ovs-ofctl(8)

NAME
ovs-ofctl - administer OpenFlow switches

SYNOPSIS
ovs-ofctl [options] command [switch] [args...]

DESCRIPTION
The ovs-ofctl program is a command line tool for monitoring and administering OpenFlow switches. It can also show the current state of an OpenFlow switch, including features, configuration, and table entries. It should work with any OpenFlow switch, not just Open vSwitch.

  OpenFlow Switch Management Commands

These commands allow ovs-ofctl to monitor and administer an OpenFlow switch. It is able to show the current state of a switch, including features, configuration, and table entries.

Most of these commands take an argument that specifies the method for connecting to an OpenFlow switch. The following connection methods are supported:

    file
        This is short for unix:file, as long as file does not contain a colon.

    bridge
        This is short for unix:@RUNDIR@/bridge.mgmt, as long as bridge does not contain a colon.

    [type@]dp
        Attempts to look up the bridge associated with dp and open as above. If type is given, it specifies the datapath provider of dp, otherwise the default provider system is assumed.

show switch
    Prints to the console information on switch, including information on its flow tables and ports.

dump-tables switch
    Prints to the console statistics for each of the flow tables used by switch.

dump-table-features switch
    Prints to the console features for each of the flow tables used by switch.

dump-table-desc switch
    Prints to the console configuration for each of the flow tables used by switch for OpenFlow 1.4+.

mod-table switch table setting
    This command configures flow table settings in switch for OpenFlow table table, which may be expressed as a number or (unless --no-names is specified) a name.

    The available settings depend on the OpenFlow version in use. In OpenFlow 1.1 and 1.2 (which must be enabled with the -O option) only, mod-table configures behavior when no flow is found when a packet is looked up in a flow table. The following setting values are available:

    drop
        Drop the packet.

    continue
        Continue to the next table in the pipeline. (This is how an OpenFlow 1.0 switch always handles packets that do not match any flow, in tables other than the last one.)

    controller
        Send to controller. (This is how an OpenFlow 1.0 switch always handles packets that do not match any flow in the last table.)

    In OpenFlow 1.3 and later (which must be enabled with the -O option) and Open vSwitch 2.11 and later only, mod-table can change the name of a table:

    name:new-name
        Changes the name of the table to new-name. Use an empty new-name to clear the name. (This will be ineffective if the name is set via the name column in the Flow_Table table in the Open_vSwitch database as described in ovs-vswitchd.conf.db(5).)

    In OpenFlow 1.4 and later (which must be enabled with the -O option) only, mod-table configures the behavior when a controller attempts to add a flow to a flow table that is full. The following setting values are available:

    evict
        Delete some existing flow from the flow table, according to the algorithm described for the Flow_Table table in ovs-vswitchd.conf.db(5).

    noevict
        Refuse to add the new flow. (Eviction might still be enabled through the overflow_policy column in the Flow_Table table documented in ovs-vswitchd.conf.db(5).)

    vacancy:low,high
        Enables sending vacancy events to controllers using TABLE_STATUS messages, based on percentage thresholds low and high.

    novacancy
        Disables vacancy events.

dump-ports switch [netdev]
    Prints to the console statistics for network devices associated with switch. If netdev is specified, only the statistics associated with that device will be printed. netdev can be an OpenFlow assigned port number or device name, e.g. eth0.

dump-ports-desc switch [port]
    Prints to the console detailed information about network devices associated with switch. To dump only a specific port, specify its number as port. Otherwise, if port is omitted, or if it is specified as ANY, then all ports are printed. This is a subset of the information provided by the show command.

    If the connection to switch negotiates OpenFlow 1.0, 1.2, or 1.2, this command uses an OpenFlow extension only implemented in Open vSwitch (version 1.7 and later).

    Only OpenFlow 1.5 and later support dumping a specific port. Earlier versions of OpenFlow always dump all ports.

mod-port switch port action
    Modify characteristics of port port in switch. port may be an OpenFlow port number or name (unless --no-names is specified) or the keyword LOCAL (the preferred way to refer to the OpenFlow local port). The action may be any one of the following:
    Enable or disable the interface. This is equivalent to ip link set up or ip link set down on a Unix system.

    stp Enable or disable 802.1D spanning tree protocol (STP) on the interface. OpenFlow implementations that don't support STP will refuse to enable it.

    receive
        Enable or disable OpenFlow processing of packets received on this interface. When packet processing is disabled, packets will be dropped instead of being processed through the OpenFlow table. The receive or no-receive setting applies to all packets except 802.1D spanning tree packets, which are separately controlled by receive-stp or no-receive-stp.

    forward
        Allow or disallow forwarding of traffic to this interface. By default, forwarding is enabled.

    flood
        Controls whether an OpenFlow flood action will send traffic out this interface. By default, flooding is enabled. Disabling flooding is primarily useful to prevent loops when a spanning tree protocol is not in use.

    packet-in
        Controls whether packets received on this interface that do not match a flow table entry generate a ``packet in'' message to the OpenFlow controller. By default, ``packet in'' messages are enabled.

    The show command displays (among other information) the configuration that mod-port changes.

get-frags switch
    Prints switch's fragment handling mode. See set-frags, below, for a description of each fragment handling mode.

    The show command also prints the fragment handling mode among its other output.

set-frags switch frag_mode
    Configures switch's treatment of IPv4 and IPv6 fragments. The choices for frag_mode are:

    normal
        Fragments pass through the flow table like non-fragmented packets. The TCP ports, UDP ports, and ICMP type and code fields are always set to 0, even for fragments where that information would otherwise be available (fragments with offset 0). This is the default fragment handling mode for an OpenFlow switch.

    drop
        Fragments are dropped without passing through the flow table.

    reassemble
        The switch reassembles fragments into full IP packets before passing them through the flow table. Open vSwitch does not implement this fragment handling mode.

    nx-match
        Fragments pass through the flow table like non-fragmented packets. The TCP ports, UDP ports, and ICMP type and code fields are available for matching for fragments with offset 0, and set to 0 in fragments with nonzero offset. This mode is a Nicira extension.

    See the description of ip_frag, in ovs-fields(7), for a way to match on whether a packet is a fragment and on its fragment offset.

dump-flows switch [flows]
    Prints to the console all flow entries in switch's tables that match flows. If flows is omitted, all flows in the switch are retrieved. See Flow Syntax, below, for the syntax of flows. The output format is described in Table Entry Output.

