path: root/utilities/ovs-ofctl.8.in

.\" -*- nroff -*-
.de IQ
.  br
.  ns
.  IP "\\$1"
..
.TH ovs\-ofctl 8 "January 2011" "Open vSwitch" "Open vSwitch Manual"
.ds PN ovs\-ofctl
.
.SH NAME
ovs\-ofctl \- administer OpenFlow switches
.
.SH SYNOPSIS
.B ovs\-ofctl
[\fIoptions\fR] \fIcommand \fR[\fIswitch\fR] [\fIargs\fR\&...]
.
.SH DESCRIPTION
The
.B 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.
.
.SS "OpenFlow Switch Management Commands"
.PP
These commands allow \fBovs\-ofctl\fR to monitor and administer an OpenFlow
switch.  It is able to show the current state of a switch, including
features, configuration, and table entries.
.PP
Most of these commands take an argument that specifies the method for
connecting to an OpenFlow switch.  The following connection methods
are supported:
.
.RS
.so lib/vconn-active.man
.
.IP "\fIfile\fR"
This is short for \fBunix:\fIfile\fR, as long as \fIfile\fR does not
contain a colon.
.
.IP \fIbridge\fR
This is short for \fBunix:@RUNDIR@/\fIbridge\fB.mgmt\fR, as long as
\fIbridge\fR does not contain a colon.
.
.IP [\fItype\fB@\fR]\fIdp\fR
Attempts to look up the bridge associated with \fIdp\fR and open as
above.  If \fItype\fR is given, it specifies the datapath provider of
\fIdp\fR, otherwise the default provider \fBsystem\fR is assumed.
.RE
.
.TP
\fBshow \fIswitch\fR
Prints to the console information on \fIswitch\fR, including
information on its flow tables and ports.
.
.TP
\fBdump\-tables \fIswitch\fR
Prints to the console statistics for each of the flow tables used by
\fIswitch\fR.
.
.TP
\fBdump\-ports \fIswitch\fR [\fInetdev\fR]
Prints to the console statistics for network devices associated with 
\fIswitch\fR.  If \fInetdev\fR is specified, only the statistics
associated with that device will be printed.  \fInetdev\fR can be an
OpenFlow assigned port number or device name, e.g. \fBeth0\fR.
.
.TP
\fBmod\-port \fIswitch\fR \fInetdev\fR \fIaction\fR
Modify characteristics of an interface monitored by \fIswitch\fR.  
\fInetdev\fR can be referred to by its OpenFlow assigned port number or 
the device name, e.g. \fBeth0\fR.  The \fIaction\fR may be any one of the
following:
.
.RS
.IP \fBup\fR
Enables the interface.  This is equivalent to ``ifconfig up'' on a Unix
system.
.
.IP \fBdown\fR
Disables the interface.  This is equivalent to ``ifconfig down'' on a Unix
system.
.
.IP \fBforward\fR
Allows forwarding of traffic on this interface.  This is the default posture
for all ports.
.
.IP \fBnoforward\fR
Disallows forwarding of traffic on this interface.
.
.IP \fBflood\fR
When a \fIflood\fR action is specified, traffic will be sent out this
interface.  This is the default posture for monitored ports.
.
.IP \fBnoflood\fR
When a \fIflood\fR action is specified, traffic will not be sent out 
this interface.  This is primarily useful to prevent loops when a
spanning tree protocol is not in use.
.
.RE
.
.IP "\fBget\-frags \fIswitch\fR"
Prints \fIswitch\fR's fragment handling mode.  See \fBset\-frags\fR,
below, for a description of each fragment handling mode.
.IP
The \fBshow\fR command also prints the fragment handling mode among
its other output.
.
.IP "\fBset\-frags \fIswitch frag_mode\fR"
Configures \fIswitch\fR's treatment of IPv4 and IPv6 fragments.  The
choices for \fIfrag_mode\fR are:
.RS
.IP "\fBnormal\fR"
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.
.IP "\fBdrop\fR"
Fragments are dropped without passing through the flow table.
.IP "\fBreassemble\fR"
The switch reassembles fragments into full IP packets before passing
them through the flow table.  Open vSwitch does not implement this
fragment handling mode.
.IP "\fBnx\-match\fR"
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.
.RE
.IP
See the description of \fBip_frag\fR, below, for a way to match on
whether a packet is a fragment and on its fragment offset.
.
.TP
\fBdump\-flows \fIswitch \fR[\fIflows\fR]
Prints to the console all flow entries in \fIswitch\fR's
tables that match \fIflows\fR.  If \fIflows\fR is omitted, all flows
in the switch are retrieved.  See \fBFlow Syntax\fR, below, for the
syntax of \fIflows\fR.  The output format is described in 
\fBTable Entry Output\fR.
.
.TP
\fBdump\-aggregate \fIswitch \fR[\fIflows\fR]
Prints to the console aggregate statistics for flows in 
\fIswitch\fR's tables that match \fIflows\fR.  If \fIflows\fR is omitted, 
the statistics are aggregated across all flows in the switch's flow
tables.  See \fBFlow Syntax\fR, below, for the syntax of \fIflows\fR.
The output format is descrbed in \fBTable Entry Output\fR.
.
.IP "\fBqueue\-stats \fIswitch \fR[\fIport \fR[\fIqueue\fR]]"
Prints to the console statistics for the specified \fIqueue\fR on
\fIport\fR within \fIswitch\fR.  Either of \fIport\fR or \fIqueue\fR
or both may be omitted (or equivalently specified as \fBALL\fR).  If
both are omitted, statistics are printed for all queues on all ports.
If only \fIqueue\fR is omitted, then statistics are printed for all
queues on \fIport\fR; if only \fIport\fR is omitted, then statistics
are printed for \fIqueue\fR on every port where it exists.
.
.SS "OpenFlow Switch Flow Table Commands"
.
