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.
OpenFlowSwitchManagementCommands
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:
ssl:host[:port]
tcp:host[:port]
The specified port on the given host, which can be expressed either as a DNS name (if built
with unbound library) or an IP address in IPv4 or IPv6 address format. Wrap IPv6 addresses
in square brackets, e.g. tcp:[::1]:6653. On Linux, use %device to designate a scope for
IPv6 link-level addresses, e.g. tcp:[fe80::1234%eth0]:6653. For ssl, the --private-key,
--certificate, and --ca-cert options are mandatory.
If port is not specified, it defaults to 6653.
unix:file
On POSIX, a Unix domain server socket named file.
On Windows, connect to a local named pipe that is represented by a file created in the path
file to mimic the behavior of a Unix domain socket.
file This is short for unix:file, as long as file does not contain a colon.
bridge This is short for unix:/var/run/openvswitch/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.
showswitch
Prints to the console information on switch, including information on its flow tables and ports.
dump-tablesswitch
Prints to the console statistics for each of the flow tables used by switch.
dump-table-featuresswitch
Prints to the console features for each of the flow tables used by switch.
dump-table-descswitch
Prints to the console configuration for each of the flow tables used by switch for OpenFlow 1.4+.
mod-tableswitchtablesetting
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-portsswitch [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-descswitch [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-portswitchportaction
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:
updown Enable or disable the interface. This is equivalent to iplinksetup or iplinksetdown
on a Unix system.
stpno-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.
receiveno-receivereceive-stpno-receive-stp
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.
forwardno-forward
Allow or disallow forwarding of traffic to this interface. By default, forwarding is
enabled.
floodno-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-inno-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-fragsswitch
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-fragsswitchfrag_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-flowsswitch [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 FlowSyntax, below, for the syntax of flows. The
output format is described in TableEntryOutput.
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-aggregateswitch [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
FlowSyntax, below, for the syntax of flows. The output format is described in TableEntryOutput.
queue-statsswitch [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-configswitch[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-bridgeswitch
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-flowswitch
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-zoneswitchzone
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-flushswitch[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.
OpenFlowSwitchFlowTableCommands
These commands manage the flow table in an OpenFlow switch. In each case, flow specifies a flow entry in
the format described in FlowSyntax, 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-flowswitchflow
[--bundle] add-flowswitch-<file
[--bundle] add-flowsswitchfile
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-flowsswitchflow
[--bundle] [--strict] mod-flowsswitch-<file
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-flowsswitch
[--bundle] [--strict] del-flowsswitch [flow]
[--bundle] [--strict] del-flowsswitch-<file
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-flowsswitchfile
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-flowssource1source2
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-outswitchpacket-out
Connects to switch and instructs it to execute the packet-out OpenFlow message, specified as
defined in Packet-OutSyntax section.
GroupTableCommands
These commands manage the group table in an OpenFlow switch. In each case, group specifies a group entry
in the format described in GroupSyntax, 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-groupswitchgroup
[--bundle] add-groupswitch-<file
[--bundle] add-groupsswitchfile
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-groupswitchgroup
[--bundle] [--may-create] mod-groupswitch-<file
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-groupsswitch
[--bundle] del-groupsswitch [group]
[--bundle] del-groupsswitch-<file
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-bucketsswitchgroup
[--bundle] insert-bucketsswitch-<file
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-bucketsswitchgroup
[--bundle] remove-bucketsswitch-<file
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-groupsswitch [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-featuresswitch
Prints to the console the group features of the switch.
dump-group-statsswitch [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.
OpenFlow1.3+SwitchMeterTableCommands
These commands manage the meter table in an OpenFlow switch. In each case, meter specifies a meter entry
in the format described in MeterSyntax, 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-meterswitchmeter
Add a meter entry to switch's tables. The meter syntax is described in section MeterSyntax,
below.
mod-meterswitchmeter
Modify an existing meter.
del-metersswitch [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-metersswitch [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-statsswitch [meter]
Print meter statistics. meter can specify a single meter with syntax meter=id, or all meters with
syntax meter=all.
meter-featuresswitch
Print meter features.
OpenFlowSwitchBundleCommand
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 FlowSyntax, GroupSyntax, or
Packet-OutSyntax, 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.
bundleswitchfile
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.
OpenFlowSwitchTunnelTLVTableCommands
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-mapswitchoption[,option]...
Add each option to switch's tables. Duplicate fields are rejected.
del-tlv-mapswitch [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-mapswitch
Show the currently mapped fields in the switch's option table as well as switch capabilities.
OpenFlowSwitchMonitoringCommandssnoopswitch
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 /var/run/openvswitch/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.
monitorswitch [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-ofctlmonitor 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-ofctlmonitor 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 RUNTIMEMANAGEMENTCOMMANDS.)
!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.
OpenFlowSwitchandControllerCommands
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.
probetarget
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.
pingtarget [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.
benchmarktargetncount
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.
OtherCommandsofp-parsefile
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-pcapfile [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/TLS encrypted traffic. It does not understand IPv6.
FlowSyntax
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 normalform. 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=...
n_packet=...
n_bytes=...
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-ofctlmod-flowsbr0cookie=1,actions=normal
Change all flows' cookies to 1 and change their actions to normal.
ovs-ofctlmod-flowsbr0cookie=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_countsno_byte_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.
TableEntryOutput
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 FlowSyntax, 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-OutSyntaxovs-ofctlbundle 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-ofctlpacket-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 tunnelfields and registerfields 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 FlowSyntax 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.
GroupSyntax
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.
fffast_failover
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=fieldfields(field[=mask]...)
The field parameters to selection method selected by the selection_method field. The syntax is
described in FlowSyntax 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 FlowSyntax 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.
MeterSyntax
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.
kbpspktps 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.
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