    By default, ovs-ofctl prints flow entries in the same order that the switch sends them, which is unlikely to be intuitive or consistent. Use --sort and --rsort to control display order. The --names/--no-names and --stats/--no-stats options also affect output formatting. See the descriptions of these options, under OPTIONS below, for more information

dump-aggregate switch [flows]
    Prints to the console aggregate statistics for flows in switch's tables that match flows. If flows is omitted, the statistics are aggregated across all flows in the switch's flow tables. See Flow Syntax, below, for the syntax of flows. The output format is described in Table Entry Output.

queue-stats switch [port [queue]]
    Prints to the console statistics for the specified queue on port within switch. port can be an OpenFlow port number or name, the keyword LOCAL (the preferred way to refer to the OpenFlow local port), or the keyword ALL. Either of port or queue or both may be omitted (or equivalently the keyword ALL). If both are omitted, statistics are printed for all queues on all ports. If only queue is omitted, then statistics are printed for all queues on port; if only port is omitted, then statistics are printed for queue on every port where it exists.

queue-get-config switch [port [queue]]
    Prints to the console the configuration of queue on port in switch. If port is omitted or ANY, reports queues for all port. If queue is omitted or ANY, reports all queues. For OpenFlow 1.3 and earlier, the output always includes all queues, ignoring queue if specified.

    This command has limited usefulness, because ports often have no configured queues and because the OpenFlow protocol provides only very limited information about the configuration of a queue.

dump-ipfix-bridge switch
    Prints to the console the statistics of bridge IPFIX for switch. If bridge IPFIX is configured on the switch, IPFIX statistics can be retrieved. Otherwise, error message will be printed.

    This command uses an Open vSwitch extension that is only in Open vSwitch 2.6 and later.

dump-ipfix-flow switch
    Prints to the console the statistics of flow-based IPFIX for switch. If flow-based IPFIX is configured on the switch, statistics of all the collector set ids on the switch will be printed. Otherwise, print error message.

    Refer to ovs-vswitchd.conf.db(5) for more details on configuring flow based IPFIX and collector set ids.

    This command uses an Open vSwitch extension that is only in Open vSwitch 2.6 and later.

ct-flush-zone switch zone
    Flushes the connection tracking entries in zone on switch.

    This command uses an Open vSwitch extension that is only in Open vSwitch 2.6 and later.

ct-flush switch [zone=N] [mark=X[/M]] [labels=Y[/N]] [ct-orig-tuple [ct-reply-tuple]]
    Flushes the connection entries on switch based on zone, mark, labels and connection tracking tuples ct-[orig|reply]-tuple.

    If ct-[orig|reply]-tuple is not provided, flushes all the connection entries. If zone is specified, only flushes the connections in zone. if mark or labels is provided, it will flush only entries that are matching specific mark/labels.

    If ct-[orig|reply]-tuple is provided, flushes the connection entry specified by ct-[orig|reply]-tuple in zone. The zone defaults to 0 if it is not provided. The mark and labels defaults to "0/0" if it is not provided. The userspace connection tracker requires flushing with the original pre-NATed tuple and a warning log will be otherwise generated. The tuple can be partial and will remove all connections that are matching on the specified fields. In order to specify only ct-reply-tuple, provide empty string as ct-orig-tuple.

    Note: Currently there is limitation for matching on ICMP, in order to partially match on ICMP parameters the ct-[orig|reply]-tuple has to include either source or destination IP.

    An example of an IPv4 ICMP ct-[orig|reply]-tuple:

    "ct_nw_src=10.1.1.1,ct_nw_dst=10.1.1.2,ct_nw_proto=1,icmp_type=8,icmp_code=0,icmp_id=10"

    An example of an IPv6 TCP ct-[orig|reply]-tuple:

    "ct_ipv6_src=fc00::1,ct_ipv6_dst=fc00::2,ct_nw_proto=6,ct_tp_src=1,ct_tp_dst=2"

    This command uses an Open vSwitch extension that is only in Open vSwitch 3.1 and later. Support for matching on mark and labels is only in Open vSwitch 3.3 and later.

  OpenFlow Switch Flow Table Commands
These commands manage the flow table in an OpenFlow switch. In each case, flow specifies a flow entry in the format described in Flow Syntax, below, file is a text file that contains zero or more flows in the same syntax, one per line, and the optional --bundle option operates the command as a single atomic transaction, see option --bundle, below.

[--bundle] add-flow switch flow
    Add each flow entry to switch's tables. Each flow specification (e.g., each line in file) may start with add, modify, delete, modify_strict, or delete_strict keyword to specify whether a flow is to be added, modified, or deleted, and whether the modify or delete is strict or not. For backwards compatibility a flow specification without one of these keywords is treated as a flow add. All flow mods are executed in the order specified.

[--bundle] [--strict] mod-flows switch flow
    Modify the actions in entries from switch's tables that match the specified flows. With --strict, wildcards are not treated as active for matching purposes.

[--bundle] del-flows switch
    Deletes entries from switch's flow table. With only a switch argument, deletes all flows. Otherwise, deletes flow entries that match the specified flows. With --strict, wildcards are not treated as active for matching purposes.

[--bundle] [--readd] replace-flows switch file
    Reads flow entries from file (or stdin if file is -) and queries the flow table from switch. Then it fixes up any differences, adding flows from flow that are missing on switch, deleting flows from switch that are not in file, and updating flows in switch whose actions, cookie, or timeouts differ in file.

    With --readd, ovs-ofctl adds all the flows from file, even those that exist with the same actions, cookie, and timeout in switch. In OpenFlow 1.0 and 1.1, re-adding a flow always resets the flow's packet and byte counters to 0, and in OpenFlow 1.2 and later, it does so only if the reset_counts flag is set.

diff-flows source1 source2
    Reads flow entries from source1 and source2 and prints the differences. A flow that is in source1 but not in source2 is printed preceded by a -, and a flow that is in source2 but not in source1 is printed preceded by a +. If a flow exists in both source1 and source2 with different actions, cookie, or timeouts, then both versions are printed preceded by - and +, respectively.

    source1 and source2 may each name a file or a switch. If a name begins with / or ., then it is considered to be a file name. A name that contains : is considered to be a switch. Otherwise, it is a file if a file by that name exists, a switch if not.

    For this command, an exit status of 0 means that no differences were found, 1 means that an error occurred, and 2 means that some differences were found.

packet-out switch packet-out
    Connects to switch and instructs it to execute the packet-out OpenFlow message, specified as defined in Packet-Out Syntax section.