These commands manage the flow table in an OpenFlow switch.  In each
case, \fIflow\fR specifies a flow entry in the format described in
\fBFlow Syntax\fR, below, and \fIfile\fR is a text file that contains
zero or more flows in the same syntax, one per line.
.
.IP "\fBadd\-flow \fIswitch flow\fR"
.IQ "\fBadd\-flow \fIswitch \fB\- < \fIfile\fR"
.IQ "\fBadd\-flows \fIswitch file\fR"
Add each flow entry to \fIswitch\fR's tables.
.
.IP "[\fB\-\-strict\fR] \fBmod\-flows \fIswitch flow\fR"
.IQ "[\fB\-\-strict\fR] \fBmod\-flows \fIswitch \fB\- < \fIfile\fR"
Modify the actions in entries from \fIswitch\fR's tables that match
the specified flows.  With \fB\-\-strict\fR, wildcards are not treated
as active for matching purposes.
.
.IP "\fBdel\-flows \fIswitch\fR"
.IQ "[\fB\-\-strict\fR] \fBdel\-flows \fIswitch \fR[\fIflow\fR]"
.IQ "[\fB\-\-strict\fR] \fBdel\-flows \fIswitch \fB\- < \fIfile\fR"
Deletes entries from \fIswitch\fR's flow table.  With only a
\fIswitch\fR argument, deletes all flows.  Otherwise, deletes flow
entries that match the specified flows.  With \fB\-\-strict\fR,
wildcards are not treated as active for matching purposes.
.
.IP "[\fB\-\-readd\fR] \fBreplace\-flows \fIswitch file\fR"
Reads flow entries from \fIfile\fR (or \fBstdin\fR if \fIfile\fR is
\fB\-\fR) and queries the flow table from \fIswitch\fR.  Then it fixes
up any differences, adding flows from \fIflow\fR that are missing on
\fIswitch\fR, deleting flows from \fIswitch\fR that are not in
\fIfile\fR, and updating flows in \fIswitch\fR whose actions, cookie,
or timeouts differ in \fIfile\fR.
.
.IP
With \fB\-\-readd\fR, \fBovs\-ofctl\fR adds all the flows from
\fIfile\fR, even those that exist with the same actions, cookie, and
timeout in \fIswitch\fR.  This resets all the flow packet and byte
counters to 0, which can be useful for debugging.
.
.IP "\fBdiff\-flows \fIsource1 source2\fR"
Reads flow entries from \fIsource1\fR and \fIsource2\fR and prints the
differences.  A flow that is in \fIsource1\fR but not in \fIsource2\fR
is printed preceded by a \fB\-\fR, and a flow that is in \fIsource2\fR
but not in \fIsource1\fR is printed preceded by a \fB+\fR.  If a flow
exists in both \fIsource1\fR and \fIsource2\fR with different actions,
cookie, or timeouts, then both versions are printed preceded by
\fB\-\fR and \fB+\fR, respectively.
.IP
\fIsource1\fR and \fIsource2\fR may each name a file or a switch.  If
a name begins with \fB/\fR or \fB.\fR, then it is considered to be a
file name.  A name that contains \fB:\fR is considered to be a switch.
Otherwise, it is a file if a file by that name exists, a switch if
not.
.IP
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.
.
.SS "OpenFlow Switch Monitoring Commands"
.
.IP "\fBsnoop \fIswitch\fR"
Connects to \fIswitch\fR and prints to the console all OpenFlow
messages received.  Unlike other \fBovs\-ofctl\fR commands, if
\fIswitch\fR is the name of a bridge, then the \fBsnoop\fR command
connects to a Unix domain socket named
\fB@RUNDIR@/\fIbridge\fB.snoop\fR.  \fBovs\-vswitchd\fR 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.
.IP
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 master or a slave (using a Nicira
extension to OpenFlow), then a controller is chosen arbitrarily among
them.  If there is a master controller, it is chosen; otherwise, if
there are any controllers that are not masters or slaves, one is
chosen arbitrarily; otherwise, a slave controller is chosen
arbitrarily.  This choice is made once at connection time and does not
change as controllers reconfigure their roles.
.IP
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.
.
.IP "\fBmonitor \fIswitch\fR [\fImiss-len\fR]"
Connects to \fIswitch\fR and prints to the console all OpenFlow
messages received.  Usually, \fIswitch\fR should specify the name of a
bridge in the \fBovs\-vswitchd\fR database.
.IP
If \fImiss-len\fR is provided, \fBovs\-ofctl\fR sends an OpenFlow ``set
configuration'' message at connection setup time that requests
\fImiss-len\fR bytes of each packet that misses the flow table.  Open vSwitch
does not send these and other asynchronous messages to an
\fBovs\-ofctl monitor\fR client connection unless a nonzero value is
specified on this argument.  (Thus, if \fImiss\-len\fR is not
specified, very little traffic will ordinarily be printed.)
.IP
This command may be useful for debugging switch or controller
implementations.
.
.SS "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.
.
.TP
\fBprobe \fItarget\fR
Sends a single OpenFlow echo-request message to \fItarget\fR and waits
for the response.  With the \fB\-t\fR or \fB\-\-timeout\fR option, this
command can test whether an OpenFlow switch or controller is up and
running.
.
.TP
\fBping \fItarget \fR[\fIn\fR]
Sends a series of 10 echo request packets to \fItarget\fR and times
each reply.  The echo request packets consist of an OpenFlow header
plus \fIn\fR bytes (default: 64) of randomly generated payload.  This
measures the latency of individual requests.
.
.TP
\fBbenchmark \fItarget n count\fR
Sends \fIcount\fR echo request packets that each consist of an
OpenFlow header plus \fIn\fR bytes of payload and waits for each
response.  Reports the total time required.  This is a measure of the
maximum bandwidth to \fItarget\fR for round-trips of \fIn\fR-byte
messages.
.
