Common Columns¶

Most tables contain two special columns, named other_config and external_ids. These columns have the same form and purpose each place that they appear, so we describe them here to save space later.

Summary:¶

Configuration:

Status:

Version Reporting:

Capabilities:

Database Configuration:

IPsec:

Common Columns:

Details:¶

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_config: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 milliseconds. This option will affect the update of the statistics column 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 datapath and re-setup the flows.

Additionally, ovs-vswitchd is prevented from connecting to controllers when this value is set to true. This prevents controllers 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 reconnect to controllers and process any new flow table modifications.

Thus, with this option, the procedure for a hot-upgrade of ovs-vswitchd becomes roughly the following:

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 activity for datapath flows regularly and may expire flows quicker 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 10000.

other_config : max-revalidator: optional string, containing an integer, at least 100

The maximum time (in ms) that revalidator threads will wait before executing flow revalidation. Note that this is maximum allowed 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 integer, at least 1

Set minimum pps that flow must have in order to be revalidated when revalidation duration exceeds half of max-revalidator config variable.

The default is 5.

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 functionality 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 integer, in range 1 to 10

Set this value to the number of threads created to manage hardware 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:

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 initialized.

The default value is false. Changing this value requires restarting the daemon

If this value is false at startup, any dpdk ports which are configured 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 default.

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 default value for each numa node. DPDK defaults will be used instead. If other_config:dpdk-socket-mem and other_config:dpdk-alloc-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 (default is /dev/hugepages). Changing this value requires restarting 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 sockets 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 migration 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 mempool. 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-mempool-mtu-list>

where

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 integer, 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 analysis 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 useful 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:

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-affinity 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 integer, at least 1

Attempts to specify the number of threads for software datapaths to use for handling new flows. Some datapaths may choose to ignore this and it will be set to a sensible option for the datapath 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 integer, 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 result 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 insertion.

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 payload, 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 maintains 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 integer, 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 offloading 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 assignment 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 Balancing 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 cycles) of any non-isolated PMD threads when a PMD Auto Load Balance may be triggered.

The default value is 95%.

other_config : pmd-auto-lb-improvement-threshold: optional string, containing an integer, in range 0 to 100

Specifies the minimum evaluated % improvement in load distribution 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-maxsleep: optional string, containing an integer, in range 0 to 10,000

Specifies the maximum sleep time that will be requested in microseconds 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 : userspace-tso-enable: optional string, either true or false

Set this value to true to enable userspace support for TCP Segmentation 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 calculation 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 support.

The feature is considered experimental.

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 library is successfully initialized.

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 common 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 running, as an integer. This may be less than the number installed, if some are not online or if they are not available to the operating 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, representing the system load average over the last 1, 5, and 15 minutes, 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:

On Linux, all five values can be determined and are included. On other operating systems, only the first two values can be determined, 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:

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 always 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:

This key-value pair is omitted if there are no local, writable file systems or if Open vSwitch cannot obtain the needed information.

These columns report the types and versions of the hardware and software running Open vSwitch. We recommend in general that software should test whether specific features are supported instead of relying on version 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.

These columns report capabilities of the Open vSwitch instance.

datapath_types: set of strings

This column reports the different dpifs registered with the system. 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.

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 determine 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 configured to honor it. The easiest way to do this is to invoke ovsdb-server with the option --remote=db:Open_vSwitch,Open_vSwitch,manager_options The startup scripts that accompany Open vSwitch do this by default.

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. Currently, all IPsec tunnels must use the same form:

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 alternative 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.

When an IPsec tunnel is configured in this database, multiple independent 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 configuration completes before the latter, then packets sent by the local host over the tunnel can be transmitted in plaintext. Using this setting, 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 enabled for the tunnel, the type of tunnel, or whether OVS is involved.

