier to track the IP destina‐ tion and source addresses used by the rules in this specific flow table. The keyword none is recognized as an explicit override of the default values, causing no prefix fields to be tracked. To set the prefix fields, the flow table record needs to exist: ovs-vsctl set Bridge br0 flow_tables:0=@N1 -- --id=@N1 create Flow_Table name=table0 Creates a flow table record for the OpenFlow table number 0. ovs-vsctl set Flow_Table table0 prefixes=ip_dst,ip_src Enables prefix tracking for IP source and destination ad‐ dress fields. There is a maximum number of fields that can be enabled for any one flow table. Currently this limit is 3. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs QoS TABLE Quality of Service (QoS) configuration for each Port that references it. Summary: type string queues map of integer-Queue pairs, key in range 0 to 4,294,967,295 Configuration for linux-htb and linux-hfsc: other_config : max-rate optional string, containing an integer Configuration for egress-policer QoS: other_config : cir optional string, containing an integer other_config : cbs optional string, containing an integer other_config : eir optional string, containing an integer other_config : ebs optional string, containing an integer Configuration for linux-sfq: other_config : perturb optional string, containing an integer other_config : quantum optional string, containing an integer Configuration for linux-netem: other_config : latency optional string, containing an integer other_config : limit optional string, containing an integer other_config : loss optional string, containing an integer other_config : jitter optional string, containing an integer Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: type: string The type of QoS to implement. The currently defined types are listed below: linux-htb Linux ``hierarchy token bucket’’ classifier. See tc- htb(8) (also at http://linux.die.net/man/8/tc-htb) and the HTB manual (http://luxik.cdi.cz/~devik/qos/htb/man‐ ual/userg.htm) for information on how this classifier works and how to configure it. linux-hfsc Linux "Hierarchical Fair Service Curve" classifier. See http://linux-ip.net/articles/hfsc.en/ for information on how this classifier works. linux-sfq Linux ``Stochastic Fairness Queueing’’ classifier. See tc-sfq(8) (also at http://linux.die.net/man/8/tc-sfq) for information on how this classifier works. linux-codel Linux ``Controlled Delay’’ classifier. See tc-codel(8) (also at http://man7.org/linux/man-pages/man8/tc-codel.8.html) for information on how this classifier works. linux-fq_codel Linux ``Fair Queuing with Controlled Delay’’ classifier. See tc-fq_codel(8) (also at http://man7.org/linux/man-pages/man8/tc-fq_codel.8.html) for information on how this classifier works. linux-netem Linux ``Network Emulator’’ classifier. See tc-netem(8) (also at http://man7.org/linux/man-pages/man8/tc-netem.8.html) for information on how this classifier works. linux-noop Linux ``No operation.’’ By default, Open vSwitch manages quality of service on all of its configured ports. This can be helpful, but sometimes administrators prefer to use other software to manage QoS. This type prevents Open vSwitch from changing the QoS configuration for a port. egress-policer A DPDK egress policer algorithm using the DPDK rte_meter library. The rte_meter library provides an implementation which allows the metering and policing of traffic. The implementation in OVS essentially creates a single token bucket used to police traffic. It should be noted that when the rte_meter is configured as part of QoS there will be a performance overhead as the rte_meter itself will consume CPU cycles in order to police traffic. These CPU cycles ordinarily are used for packet proccessing. As such the drop in performance will be noticed in terms of overall aggregate traffic throughput. trtcm-policer A DPDK egress policer algorithm using RFC 4115’s Two- Rate, Three-Color marker. It’s a two-level hierarchical policer which first does a color-blind marking of the traffic at the queue level, followed by a color-aware marking at the port level. At the end traffic marked as Green or Yellow is forwarded, Red is dropped. For details on how traffic is marked, see RFC 4115. If the ``default queue’’, 0, is not configured it’s automatically created with the same other_config values as the physical port. queues: map of integer-Queue pairs, key in range 0 to 4,294,967,295 A map from queue numbers to Queue records. The supported range of queue numbers depend on type. The queue numbers are the same as the queue_id used in OpenFlow in struct ofp_action_enqueue and other structures. Queue 0 is the ``default queue.’’ It is used by OpenFlow output actions when no specific queue has been set. When no configura‐ tion for queue 0 is present, it is automatically configured as if a Queue record with empty dscp and other_config columns had been specified. (Before version 1.6, Open vSwitch would leave queue 0 unconfigured in this case. With some queuing disci‐ plines, this dropped all packets destined for the default queue.) Configuration for linux-htb and linux-hfsc: The linux-htb and linux-hfsc classes support the following key-value pair: other_config : max-rate: optional string, containing an integer Maximum rate shared by all queued traffic, in bit/s. Optional. If not specified, for physical interfaces, the default is the link rate. For other interfaces or if the link rate cannot be determined, the default is currently 10 Gbps. Configuration for egress-policer QoS: QoS type egress-policer provides egress policing for userspace port types with DPDK. It has the following key-value pairs defined. other_config : cir: optional string, containing an integer The Committed Information Rate (CIR) is measured in bytes of IP packets per second, i.e. it includes the IP header, but not link specific (e.g. Ethernet) headers. This represents the bytes per second rate at which the token bucket will be updated. The cir value is calculated by (pps x packet data size). For example as‐ suming a user wishes to limit a stream consisting of 64 byte packets to 1 million packets per second the CIR would be set to to to 46000000. This value can be broken into ’1,000,000 x 46’. Where 1,000,000 is the policing rate for the number of packets per second and 46 represents the size of the packet data for a 64 bytes IP packet without 14 bytes Ethernet and 4 bytes FCS header. other_config : cbs: optional string, containing an integer The Committed Burst Size (CBS) is measured in bytes and repre‐ sents a token bucket. At a minimum this value should be be set to the expected largest size packet in the traffic stream. In practice larger values may be used to increase the size of the token bucket. If a packet can be transmitted then the cbs will be decremented by the number of bytes/tokens of the packet. If there are not enough tokens in the cbs bucket the packet will be dropped. other_config : eir: optional string, containing an integer The Excess Information Rate (EIR) is measured in bytes of IP packets per second, i.e. it includes the IP header, but not link specific (e.g. Ethernet) headers. This represents the bytes per second rate at which the token bucket will be updated. The eir value is calculated by (pps x packet data size). For example as‐ suming a user wishes to limit a stream consisting of 64 byte packets to 1 million packets per second the EIR would be set to to to 46000000. This value can be broken into ’1,000,000 x 46’. Where 1,000,000 is the policing rate for the number of packets per second and 46 represents the size of the packet data for a 64 bytes IP packet without 14 bytes Ethernet and 4 bytes FCS header. other_config : ebs: optional string, containing an integer The Excess Burst Size (EBS) is measured in bytes and represents a token bucket. At a minimum this value should be be set to the expected largest size packet in the traffic stream. In practice larger values may be used to increase the size of the token bucket. If a packet can be transmitted then the ebs will be decremented by the number of bytes/tokens of the packet. If there are not enough tokens in the cbs bucket the packet might be dropped. Configuration for linux-sfq: The linux-sfq QoS supports the following key-value pairs: other_config : perturb: optional string, containing an integer Number of seconds between consecutive perturbations in hashing algorithm. Different flows can end up in the same hash bucket causing unfairness. Perturbation’s goal is to remove possible unfairness. The default and recommended value is 10. Too low a value is discouraged because each perturbation can cause packet reordering. other_config : quantum: optional string, containing an integer Number of bytes linux-sfq QoS can dequeue in one turn in round- robin from one flow. The default and recommended value is equal to interface’s MTU. Configuration for linux-netem: The linux-netem QoS supports the following key-value pairs: other_config : latency: optional string, containing an integer Adds the chosen delay to the packets outgoing to chosen network interface. The latency value expressed in us. other_config : limit: optional string, containing an integer Maximum number of packets the qdisc may hold queued at a time. The default value is 1000. other_config : loss: optional string, containing an integer Adds an independent loss probability to the packets outgoing from the chosen network interface. other_config : jitter: optional string, containing an integer Adds the provided jitter to the latency outgoing to the chosen network interface. The jitter value expressed in us. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Queue TABLE A configuration for a port output queue, used in configuring Quality of Service (QoS) features. May be referenced by queues column in QoS ta‐ ble. Summary: dscp optional integer, in range 0 to 63 Configuration for linux-htb QoS: other_config : min-rate optional string, containing an integer, at least 1 other_config : max-rate optional string, containing an integer, at least 1 other_config : burst optional string, containing an integer, at least 1 other_config : priority optional string, containing an integer, in range 0 to 4,294,967,295 Configuration for linux-hfsc QoS: other_config : min-rate optional string, containing an integer, at least 1 other_config : max-rate optional string, containing an integer, at least 1 Common Columns: other_config map of string-string pairs external_ids map of string-string pairs Details: dscp: optional integer, in range 0 to 63 If set, Open vSwitch will mark all traffic egressing this Queue with the given DSCP bits. Traffic egressing the default Queue is only marked if it was explicitly selected as the Queue at the time the packet was output. If unset, the DSCP bits of traffic egressing this Queue will remain unchanged. Configuration for linux-htb QoS: QoS type linux-htb may use queue_ids less than 61440. It has the fol‐ lowing key-value pairs defined. other_config : min-rate: optional string, containing an integer, at least 1 Minimum guaranteed bandwidth, in bit/s. other_config : max-rate: optional string, containing an integer, at least 1 Maximum allowed bandwidth, in bit/s. Optional. If specified, the queue’s rate will not be allowed to exceed the specified value, even if excess bandwidth is available. If unspecified, defaults to no limit. other_config : burst: optional string, containing an integer, at least 1 Burst size, in bits. This is the maximum amount of ``credits’’ that a queue can accumulate while it is idle. Optional. Details of the linux-htb implementation require a minimum burst size, so a too-small burst will be silently ignored. other_config : priority: optional string, containing an integer, in range 0 to 4,294,967,295 A queue with a smaller priority will receive all the excess bandwidth that it can use before a queue with a larger value re‐ ceives any. Specific priority values are unimportant; only rela‐ tive ordering matters. Defaults to 0 if unspecified. Configuration for linux-hfsc QoS: QoS type linux-hfsc may use queue_ids less than 61440. It has the fol‐ lowing key-value pairs defined. other_config : min-rate: optional string, containing an integer, at least 1 Minimum guaranteed bandwidth, in bit/s. other_config : max-rate: optional string, containing an integer, at least 1 Maximum allowed bandwidth, in bit/s. Optional. If specified, the queue’s rate will not be allowed to exceed the specified value, even if excess bandwidth is available. If unspecified, defaults to no limit. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. other_config: map of string-string pairs external_ids: map of string-string pairs Mirror TABLE A port mirror within a Bridge. A port mirror configures a bridge to send selected frames to special ``mirrored’’ ports, in addition to their normal destinations. Mirroring traffic may also be referred to as SPAN or RSPAN, depending on how the mirrored traffic is sent. When a packet enters an Open vSwitch bridge, it becomes eligible for mirroring based on its ingress port and VLAN. As the packet travels through the flow tables, each time it is output to a port, it becomes eligible for mirroring based on the egress port and VLAN. In Open vSwitch 2.5 and later, mirroring occurs just after a packet first be‐ comes eligible, using the packet as it exists at that point; in Open vSwitch 2.4 and earlier, mirroring occurs only after a packet has tra‐ versed all the flow tables, using the original packet as it entered the bridge. This makes a difference only when the flow table modifies the packet: in Open vSwitch 2.4, the modifications are never visible to mirrors, whereas in Open vSwitch 2.5 and later modifications made be‐ fore the first output that makes it eligible for mirroring to a partic‐ ular destination are visible. A packet that enters an Open vSwitch bridge is mirrored to a particular destination only once, even if it is eligible for multiple reasons. For example, a packet would be mirrored to a particular output_port only once, even if it is selected for mirroring to that port by se‐ lect_dst_port and select_src_port in the same or different Mirror records. Summary: name string Selecting Packets for Mirroring: select_all boolean select_dst_port set of weak reference to Ports select_src_port set of weak reference to Ports select_vlan set of up to 4,096 integers, in range 0 to 4,095 Mirroring Destination Configuration: output_port optional weak reference to Port output_vlan optional integer, in range 1 to 4,095 snaplen optional integer, in range 14 to 65,535 Statistics: Mirror counters: statistics : tx_packets optional integer statistics : tx_bytes optional integer Common Columns: external_ids map of string-string pairs Details: name: string Arbitrary identifier for the Mirror. Selecting Packets for Mirroring: To be selected for mirroring, a given packet must enter or leave the bridge through a selected port and it must also be in one of the se‐ lected VLANs. select_all: boolean If true, every packet arriving or departing on any port is se‐ lected for mirroring. select_dst_port: set of weak reference to Ports Ports on which departing packets are selected for mirroring. select_src_port: set of weak reference to Ports Ports on which arriving packets are selected for mirroring. select_vlan: set of up to 4,096 integers, in range 0 to 4,095 VLANs on which packets are selected for mirroring. An empty set selects packets on all VLANs. Mirroring Destination Configuration: These columns are mutually exclusive. Exactly one of them must be nonempty. output_port: optional weak reference to Port Output port for selected packets, if nonempty. Specifying a port for mirror output reserves that port exclu‐ sively for mirroring. No frames other than those selected for mirroring via this column will be forwarded to the port, and any frames received on the port will be discarded. The output port may be any kind of port supported by Open vSwitch. It may be, for example, a physical port (sometimes called SPAN) or a GRE tunnel. output_vlan: optional integer, in range 1 to 4,095 Output VLAN for selected packets, if nonempty. The frames will be sent out all ports that trunk output_vlan, as well as any ports with implicit VLAN output_vlan. When a mir‐ rored frame is sent out a trunk port, the frame’s VLAN tag will be set to output_vlan, replacing any existing tag; when it is sent out an implicit VLAN port, the frame will not be tagged. This type of mirroring is sometimes called RSPAN. See the documentation for other_config:forward-bpdu in the In‐ terface table for a list of destination MAC addresses which will not be mirrored to a VLAN to avoid confusing switches that in‐ terpret the protocols that they represent. Please note: Mirroring to a VLAN can disrupt a network that con‐ tains unmanaged switches. Consider an unmanaged physical switch with two ports: port 1, connected to an end host, and port 2, connected to an Open vSwitch configured to mirror received pack‐ ets into VLAN 123 on port 2. Suppose that the end host sends a packet on port 1 that the physical switch forwards to port 2. The Open vSwitch forwards this packet to its destination and then reflects it back on port 2 in VLAN 123. This reflected packet causes the unmanaged physical switch to replace the MAC learning table entry, which correctly pointed to port 1, with one that incorrectly points to port 2. Afterward, the physical switch will direct packets destined for the end host to the Open vSwitch on port 2, instead of to the end host on port 1, dis‐ rupting connectivity. If mirroring to a VLAN is desired in this scenario, then the physical switch must be replaced by one that learns Ethernet addresses on a per-VLAN basis. In addition, learning should be disabled on the VLAN containing mirrored traffic. If this is not done then intermediate switches will learn the MAC address of each end host from the mirrored traf‐ fic. If packets being sent to that end host are also mirrored, then they will be dropped since the switch will attempt to send them out the input port. Disabling learning for the VLAN will cause the switch to correctly send the packet out all ports con‐ figured for that VLAN. If Open vSwitch is being used as an in‐ termediate switch, learning can be disabled by adding the mir‐ rored VLAN to flood_vlans in the appropriate Bridge table or ta‐ bles. Mirroring to a GRE tunnel has fewer caveats than mirroring to a VLAN and should generally be preferred. snaplen: optional integer, in range 14 to 65,535 Maximum per-packet number of bytes to mirror. A mirrored packet with size larger than snaplen will be trun‐ cated in datapath to snaplen bytes before sending to the mirror output port. If omitted, packets are not truncated. Statistics: Mirror counters: Key-value pairs that report mirror statistics. The update period is controlled by other_config:stats-update-interval in the Open_vSwitch table. statistics : tx_packets: optional integer Number of packets transmitted through this mirror. statistics : tx_bytes: optional integer Number of bytes transmitted through this mirror. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs Controller TABLE An OpenFlow controller. Summary: Core Features: type optional string, either primary or ser‐ vice target string connection_mode optional string, either in-band or out-of-band Controller Failure Detection and Handling: max_backoff optional integer, at least 1,000 inactivity_probe optional integer Asynchronous Messages: enable_async_messages optional boolean Controller Rate Limiting: controller_queue_size optional integer, in range 1 to 512 controller_rate_limit optional integer, at least 100 controller_burst_limit optional integer, at least 25 Controller Rate Limiting Statistics: status : packet-in-TYPE-bypassed optional string, containing an integer, at least 0 status : packet-in-TYPE-queued optional string, containing an integer, at least 0 status : packet-in-TYPE-dropped optional string, containing an integer, at least 0 status : packet-in-TYPE-backlog optional string, containing an integer, at least 0 Additional In-Band Configuration: local_ip optional string local_netmask optional string local_gateway optional string Controller Status: is_connected boolean role optional string, one of master, other, or slave status : last_error optional string status : state optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID status : sec_since_connect optional string, containing an integer, at least 0 status : sec_since_disconnect optional string, containing an integer, at least 1 Connection Parameters: other_config : dscp optional string, containing an integer Common Columns: external_ids map of string-string pairs other_config map of string-string pairs Details: Core Features: type: optional string, either primary or service Open vSwitch supports two kinds of OpenFlow controllers. A bridge may have any number of each kind: Primary controllers This is the kind of controller envisioned by the OpenFlow specifications. Usually, a primary controller implements a network policy by taking charge of the switch’s flow table. The fail_mode column in the Bridge table applies to pri‐ mary controllers. When multiple primary controllers are configured, Open vSwitch connects to all of them simultaneously. OpenFlow provides few facilities to allow multiple controllers to coordinate in interacting with a single switch, so more than one primary controller should be specified only if the controllers are themselves designed to coordinate with each other. Service controllers These kinds of OpenFlow controller connections are in‐ tended for occasional support and maintenance use, e.g. with ovs-ofctl. Usually a service controller connects only briefly to inspect or modify some of a switch’s state. The fail_mode column in the Bridge table does not apply to service controllers. By default, Open vSwitch treats controllers with active connec‐ tion methods as primary controllers and those with passive con‐ nection methods as service controllers. Set this column to the desired type to override this default. target: string Connection method for controller. The following active connection methods are currently supported: ssl:host[:port] The specified SSL port on the host at the given host, which can either be a DNS name (if built with unbound li‐ brary) or an IP address. The ssl column in the Open_vSwitch table must point to a valid SSL configura‐ tion when this form is used. If port is not specified, it defaults to 6653. SSL support is an optional feature that is not always built as part of Open vSwitch. tcp:host[:port] The specified TCP port on the host at the given host, which can either be a DNS name (if built with unbound li‐ brary) or an IP address (IPv4 or IPv6). If host is an IPv6 address, wrap it in square brackets, e.g. tcp:[::1]:6653. If port is not specified, it defaults to 6653. The following passive connection methods are currently sup‐ ported: pssl:[port][:host] Listens for SSL connections on the specified TCP port. If host, which can either be a DNS name (if built with un‐ bound library) or an IP address, is specified, then con‐ nections are restricted to the resolved or specified lo‐ cal IP address (either IPv4 or IPv6). If host is an IPv6 address, wrap it in square brackets, e.g. pssl:6653:[::1]. If port is not specified, it defaults to 6653. If host is not specified then it listens only on IPv4 (but not IPv6) addresses. The ssl column in the Open_vSwitch table must point to a valid SSL configuration when this form is used. If port is not specified, it currently to 6653. SSL support is an optional feature that is not always built as part of Open vSwitch. ptcp:[port][:host] Listens for connections on the specified TCP port. If host, which can either be a DNS name (if built with un‐ bound library) or an IP address, is specified, then con‐ nections are restricted to the resolved or specified lo‐ cal IP address (either IPv4 or IPv6). If host is an IPv6 address, wrap it in square brackets, e.g. ptcp:6653:[::1]. If host is not specified then it listens only on IPv4 addresses. If port is not specified, it defaults to 6653. When multiple controllers are configured for a single bridge, the target values must be unique. Duplicate target values yield unspecified results. connection_mode: optional string, either in-band or out-of-band If it is specified, this setting must be one of the following strings that describes how Open vSwitch contacts this OpenFlow controller over the network: in-band In this mode, this controller’s OpenFlow traffic travels over the bridge associated with the controller. With this setting, Open vSwitch allows traffic to and from the con‐ troller regardless of the contents of the OpenFlow flow table. (Otherwise, Open vSwitch would never be able to connect to the controller, because it did not have a flow to enable it.) This is the most common connection mode because it is not necessary to maintain two independent networks. out-of-band In this mode, OpenFlow traffic uses a control network separate from the bridge associated with this controller, that is, the bridge does not use any of its own network devices to communicate with the controller. The control network must be configured separately, before or after ovs-vswitchd is started. If not specified, the default is implementation-specific. Controller Failure Detection and Handling: max_backoff: optional integer, at least 1,000 Maximum number of milliseconds to wait between connection at‐ tempts. Default is implementation-specific. inactivity_probe: optional integer Maximum number of milliseconds of idle time on connection to controller before sending an inactivity probe message. If Open vSwitch does not communicate with the controller for the speci‐ fied number of seconds, it will send a probe. If a response is not received for the same additional amount of time, Open vSwitch assumes the connection has been broken and attempts to reconnect. Default is implementation-specific. A value of 0 dis‐ ables inactivity probes. Asynchronous Messages: OpenFlow switches send certain messages to controllers spontanenously, that is, not in response to any request from the controller. These mes‐ sages are called ``asynchronous messages.’’ These columns allow asyn‐ chronous messages to be limited or disabled to ensure the best use of network resources. enable_async_messages: optional boolean The OpenFlow protocol enables asynchronous messages at time of connection establishment, which means that a controller can re‐ ceive asynchronous messages, potentially many of them, even if it turns them off immediately after connecting. Set this column to false to change Open vSwitch behavior to disable, by default, all asynchronous messages. The controller can use the NXT_SET_ASYNC_CONFIG Nicira extension to OpenFlow to turn on any messages that it does want to receive, if any. Controller Rate Limiting: A switch can forward packets to a controller over the OpenFlow proto‐ col. Forwarding packets this way at too high a rate can overwhelm a controller, frustrate use of the OpenFlow connection for other pur‐ poses, increase the latency of flow setup, and use an unreasonable amount of bandwidth. Therefore, Open vSwitch supports limiting the rate of packet forwarding to a controller. There are two main reasons in OpenFlow for a packet to be sent to a controller: either the packet ``misses’’ in the flow table, that is, there is no matching flow, or a flow table action says to send the packet to the controller. Open vSwitch limits the rate of each kind of packet separately at the configured rate. Therefore, the actual rate that packets are sent to the controller can be up to twice the config‐ ured rate, when packets are sent for both reasons. This feature is specific to forwarding packets over an OpenFlow connec‐ tion. It is not general-purpose QoS. See the QoS table for quality of service configuration, and ingress_policing_rate in the Interface table for ingress policing configuration. controller_queue_size: optional integer, in range 1 to 512 This sets the maximum size of the queue of packets that need to be sent to this OpenFlow controller. The value must be less than 512. If not specified the queue size is limited to the value set for the management controller in other_config:controller-queue- size if present or 100 packets by default. Note: increasing the queue size might have a negative impact on latency. controller_rate_limit: optional integer, at least 100 The maximum rate at which the switch will forward packets to the OpenFlow controller, in packets per second. If no value is spec‐ ified, rate limiting is disabled. controller_burst_limit: optional integer, at least 25 When a high rate triggers rate-limiting, Open vSwitch queues packets to the controller for each port and transmits them to the controller at the configured rate. This value limits the number of queued packets. Ports on a bridge share the packet queue fairly. This value has no effect unless controller_rate_limit is config‐ ured. The current default when this value is not specified is one-quarter of controller_rate_limit, meaning that queuing can delay forwarding a packet to the controller by up to 250 ms. Controller Rate Limiting Statistics: These values report the effects of rate limiting. Their values are rel‐ ative to establishment of the most recent OpenFlow connection, or since rate limiting was enabled, whichever happened more recently. Each con‐ sists of two values, one with TYPE replaced by miss for rate limiting flow table misses, and the other with TYPE replaced by action for rate limiting packets sent by OpenFlow actions. These statistics are reported only when controller rate limiting is en‐ abled. status : packet-in-TYPE-bypassed: optional string, containing an inte‐ ger, at least 0 Number of packets sent directly to the controller, without queu‐ ing, because the rate did not exceed the configured maximum. status : packet-in-TYPE-queued: optional string, containing an integer, at least 0 Number of packets added to the queue to send later. status : packet-in-TYPE-dropped: optional string, containing an inte‐ ger, at least 0 Number of packets added to the queue that were later dropped due to overflow. This value is less than or equal to status:packet- in-TYPE-queued. status : packet-in-TYPE-backlog: optional string, containing an inte‐ ger, at least 0 Number of packets currently queued. The other statistics in‐ crease monotonically, but this one fluctuates between 0 and the controller_burst_limit as conditions change. Additional In-Band Configuration: These values are considered only in in-band control mode (see connec‐ tion_mode). When multiple controllers are configured on a single bridge, there should be only one set of unique values in these columns. If different values are set for these columns in different controllers, the effect is unspecified. local_ip: optional string The IP address to configure on the local port, e.g. 192.168.0.123. If this value is unset, then local_netmask and local_gateway are ignored. local_netmask: optional string The IP netmask to configure on the local port, e.g. 255.255.255.0. If local_ip is set but this value is unset, then the default is chosen based on whether the IP address is class A, B, or C. local_gateway: optional string The IP address of the gateway to configure on the local port, as a string, e.g. 192.168.0.1. Leave this column unset if this net‐ work has no gateway. Controller Status: is_connected: boolean true if currently connected to this controller, false otherwise. role: optional string, one of master, other, or slave The level of authority this controller has on the associated bridge. Possible values are: other Allows the controller access to all OpenFlow features. master Equivalent to other, except that there may be at most one such controller at a time. If a given controller promotes itself to this role, ovs-vswitchd demotes any existing controller with the role to slave. slave Allows the controller read-only access to OpenFlow fea‐ tures. Attempts to modify the flow table will be rejected with an error. Such controllers do not receive OFPT_PACKET_IN or OFPT_FLOW_REMOVED messages, but they do receive OFPT_PORT_STATUS messages. status : last_error: optional string A human-readable description of the last error on the connection to the controller; i.e. strerror(errno). This key will exist only if an error has occurred. status : state: optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID The state of the connection to the controller: VOID Connection is disabled. BACKOFF Attempting to reconnect at an increasing period. CONNECTING Attempting to connect. ACTIVE Connected, remote host responsive. IDLE Connection is idle. Waiting for response to keep-alive. These values may change in the future. They are provided only for human consumption. status : sec_since_connect: optional string, containing an integer, at least 0 The amount of time since this controller last successfully con‐ nected to the switch (in seconds). Value is empty if controller has never successfully connected. status : sec_since_disconnect: optional string, containing an integer, at least 1 The amount of time since this controller last disconnected from the switch (in seconds). Value is empty if controller has never disconnected. Connection Parameters: Additional configuration for a connection between the controller and the Open vSwitch. other_config : dscp: optional string, containing an integer The Differentiated Service Code Point (DSCP) is specified using 6 bits in the Type of Service (TOS) field in the IP header. DSCP provides a mechanism to classify the network traffic and provide Quality of Service (QoS) on IP networks. The DSCP value speci‐ fied here is used when establishing the connection between the controller and the Open vSwitch. If no value is specified, a de‐ fault value of 48 is chosen. Valid DSCP values must be in the range 0 to 63. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs other_config: map of string-string pairs Manager TABLE Configuration for a database connection to an Open vSwitch database (OVSDB) client. This table primarily configures the Open vSwitch database (ovsdb-server), not the Open vSwitch switch (ovs-vswitchd). The switch does read the table to determine what connections should be treated as in-band. The Open vSwitch database server can initiate and maintain active con‐ nections to remote clients. It can also listen for database connec‐ tions. Summary: Core Features: target string (must be unique within table) connection_mode optional string, either in-band or out-of-band Client Failure Detection and Handling: max_backoff optional integer, at least 1,000 inactivity_probe optional integer Status: is_connected boolean status : last_error optional string status : state optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID status : sec_since_connect optional string, containing an integer, at least 0 status : sec_since_disconnect optional string, containing an integer, at least 0 status : locks_held optional string status : locks_waiting optional string status : locks_lost optional string status : n_connections optional string, containing an integer, at least 2 status : bound_port optional string, containing an integer Connection Parameters: other_config : dscp optional string, containing an integer Common Columns: external_ids map of string-string pairs other_config map of string-string pairs Details: Core Features: target: string (must be unique within table) Connection method for managers. The following connection methods are currently supported: ssl:host[:port] The specified SSL port on the host at the given host, which can either be a DNS name (if built with unbound li‐ brary) or an IP address. The ssl column in the Open_vSwitch table must point to a valid SSL configura‐ tion when this form is used. If port is not specified, it defaults to 6640. SSL support is an optional feature that is not always built as part of Open vSwitch. tcp:host[:port] The specified TCP port on the host at the given host, which can either be a DNS name (if built with unbound li‐ brary) or an IP address (IPv4 or IPv6). If host is an IPv6 address, wrap it in square brackets, e.g. tcp:[::1]:6640. If port is not specified, it defaults to 6640. pssl:[port][:host] Listens for SSL connections on the specified TCP port. Specify 0 for port to have the kernel automatically choose an available port. If host, which can either be a DNS name (if built with unbound library) or an IP ad‐ dress, is specified, then connections are restricted to the resolved or specified local IP address (either IPv4 or IPv6 address). If host is an IPv6 address, wrap in square brackets, e.g. pssl:6640:[::1]. If host is not specified then it listens only on IPv4 (but not IPv6) ad‐ dresses. The ssl column in the Open_vSwitch table must point to a valid SSL configuration when this form is used. If port is not specified, it defaults to 6640. SSL support is an optional feature that is not always built as part of Open vSwitch. ptcp:[port][:host] Listens for connections on the specified TCP port. Spec‐ ify 0 for port to have the kernel automatically choose an available port. If host, which can either be a DNS name (if built with unbound library) or an IP address, is specified, then connections are restricted to the re‐ solved or specified local IP address (either IPv4 or IPv6 address). If host is an IPv6 address, wrap it in square brackets, e.g. ptcp:6640:[::1]. If host is not specified then it listens only on IPv4 addresses. If port is not specified, it defaults to 6640. When multiple managers are configured, the target values must be unique. Duplicate target values yield unspecified results. connection_mode: optional string, either in-band or out-of-band If it is specified, this setting must be one of the following strings that describes how Open vSwitch contacts this OVSDB client over the network: in-band In this mode, this connection’s traffic travels over a bridge managed by Open vSwitch. With this setting, Open vSwitch allows traffic to and from the client regardless of the contents of the OpenFlow flow table. (Otherwise, Open vSwitch would never be able to connect to the client, because it did not have a flow to enable it.) This is the most common connection mode because it is not necessary to maintain two independent networks. out-of-band In this mode, the client’s traffic uses a control network separate from that managed by Open vSwitch, that is, Open vSwitch does not use any of its own network devices to communicate with the client. The control network must be configured separately, before or after ovs-vswitchd is started. If not specified, the default is implementation-specific. Client Failure Detection and Handling: max_backoff: optional integer, at least 1,000 Maximum number of milliseconds to wait between connection at‐ tempts. Default is implementation-specific. inactivity_probe: optional integer Maximum number of milliseconds of idle time on connection to the client before sending an inactivity probe message. If Open vSwitch does not communicate with the client for the specified number of seconds, it will send a probe. If a response is not received for the same additional amount of time, Open vSwitch assumes the connection has been broken and attempts to recon‐ nect. Default is implementation-specific. A value of 0 disables inactivity probes. Status: Key-value pair of is_connected is always updated. Other key-value pairs in the status columns may be updated depends on the target type. When target specifies a connection method that listens for inbound con‐ nections (e.g. ptcp: or punix:), both n_connections and is_connected may also be updated while the remaining key-value pairs are omitted. On the other hand, when target specifies an outbound connection, all key-value pairs may be updated, except the above-mentioned two key- value pairs associated with inbound connection targets. They are omit‐ ted. is_connected: boolean true if currently connected to this manager, false otherwise. status : last_error: optional string A human-readable description of the last error on the connection to the manager; i.e. strerror(errno). This key will exist only if an error has occurred. status : state: optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID The state of the connection to the manager: VOID Connection is disabled. BACKOFF Attempting to reconnect at an increasing period. CONNECTING Attempting to connect. ACTIVE Connected, remote host responsive. IDLE Connection is idle. Waiting for response to keep-alive. These values may change in the future. They are provided only for human consumption. status : sec_since_connect: optional string, containing an integer, at least 0 The amount of time since this manager last successfully con‐ nected to the database (in seconds). Value is empty if manager has never successfully connected. status : sec_since_disconnect: optional string, containing an integer, at least 0 The amount of time since this manager last disconnected from the database (in seconds). Value is empty if manager has never dis‐ connected. status : locks_held: optional string Space-separated list of the names of OVSDB locks that the con‐ nection holds. Omitted if the connection does not hold any locks. status : locks_waiting: optional string Space-separated list of the names of OVSDB locks that the con‐ nection is currently waiting to acquire. Omitted if the connec‐ tion is not waiting for any locks. status : locks_lost: optional string Space-separated list of the names of OVSDB locks that the con‐ nection has had stolen by another OVSDB client. Omitted if no locks have been stolen from this connection. status : n_connections: optional string, containing an integer, at least 2 When target specifies a connection method that listens for in‐ bound connections (e.g. ptcp: or pssl:) and more than one con‐ nection is actually active, the value is the number of active connections. Otherwise, this key-value pair is omitted. status : bound_port: optional string, containing an integer When target is ptcp: or pssl:, this is the TCP port on which the OVSDB server is listening. (This is particularly useful when target specifies a port of 0, allowing the kernel to choose any available port.) Connection Parameters: Additional configuration for a connection between the manager and the Open vSwitch Database. other_config : dscp: optional string, containing an integer The Differentiated Service Code Point (DSCP) is specified using 6 bits in the Type of Service (TOS) field in the IP header. DSCP provides a mechanism to classify the network traffic and provide Quality of Service (QoS) on IP networks. The DSCP value speci‐ fied here is used when establishing the connection between the manager and the Open vSwitch. If no value is specified, a de‐ fault value of 48 is chosen. Valid DSCP values must be in the range 0 to 63. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs other_config: map of string-string pairs NetFlow TABLE A NetFlow target. NetFlow is a protocol that exports a number of de‐ tails about terminating IP flows, such as the principals involved and duration. Summary: targets set of 1 or more strings engine_id optional integer, in range 0 to 255 engine_type optional integer, in range 0 to 255 active_timeout integer, at least -1 add_id_to_interface boolean Common Columns: external_ids map of string-string pairs Details: targets: set of 1 or more strings NetFlow targets in the form ip:port. The ip must be specified numerically, not as a DNS name. engine_id: optional integer, in range 0 to 255 Engine ID to use in NetFlow messages. Defaults to datapath index if not specified. engine_type: optional integer, in range 0 to 255 Engine type to use in NetFlow messages. Defaults to datapath in‐ dex if not specified. active_timeout: integer, at least -1 The interval at which NetFlow records are sent for flows that are still active, in seconds. A value of 0 requests the default timeout (currently 600 seconds); a value of -1 disables active timeouts. The NetFlow passive timeout, for flows that become inactive, is not configurable. It will vary depending on the Open vSwitch version, the forms and contents of the OpenFlow flow tables, CPU and memory usage, and network activity. A typical passive time‐ out is about a second. add_id_to_interface: boolean If this column’s value is false, the ingress and egress inter‐ face fields of NetFlow flow records are derived from OpenFlow port numbers. When it is true, the 7 most significant bits of these fields will be replaced by the least significant 7 bits of the engine id. This is useful because many NetFlow collectors do not expect multiple switches to be sending messages from the same host, so they do not store the engine information which could be used to disambiguate the traffic. When this option is enabled, a maximum of 508 ports are sup‐ ported. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs Datapath TABLE Configuration for a datapath within Open_vSwitch. A datapath is responsible for providing the packet handling in Open vSwitch. There are two primary datapath implementations used by Open vSwitch: kernel and userspace. Kernel datapath implementations are available for Linux and Hyper-V, and selected as system in the data‐ path_type column of the Bridge table. The userspace datapath is used by DPDK and AF-XDP, and is selected as netdev in the datapath_type column of the Bridge table. A datapath of a particular type is shared by all the bridges that use that datapath. Thus, configurations applied to this table affect all bridges that use this datapath. Summary: datapath_version string ct_zones map of integer-CT_Zone pairs, key in range 0 to 65,535 Capabilities: capabilities : max_vlan_headers optional string, containing an integer, at least 0 capabilities : recirc optional string, either true or false capabilities : lb_output_action optional string, either true or false Connection-Tracking Capabilities: capabilities : ct_state optional string, either true or false capabilities : ct_state_nat optional string, either true or false capabilities : ct_zone optional string, either true or false capabilities : ct_mark optional string, either true or false capabilities : ct_label optional string, either true or false capabilities : ct_orig_tuple optional string, either true or false capabilities : ct_orig_tuple6 optional string, either true or false capabilities : masked_set_action optional string, either true or false capabilities : tnl_push_pop optional string, either true or false capabilities : ufid optional string, either true or false capabilities : trunc optional string, either true or false capabilities : nd_ext optional string, either true or false Clone Actions: capabilities : clone optional string, either true or false capabilities : sample_nesting optional string, containing an integer, at least 0 capabilities : ct_eventmask optional string, either true or false capabilities : ct_clear optional string, either true or false capabilities : max_hash_alg optional string, containing an integer, at least 0 capabilities : check_pkt_len optional string, either true or false capabilities : ct_timeout optional string, either true or false capabilities : explicit_drop_action optional string, either true or false capabilities : ct_zero_snat optional string, either true or false capabilities : ct_flush optional string, either true or false ct_zone_default_limit optional integer, in range 0 to 4,294,967,295 Common Columns: external_ids map of string-string pairs Details: datapath_version: string Reports the version number of the Open vSwitch datapath in use. This allows management software to detect and report discrepan‐ cies between Open vSwitch userspace and datapath versions. (The ovs_version column in the Open_vSwitch reports the Open vSwitch userspace version.) The version reported depends on the datapath in use: • When the kernel module included in the Open vSwitch source tree is used, this column reports the Open vSwitch version from which the module was taken. • When the kernel module that is part of the upstream Linux kernel is used, this column reports . • When the datapath is built into the ovs-vswitchd binary, this column reports . A built-in datapath is by definition the same version as the rest of the Open vSwitch userspace. • Other datapaths (such as the Hyper-V kernel datapath) currently report . A version discrepancy between ovs-vswitchd and the datapath in use is not normally cause for alarm. The Open vSwitch kernel datapaths for Linux and Hyper-V, in particular, are designed for maximum inter-version compatibility: any userspace version works with with any kernel version. Some reasons do exist to insist on particular user/kernel pairings. First, newer kernel versions add new features, that can only be used by new-enough userspace, e.g. VXLAN tunneling requires certain minimal userspace and ker‐ nel versions. Second, as an extension to the first reason, some newer kernel versions add new features for enhancing performance that only new-enough userspace versions can take advantage of. ct_zones: map of integer-CT_Zone pairs, key in range 0 to 65,535 Configuration for connection tracking zones. Each pair maps from a zone id to a configuration for that zone. Zone 0 applies to the default zone (ie, the one used if a zone is not specified in connection tracking-related OpenFlow matches and actions). Capabilities: The capabilities column reports a datapath’s features. For the netdev datapath, the