.SS "Flow Syntax"
.PP
Some \fBovs\-ofctl\fR commands accept an argument that describes a flow or
flows.  Such flow descriptions comprise a series
\fIfield\fB=\fIvalue\fR 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.)
.PP
Flow descriptions should be in \fBnormal form\fR.  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 \fBdl_type\fR is wildcarded, then L3
fields \fBnw_src\fR, \fBnw_dst\fR, and \fBnw_proto\fR must also be
wildcarded.  Similarly, if \fBdl_type\fR or \fBnw_proto\fR (the L3
protocol type) is wildcarded, so must be \fBtp_dst\fR and
\fBtp_src\fR, which are L4 fields.  \fBovs\-ofctl\fR will warn about
flows not in normal form.
.PP
The following field assignments describe how a flow matches a packet.
If any of these assignments is omitted from the flow syntax, the field
is treated as a wildcard; thus, if all of them are omitted, the
resulting flow matches all packets.  The string \fB*\fR or \fBANY\fR
may be specified to explicitly mark any of these fields as a wildcard.  
(\fB*\fR should be quoted to protect it from shell expansion.)
.
.IP \fBin_port=\fIport_no\fR
Matches OpenFlow port \fIport_no\fR.  Ports are numbered as
displayed by \fBovs\-ofctl show\fR.
.IP
(The \fBresubmit\fR action can search OpenFlow flow tables with
arbitrary \fBin_port\fR values, so flows that match port numbers that
do not exist from an OpenFlow perspective can still potentially be
matched.)
.
.IP \fBdl_vlan=\fIvlan\fR
Matches IEEE 802.1q Virtual LAN tag \fIvlan\fR.  Specify \fB0xffff\fR
as \fIvlan\fR to match packets that are not tagged with a Virtual LAN;
otherwise, specify a number between 0 and 4095, inclusive, as the
12-bit VLAN ID to match.
.
.IP \fBdl_vlan_pcp=\fIpriority\fR
Matches IEEE 802.1q Priority Code Point (PCP) \fIpriority\fR, which is
specified as a value between 0 and 7, inclusive.  A higher value
indicates a higher frame priority level.
.
.IP \fBdl_src=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBdl_dst=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
Matches an Ethernet source (or destination) address specified as 6
pairs of hexadecimal digits delimited by colons
(e.g. \fB00:0A:E4:25:6B:B0\fR).
.
.IP \fBdl_dst=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB/\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
Matches an Ethernet destination address specified as 6 pairs of
hexadecimal digits delimited by colons (e.g. \fB00:0A:E4:25:6B:B0\fR),
with a wildcard mask following the slash.  Only
the following masks are allowed:
.RS
.IP \fB01:00:00:00:00:00\fR
Match only the multicast bit.  Thus,
\fBdl_dst=01:00:00:00:00:00/01:00:00:00:00:00\fR matches all multicast
(including broadcast) Ethernet packets, and
\fBdl_dst=00:00:00:00:00:00/01:00:00:00:00:00\fR matches all unicast
Ethernet packets.
.IP \fBfe:ff:ff:ff:ff:ff\fR
Match all bits except the multicast bit.  This is probably not useful.
.IP \fBff:ff:ff:ff:ff:ff\fR
Exact match (equivalent to omitting the mask).
.IP \fB00:00:00:00:00:00\fR
Wildcard all bits (equivalent to \fBdl_dst=*\fR.)
.RE
.
.IP \fBdl_type=\fIethertype\fR
Matches Ethernet protocol type \fIethertype\fR, which is specified as an
integer between 0 and 65535, inclusive, either in decimal or as a 
hexadecimal number prefixed by \fB0x\fR (e.g. \fB0x0806\fR to match ARP 
packets).
.
.IP \fBnw_src=\fIip\fR[\fB/\fInetmask\fR]
.IQ \fBnw_dst=\fIip\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR is 0x0800 (possibly via shorthand, e.g. \fBip\fR
or \fBtcp\fR), matches IPv4 source (or destination) address \fIip\fR,
which may be specified as an IP address or host name
(e.g. \fB192.168.1.1\fR or \fBwww.example.com\fR).  The optional
\fInetmask\fR allows restricting a match to an IPv4 address prefix.
The netmask may be specified as a dotted quad
(e.g. \fB192.168.1.0/255.255.255.0\fR) or as a CIDR block
(e.g. \fB192.168.1.0/24\fR).
.IP
When \fBdl_type=0x0806\fR or \fBarp\fR is specified, matches the
\fBar_spa\fR or \fBar_tpa\fR field, respectively, in ARP packets for
IPv4 and Ethernet.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800
or 0x0806, the values of \fBnw_src\fR and \fBnw_dst\fR are ignored
(see \fBFlow Syntax\fR above).
.
.IP \fBnw_proto=\fIproto\fR
When \fBip\fR or \fBdl_type=0x0800\fR is specified, matches IP
protocol type \fIproto\fR, which is specified as a decimal number
between 0 and 255, inclusive (e.g. 1 to match ICMP packets or 6 to match
TCP packets).
.IP
When \fBipv6\fR or \fBdl_type=0x86dd\fR is specified, matches IPv6
header type \fIproto\fR, which is specified as a decimal number between
0 and 255, inclusive (e.g. 58 to match ICMPv6 packets or 6 to match
TCP).  The header type is the terminal header as described in the
\fBDESIGN\fR document.
.IP
When \fBarp\fR or \fBdl_type=0x0806\fR is specified, matches the lower
8 bits of the ARP opcode.  ARP opcodes greater than 255 are treated as
0.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800,
0x0806, or 0x86dd, the value of \fBnw_proto\fR is ignored (see \fBFlow
Syntax\fR above).
.
.IP \fBnw_tos=\fItos\fR
Matches IP ToS/DSCP or IPv6 traffic class field \fItos\fR, which is
specified as a decimal number between 0 and 255, inclusive.  Note that
the two lower reserved bits are ignored for matching purposes.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_tos\fR is ignored (see \fBFlow Syntax\fR
above).