Example policies:

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

Summary:¶

Core Features:

OpenFlow Configuration:

Spanning Tree Configuration:

Rapid Spanning Tree:

Multicast Snooping Configuration:

Other Features:

Common Columns:

Details:¶

name: immutable string (must be unique within table)

Bridge identifier. Must be unique among the names of ports, interfaces, 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 Interface 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 disabled, so that packets are flooded instead of being sent to specific 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 incompatible with flood_vlans. Consider using another bonding mode or a different type of mirror instead.

auto_attach: optional AutoAttach

Auto Attach 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 removing 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 OpenFlow 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 determines the switch’s response to such a situation. It may be set to one of the following:

The default is standalone if the value is unset, but future versions 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-config:datapath-id instead.)

datapath_version: string

Reports the datapath version. This column is maintained for backwards compatibility. The preferred locatation is the datapath_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 debugging 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 returned by the switch as a part of reply to OFPMP_DESC request (ofp_desc). Same as mentioned in the description of other-config:dp-desc, the string should be no more than 31 ASCII characters 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 instead.

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.

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 supported 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_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 designated ports, in seconds. By default the hello interval is 2 seconds.

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 integer, in range 4 to 30

The delay to wait between transitioning root and designated ports to forwarding, in seconds. By default, the forwarding delay 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 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.

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.

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 differ.

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 Protocol (RSTP), like STP, is a network protocol that ensures loop-free topologies. RSTP superseded STP with the publication of 802.1D-2004. Compared to STP, RSTP converges more quickly and recovers more quickly from failures.

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 integer, 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 integer, 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.

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 system 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_status: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 integer, 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_status: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 (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 connected 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.

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 unset, 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:

Set this option to true if the Open vSwitch bridge connects different Ethernet networks and is not configured to participate in STP.

This option affects packets with the following destination MAC addresses:

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 unnecessarily, when they are addressed to a connected host that rarely transmits packets. To reduce the incidence of unnecessary flooding, 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 reasonable range, currently 10 to 1,000,000.

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

Summary:¶

name

immutable string (must be unique within table)

interfaces

set of 1 or more Interfaces

VLAN Configuration:

Bonding Configuration:

Spanning Tree Protocol:

Rapid Spanning Tree Protocol:

Multicast Snooping:

Other Features:

bond_active_slave

optional string

Port Statistics:

Common Columns:

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 Interface 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.

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:

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:

tag: optional integer, in range 0 to 4,095

For an access port, the port’s implicitly tagged VLAN. For a native-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 includes. 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 itself. 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 default 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-nonzero, 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 default Open vSwitch does not output priority-tagged frames, instead 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.

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:

The following modes require the upstream switch to support 802.3ad with successful LACP negotiation. If LACP negotiation fails and other-config:lacp-fallback-ab is true, then active-backup mode is used:

These columns apply only to bonded ports. Their values are otherwise ignored.

bond_mode: optional string, one of active-backup, balance-slb, or balance-tcp

The type of bonding used for a bonded port. Defaults to active-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 decisions to change. Does not affect bonding modes which do not employ 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 balance-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_config:bond_mode is active-backup or if balance-tcp falls back to active-backup (e.g., LACP negotiation fails and other_config:lacp-fallback-ab is true).

other_config : all-members-active: optional string, either true or false

Enable/Disable delivery of broadcast/multicast packets on secondary interface of a balance-slb bond. Relevant only when lacp is off.

This parameter is identical to all_slaves_active for Linux kernel bonds. Disabled by default as it is not a desirable configuration for most users.

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 miimon

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 integer

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, the Link Aggregation Control Protocol, is an IEEE standard that allows switches to automatically detect that they are connected by multiple 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 enabled 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 integer, 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 numerically 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 requested at a rate of once per second causing connectivity problems 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 option 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.

These settings control behavior when a bond is in balance-slb or balance-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 between successive attempts to rebalance the bond, that is, to move flows from one interface on the bond to another in an attempt 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.