  Group Table Commands
These commands manage the group table in an OpenFlow switch. In each case, group specifies a group entry in the format described in Group Syntax, below, and file is a text file that contains zero or more groups in the same syntax, one per line, and the optional --bundle option operates the command as a single atomic transaction, see option --bundle, below.

The group commands work only with switches that support OpenFlow 1.1 or later or the Open vSwitch group extensions to OpenFlow 1.0 (added in Open vSwitch 2.9.90). For OpenFlow 1.1 or later, it is necessary to explicitly enable these protocol versions in ovs-ofctl (using -O). For more information, see ``Q: What versions of OpenFlow does Open vSwitch support?'' in the Open vSwitch FAQ.

[--bundle] add-group switch group
    Add each group entry to switch's tables. Each group specification (e.g., each line in file) may start with add, modify, add_or_mod, delete, insert_bucket, or remove_bucket keyword to specify whether a flow is to be added, modified, or deleted, or whether a group bucket is to be added or removed. For backwards compatibility a group specification without one of these keywords is treated as a group add. All group mods are executed in the order specified.

[--bundle] [--may-create] mod-group switch group
    Modify the action buckets in entries from switch's tables for each group entry. If a specified group does not already exist, then without --may-create, this command has no effect; with --may-create, it creates a new group. The --may-create option uses an Open vSwitch extension to OpenFlow only implemented in Open vSwitch 2.6 and later.

[--bundle] del-groups switch
    Deletes entries from switch's group table. With only a switch argument, deletes all groups. Otherwise, deletes the group for each group entry.

[--bundle] insert-buckets switch group
    Add buckets to an existing group present in the switch's group table. If no command_bucket_id is present in the group specification then all buckets of the group are removed.

[--bundle] remove-buckets switch group
    Remove buckets to an existing group present in the switch's group table. If no command_bucket_id is present in the group specification then all buckets of the group are removed.

dump-groups switch [group]
    Prints group entries in switch's tables to console. To dump only a specific group, specify its number as group. Otherwise, if group is omitted, or if it is specified as ALL, then all groups are printed.

    Only OpenFlow 1.5 and later support dumping a specific group. Earlier versions of OpenFlow always dump all groups.

dump-group-features switch
    Prints to the console the group features of the switch.

dump-group-stats switch [group]
    Prints to the console statistics for the specified group in switch's tables. If group is omitted then statistics for all groups are printed.

  OpenFlow 1.3+ Switch Meter Table Commands
These commands manage the meter table in an OpenFlow switch. In each case, meter specifies a meter entry in the format described in Meter Syntax, below.

OpenFlow 1.3 introduced support for meters, so these commands only work with switches that support OpenFlow 1.3 or later. It is necessary to explicitly enable these protocol versions in ovs-ofctl (using -O) and in the switch itself (with the protocols column in the Bridge table). For more information, see ``Q: What versions of OpenFlow does Open vSwitch support?'' in the Open vSwitch FAQ.

add-meter switch meter
    Add a meter entry to switch's tables. The meter syntax is described in section Meter Syntax, below.

mod-meter switch meter
    Modify an existing meter.

del-meters switch [meter]
    Delete entries from switch's meter table. To delete only a specific meter, specify its number as meter. Otherwise, if meter is omitted, or if it is specified as all, then all meters are deleted.

dump-meters switch [meter]
    Print entries from switch's meter table. To print only a specific meter, specify its number as meter. Otherwise, if meter is omitted, or if it is specified as all, then all meters are printed.

meter-stats switch [meter]
    Print meter statistics. meter can specify a single meter with syntax meter=id, or all meters with syntax meter=all.

meter-features switch
    Print meter features.

  OpenFlow Switch Bundle Command
Transactional updates to both flow and group tables can be made with the bundle command. file is a text file that contains zero or more flow mods, group mods, or packet-outs in Flow Syntax, Group Syntax, or Packet-Out Syntax, each line preceded by flow, group, or packet-out keyword, correspondingly. The flow keyword may be optionally followed by one of the keywords add, modify, modify_strict, delete, or delete_strict, of which the add is assumed if a bare flow is given. Similarly, the group keyword may be optionally followed by one of the keywords add, modify, add_or_mod, delete, insert_bucket, or remove_bucket, of which the add is assumed if a bare group is given.

bundle switch file
    Execute all flow and group mods in file as a single atomic transaction against switch's tables. All bundled mods are executed in the order specified.

  OpenFlow Switch Tunnel TLV Table Commands
Open vSwitch maintains a mapping table between tunnel option TLVs (defined by <class, type, length>) and NXM fields tun_metadatan, where n ranges from 0 to 63, that can be operated on for the purposes of matches, actions, etc. This TLV table can be used for Geneve option TLVs or other protocols with options in same TLV format as Geneve options. This mapping must be explicitly specified by the user through the following commands. A TLV mapping is specified with the syntax {class=class,type=type,len=length}->tun_metadatan. When an option mapping exists for a given tun_metadatan, matching on the defined field becomes possible, e.g.:
    ovs-ofctl add-tlv-map br0 "{class=0xffff,type=0,len=4}->tun_metadata0"

    ovs-ofctl add-flow br0 tun_metadata0=1234,actions=controller
A mapping should not be changed while it is in active use by a flow. The result of doing so is undefined. These commands are Nicira extensions to OpenFlow and require Open vSwitch 2.5 or later.

add-tlv-map switch option[,option]...
    Add each option to switch's tables. Duplicate fields are rejected.

del-tlv-map switch [option[,option]]...
    Delete each option from switch's table, or all option TLV mapping if no option is specified. Fields that aren't mapped are ignored.

dump-tlv-map switch
    Show the currently mapped fields in the switch's option table as well as switch capabilities.

  OpenFlow Switch Monitoring Commands

snoop switch
    Connects to switch and prints to the console all OpenFlow messages received. Unlike other ovs-ofctl commands, if switch is the name of a bridge, then the snoop command connects to a Unix domain socket named @RUNDIR@/switch.snoop. ovs-vswitchd listens on such a socket for each bridge and sends to it all of the OpenFlow messages sent to or received from its configured OpenFlow controller. Thus, this command can be used to view OpenFlow protocol activity between a switch and its controller.

    When a switch has more than one controller configured, only the traffic to and from a single controller is output. If none of the controllers is configured as a primary or a secondary (using a Nicira extension to OpenFlow 1.0 or 1.1, or a standard request in OpenFlow 1.2 or later), then a controller is chosen arbitrarily among them. If there is a primary controller, it is chosen; otherwise, if there are any controllers that are not primaries or secondaries, one is chosen arbitrarily; otherwise, a secondary controller is chosen arbitrarily. This choice is made once at connection time and does not change as controllers reconfigure their roles.