.
.IP \fBnw_ecn=\fIecn\fR
Matches \fIecn\fR bits in IP ToS or IPv6 traffic class fields, which is
specified as a decimal number between 0 and 3, inclusive.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_ecn\fR is ignored (see \fBFlow Syntax\fR
above).
.
.IP \fBnw_ttl=\fIttl\fR
Matches IP TTL or IPv6 hop limit value \fIttl\fR, which is
specified as a decimal number between 0 and 255, inclusive.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_ttl\fR is ignored (see \fBFlow Syntax\fR
above).
.IP
.
.IP \fBtp_src=\fIport\fR
.IQ \fBtp_dst=\fIport\fR
When \fBdl_type\fR and \fBnw_proto\fR specify TCP or UDP, \fBtp_src\fR
and \fBtp_dst\fR match the UDP or TCP source or destination port
\fIport\fR, respectively. which is specified as a decimal number
between 0 and 65535, inclusive (e.g. 80 to match packets originating
from a HTTP server).
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
these settings are ignored (see \fBFlow Syntax\fR above).
.
.IP \fBicmp_type=\fItype\fR
.IQ \fBicmp_code=\fIcode\fR
When \fBdl_type\fR and \fBnw_proto\fR specify ICMP or ICMPv6, \fItype\fR
matches the ICMP type and \fIcode\fR matches the ICMP code.  Each is
specified as a decimal number between 0 and 255, inclusive.
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
these settings are ignored (see \fBFlow Syntax\fR above).
.
.IP \fBtable=\fInumber\fR
If specified, limits the flow manipulation and flow dump commands to
only apply to the table with the given \fInumber\fR between 0 and 254.
.
Behavior varies if \fBtable\fR is not specified (equivalent to
specifying 255 as \fInumber\fR).  For flow table
modification commands without \fB\-\-strict\fR, the switch will choose
the table for these commands to operate on.  For flow table
modification commands with \fB\-\-strict\fR, 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 \fBdump-flows\fR and
\fBdump-aggregate\fR commands will gather statistics about flows from
all tables.
.IP
When this field is specified in \fBadd-flow\fR, \fBadd-flows\fR,
\fBmod-flows\fR and \fBdel-flows\fR commands, it activates a Nicira
extension to OpenFlow, which as of this writing is only known to be
implemented by Open vSwitch.
.
.PP
The following shorthand notations are also available:
.
.IP \fBip\fR
Same as \fBdl_type=0x0800\fR.
.
.IP \fBicmp\fR
Same as \fBdl_type=0x0800,nw_proto=1\fR.
.
.IP \fBtcp\fR
Same as \fBdl_type=0x0800,nw_proto=6\fR.
.
.IP \fBudp\fR
Same as \fBdl_type=0x0800,nw_proto=17\fR.
.
.IP \fBarp\fR
Same as \fBdl_type=0x0806\fR.
.
.PP
The following field assignments require support for the NXM (Nicira
Extended Match) extension to OpenFlow.  When one of these is specified,
\fBovs\-ofctl\fR will automatically attempt to negotiate use of this
extension.  If the switch does not support NXM, then \fBovs\-ofctl\fR
will report a fatal error.
.
.IP \fBvlan_tci=\fItci\fR[\fB/\fImask\fR]
Matches modified VLAN TCI \fItci\fR.  If \fImask\fR is omitted,
\fItci\fR is the exact VLAN TCI to match; if \fImask\fR is specified,
then a 1-bit in \fImask\fR indicates that the corresponding bit in
\fItci\fR must match exactly, and a 0-bit wildcards that bit.  Both
\fItci\fR and \fImask\fR are 16-bit values that are decimal by
default; use a \fB0x\fR prefix to specify them in hexadecimal.
.
.IP
The value that \fBvlan_tci\fR matches against is 0 for a packet that
has no 802.1Q header.  Otherwise, it is the TCI value from the 802.1Q
header with the CFI bit (with value \fB0x1000\fR) forced to 1.
.IP
Examples:
.RS
.IP \fBvlan_tci=0\fR
Match only packets without an 802.1Q header.
.IP \fBvlan_tci=0xf123\fR
Match packets tagged with priority 7 in VLAN 0x123.
.IP \fBvlan_tci=0x1123/0x1fff\fR
Match packets tagged with VLAN 0x123 (and any priority).
.IP \fBvlan_tci=0x5000/0xf000\fR
Match packets tagged with priority 2 (in any VLAN).
.IP \fBvlan_tci=0/0xfff\fR
Match packets with no 802.1Q header or tagged with VLAN 0 (and any
priority).
.IP \fBvlan_tci=0x5000/0xe000\fR
Match packets with no 802.1Q header or tagged with priority 2 (in any
VLAN).
.IP \fBvlan_tci=0/0xefff\fR
Match packets with no 802.1Q header or tagged with VLAN 0 and priority
0.
.RE
.IP
Some of these matching possibilities can also be achieved with
\fBdl_vlan\fR and \fBdl_vlan_pcp\fR.
.
.IP \fBip_frag=\fIfrag_type\fR
When \fBdl_type\fR specifies IP or IPv6, \fIfrag_type\fR
specifies what kind of IP fragments or non-fragments to match.  The
following values of \fIfrag_type\fR are supported:
.RS
.IP "\fBno\fR"
Matches only non-fragmented packets.
.IP "\fByes\fR"
Matches all fragments.
.IP "\fBfirst\fR"
Matches only fragments with offset 0.
.IP "\fBlater\fR"
Matches only fragments with nonzero offset.
.IP "\fBnot_later\fR"
Matches non-fragmented packets and fragments with zero offset.
.RE
.IP
The \fBip_frag\fR match type is likely to be most useful in
\fBnx\-match\fR mode.  See the description of the \fBset\-frags\fR
command, above, for more details.
.