The configuration here is only meaningful, and the status is only populated, when 802.1D-1998 Spanning Tree Protocol is enabled on the port’s Bridge with its stp_enable column.

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 default, 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 integer, 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.

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 section earlier.

status : stp_state: optional string, one of blocking, disabled, forwarding, 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.

The configuration here is only meaningful, and the status and statistics are only populated, when 802.1D-1998 Spanning Tree Protocol is enabled on the port’s Bridge with its stp_enable column.

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 integer, 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 significant 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 transmit 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 subsequently changing the value from false to true.

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, Discarding, 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_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.

other_config : mcast-snooping-flood: optional string, either true or false

If set to true, multicast packets (except Reports) are unconditionally 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.

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 reflect 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 designated as protected. Traffic between protected ports is blocked. Protected ports can send traffic to unprotected ports. Unprotected 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.

Key-value pairs that report port statistics. The update period is controlled by other_config:stats-update-interval in the Open_vSwitch table.

statistics : stp_tx_count: optional integer

Number of STP BPDUs sent on this port by the spanning tree library.

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.

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

Summary:¶

Core Features:

System-Specific Details:

Tunnel Options:

Tunnel Options: erspan only:

Tunnel Options: Bareudp only:

Patch Options:

PMD (Poll Mode Driver) Options:

EMC (Exact Match Cache) Configuration:

MTU:

Interface Status:

Statistics:

Ingress Policing:

Bidirectional Forwarding Detection (BFD):

Connectivity Fault Management:

Bonding Configuration:

Virtual Machine Identifiers:

Auto Attach Configuration:

Flow control Configuration:

Link State Change detection mode:

Common Columns:

Details:¶

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 underlying datapath:

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:

Some interfaces may not have a software-controllable MAC address. This option only affects internal ports. For other type ports, you can change the MAC address outside Open vSwitch, using 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.

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 OpenFlow 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 obtained, 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 controllers: 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 automatically assigned port number, Open vSwitch chooses a new port number for the latter port.

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:

These options apply to interfaces with type of geneve, bareudp, gre, ip6gre, vxlan, lisp and stt.

Each tunnel must be uniquely identified by the combination of type, options: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 tunnels. Hence it is not considered while identifying a bareudp tunnel.

options : remote_ip: optional string

Required. The remote tunnel endpoint, one of:

The remote tunnel endpoint for any packet received from a tunnel is available in the tun_src field for matching in the flow table.

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:

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. The key that received packets must contain, one of:

options : out_key: optional string

Optional, not applicable for bareudp. The key to be set on outgoing packets, one of:

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 encapsulating 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 default TTL.

options : df_default: optional string, either true or false

Optional. If enabled, the Don’t Fragment bit will be set on tunnel outer headers to allow path MTU discovery. Default is enabled; 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.

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:

options : exts: optional string

Optional. Comma separated list of optional VXLAN extensions to enable. The following extensions are supported:

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:

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:

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.

gre, ip6gre, geneve, bareudp and vxlan interfaces support these options.

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 validated 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.

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 containing 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 remote certificate.

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 platform 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.

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.

These options apply only to patch ports, that is, interfaces whose type column is patch. Patch ports are mainly a way to connect otherwise independent bridges to one another, similar to how one might plug an Ethernet 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.

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 supported 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=<rxq-affinity-list>

where

options : xdp-mode: optional string, one of best-effort, generic, native-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 requires device driver support and has the best performance because 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 allocation 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 unnecessary 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 interface. 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 supported by the hardware of the device being configured. If not specified or an incorrect value is specified, 2048 rx descriptors 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 supported by the hardware of the device being configured. If not specified or an incorrect value is specified, 2048 tx descriptors 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:

This option may only be used with dpdk VF representors.

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 number of Tx queues is greater than number of PMD threads, and dynamic (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 packets on all the transmit queues based on their 5-tuples hashes.

Defaults to thread.