    If a switch has no controller configured, or if the configured controller is disconnected, no traffic is sent, so monitoring will not show any traffic.

monitor switch [miss-len] [invalid_ttl] [watch:[spec...]]
    Connects to switch and prints to the console all OpenFlow messages received. Usually, switch should specify the name of a bridge in the ovs-vswitchd database. This is available only in OpenFlow 1.0 as Nicira extension.

    If miss-len is provided, ovs-ofctl sends an OpenFlow ``set configuration'' message at connection setup time that requests miss-len bytes of each packet that misses the flow table. Open vSwitch does not send these and other asynchronous messages to an ovs-ofctl monitor client connection unless a nonzero value is specified on this argument. (Thus, if miss-len is not specified, very little traffic will ordinarily be printed.)

    If invalid_ttl is passed, ovs-ofctl sends an OpenFlow ``set configuration'' message at connection setup time that requests INVALID_TTL_TO_CONTROLLER, so that ovs-ofctl monitor can receive ``packet-in'' messages when TTL reaches zero on dec_ttl action. Only OpenFlow 1.1 and 1.2 support invalid_ttl; Open vSwitch also implements it for OpenFlow 1.0 as an extension.

    watch:[spec...] causes ovs-ofctl to send a ``monitor request'' Nicira extension message to the switch at connection setup time. This message causes the switch to send information about flow table changes as they occur. The following comma-separated spec syntax is available:

    !initial
        Do not report the switch's initial flow table contents.

    !add
        Do not report newly added flows.

    !delete
        Do not report deleted flows.

    !modify
        Do not report modifications to existing flows.

    !own
        Abbreviate changes made to the flow table by ovs-ofctl's own connection to the switch. (These could only occur using the ofctl/send command described below under RUNTIME MANAGEMENT COMMANDS.)

    !actions
        Do not report actions as part of flow updates.

    table=table
        Limits the monitoring to the table with the given table, which may be expressed as a number between 0 and 254 or (unless --no-names is specified) a name. By default, all tables are monitored.

    out_port=port
        If set, only flows that output to port are monitored. The port may be an OpenFlow port number or keyword (e.g. LOCAL).

    out_group=group
        If set, only flows that output to group number are monitored. This field requires OpenFlow 1.4 (-OOpenFlow14) or later.

    field=value
        Monitors only flows that have field specified as the given value. Any syntax valid for matching on dump-flows may be used.

    This command may be useful for debugging switch or controller implementations. With watch:, it is particularly useful for observing how a controller updates flow tables.

  OpenFlow Switch and Controller Commands
The following commands, like those in the previous section, may be applied to OpenFlow switches, using any of the connection methods described in that section. Unlike those commands, these may also be applied to OpenFlow controllers.

probe target
    Sends a single OpenFlow echo-request message to target and waits for the response. With the -t or --timeout option, this command can test whether an OpenFlow switch or controller is up and running.

ping target [n]
    Sends a series of 10 echo request packets to target and times each reply. The echo request packets consist of an OpenFlow header plus n bytes (default: 64) of randomly generated payload. This measures the latency of individual requests.

benchmark target n count
    Sends count echo request packets that each consist of an OpenFlow header plus n bytes of payload and waits for each response. Reports the total time required. This is a measure of the maximum bandwidth to target for round-trips of n-byte messages.

  Other Commands

ofp-parse file
    Reads file (or stdin if file is -) as a series of OpenFlow messages in the binary format used on an OpenFlow connection, and prints them to the console. This can be useful for printing OpenFlow messages captured from a TCP stream.

ofp-parse-pcap file [port...]
    Reads file, which must be in the PCAP format used by network capture tools such as tcpdump or wireshark, extracts all the TCP streams for OpenFlow connections, and prints the OpenFlow messages in those connections in human-readable format on stdout.

    OpenFlow connections are distinguished by TCP port number. Non-OpenFlow packets are ignored. By default, data on TCP ports 6633 and 6653 are considered to be OpenFlow. Specify one or more port arguments to override the default.

    This command cannot usefully print SSL encrypted traffic. It does not understand IPv6.

  Flow Syntax

Some ovs-ofctl commands accept an argument that describes a flow or flows. Such flow descriptions comprise a series of field=value assignments, separated by commas or white space. (Embedding spaces into a flow description normally requires quoting to prevent the shell from breaking the description into multiple arguments.)

Flow descriptions should be in normal form. This means that a flow may only specify a value for an L3 field if it also specifies a particular L2 protocol, and that a flow may only specify an L4 field if it also specifies particular L2 and L3 protocol types. For example, if the L2 protocol type dl_type is wildcarded, then L3 fields nw_src, nw_dst, and nw_proto must also be wildcarded. Similarly, if dl_type or nw_proto (the L3 protocol type) is wildcarded, so must be the L4 fields tcp_dst and tcp_src. ovs-ofctl will warn about flows not in normal form.

ovs-fields(7) describes the supported fields and how to match them. In addition to match fields, commands that operate on flows accept a few additional key-value pairs:

table=table
    For flow dump commands, limits the flows dumped to those in table, which may be expressed as a number between 0 and 255 or (unless --no-names is specified) a name. If not specified (or if 255 is specified as table), then flows in all tables are dumped.

    For flow table modification commands, behavior varies based on the OpenFlow version used to connect to the switch:

    OpenFlow 1.0
        OpenFlow 1.0 does not support table for modifying flows. ovs-ofctl will exit with an error if table (other than table=255) is specified for a switch that only supports OpenFlow 1.0.

        In OpenFlow 1.0, the switch chooses the table into which to insert a new flow. The Open vSwitch software switch always chooses table 0. Other Open vSwitch datapaths and other OpenFlow implementations may choose different tables.

        The OpenFlow 1.0 behavior in Open vSwitch for modifying or removing flows depends on whether --strict is used. Without --strict, the command applies to matching flows in all tables. With --strict, the command will operate on any single matching flow in any table; it will do nothing if there are matches in more than one table. (The distinction between these behaviors only matters if non-OpenFlow 1.0 commands were also used, because OpenFlow 1.0 alone cannot add flows with the same matching criteria to multiple tables.)

    OpenFlow 1.0 with table_id extension
        Open vSwitch implements an OpenFlow extension that allows the controller to specify the table on which to operate. ovs-ofctl automatically enables the extension when table is specified and OpenFlow 1.0 is used. ovs-ofctl automatically detects whether the switch supports the extension. As of this writing, this extension is only known to be implemented by Open vSwitch.