.IP \fBarp_sha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBarp_tha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR specifies ARP, \fBarp_sha\fR and \fBarp_tha\fR match
the source and target hardware address, respectively.  An address is
specified as 6 pairs of hexadecimal digits delimited by colons.
.
.IP \fBipv6_src=\fIipv6\fR[\fB/\fInetmask\fR]
.IQ \fBipv6_dst=\fIipv6\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR is 0x86dd (possibly via shorthand, e.g., \fBipv6\fR
or \fBtcp6\fR), matches IPv6 source (or destination) address \fIipv6\fR,
which may be specified as defined in RFC 2373.  The preferred format is 
\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fR, where
\fIx\fR are the hexadecimal values of the eight 16-bit pieces of the
address.  A single instance of \fB::\fR may be used to indicate multiple
groups of 16-bits of zeros.  The optional \fInetmask\fR allows
restricting a match to an IPv6 address prefix.  A netmask is specified
as a CIDR block (e.g. \fB2001:db8:3c4d:1::/64\fR).
.
.IP \fBipv6_label=\fIlabel\fR
When \fBdl_type\fR is 0x86dd (possibly via shorthand, e.g., \fBipv6\fR
or \fBtcp6\fR), matches IPv6 flow label \fIlabel\fR.
.
.IP \fBnd_target=\fIipv6\fR
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify
IPv6 Neighbor Discovery (ICMPv6 type 135 or 136), matches the target address
\fIipv6\fR.  \fIipv6\fR is in the same format described earlier for the
\fBipv6_src\fR and \fBipv6_dst\fR fields.
.
.IP \fBnd_sll=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify IPv6
Neighbor Solicitation (ICMPv6 type 135), matches the source link\-layer
address option.  An address is specified as 6 pairs of hexadecimal
digits delimited by colons.
.
.IP \fBnd_tll=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify IPv6
Neighbor Advertisement (ICMPv6 type 136), matches the target link\-layer
address option.  An address is specified as 6 pairs of hexadecimal
digits delimited by colons.
.
.IP \fBtun_id=\fItunnel-id\fR[\fB/\fImask\fR]
Matches tunnel identifier \fItunnel-id\fR.  Only packets that arrive
over a tunnel that carries a key (e.g. GRE with the RFC 2890 key
extension) will have a nonzero tunnel ID.  If \fImask\fR is omitted,
\fItunnel-id\fR is the exact tunnel ID to match; if \fImask\fR is
specified, then a 1-bit in \fImask\fR indicates that the corresponding
bit in \fItunnel-id\fR must match exactly, and a 0-bit wildcards that
bit.
.IP
In an attempt to be compatible with more switches, \fBovs\-ofctl\fR will
prefer to use the ``tunnel ID from cookie'' Nicira extension to NXM.
The use of this extension comes with three caveats: the top 32 bits of
the \fBcookie\fR (see below) are used for \fItunnel-id\fR and thus
unavailable for other use, specifying \fBtun_id\fR on \fBdump\-flows\fR
or \fBdump\-aggregate\fR has no effect, and \fImask\fR is not supported.
If any of these caveats apply, \fBovs-ofctl\fR will use NXM.
.
.IP "\fBreg\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in
register number \fIidx\fR.  The valid range of \fIidx\fR depends on
the switch.  \fIvalue\fR and \fImask\fR are 32-bit integers, by
default in decimal (use a \fB0x\fR prefix to specify hexadecimal).
Arbitrary \fImask\fR values are allowed: a 1-bit in \fImask\fR
indicates that the corresponding bit in \fIvalue\fR must match
exactly, and a 0-bit wildcards that bit.
.IP
When a packet enters an OpenFlow switch, all of the registers are set
to 0.  Only explicit Nicira extension actions change register values.
.
.PP
Defining IPv6 flows (those with \fBdl_type\fR equal to 0x86dd) requires
support for NXM.  The following shorthand notations are available for
IPv6-related flows:
.
.IP \fBipv6\fR
Same as \fBdl_type=0x86dd\fR.
.
.IP \fBtcp6\fR
Same as \fBdl_type=0x86dd,nw_proto=6\fR.
.
.IP \fBudp6\fR
Same as \fBdl_type=0x86dd,nw_proto=17\fR.
.
.IP \fBicmp6\fR
Same as \fBdl_type=0x86dd,nw_proto=58\fR.
.
.PP
Finally, field assignments to \fBduration\fR, \fBn_packets\fR, or
\fBn_bytes\fR are ignored to allow output from the \fBdump\-flows\fR
command to be used as input for other commands that parse flows.
.
.PP
The \fBadd\-flow\fR, \fBadd\-flows\fR, and \fBmod\-flows\fR commands
require an additional field, which must be the final field specified:
.
.IP \fBactions=\fR[\fItarget\fR][\fB,\fItarget\fR...]\fR
Specifies a comma-separated list of actions to take on a packet when the 
flow entry matches.  If no \fItarget\fR is specified, then packets
matching the flow are dropped.  The \fItarget\fR may be a decimal port 
number designating the physical port on which to output the packet, or one 
of the following keywords:
.
.RS
.IP \fBoutput\fR:\fIport\fR
.IQ \fBoutput\fR:\fIsrc\fB[\fIstart\fB..\fIend\fB]
Outputs the packet. If \fIport\fR is an OpenFlow port number, outputs directly
to it.  Otherwise, outputs to the OpenFlow port number read from \fIsrc\fR
which must be an NXM field as described above.  Outputting to an NXM field is
an OpenFlow extension which is not supported by standard OpenFlow switches.
.IP
Example: \fBoutput:NXM_NX_REG0[16..31]\fR outputs to the OpenFlow port number
written in the upper half of register 0.
.
.IP \fBenqueue\fR:\fIport\fB:\fIqueue\fR
Enqueues the packet on the specified \fIqueue\fR within port
\fIport\fR.  The number of supported queues depends on the switch;
some OpenFlow implementations do not support queuing at all.