capabilities are fixed for a given version of Open vSwitch because this datapath is built into the ovs-vswitchd binary. The Linux kernel and Windows and other datapaths, which are external to OVS userspace, can vary in version and capabilities independently from ovs-vswitchd. Some of these features indicate whether higher-level Open vSwitch fea‐ tures are available. For example, OpenFlow features for connection- tracking are available only when capabilities:ct_state is true. A con‐ troller that wishes to determine whether a feature is supported could, therefore, consult the relevant capabilities in this table. However, as a general rule, it is better for a controller to try to use the higher- level feature and use the result as an indication of support, since the low-level capabilities are more likely to shift over time than the high-level features that rely on them. capabilities : max_vlan_headers: optional string, containing an inte‐ ger, at least 0 Number of 802.1q VLAN headers supported by the datapath, as probed by the ovs-vswitchd slow path. If the datapath supports more VLAN headers than the slow path, this reports the slow path’s limit. The value of other-config:vlan-limit in the Open_vSwitch table does not influence the number reported here. capabilities : recirc: optional string, either true or false If this is true, then the datapath supports recirculation, specifically OVS_KEY_ATTR_RECIRC_ID. Recirculation enables higher performance for MPLS and active-active load balancing bonding modes. capabilities : lb_output_action: optional string, either true or false If this is true, then the datapath supports optimized balance- tcp bond mode. This capability replaces existing hash and recirc actions with new action lb_output and avoids recirculation of packet in datapath. It is supported only for balance-tcp bond mode in netdev datapath. The new action gives higher performance by using bond buckets instead of post recirculation flows for selection of slave port from bond. By default this new action is disabled, however it can be enabled by setting other-config:lb- output-action in Port table. Connection-Tracking Capabilities: These capabilities are granular because Open vSwitch and its datapaths added support for connection tracking over several releases, with fea‐ tures added individually over that time. capabilities : ct_state: optional string, either true or false If true, datapath supports OVS_KEY_ATTR_CT_STATE, which indi‐ cates support for the bits in the OpenFlow ct_state field (see ovs-fields(7)) other than snat and dnat, which have a separate capability. If this is false, the datapath does not support connection- tracking at all and the remaining connection-tracking capabili‐ ties should all be false. In this case, Open vSwitch will reject flows that match on the ct_state field or use the ct action. capabilities : ct_state_nat: optional string, either true or false If true, it means that the datapath supports the snat and dnat flags in the OpenFlow ct_state field. The ct_state capability must be true for this to make sense. If false, Open vSwitch will reject flows that match on the snat or dnat bits in ct_state or use nat in the ct action. capabilities : ct_zone: optional string, either true or false If true, datapath supports OVS_KEY_ATTR_CT_ZONE. If false, Open vSwitch rejects flows that match on the ct_zone field or that specify a nonzero zone or a zone field on the ct action. capabilities : ct_mark: optional string, either true or false If true, datapath supports OVS_KEY_ATTR_CT_MARK. If false, Open vSwitch rejects flows that match on the ct_mark field or that set ct_mark in the ct action. capabilities : ct_label: optional string, either true or false If true, datapath supports OVS_KEY_ATTR_CT_LABEL. If false, Open vSwitch rejects flows that match on the ct_label field or that set ct_label in the ct action. capabilities : ct_orig_tuple: optional string, either true or false If true, the datapath supports matching the 5-tuple from the connection’s original direction for IPv4 traffic. If false, Open vSwitch rejects flows that match on ct_nw_src or ct_nw_dst, that use the ct feature of the resubmit action, or the force keyword in the ct action. (The latter isn’t tied to connection tracking support of original tuples in any technical way. They are con‐ flated because all current datapaths implemented the two fea‐ tures at the same time.) If this and capabilities:ct_orig_tuple6 are both false, Open vSwitch rejects flows that match on ct_nw_proto, ct_tp_src, or ct_tp_dst. capabilities : ct_orig_tuple6: optional string, either true or false If true, the datapath supports matching the 5-tuple from the connection’s original direction for IPv6 traffic. If false, Open vSwitch rejects flows that match on ct_ipv6_src or ct_ipv6_dst. capabilities : masked_set_action: optional string, either true or false True if the datapath supports masked data in OVS_ACTION_ATTR_SET actions. Masked data can improve performance by allowing megaflows to match on fewer fields. capabilities : tnl_push_pop: optional string, either true or false True if the datapath supports tnl_push and pop actions. This is a prerequisite for a datapath to support native tunneling. capabilities : ufid: optional string, either true or false True if the datapath supports OVS_FLOW_ATTR_UFID. UFID support improves revalidation performance by transferring less data be‐ tween the slow path and the datapath. capabilities : trunc: optional string, either true or false True if the datapath supports OVS_ACTION_ATTR_TRUNC action. If false, the output action with packet truncation requires every packet to be sent to the Open vSwitch slow path, which is likely to make it too slow for mirroring traffic in bulk. capabilities : nd_ext: optional string, either true or false True if the datapath supports OVS_KEY_ATTR_ND_EXTENSIONS to match on ICMPv6 "ND reserved" and "ND option type" header fields. If false, the datapath reports error if the feature is used. Clone Actions: When Open vSwitch translates actions from OpenFlow into the datapath representation, some of the datapath actions may modify the packet or have other side effects that later datapath actions can’t undo. The OpenFlow ct, meter, output with truncation, encap, decap, and dec_nsh_ttl actions fall into this category. Often, this is not a prob‐ lem because nothing later on needs the original packet. Such actions can, however, occur in circumstances where the translation does require the original packet. For example, an OpenFlow output ac‐ tion might direct a packet to a patch port, which might in turn lead to a ct action that NATs the packet (which cannot be undone), and then af‐ terward when control flow pops back across the patch port some other action might need to act on the original packet. Open vSwitch has two different ways to implement this ``save and re‐ store’’ via datapath actions. These capabilities indicate which one Open vSwitch will choose. When neither is available, Open vSwitch sim‐ ply fails in situations that require this feature. capabilities : clone: optional string, either true or false True if the datapath supports OVS_ACTION_ATTR_CLONE action. This is the preferred option for saving and restoring packets, since it is intended for the purpose, but old datapaths do not support it. Open vSwitch will use it whenever it is available. (The OpenFlow clone action does not always yield a OVS_AC‐ TION_ATTR_CLONE action. It only does so when the datapath sup‐ ports it and the clone brackets actions that otherwise cannot be undone.) capabilities : sample_nesting: optional string, containing an integer, at least 0 Maximum level of nesting allowed by OVS_ACTION_ATTR_SAMPLE ac‐ tion. Open vSwitch misuses this action for saving and restoring packets when the datapath supports more than 3 levels of nesting and OVS_ACTION_ATTR_CLONE is not available. capabilities : ct_eventmask: optional string, either true or false True if the datapath’s OVS_ACTION_ATTR_CT action implements the OVS_CT_ATTR_EVENTMASK attribute. When this is true, Open vSwitch uses the event mask feature to limit the kinds of events re‐ ported to conntrack update listeners. When Open vSwitch doesn’t limit the event mask, listeners receive reports of numerous usu‐ ally unimportant events, such as TCP state machine changes, which can waste CPU time. capabilities : ct_clear: optional string, either true or false True if the datapath supports OVS_ACTION_ATTR_CT_CLEAR action. If false, the OpenFlow ct_clear action has no effect on the datapath. capabilities : max_hash_alg: optional string, containing an integer, at least 0 Highest supported dp_hash algorithm. This allows Open vSwitch to avoid requesting a packet hash that the datapath does not sup‐ port. capabilities : check_pkt_len: optional string, either true or false True if the datapath supports OVS_ACTION_ATTR_CHECK_PKT_LEN. If false, Open vSwitch implements the check_pkt_larger action by sending every packet through the Open vSwitch slow path, which is likely to make it too slow for handling traffic in bulk. capabilities : ct_timeout: optional string, either true or false True if the datapath supports OVS_CT_ATTR_TIMEOUT in the OVS_AC‐ TION_ATTR_CT action. If false, Open vswitch cannot implement timeout policies based on connection tracking zones, as config‐ ured through the CT_Timeout_Policy table. capabilities : explicit_drop_action: optional string, either true or false True if the datapath supports OVS_ACTION_ATTR_DROP. If false, explicit drop action will not be sent to the datapath. capabilities : ct_zero_snat: optional string, either true or false True if the datapath supports all-zero SNAT. This is a special case if the src IP address is configured as all 0’s, i.e., nat(src=0.0.0.0). In this case, when a source port collision is detected during the commit, the source port will be translated to an ephemeral port. If there is no collision, no SNAT is per‐ formed. capabilities : ct_flush: optional string, either true or false True if the datapath supports CT flush OpenFlow Nicira extension called NXT_CT_FLUSH. The NXT_CT_FLUSH extensions allows to flush CT entries based on specified parameters. ct_zone_default_limit: optional integer, in range 0 to 4,294,967,295 Default connection tracking zone limit that is applied to all zones that didn’t specify the limit explicitly. If the limit is unspecified the default limit configuration for the datapath is left intact. The value 0 means unlimited. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs CT_Zone TABLE Connection tracking zone configuration Summary: timeout_policy optional CT_Timeout_Policy limit optional integer, in range 0 to 4,294,967,295 Common Columns: external_ids map of string-string pairs Details: timeout_policy: optional CT_Timeout_Policy Connection tracking timeout policy for this zone. If a timeout policy is not specified, it defaults to the timeout policy in the system. limit: optional integer, in range 0 to 4,294,967,295 Connection tracking limit for this zone. If the limit is unspec‐ ified the ct_zone_default_limit will be used. The value 0 means unlimited. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs CT_Timeout_Policy TABLE Connection tracking timeout policy configuration Summary: Timeouts: timeouts map of string-integer pairs, key one of icmp_first, icmp_reply, tcp_close, tcp_close_wait, tcp_established, tcp_fin_wait, tcp_last_ack, tcp_retrans‐ mit, tcp_syn_recv, tcp_syn_sent2, tcp_syn_sent, tcp_time_wait, tcp_unack, udp_first, udp_multiple, or udp_single, value in range 0 to 4,294,967,295 TCP Timeouts: timeouts : tcp_syn_sent optional integer, in range 0 to 4,294,967,295 timeouts : tcp_syn_recv optional integer, in range 0 to 4,294,967,295 timeouts : tcp_established optional integer, in range 0 to 4,294,967,295 timeouts : tcp_fin_wait optional integer, in range 0 to 4,294,967,295 timeouts : tcp_close_wait optional integer, in range 0 to 4,294,967,295 timeouts : tcp_last_ack optional integer, in range 0 to 4,294,967,295 timeouts : tcp_time_wait optional integer, in range 0 to 4,294,967,295 timeouts : tcp_close optional integer, in range 0 to 4,294,967,295 timeouts : tcp_syn_sent2 optional integer, in range 0 to 4,294,967,295 timeouts : tcp_retransmit optional integer, in range 0 to 4,294,967,295 timeouts : tcp_unack optional integer, in range 0 to 4,294,967,295 UDP Timeouts: timeouts : udp_first optional integer, in range 0 to 4,294,967,295 timeouts : udp_single optional integer, in range 0 to 4,294,967,295 timeouts : udp_multiple optional integer, in range 0 to 4,294,967,295 ICMP Timeouts: timeouts : icmp_first optional integer, in range 0 to 4,294,967,295 timeouts : icmp_reply optional integer, in range 0 to 4,294,967,295 Common Columns: external_ids map of string-string pairs Details: Timeouts: timeouts: map of string-integer pairs, key one of icmp_first, icmp_re‐ ply, tcp_close, tcp_close_wait, tcp_established, tcp_fin_wait, tcp_last_ack, tcp_retransmit, tcp_syn_recv, tcp_syn_sent2, tcp_syn_sent, tcp_time_wait, tcp_unack, udp_first, udp_multiple, or udp_single, value in range 0 to 4,294,967,295 The timeouts column contains key-value pairs used to configure connection tracking timeouts in a datapath. Key-value pairs that are not supported by a datapath are ignored. The timeout value is in seconds. TCP Timeouts: timeouts : tcp_syn_sent: optional integer, in range 0 to 4,294,967,295 The timeout for the connection after the first TCP SYN packet has been seen by conntrack. timeouts : tcp_syn_recv: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first TCP SYN-ACK packet has been seen by conntrack. timeouts : tcp_established: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the connection has been fully established. timeouts : tcp_fin_wait: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first TCP FIN packet has been seen by conntrack. timeouts : tcp_close_wait: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first TCP ACK packet has been seen after it receives TCP FIN packet. This timeout is only supported by the Linux kernel datapath. timeouts : tcp_last_ack: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after TCP FIN packets have been seen by conntrack from both directions. This timeout is only supported by the Linux kernel datapath. timeouts : tcp_time_wait: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after conntrack has seen the TCP ACK packet for the second TCP FIN packet. timeouts : tcp_close: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first TCP RST packet has been seen by conntrack. timeouts : tcp_syn_sent2: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when only a TCP SYN packet has been seen by conntrack from both directions (simultaneous open). This timeout is only supported by the Linux kernel datapath. timeouts : tcp_retransmit: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when it exceeds the maximum number of retransmissions. This timeout is only supported by the Linux kernel datapath. timeouts : tcp_unack: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when non-SYN packets create an es‐ tablished connection in TCP loose tracking mode. This timeout is only supported by the Linux kernel datapath. UDP Timeouts: timeouts : udp_first: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first UDP packet has been seen by conntrack. This timeout is only supported by the userspace datapath. timeouts : udp_single: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when conntrack only seen UDP packet from the source host, but the destination host has never sent one back. timeouts : udp_multiple: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when UDP packets have been seen in both directions. ICMP Timeouts: timeouts : icmp_first: optional integer, in range 0 to 4,294,967,295 The timeout of the connection after the first ICMP packet has been seen by conntrack. timeouts : icmp_reply: optional integer, in range 0 to 4,294,967,295 The timeout of the connection when ICMP packets have been seen in both direction. This timeout is only supported by the userspace datapath. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs SSL TABLE SSL configuration for an Open_vSwitch. Summary: private_key string certificate string ca_cert string bootstrap_ca_cert boolean Common Columns: external_ids map of string-string pairs Details: private_key: string Name of a PEM file containing the private key used as the switch’s identity for SSL connections to the controller. certificate: string Name of a PEM file containing a certificate, signed by the cer‐ tificate authority (CA) used by the controller and manager, that certifies the switch’s private key, identifying a trustworthy switch. ca_cert: string Name of a PEM file containing the CA certificate used to verify that the switch is connected to a trustworthy controller. bootstrap_ca_cert: boolean If set to true, then Open vSwitch will attempt to obtain the CA certificate from the controller on its first SSL connection and save it to the named PEM file. If it is successful, it will im‐ mediately drop the connection and reconnect, and from then on all SSL connections must be authenticated by a certificate signed by the CA certificate thus obtained. This option exposes the SSL connection to a man-in-the-middle attack obtaining the initial CA certificate. It may still be useful for bootstrap‐ ping. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs sFlow TABLE A set of sFlow(R) targets. sFlow is a protocol for remote monitoring of switches. Summary: agent optional string header optional integer polling optional integer sampling optional integer targets set of 1 or more strings Common Columns: external_ids map of string-string pairs Details: agent: optional string Determines the agent address, that is, the IP address reported to collectors as the source of the sFlow data. It may be an IP address or the name of a network device. In the latter case, the network device’s IP address is used, If not specified, the agent device is figured from the first target address and the routing table. If the routing table does not contain a route to the target, the IP address defaults to the local_ip in the collector’s Controller. If an agent IP address cannot be determined, sFlow is disabled. header: optional integer Number of bytes of a sampled packet to send to the collector. If not specified, the default is 128 bytes. polling: optional integer Polling rate in seconds to send port statistics to the collec‐ tor. If not specified, defaults to 30 seconds. sampling: optional integer Rate at which packets should be sampled and sent to the collec‐ tor. If not specified, defaults to 400, which means one out of 400 packets, on average, will be sent to the collector. targets: set of 1 or more strings sFlow targets in the form ip:port. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs IPFIX TABLE Configuration for sending packets to IPFIX collectors. IPFIX is a protocol that exports a number of details about flows. The IPFIX implementation in Open vSwitch samples packets at a configurable rate, extracts flow information from those packets, optionally caches and aggregates the flow information, and sends the result to one or more collectors. IPFIX in Open vSwitch can be configured two different ways: • With per-bridge sampling, Open vSwitch performs IPFIX sampling automatically on all packets that pass through a bridge. To configure per-bridge sampling, create an IPFIX record and point a Bridge table’s ipfix column to it. The Flow_Sample_Collector_Set table is not used for per- bridge sampling. • With flow-based sampling, sample actions in the OpenFlow flow table drive IPFIX sampling. See ovs-actions(7) for a description of the sample action. Flow-based sampling also requires database configuration: create a IPFIX record that describes the IPFIX configura‐ tion and a Flow_Sample_Collector_Set record that points to the Bridge whose flow table holds the sample actions and to IPFIX record. The ipfix in the Bridge table is not used for flow-based sampling. Summary: targets set of strings cache_active_timeout optional integer, in range 0 to 4,200 cache_max_flows optional integer, in range 0 to 4,294,967,295 stats_interval optional integer, in range 1 to 3,600 template_interval optional integer, in range 1 to 3,600 other_config : enable-tunnel-sampling optional string, either true or false other_config : virtual_obs_id optional string Per-Bridge Sampling: sampling optional integer, in range 1 to 4,294,967,295 obs_domain_id optional integer, in range 0 to 4,294,967,295 obs_point_id optional integer, in range 0 to 4,294,967,295 other_config : enable-input-sampling optional string, either true or false other_config : enable-output-sampling optional string, either true or false Common Columns: external_ids map of string-string pairs Details: targets: set of strings IPFIX target collectors in the form ip:port. cache_active_timeout: optional integer, in range 0 to 4,200 The maximum period in seconds for which an IPFIX flow record is cached and aggregated before being sent. If not specified, de‐ faults to 0. If 0, caching is disabled. cache_max_flows: optional integer, in range 0 to 4,294,967,295 The maximum number of IPFIX flow records that can be cached at a time. If not specified, defaults to 0. If 0, caching is dis‐ abled. stats_interval: optional integer, in range 1 to 3,600 Interval (in seconds) for sending IPFIX exporting process sta‐ tistics according to IETF RFC 5101 Section 4.3. Default value is 600 template_interval: optional integer, in range 1 to 3,600 Interval (in seconds) for sending IPFIX Template information for each Observation Domain ID. Default value is 600 other_config : enable-tunnel-sampling: optional string, either true or false Set to true to enable sampling and reporting tunnel header 7-tu‐ ples in IPFIX flow records. Tunnel sampling is enabled by de‐ fault. The following enterprise entities report the sampled tunnel info: tunnelType: ID: 891, and enterprise ID 6876 (VMware). type: unsigned 8-bit integer. data type semantics: identifier. description: Identifier of the layer 2 network overlay network encapsulation type: 0x01 VxLAN, 0x02 GRE, 0x03 LISP, 0x07 GENEVE. tunnelKey: ID: 892, and enterprise ID 6876 (VMware). type: variable-length octetarray. data type semantics: identifier. description: Key which is used for identifying an indi‐ vidual traffic flow within a VxLAN (24-bit VNI), GENEVE (24-bit VNI), GRE (32-bit key), or LISP (24-bit instance ID) tunnel. The key is encoded in this octetarray as a 3-, 4-, or 8-byte integer ID in network byte order. tunnelSourceIPv4Address: ID: 893, and enterprise ID 6876 (VMware). type: unsigned 32-bit integer. data type semantics: identifier. description: The IPv4 source address in the tunnel IP packet header. tunnelDestinationIPv4Address: ID: 894, and enterprise ID 6876 (VMware). type: unsigned 32-bit integer. data type semantics: identifier. description: The IPv4 destination address in the tunnel IP packet header. tunnelProtocolIdentifier: ID: 895, and enterprise ID 6876 (VMware). type: unsigned 8-bit integer. data type semantics: identifier. description: The value of the protocol number in the tun‐ nel IP packet header. The protocol number identifies the tunnel IP packet payload type. tunnelSourceTransportPort: ID: 896, and enterprise ID 6876 (VMware). type: unsigned 16-bit integer. data type semantics: identifier. description: The source port identifier in the tunnel transport header. For the transport protocols UDP, TCP, and SCTP, this is the source port number given in the re‐ spective header. tunnelDestinationTransportPort: ID: 897, and enterprise ID 6876 (VMware). type: unsigned 16-bit integer. data type semantics: identifier. description: The destination port identifier in the tun‐ nel transport header. For the transport protocols UDP, TCP, and SCTP, this is the destination port number given in the respective header. Before Open vSwitch 2.5.90, other_config:enable-tunnel-sampling was only supported with per-bridge sampling, and ignored other‐ wise. Open vSwitch 2.5.90 and later support other_config:enable- tunnel-sampling for per-bridge and per-flow sampling. other_config : virtual_obs_id: optional string A string that accompanies each IPFIX flow record. Its intended use is for the ``virtual observation ID,’’ an identifier of a virtual observation point that is locally unique in a virtual network. It describes a location in the virtual network where IP packets can be observed. The maximum length is 254 bytes. If not specified, the field is omitted from the IPFIX flow record. The following enterprise entity reports the specified virtual observation ID: virtualObsID: ID: 898, and enterprise ID 6876 (VMware). type: variable-length string. data type semantics: identifier. description: A virtual observation domain ID that is lo‐ cally unique in a virtual network. This feature was introduced in Open vSwitch 2.5.90. Per-Bridge Sampling: These values affect only per-bridge sampling. See above for a descrip‐ tion of the differences between per-bridge and flow-based sampling. sampling: optional integer, in range 1 to 4,294,967,295 The rate at which packets should be sampled and sent to each target collector. If not specified, defaults to 400, which means one out of 400 packets, on average, will be sent to each target collector. obs_domain_id: optional integer, in range 0 to 4,294,967,295 The IPFIX Observation Domain ID sent in each IPFIX packet. If not specified, defaults to 0. obs_point_id: optional integer, in range 0 to 4,294,967,295 The IPFIX Observation Point ID sent in each IPFIX flow record. If not specified, defaults to 0. other_config : enable-input-sampling: optional string, either true or false By default, Open vSwitch samples and reports flows at bridge port input in IPFIX flow records. Set this column to false to disable input sampling. other_config : enable-output-sampling: optional string, either true or false By default, Open vSwitch samples and reports flows at bridge port output in IPFIX flow records. Set this column to false to disable output sampling. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs Flow_Sample_Collector_Set TABLE A set of IPFIX collectors of packet samples generated by OpenFlow sam‐ ple actions. This table is used only for IPFIX flow-based sampling, not for per-bridge sampling (see the IPFIX table for a description of the two forms). Summary: id integer, in range 0 to 4,294,967,295 bridge Bridge ipfix optional IPFIX Common Columns: external_ids map of string-string pairs Details: id: integer, in range 0 to 4,294,967,295 The ID of this collector set, unique among the bridge’s collec‐ tor sets, to be used as the collector_set_id in OpenFlow sample actions. bridge: Bridge The bridge into which OpenFlow sample actions can be added to send packet samples to this set of IPFIX collectors. ipfix: optional IPFIX Configuration of the set of IPFIX collectors to send one flow record per sampled packet to. Common Columns: The overall purpose of these columns is described under Common Columns at the beginning of this document. external_ids: map of string-string pairs AutoAttach TABLE Auto Attach configuration within a bridge. The IETF Auto-Attach SPBM draft standard describes a compact method of using IEEE 802.1AB Link Layer Discovery Protocol (LLDP) together with a IEEE 802.1aq Shortest Path Bridging (SPB) network to automatically attach network devices to individual services in a SPB network. The intent here is to allow net‐ work applications and devices using OVS to be able to easily take ad‐ vantage of features offered by industry standard SPB networks. Auto Attach (AA) uses LLDP to communicate between a directly connected Auto Attach Client (AAC) and Auto Attach Server (AAS). The LLDP proto‐ col is extended to add two new Type-Length-Value tuples (TLVs). The first new TLV supports the ongoing discovery of directly connected AA correspondents. Auto Attach operates by regularly transmitting AA dis‐ covery TLVs between the AA client and AA server. By exchanging these discovery messages, both the AAC and AAS learn the system name and sys‐ tem description of their peer. In the OVS context, OVS operates as the AA client and the AA server resides on a switch at the edge of the SPB network. Once AA discovery has been completed the AAC then uses the second new TLV to deliver identifier mappings from the AAC to the AAS. A primary feature of Auto Attach is to facilitate the mapping of VLANs defined outside the SPB network onto service ids (ISIDs) defined within the SPM network. By doing so individual external VLANs can be mapped onto spe‐ cific SPB network services. These VLAN id to ISID mappings can be con‐ figured and managed locally using new options added to the ovs-vsctl command. The Auto Attach OVS feature does not provide a full implementation of the LLDP protocol. Support for the mandatory TLVs as defined by the LLDP standard and support for the AA TLV extensions is provided. LLDP protocol support in OVS can be enabled or disabled on a port by port basis. LLDP support is disabled by default. Summary: system_name string system_description string mappings map of integer-integer pairs, key in range 0 to 16,777,215, value in range 0 to 4,095 Details: system_name: string The system_name string is exported in LLDP messages. It should uniquely identify the bridge in the network. system_description: string The system_description string is exported in LLDP messages. It should describe the type of software and hardware. mappings: map of integer-integer pairs, key in range 0 to 16,777,215, value in range 0 to 4,095 A mapping from SPB network Individual Service Identifier (ISID) to VLAN id. Open vSwitch 3.3.0 DB Schema 8.5.0 ovs-vswitchd.conf.db(5)