        With this extension, ovs-ofctl operates on the requested table when table is specified, and acts as described for OpenFlow 1.0 above when no table is specified (or for table=255).

    OpenFlow 1.1
        OpenFlow 1.1 requires flow table modification commands to specify a table. When table is not specified (or table=255 is specified), ovs-ofctl defaults to table 0.

    OpenFlow 1.2 and later
        OpenFlow 1.2 and later allow flow deletion commands, but not other flow table modification commands, to operate on all flow tables, with the behavior described above for OpenFlow 1.0.

duration=...
    ovs-ofctl ignores assignments to these ``fields'' to allow output from the dump-flows command to be used as input for other commands that parse flows.

The add-flow, add-flows, and mod-flows commands require an additional field, which must be the final field specified:

actions=[action][,action...]
    Specifies a comma-separated list of actions to take on a packet when the flow entry matches. If no action is specified, then packets matching the flow are dropped. See ovs-actions(7) for details on the syntax and semantics of actions. K

An opaque identifier called a cookie can be used as a handle to identify a set of flows:

cookie=value
    A cookie can be associated with a flow using the add-flow, add-flows, and mod-flows commands. value can be any 64-bit number and need not be unique among flows. If this field is omitted, a default cookie value of 0 is used.

cookie=value/mask
    When using NXM, the cookie can be used as a handle for querying, modifying, and deleting flows. value and mask may be supplied for the del-flows, mod-flows, dump-flows, and dump-aggregate commands to limit matching cookies. A 1-bit in mask indicates that the corresponding bit in cookie must match exactly, and a 0-bit wildcards that bit. A mask of -1 may be used to exactly match a cookie.

    The mod-flows command can update the cookies of flows that match a cookie by specifying the cookie field twice (once with a mask for matching and once without to indicate the new value):

    ovs-ofctl mod-flows br0 cookie=1,actions=normal
        Change all flows' cookies to 1 and change their actions to normal.

    ovs-ofctl mod-flows br0 cookie=1/-1,cookie=2,actions=normal
        Update cookies with a value of 1 to 2 and change their actions to normal.

    The ability to match on cookies was added in Open vSwitch 1.5.0.

The following additional field sets the priority for flows added by the add-flow and add-flows commands. For mod-flows and del-flows when --strict is specified, priority must match along with the rest of the flow specification. For mod-flows without --strict, priority is only significant if the command creates a new flow, that is, non-strict mod-flows does not match on priority and will not change the priority of existing flows. Other commands do not allow priority to be specified.

priority=value
    The priority at which a wildcarded entry will match in comparison to others. value is a number between 0 and 65535, inclusive. A higher value will match before a lower one. An exact-match entry will always have priority over an entry containing wildcards, so it has an implicit priority value of 65535. When adding a flow, if the field is not specified, the flow's priority will default to 32768.

    OpenFlow leaves behavior undefined when two or more flows with the same priority can match a single packet. Some users expect ``sensible'' behavior, such as more specific flows taking precedence over less specific flows, but OpenFlow does not specify this and Open vSwitch does not implement it. Users should therefore take care to use priorities to ensure the behavior that they expect.

The add-flow, add-flows, and mod-flows commands support the following additional options. These options affect only new flows. Thus, for add-flow and add-flows, these options are always significant, but for mod-flows they are significant only if the command creates a new flow, that is, their values do not update or affect existing flows.

idle_timeout=seconds
    Causes the flow to expire after the given number of seconds of inactivity. A value of 0 (the default) prevents a flow from expiring due to inactivity.

hard_timeout=seconds
    Causes the flow to expire after the given number of seconds, regardless of activity. A value of 0 (the default) gives the flow no hard expiration deadline.

importance=value
    Sets the importance of a flow. The flow entry eviction mechanism can use importance as a factor in deciding which flow to evict. A value of 0 (the default) makes the flow non-evictable on the basis of importance. Specify a value between 0 and 65535.

    Only OpenFlow 1.4 and later support importance.

send_flow_rem
    Marks the flow with a flag that causes the switch to generate a ``flow removed'' message and send it to interested controllers when the flow later expires or is removed.

check_overlap
    Forces the switch to check that the flow match does not overlap that of any different flow with the same priority in the same table. (This check is expensive so it is best to avoid it.)

reset_counts
    When this flag is specified on a flow being added to a switch, and the switch already has a flow with an identical match, an OpenFlow 1.2 (or later) switch resets the flow's packet and byte counters to 0. Without the flag, the packet and byte counters are preserved.

    OpenFlow 1.0 and 1.1 switches always reset counters in this situation, as if reset_counts were always specified.

    Open vSwitch 1.10 added support for reset_counts.

no_packet_counts
    Adding these flags to a flow advises an OpenFlow 1.3 (or later) switch that the controller does not need packet or byte counters, respectively, for the flow. Some switch implementations might achieve higher performance or reduce resource consumption when these flags are used. These flags provide no benefit to the Open vSwitch software switch implementation.

    OpenFlow 1.2 and earlier do not support these flags.

    Open vSwitch 1.10 added support for no_packet_counts and no_byte_counts.

The dump-flows, dump-aggregate, del-flow and del-flows commands support these additional optional fields:

out_port=port
    If set, a matching flow must include an output action to port, which must be an OpenFlow port number or name (e.g. local).

out_group=group
    If set, a matching flow must include an group action naming group, which must be an OpenFlow group number. This field is supported in Open vSwitch 2.5 and later and requires OpenFlow 1.1 or later.

  Table Entry Output
The dump-tables and dump-aggregate commands print information about the entries in a datapath's tables. Each line of output is a flow entry as described in Flow Syntax, above, plus some additional fields:

duration=secs
    The time, in seconds, that the entry has been in the table. secs includes as much precision as the switch provides, possibly to nanosecond resolution.

n_packets
    The number of packets that have matched the entry.

n_bytes
    The total number of bytes from packets that have matched the entry.

The following additional fields are included only if the switch is Open vSwitch 1.6 or later and the NXM flow format is used to dump the flow (see the description of the --flow-format option below). The values of these additional fields are approximations only and in particular idle_age will sometimes become nonzero even for busy flows.

hard_age=secs
    The integer number of seconds since the flow was added or modified. hard_age is displayed only if it differs from the integer part of duration. (This is separate from duration because mod-flows restarts the hard_timeout timer without zeroing duration.)

idle_age=secs
    The integer number of seconds that have passed without any packets passing through the flow.