.
.IP \fBnormal\fR
Subjects the packet to the device's normal L2/L3 processing.  (This
action is not implemented by all OpenFlow switches.)
.
.IP \fBflood\fR
Outputs the packet on all switch physical ports other than the port on
which it was received and any ports on which flooding is disabled
(typically, these would be ports disabled by the IEEE 802.1D spanning
tree protocol).
.
.IP \fBall\fR
Outputs the packet on all switch physical ports other than the port on
which it was received.
.
.IP \fBcontroller\fR:\fImax_len\fR
Sends the packet to the OpenFlow controller as a ``packet in''
message.  If \fImax_len\fR is a number, then it specifies the maximum
number of bytes that should be sent.  If \fImax_len\fR is \fBALL\fR or
omitted, then the entire packet is sent.
.
.IP \fBlocal\fR
Outputs the packet on the ``local port,'' which corresponds to the
network device that has the same name as the bridge.
.
.IP \fBin_port\fR
Outputs the packet on the port from which it was received.
.
.IP \fBdrop\fR
Discards the packet, so no further processing or forwarding takes place.
If a drop action is used, no other actions may be specified.
.
.IP \fBmod_vlan_vid\fR:\fIvlan_vid\fR
Modifies the VLAN id on a packet.  The VLAN tag is added or modified 
as necessary to match the value specified.  If the VLAN tag is added,
a priority of zero is used (see the \fBmod_vlan_pcp\fR action to set
this).
.
.IP \fBmod_vlan_pcp\fR:\fIvlan_pcp\fR
Modifies the VLAN priority on a packet.  The VLAN tag is added or modified 
as necessary to match the value specified.  Valid values are between 0
(lowest) and 7 (highest).  If the VLAN tag is added, a vid of zero is used 
(see the \fBmod_vlan_vid\fR action to set this).
.
.IP \fBstrip_vlan\fR
Strips the VLAN tag from a packet if it is present.
.
.IP \fBmod_dl_src\fB:\fImac\fR
Sets the source Ethernet address to \fImac\fR.
.
.IP \fBmod_dl_dst\fB:\fImac\fR
Sets the destination Ethernet address to \fImac\fR.
.
.IP \fBmod_nw_src\fB:\fIip\fR
Sets the IPv4 source address to \fIip\fR.
.
.IP \fBmod_nw_dst\fB:\fIip\fR
Sets the IPv4 destination address to \fIip\fR.
.
.IP \fBmod_tp_src\fB:\fIport\fR
Sets the TCP or UDP source port to \fIport\fR.
.
.IP \fBmod_tp_dst\fB:\fIport\fR
Sets the TCP or UDP destination port to \fIport\fR.
.
.IP \fBmod_nw_tos\fB:\fItos\fR
Sets the IP ToS/DSCP field to \fItos\fR.  Valid values are between 0 and
255, inclusive.  Note that the two lower reserved bits are never
modified.
.
.RE
.IP
The following actions are Nicira vendor extensions that, as of this writing, are
only known to be implemented by Open vSwitch:
.
.RS
.
.IP \fBresubmit\fB:\fIport\fR
.IQ \fBresubmit\fB(\fR[\fIport\fR]\fB,\fR[\fItable\fR]\fB)
Re-searches this OpenFlow flow table (or the table whose number is
specified by \fItable\fR) with the \fBin_port\fR field replaced by
\fIport\fR (if \fIport\fR is specified) and executes the actions
found, if any, in addition to any other actions in this flow entry.
.IP
Recursive \fBresubmit\fR actions are obeyed up to an
implementation-defined maximum depth.  Open vSwitch 1.0.1 and earlier
did not support recursion; Open vSwitch before 1.2.90 did not support
\fItable\fR.
.
.IP \fBset_tunnel\fB:\fIid\fR
.IQ \fBset_tunnel64\fB:\fIid\fR
If outputting to a port that encapsulates the packet in a tunnel and
supports an identifier (such as GRE), sets the identifier to \fIid\fR.
If the \fBset_tunnel\fR form is used and \fIid\fR fits in 32 bits,
then this uses an action extension that is supported by Open vSwitch
1.0 and later.  Otherwise, if \fIid\fR is a 64-bit value, it requires
Open vSwitch 1.1 or later.
.
.IP \fBset_queue\fB:\fIqueue\fR
Sets the queue that should be used to \fIqueue\fR when packets are
output.  The number of supported queues depends on the switch; some
OpenFlow implementations do not support queuing at all.
.
.IP \fBpop_queue\fR
Restores the queue to the value it was before any \fBset_queue\fR
actions were applied.
.
.IP \fBnote:\fR[\fIhh\fR]...
Does nothing at all.  Any number of bytes represented as hex digits
\fIhh\fR may be included.  Pairs of hex digits may be separated by
periods for readability.
.
.IP "\fBmove:\fIsrc\fB[\fIstart\fB..\fIend\fB]\->\fIdst\fB[\fIstart\fB..\fIend\fB]\fR"
Copies the named bits from field \fIsrc\fR to field \fIdst\fR.
\fIsrc\fR and \fIdst\fR must be NXM field names as defined in
\fBnicira\-ext.h\fR, e.g. \fBNXM_OF_UDP_SRC\fR or \fBNXM_NX_REG0\fR.
Each \fIstart\fR and \fIend\fR pair, which are inclusive, must specify
the same number of bits and must fit within its respective field.
Shorthands for \fB[\fIstart\fB..\fIend\fB]\fR exist: use
\fB[\fIbit\fB]\fR to specify a single bit or \fB[]\fR to specify an
entire field.
.IP
Examples: \fBmove:NXM_NX_REG0[0..5]\->NXM_NX_REG1[26..31]\fR copies the
six bits numbered 0 through 5, inclusive, in register 0 into bits 26
through 31, inclusive;
\fBmove:NXM_NX_REG0[0..15]\->NXM_OF_VLAN_TCI[]\fR copies the least
significant 16 bits of register 0 into the VLAN TCI field.