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 processing packets received from this interface. If true, other_config:emc-insert-inv-prob will have effect on this interface.

Defaults to true.

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.

Status information about interfaces attached to bridges, updated every 5 seconds. Not all interfaces have all of these properties; virtual interfaces 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 ordinarily 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 status: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 available.

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 tunnels on Linux systems, this column will show the name of the interface which is responsible for routing traffic destined for the configured options:remote_ip. This could be an internal interface 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 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 : if_type: optional string

Interface type ID according to IANA ifTYPE MIB definitions.

status : if_descr: optional string

Interface description string.

status : pci-vendor_id: optional string

Vendor ID of PCI device.

status : pci-device_id: optional string

Device ID of PCI device.

Key-value pairs that report interface statistics. The current implementation updates these counters periodically. The update period is controlled by other_config:stats-update-interval in the Open_vSwitch table. Future implementations may update them when an interface is created, 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 periodic 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 : 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 : 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 : 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.

These settings control ingress policing for packets received on this interface. On a physical interface, this limits the rate at which traffic 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 packets 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’’ approach.

Byte rate policing:

Packet rate policing:

Policing interacts badly with some network protocols, and especially with fragmented IP packets. Suppose that there is enough network activity 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 possible 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 default) 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 forgiving, which is important for protocols like TCP that react severely to dropped packets. The burst size should be at least the size of the interface’s MTU. Specifying a value that is numerically 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_kpkts_rate is 0.

Specifying a larger burst size lets the algorithm be more forgiving, which is important for protocols like TCP that react severely to dropped packets. Specifying a value that is numerically at least as large as 80% of ingress_policing_kpkts_rate helps TCP come closer to achieving the full rate.

BFD, defined in RFC 5880 and RFC 5881, allows point-to-point detection of connectivity failures by occasional transmission of BFD control messages. Open vSwitch implements BFD to serve as a more popular and standards 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 connectivity fault if three consecutive BFD control messages fail to arrive. 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 Authentication 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.

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 session 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 session 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 incoming 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 whenever 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 typical 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 tunnel 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 default 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 packets. Packets with different destination MAC will not be considered as BFD packets. If not specified the destination MAC address 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.

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:enable, 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.

802.1ag Connectivity Fault Management (CFM) allows a group of Maintenance Points (MPs) called a Maintenance Association (MA) to detect connectivity problems with each other. MPs within a MA should have complete and exclusive interconnectivity. This is verified by occasionally broadcasting Continuity Check Messages (CCMs) at a configurable transmission 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 specification in this area. It simply assumes the link is faulted if no Remote Maintenance Points are reachable, and considers it not faulted otherwise.

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 between [1, 8191]. However, extended mode (see other_config:cfm_extended) supports eight byte MPIDs.

cfm_flap_count: optional integer

Counts the number of cfm fault flapps since boot. A flap is considered to be a change of the cfm_fault value.

cfm_fault: optional boolean

Indicates a connectivity fault triggered by an inability to receive heartbeats from any remote endpoint. When a fault is triggered on Interfaces participating in bonds, they will be disabled.

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 receiving CCMs but able to send them. Finally, a fault is triggered if a CCM is received which indicates unexpected configuration. Notably, 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 received 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 broadcasts 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 received 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_opstate.

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 refreshed.

As mentioned above, the faults can be triggered for several reasons. 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 Interface 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 connectivity 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 accuracy 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 every 100 * other_config:cfm_interval amount of time. Otherwise, even if traffic are received, the CFM module will raise the connectivity fault.

Demand mode has a couple of caveats:

other_config : cfm_opstate: optional string, either down or up

When down, the CFM module marks all CCMs it generates as operationally down without triggering a fault. This allows remote maintenance points to choose not to forward traffic to the Interface 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 ignored 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.

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 integer, 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 integer, in range 1 to 65,535

The LACP aggregation key of this Interface. Interfaces with different aggregation keys may not be active within a given Port at the same time.