  Packet-Out Syntax

ovs-ofctl bundle command accepts packet-outs to be specified in the bundle file. Each packet-out comprises of a series of field=value assignments, separated by commas or white space. (Embedding spaces into a packet-out description normally requires quoting to prevent the shell from breaking the description into multiple arguments.). Unless noted otherwise only the last instance of each field is honoured. This same syntax is also supported by the ovs-ofctl packet-out command.

in_port=port
    The port number to be considered the in_port when processing actions. This can be any valid OpenFlow port number, or any of the LOCAL, CONTROLLER, or NONE. This field is required.

pipeline_field=value
    Optionally, user can specify a list of pipeline fields for a packet-out message. The supported pipeline fields includes tunnel fields and register fields as defined in ovs-fields(7).

packet=hex-string
    The actual packet to send, expressed as a string of hexadecimal bytes. This field is required.

actions=[action][,action...]
    The syntax of actions are identical to the actions= field described in Flow Syntax above. Specifying actions= is optional, but omitting actions is interpreted as a drop, so the packet will not be sent anywhere from the switch. actions must be specified at the end of each line, like for flow mods.

  Group Syntax

Some ovs-ofctl commands accept an argument that describes a group or groups. Such flow descriptions comprise a series field=value assignments, separated by commas or white space. (Embedding spaces into a group description normally requires quoting to prevent the shell from breaking the description into multiple arguments.). Unless noted otherwise only the last instance of each field is honoured.

group_id=id
    The integer group id of group. When this field is specified in del-groups or dump-groups, the keyword "all" may be used to designate all groups. This field is required.

type=type
    The type of the group. The add-group, add-groups and mod-groups commands require this field. It is prohibited for other commands. The following keywords designated the allowed types:

    all Execute all buckets in the group.

    select
        Execute one bucket in the group, balancing across the buckets according to their weights. To select a bucket, for each live bucket, Open vSwitch hashes flow data with the bucket ID and multiplies by the bucket weight to obtain a ``score,'' and then selects the bucket with the highest score. Use selection_method to control the flow data used for selection.

    indirect
        Executes the one bucket in the group.

    ff  Executes the first live bucket in the group which is associated with a live port or group.

command_bucket_id=id
    The bucket to operate on. The insert-buckets and remove-buckets commands require this field. It is prohibited for other commands. id may be an integer or one of the following keywords:

    all Operate on all buckets in the group. Only valid when used with the remove-buckets command in which case the effect is to remove all buckets from the group.

    first
        Operate on the first bucket present in the group. In the case of the insert-buckets command the effect is to insert new bucets just before the first bucket already present in the group; or to replace the buckets of the group if there are no buckets already present in the group. In the case of the remove-buckets command the effect is to remove the first bucket of the group; or do nothing if there are no buckets present in the group.

    last
        Operate on the last bucket present in the group. In the case of the insert-buckets command the effect is to insert new bucets just after the last bucket already present in the group; or to replace the buckets of the group if there are no buckets already present in the group. In the case of the remove-buckets command the effect is to remove the last bucket of the group; or do nothing if there are no buckets present in the group.

    If id is an integer then it should correspond to the bucket_id of a bucket present in the group. In case of the insert-buckets command the effect is to insert buckets just before the bucket in the group whose bucket_id is id. In case of the iremove-buckets command the effect is to remove the in the group whose bucket_id is id. It is an error if there is no bucket persent group in whose bucket_id is id.

selection_method=method
    The selection method used to select a bucket for a select group. This is a string of 1 to 15 bytes in length known to lower layers. This field is optional for add-group, add-groups and mod-group commands on groups of type select. Prohibited otherwise. If no selection method is specified, Open vSwitch up to release 2.9 applies the hash method with default fields. From 2.10 onwards Open vSwitch defaults to the dp_hash method with symmetric L3/L4 hash algorithm, as long as the weighted group buckets can be mapped to dp_hash values with sufficient accuracy. In 2.10 this was restricted to a maximum of 64 buckets, and in 2.17 the limit was raised to 256 buckets. In those rare cases Open vSwitch 2.10 and later fall back to the hash method with the default set of hash fields.

    dp_hash
        Use a datapath computed hash value. The hash algorithm varies across different datapath implementations. dp_hash uses the upper 32 bits of the selection_method_param as the datapath hash algorithm selector. The supported values are 0 (corresponding to hash computation over the IP 5-tuple) and 1 (corresponding to a symmetric hash computation over the IP 5-tuple). Selecting specific fields with the fields option is not supported with dp_hash). The lower 32 bits are used as the hash basis.

        Using dp_hash has the advantage that it does not require the generated datapath flows to exact match any additional packet header fields. For example, even if multiple TCP connections thus hashed to different select group buckets have different source port numbers, generally all of them would be handled with a small set of already established datapath flows, resulting in less latency for TCP SYN packets. The downside is that the shared datapath flows must match each packet twice, as the datapath hash value calculation happens only when needed, and a second match is required to match some bits of its value. This double-matching incurs a small additional latency cost for each packet, but this latency is orders of magnitude less than the latency of creating new datapath flows for new TCP connections.

    hash
        Use a hash computed over the fields specified with the fields option, see below. If no hash fields are specified, hash defaults to a symmetric hash over the combination of MAC addresses, VLAN tags, Ether type, IP addresses and L4 port numbers. hash uses the selection_method_param as the hash basis.

        Note that the hashed fields become exact matched by the datapath flows. For example, if the TCP source port is hashed, the created datapath flows will match the specific TCP source port value present in the packet received. Since each TCP connection generally has a different source port value, a separate datapath flow will be need to be inserted for each TCP connection thus hashed to a select group bucket.

    This option uses a Netronome OpenFlow extension which is only supported when using Open vSwitch 2.4 and later with OpenFlow 1.5 and later.

selection_method_param=param
    64-bit integer parameter to the selection method selected by the selection_method field. The parameter's use is defined by the lower-layer that implements the selection_method. It is optional if the selection_method field is specified as a non-empty string. Prohibited otherwise. The default value is zero.

    This option uses a Netronome OpenFlow extension which is only supported when using Open vSwitch 2.4 and later with OpenFlow 1.5 and later.

fields=field
    The field parameters to selection method selected by the selection_method field. The syntax is described in Flow Syntax with the additional restrictions that if a value is provided it is treated as a wildcard mask and wildcard masks following a slash are prohibited. The pre-requisites of fields must be provided by any flows that output to the group. The use of the fields is defined by the lower-layer that implements the selection_method. They are optional if the selection_method field is specified as ``hash', prohibited otherwise. The default is no fields.