.
.IP "\fBload:\fIvalue\fB\->\fIdst\fB[\fIstart\fB..\fIend\fB]"
Writes \fIvalue\fR to bits \fIstart\fR through \fIend\fR, inclusive,
in field \fIdst\fR.
.IP
Example: \fBload:55\->NXM_NX_REG2[0..5]\fR loads value 55 (bit pattern
\fB110111\fR) into bits 0 through 5, inclusive, in register 2.
.
.IP "\fBmultipath(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIn_links\fB, \fIarg\fB, \fIdst\fB[\fIstart\fB..\fIend\fB])\fR"
Hashes \fIfields\fR using \fIbasis\fR as a universal hash parameter,
then the applies multipath link selection \fIalgorithm\fR (with
parameter \fIarg\fR) to choose one of \fIn_links\fR output links
numbered 0 through \fIn_links\fR minus 1, and stores the link into
\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as
described above.
.IP
Currently, \fIfields\fR must be either \fBeth_src\fR or
\fBsymmetric_l4\fR and \fIalgorithm\fR must be one of \fBmodulo_n\fR,
\fBhash_threshold\fR, \fBhrw\fR, and \fBiter_hash\fR.  Only
the \fBiter_hash\fR algorithm uses \fIarg\fR.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBautopath(\fIid\fB, \fIdst\fB[\fIstart\fB..\fIend\fB])\fR"
Given \fIid\fR, chooses an OpenFlow port and populates it in
\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as
described above.
.IP
Currently, \fIid\fR should be the OpenFlow port number of an interface on the
bridge.  If it isn't then \fIdst\fB[\fIstart\fB..\fIend\fB]\fR will be
populated with the OpenFlow port "none".  If \fIid\fR is a member of a bond,
the normal bond selection logic will be used to choose the destination port.
Otherwise, the register will be populated with \fIid\fR itself.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBbundle(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIslave_type\fB, slaves:[\fIs1\fB, \fIs2\fB, ...])\fR"
Hashes \fIfields\fR using \fIbasis\fR as a universal hash parameter, then
applies the bundle link selection \fIalgorithm\fR to choose one of the listed
slaves represented as \fIslave_type\fR.  Currently the only supported
\fIslave_type\fR is \fBofport\fR.  Thus, each \fIs1\fR through \fIsN\fR should
be an OpenFlow port number. Outputs to the selected slave.
.IP
Currently, \fIfields\fR must be either \fBeth_src\fR or \fBsymmetric_l4\fR and
\fIalgorithm\fR must be one of \fBhrw\fR and \fBactive_backup\fR.
.IP
Example: \fBbundle(eth_src,0,hrw,ofport,slaves:4,8)\fR uses an Ethernet source
hash with basis 0, to select between OpenFlow ports 4 and 8 using the Highest
Random Weight algorithm.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBbundle_load(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIslave_type\fB, \fIdst\fB[\fIstart\fB..\fIend\fB], slaves:[\fIs1\fB, \fIs2\fB, ...])\fR"
Has the same behavior as the \fBbundle\fR action, with one exception.  Instead
of outputting to the selected slave, it writes its selection to
\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as described
above.
.IP
Example: \fBbundle_load(eth_src, 0, hrw, ofport, NXM_NX_REG0[],
slaves:4, 8)\fR uses an Ethernet source hash with basis 0, to select
between OpenFlow ports 4 and 8 using the Highest Random Weight
algorithm, and writes the selection to \fBNXM_NX_REG0[]\fR.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBlearn(\fIargument\fR[\fB,\fIargument\fR]...\fB)\fR"
This action adds or modifies a flow in an OpenFlow table, similar to
\fBovs\-ofctl \-\-strict mod\-flows\fR.  The arguments specify the
flow's match fields, actions, and other properties, as follows.  At
least one match criterion and one action argument should ordinarily be
specified.
.RS
.IP \fBidle_timeout=\fIseconds\fR
.IQ \fBhard_timeout=\fIseconds\fR
.IQ \fBpriority=\fIvalue\fR
These key-value pairs have the same meaning as in the usual
\fBovs\-ofctl\fR flow syntax.
.
.IP \fBtable=\fInumber\fR
The table in which the new flow should be inserted.  Specify a decimal
number between 0 and 254.  The default, if \fBtable\fR is unspecified,
is table 1.
.
.IP \fIfield\fB=\fIvalue\fR
.IQ \fIfield\fB[\fIstart\fB..\fIend\fB]=\fIsrc\fB[\fIstart\fB..\fIend\fB]\fR
.IQ \fIfield\fB[\fIstart\fB..\fIend\fB]\fR
Adds a match criterion to the new flow.
.IP
The first form specifies that \fIfield\fR must match the literal
\fIvalue\fR, e.g. \fBdl_type=0x0800\fR.  All of the fields and values
for \fBovs\-ofctl\fR flow syntax are available with their usual
meanings.
.IP
The second form specifies that \fIfield\fB[\fIstart\fB..\fIend\fB]\fR
in the new flow must match \fIsrc\fB[\fIstart\fB..\fIend\fB]\fR taken
from the flow currently being processed.
.IP
The third form is a shorthand for the second form.  It specifies that
\fIfield\fB[\fIstart\fB..\fIend\fB]\fR in the new flow must match
\fIfield\fB[\fIstart\fB..\fIend\fB]\fR taken from the flow currently
being processed.
.
.IP \fBload:\fIvalue\fB\->\fIdst\fB[\fIstart\fB..\fIend\fB]
.IQ \fBload:\fIsrc\fB[\fIstart\fB..\fIend\fB]\->\fIdst\fB[\fIstart\fB..\fIend\fB]
.
Adds a \fBload\fR action to the new flow.