These key-value pairs specifically apply to an interface that represents a virtual Ethernet interface connected to a virtual machine. These key-value pairs should not be present for other types of interfaces. 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 associated with a given external_ids:iface-id, only one of which is actually in use at a given time. For example, in some circumstances hypervisor may have both a ``tap’’ and a ``vif’’ interface 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 hypervisor that never has more than one interface for a given external_ids:iface-id may mark that interface active or omit external_ids:iface-status entirely.

During VM migration, a given external_ids:iface-id might transiently be marked active on two different hypervisors. That is, active means that this external_ids:iface-id is the active instance 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). During such a ``migration,’’ two instances of a single external_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 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.

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 default, 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 default, 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.

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.

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

Summary:¶

name

optional string

Eviction Policy:

Classifier Optimization:

Common Columns:

Details:¶

name: optional string

The table’s name. Set this column to change the name that controllers will receive when they request table statistics, e.g. ovs-ofctl dump-tables. The name does not affect switch behavior.

Open vSwitch supports limiting the number of flows that may be installed 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:

When a flow must be evicted due to overflow, the flow to evict is chosen through an approximation of the following algorithm. This algorithm is used regardless of how eviction was enabled:

The eviction process only considers flows that have an idle timeout or a hard timeout. That is, eviction never deletes permanent flows. (Permanent 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 table. 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 modification request would add flows in excess of flow_limit. The supported values are:

groups: set of strings

When overflow_policy is evict, this controls how flows are chosen 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 specifications.

When eviction is not enabled, via overflow_policy or an OpenFlow 1.4+ ``table mod,’’ this column has no effect.

prefixes: set of up to 3 strings

This string set specifies which fields should be used for address 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 table. This instructs the flow classifier to track the IP destination 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:

There is a maximum number of fields that can be enabled for any one flow table. Currently this limit is 3.

The overall purpose of these columns is described under Common Columns at the beginning of this document.

external_ids: map of string-string pairs

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:

Configuration for egress-policer QoS:

Configuration for linux-sfq:

Configuration for linux-netem:

Common Columns:

Details:¶

type: string

The type of QoS to implement. The currently defined types are listed below:

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 configuration 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 disciplines, this dropped all packets destined for the default queue.)

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.

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 assuming 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 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 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 assuming 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.

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.

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.

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

Summary:¶

dscp

optional integer, in range 0 to 63

Configuration for linux-htb QoS:

Configuration for linux-hfsc QoS:

Common Columns:

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.

QoS type linux-htb may use queue_ids less than 61440. It has the following 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 receives any. Specific priority values are unimportant; only relative ordering matters. Defaults to 0 if unspecified.

QoS type linux-hfsc may use queue_ids less than 61440. It has the following 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.

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

Summary:¶

name

string

Selecting Packets for Mirroring:

Mirroring Destination Configuration:

Statistics: Mirror counters:

Common Columns:

Details:¶

name: string

Arbitrary identifier for the Mirror.

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 selected VLANs.

select_all: boolean

If true, every packet arriving or departing on any port is selected 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.

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 exclusively 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 mirrored 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 Interface table for a list of destination MAC addresses which will not be mirrored to a VLAN to avoid confusing switches that interpret the protocols that they represent.

Please note: Mirroring to a VLAN can disrupt a network that contains 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 packets 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, disrupting 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 traffic. 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 configured for that VLAN. If Open vSwitch is being used as an intermediate switch, learning can be disabled by adding the mirrored VLAN to flood_vlans in the appropriate Bridge table or tables.

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 truncated in datapath to snaplen bytes before sending to the mirror output port. If omitted, packets are not truncated.

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.