    This option will use a Netronome OpenFlow extension which is only supported when using Open vSwitch 2.4 and later with OpenFlow 1.5 and later.

bucket=bucket_parameters
    The add-group, add-groups and mod-group commands require at least one bucket field. Bucket fields must appear after all other fields. Multiple bucket fields to specify multiple buckets. The order in which buckets are specified corresponds to their order in the group. If the type of the group is "indirect" then only one group may be specified. bucket_parameters consists of a list of field=value assignments, separated by commas or white space followed by a comma-separated list of actions. The fields for bucket_parameters are:

    bucket_id=id
        The 32-bit integer group id of the bucket. Values greater than 0xffffff00 are reserved. This field was added in Open vSwitch 2.4 to conform with the OpenFlow 1.5 specification. It is not supported when earlier versions of OpenFlow are used. Open vSwitch will automatically allocate bucket ids when they are not specified.

    actions=[action][,action...]
        The syntax of actions are identical to the actions= field described in Flow Syntax above. Specifying actions= is optional, any unknown bucket parameter will be interpreted as an action.

    weight=value
        The relative weight of the bucket as an integer. This may be used by the switch during bucket select for groups whose type is select.

    watch_port=port
        Port used to determine liveness of group. This or the watch_group field is required for groups whose type is ff or fast_failover. This or the watch_group field can also be used for groups whose type is select.

    watch_group=group_id
        Group identifier of group used to determine liveness of group. This or the watch_port field is required for groups whose type is ff or fast_failover. This or the watch_port field can also be used for groups whose type is select.

  Meter Syntax

The meter table commands accept an argument that describes a meter. Such meter descriptions comprise a series field=value assignments, separated by commas or white space. (Embedding spaces into a group description normally requires quoting to prevent the shell from breaking the description into multiple arguments.). Unless noted otherwise only the last instance of each field is honoured.

meter=id
    The identifier for the meter. An integer is used to specify a user-defined meter. In addition, the keywords "all", "controller", and "slowpath", are also supported as virtual meters. The "controller" and "slowpath" virtual meters apply to packets sent to the controller and to the OVS userspace, respectively.

    When this field is specified in del-meter, dump-meter, or meter-stats, the keyword "all" may be used to designate all meters. This field is required, except for meter-stats, which dumps all stats when this field is not specified.

kbps
    The unit for the rate and burst_size band parameters. kbps specifies kilobits per second, and pktps specifies packets per second. A unit is required for the add-meter and mod-meter commands.

burst
    If set, enables burst support for meter bands through the burst_size parameter.

stats
    If set, enables the collection of meter and band statistics.

bands=band_parameters
    The add-meter and mod-meter commands require at least one band specification. Bands must appear after all other fields.

    type=type
        The type of the meter band. This keyword starts a new band specification. Each band specifies a rate above which the band is to take some action. The action depends on the band type. If multiple bands' rate is exceeded, then the band with the highest rate among the exceeded bands is selected. The following keywords designate the allowed meter band types:

        drop
            Drop packets exceeding the band's rate limit.

    The other band_parameters are:

    rate=value
        The relative rate limit for this band, in kilobits per second or packets per second, depending on whether kbps or pktps was specified.

    burst_size=size
        If burst is specified for the meter entry, configures the maximum burst allowed for the band in kilobits or packets, depending on whether kbps or pktps was specified. If unspecified, the switch is free to select some reasonable value depending on its configuration.

OPTIONS

--strict
    Uses strict matching when running flow modification commands.

--names
    Every OpenFlow port has a name and a number, and every OpenFlow flow table has a number and sometimes a name. By default, ovs-ofctl commands accept both port and table names and numbers, and they display port and table names if ovs-ofctl is running on an interactive console, numbers otherwise. With --names, ovs-ofctl commands both accept and display port and table names; with --no-names, commands neither accept nor display port and table names.

    If a port or table name contains special characters or might be confused with a keyword within a flow, it may be enclosed in double quotes (escaped from the shell). If necessary, JSON-style escape sequences may be used inside quotes, as specified in RFC 7159. When it displays port and table names, ovs-ofctl quotes any name that does not start with a letter followed by letters or digits.

    Open vSwitch added support for port names and these options. Open vSwitch 2.10 added support for table names. Earlier versions always behaved as if --no-names were specified.

    Open vSwitch does not place its own limit on the length of port names, but OpenFlow limits port names to 15 bytes. Because ovs-ofctl uses OpenFlow to retrieve the mapping between port names and numbers, names longer than this limit will be truncated for both display and acceptance. Truncation can also cause long names that are different to appear to be the same; when a switch has two ports with the same (truncated) name, ovs-ofctl refuses to display or accept the name, using the number instead.

    OpenFlow and Open vSwitch limit table names to 32 bytes.

--stats
    The dump-flows command by default, or with --stats, includes flow duration, packet and byte counts, and idle and hard age in its output. With --no-stats, it omits all of these, as well as cookie values and table IDs if they are zero.

--read-only
    Do not execute read/write commands.

--bundle
    Execute flow mods as an OpenFlow 1.4 atomic bundle transaction.

    •   Within a bundle, all flow mods are processed in the order they appear and as a single atomic transaction, meaning that if one of them fails, the whole transaction fails and none of the changes are made to the switch's flow table, and that each given datapath packet traversing the OpenFlow tables sees the flow tables either as before the transaction, or after all the flow mods in the bundle have been successfully applied.

    •   The beginning and the end of the flow table modification commands in a bundle are delimited with OpenFlow 1.4 bundle control messages, which makes it possible to stream the included commands without explicit OpenFlow barriers, which are otherwise used after each flow table modification command. This may make large modifications execute faster as a bundle.

    •   Bundles require OpenFlow 1.4 or higher. An explicit -O OpenFlow14 option is not needed, but you may need to enable OpenFlow 1.4 support for OVS by setting the OVSDB protocols column in the bridge table.

-F format[,format...]
    ovs-ofctl supports the following individual flow formats, any number of which may be listed as format:

    OpenFlow10-table_id
        This is the standard OpenFlow 1.0 flow format. All OpenFlow switches and all versions of Open vSwitch support this flow format.

    OpenFlow10+table_id
        This is the standard OpenFlow 1.0 flow format plus a Nicira extension that allows ovs-ofctl to specify the flow table in which a particular flow should be placed. Open vSwitch 1.2 and later supports this flow format.