.IP
The first form loads the literal \fIvalue\fR into bits \fIstart\fR
through \fIend\fR, inclusive, in field \fIdst\fR.  Its syntax is the
same as the \fBload\fR action described earlier in this section.
.IP
The second form loads \fIsrc\fB[\fIstart\fB..\fIend\fB]\fR, a value
from the flow currently being processed, into bits \fIstart\fR
through \fIend\fR, inclusive, in field \fIdst\fR.
.
.IP \fBoutput:\fIfield\fB[\fIstart\fB..\fIend\fB]\fR
Add an \fBoutput\fR action to the new flow's actions, that outputs to
the OpenFlow port taken from \fIfield\fB[\fIstart\fB..\fIend\fB]\fR,
which must be an NXM field as described above.
.RE
.IP
For best performance, segregate learned flows into a table (using
\fBtable=\fInumber\fR) that is not used for any other flows except
possibly for a lowest-priority ``catch-all'' flow, that is, a flow
with no match criteria.  (This is why the default \fBtable\fR is 1, to
keep the learned flows separate from the primary flow table 0.)
.RE
.
.IP "\fBexit\fR"
This action causes Open vSwitch to immediately halt execution of further
actions.  Those actions which have already been executed are unaffected.  Any
further actions, including those which may be in other tables, or different
levels of the \fBresubmit\fR call stack, are ignored.
.
.PP
The \fBadd\-flow\fR, \fBadd\-flows\fR, and \fBmod\-flows\fR commands
support an additional optional field:
.
.IP \fBcookie=\fIvalue\fR
.
A cookie is an opaque identifier that can be associated with the flow.
\fIvalue\fR can be any 64-bit number and need not be unique among
flows.  If this field is omitted, these commands set a default cookie
value of 0.
.
.PP
The following additional field sets the priority for flows added by
the \fBadd\-flow\fR and \fBadd\-flows\fR commands.  For
\fBmod\-flows\fR and \fBdel\-flows\fR when \fB\-\-strict\fR is
specified, priority must match along with the rest of the flow
specification.  Other commands do not allow priority to be specified.
.
.IP \fBpriority=\fIvalue\fR
The priority at which a wildcarded entry will match in comparison to
others.  \fIvalue\fR is a number between 0 and 65535, inclusive.  A higher 
\fIvalue\fR 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.
.
.PP
The \fBadd\-flow\fR and \fBadd\-flows\fR commands support additional
optional fields:
.
.TP
\fBidle_timeout=\fIseconds\fR
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.
.
.IP \fBhard_timeout=\fIseconds\fR
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.
.
.PP
The \fBdump\-flows\fR, \fBdump\-aggregate\fR, \fBdel\-flow\fR 
and \fBdel\-flows\fR commands support one additional optional field:
.
.TP
\fBout_port=\fIport\fR
If set, a matching flow must include an output action to \fIport\fR.
.
.SS "Table Entry Output"
.
The \fBdump\-tables\fR and \fBdump\-aggregate\fR commands print information 
about the entries in a datapath's tables.  Each line of output is a 
unique flow entry, which begins with some common information:
.
.IP \fBduration\fR
The number of seconds the entry has been in the table.
.
.IP \fBtable_id\fR
The table that contains the flow.  When a packet arrives, the switch 
begins searching for an entry at the lowest numbered table.  Tables are 
numbered as shown by the \fBdump\-tables\fR command.
.
.IP \fBpriority\fR
The priority of the entry in relation to other entries within the same
table.  A higher value will match before a lower one.
.
.IP \fBn_packets\fR
The number of packets that have matched the entry.
.
.IP \fBn_bytes\fR
The total number of bytes from packets that have matched the entry.
.
.PP
The rest of the line consists of a description of the flow entry as 
described in \fBFlow Syntax\fR, above.
.
.
.SH OPTIONS
.TP
\fB\-\-strict\fR
Uses strict matching when running flow modification commands.
.
.IP "\fB\-F \fIformat\fR"
.IQ "\fB\-\-flow\-format=\fIformat\fR"
\fBovs\-ofctl\fR supports the following flow formats, in order of
increasing capability:
.RS
.IP "\fBopenflow10\fR"
This is the standard OpenFlow 1.0 flow format.  It should be supported
by all OpenFlow switches.
.
.IP "\fBnxm\fR (Nicira Extended Match)"
This Nicira extension to OpenFlow is flexible and extensible.  It
supports all of the Nicira flow extensions, such as \fBtun_id\fR and
registers.
.RE
.IP
Usually, \fBovs\-ofctl\fR picks the correct format automatically.  For
commands that modify the flow table, \fBovs\-ofctl\fR by default uses
the most widely supported flow format that supports the flows being
added.  For commands that query the flow table, \fBovs\-ofctl\fR by
default queries and uses the most advanced format supported by the
switch.
.IP
This option, where \fIformat\fR is one of the formats listed in the
above table, overrides \fBovs\-ofctl\fR's default choice of flow
format.  If a command cannot work as requested using the requested
flow format, \fBovs\-ofctl\fR will report a fatal error.
.
.IP "\fB\-m\fR"
.IQ "\fB\-\-more\fR"
Increases the verbosity of OpenFlow messages printed and logged by
\fBovs\-ofctl\fR commands.  Specify this option more than once to
increase verbosity further.
.SS "Public Key Infrastructure Options"
.so lib/ssl.man
.so lib/vlog.man
.so lib/common.man
.
.SH EXAMPLES
.
The following examples assume that \fBovs\-vswitchd\fR has a bridge
named \fBbr0\fR configured.
.
.TP
\fBovs\-ofctl dump\-tables br0\fR
Prints out the switch's table stats.  (This is more interesting after
some traffic has passed through.)
.
.TP
\fBovs\-ofctl dump\-flows br0\fR
Prints the flow entries in the switch.
.
.SH "SEE ALSO"
.
.BR ovs\-appctl (8),
.BR ovs\-controller (8),
.BR ovs\-vswitchd (8)