The overall purpose of these columns is described under Common Columns at the beginning of this document.

external_ids: map of string-string pairs

Summary:¶

Core Features:

Controller Failure Detection and Handling:

Asynchronous Messages:

Additional In-Band Configuration:

Controller Status:

Connection Parameters:

Common Columns:

Details:¶

type: optional string, either primary or service

Open vSwitch supports two kinds of OpenFlow controllers. A bridge may have any number of each kind:

By default, Open vSwitch treats controllers with active connection methods as primary controllers and those with passive connection 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:

The following passive connection methods are currently supported:

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:

If not specified, the default is implementation-specific.

max_backoff: optional integer, at least 1,000

Maximum number of milliseconds to wait between connection attempts. 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 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 reconnect. Default is implementation-specific. A value of 0 disables inactivity probes.

OpenFlow switches send certain messages to controllers spontanenously, that is, not in response to any request from the controller. These messages are called ``asynchronous messages.’’ These columns allow asynchronous 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 receive 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.

A switch can forward packets to a controller over the OpenFlow protocol. Forwarding packets this way at too high a rate can overwhelm a controller, frustrate use of the OpenFlow connection for other purposes, 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 configured rate, when packets are sent for both reasons.

This feature is specific to forwarding packets over an OpenFlow connection. 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 specified, 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 configured. 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.

These values report the effects of rate limiting. Their values are relative to establishment of the most recent OpenFlow connection, or since rate limiting was enabled, whichever happened more recently. Each consists 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 enabled.

status : packet-in-TYPE-bypassed: optional string, containing an integer, at least 0

Number of packets sent directly to the controller, without queuing, 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 integer, 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 integer, at least 0

Number of packets currently queued. The other statistics increase monotonically, but this one fluctuates between 0 and the controller_burst_limit as conditions change.

These values are considered only in in-band control mode (see connection_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 network has no gateway.

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:

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:

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 connected 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.

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 specified here is used when establishing the connection between the controller and the Open vSwitch. If no value is specified, a default value of 48 is chosen. Valid DSCP values must be in the range 0 to 63.

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

Summary:¶

Core Features:

Client Failure Detection and Handling:

Status:

Connection Parameters:

Common Columns:

Details:¶

target: string (must be unique within table)

Connection method for managers.

The following connection methods are currently supported:

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:

If not specified, the default is implementation-specific.

max_backoff: optional integer, at least 1,000

Maximum number of milliseconds to wait between connection attempts. 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 reconnect. Default is implementation-specific. A value of 0 disables inactivity probes.

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 connections (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 omitted.

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:

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 connected 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 disconnected.

status : locks_held: optional string

Space-separated list of the names of OVSDB locks that the connection 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 connection is currently waiting to acquire. Omitted if the connection is not waiting for any locks.

status : locks_lost: optional string

Space-separated list of the names of OVSDB locks that the connection 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 inbound connections (e.g. ptcp: or pssl:) and more than one connection 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.)

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 specified here is used when establishing the connection between the manager and the Open vSwitch. If no value is specified, a default value of 48 is chosen. Valid DSCP values must be in the range 0 to 63.

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

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:

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 index 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 timeout is about a second.

add_id_to_interface: boolean

If this column’s value is false, the ingress and egress interface 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 supported.

The overall purpose of these columns is described under Common Columns at the beginning of this document.

external_ids: map of string-string pairs

Summary:¶

datapath_version

string

ct_zones

map of integer-CT_Zone pairs, key in range 0 to 65,535

Capabilities:

Common Columns:

Details:¶

datapath_version: string

Reports the version number of the Open vSwitch datapath in use. This allows management software to detect and report discrepancies 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:

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 kernel 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).

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 features are available. For example, OpenFlow features for connection-tracking are available only when capabilities:ct_state is true. A controller 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 integer, 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.

These capabilities are granular because Open vSwitch and its datapaths added support for connection tracking over several releases, with features added individually over that time.

capabilities : ct_state: optional string, either true or false

If true, datapath supports OVS_KEY_ATTR_CT_STATE, which indicates 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 capabilities 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 conflated because all current datapaths implemented the two features 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 between 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.