    NXM-table_id (Nicira Extended Match)
        This Nicira extension to OpenFlow is flexible and extensible. It supports all of the Nicira flow extensions, such as tun_id and registers. Open vSwitch 1.1 and later supports this flow format.

    NXM+table_id (Nicira Extended Match)
        This combines Nicira Extended match with the ability to place a flow in a specific table. Open vSwitch 1.2 and later supports this flow format.

    OXM-OpenFlow12
        These are the standard OXM (OpenFlow Extensible Match) flow format in OpenFlow 1.2 and later.

    ovs-ofctl also supports the following abbreviations for collections of flow formats:

    any Any supported flow format.

    OpenFlow10
        OpenFlow10-table_id or OpenFlow10+table_id.

    NXM NXM-table_id or NXM+table_id.

    OXM OXM-OpenFlow12, OXM-OpenFlow13, or OXM-OpenFlow14.

    For commands that modify the flow table, ovs-ofctl by default negotiates the most widely supported flow format that supports the flows being added. For commands that query the flow table, ovs-ofctl by default uses the most advanced format supported by the switch.

    This option, where format is a comma-separated list of one or more of the formats listed above, limits ovs-ofctl's choice of flow format. If a command cannot work as requested using one of the specified flow formats, ovs-ofctl will report a fatal error.

-P format
    ovs-ofctl supports the following ``packet-in'' formats, in order of increasing capability:

    standard
        This uses the OFPT_PACKET_IN message, the standard ``packet-in'' message for any given OpenFlow version. Every OpenFlow switch that supports a given OpenFlow version supports this format.

    nxt_packet_in
        This uses the NXT_PACKET_IN message, which adds many of the capabilities of the OpenFlow 1.1 and later ``packet-in'' messages before those OpenFlow versions were available in Open vSwitch. Open vSwitch 1.1 and later support this format. Only Open vSwitch 2.6 and later, however, support it for OpenFlow 1.1 and later (but there is little reason to use it with those versions of OpenFlow).

    nxt_packet_in2
        This uses the NXT_PACKET_IN2 message, which is extensible and should avoid the need to define new formats later. In particular, this format supports passing arbitrary user-provided data to a controller using the userdata option on the controller action. Open vSwitch 2.6 and later support this format.

    Without this option, ovs-ofctl prefers nxt_packet_in2 if the switch supports it. Otherwise, if OpenFlow 1.0 is in use, ovs-ofctl prefers nxt_packet_in if the switch supports it. Otherwise, ovs-ofctl falls back to the standard packet-in format. When this option is specified, ovs-ofctl insists on the selected format. If the switch does not support the requested format, ovs-ofctl will report a fatal error.

    Before version 2.6, Open vSwitch called standard format openflow10 and nxt_packet_in format nxm, and ovs-ofctl still accepts these names as synonyms. (The name openflow10 was a misnomer because this format actually varies from one OpenFlow version to another; it is not consistently OpenFlow 1.0 format. Similarly, when nxt_packet_in2 was introduced, the name nxm became confusing because it also uses OXM/NXM.)

    This option affects only the monitor command.

--timestamp
    Print a timestamp before each received packet. This option only affects the monitor, snoop, and ofp-parse-pcap commands.

-m  Increases the verbosity of OpenFlow messages printed and logged by ovs-ofctl commands. Specify this option more than once to increase verbosity further.

--sort[=field]
    Display output sorted by flow field in ascending (--sort) or descending (--rsort) order, where field is any of the fields that are allowed for matching or priority to sort by priority. When field is omitted, the output is sorted by priority. Specify these options multiple times to sort by multiple fields.

    Any given flow will not necessarily specify a value for a given field. This requires special treatement:

    •   A flow that does not specify any part of a field that is used for sorting is sorted after all the flows that do specify the field. For example, --sort=tcp_src will sort all the flows that specify a TCP source port in ascending order, followed by the flows that do not specify a TCP source port at all.

    •   A flow that only specifies some bits in a field is sorted as if the wildcarded bits were zero. For example, --sort=nw_src would sort a flow that specifies nw_src=192.168.0.0/24 the same as nw_src=192.168.0.0.

    These options currently affect only dump-flows output.

  Daemon Options

  Public Key Infrastructure Options

RUNTIME MANAGEMENT COMMANDS
ovs-appctl(8) can send commands to a running ovs-ofctl process. The supported commands are listed below.

exit
    Causes ovs-ofctl to gracefully terminate. This command applies only when executing the monitor or snoop commands.

ofctl/set-output-file file
    Causes all subsequent output to go to file instead of stderr. This command applies only when executing the monitor or snoop commands.

ofctl/send ofmsg...
    Sends each ofmsg, specified as a sequence of hex digits that express an OpenFlow message, on the OpenFlow connection. This command is useful only when executing the monitor command.

ofctl/packet-out packet-out
    Sends an OpenFlow PACKET_OUT message specified in Packet-Out Syntax, on the OpenFlow connection. See Packet-Out Syntax section for more information. This command is useful only when executing the monitor command.

ofctl/barrier
    Sends an OpenFlow barrier request on the OpenFlow connection and waits for a reply. This command is useful only for the monitor command.

EXAMPLES
The following examples assume that ovs-vswitchd has a bridge named br0 configured.

ovs-ofctl dump-tables br0
    Prints out the switch's table stats. (This is more interesting after some traffic has passed through.)

ovs-ofctl dump-flows br0
    Prints the flow entries in the switch.

ovs-ofctl add-flow table=0 actions=learn(table=1,hard_timeout=10, NXM_OF_VLAN_TCI[0..11],output:NXM_OF_IN_PORT[]), resubmit(,1)
    ovs-ofctl add-flow table=1 priority=0 actions=flood Implements a level 2 MAC learning switch using the learn.

ovs-ofctl add-flow br0 'table=0,priority=0 actions=load:3->NXM_NX_REG0[0..15],learn(table=0,priority=1,idle_timeout=10,NXM_OF_ETH_SRC[],NXM_OF_VLAN_TCI[0..11],output:NXM_NX_REG0[0..15]),output:2
    In this use of a learn action, the first packet from each source MAC will be sent to port 2. Subsequent packets will be output to port 3, with an idle timeout of 10 seconds. NXM field names and match field names are both accepted, e.g. NXM_NX_REG0 or reg0 for the first register, and empty brackets may be omitted.

    Additional examples may be found documented as part of related sections.

SEE ALSO
ovs-fields(7), ovs-actions(7), ovs-appctl(8), ovs-vswitchd(8), ovs-vswitchd.conf.db(8)