BRIDGE(8) Linux

BRIDGE(8)

NAME
bridge - show / manipulate bridge addresses and devices

SYNOPSIS
bridge [ OPTIONS ] OBJECT { COMMAND | help }

OBJECT := { link | fdb | mdb | vlan | monitor }

OPTIONS := { -V[ersion] | -s[tatistics] | -n[etns] name | -b[atch] filename

| -j[son] }

bridge link set dev DEV [ cost COST ] [ priority PRIO ] [ state STATE]
[ guard { on | off } ] [ hairpin { on | off } ] [
fastleave { on | off } ] [ root_block { on | off } ] [ learning { on
| off } ] [ learning_sync { on | off } ] [
flood { on | off } ] [ hwmode { vepa | veb } ] [ mcast_flood { on |
off } ] [ self ] [ master ]

bridge link [ show ] [ dev DEV ]

bridge fdb { add | append | del | replace } LLADDR dev DEV { local | static
| dynamic } [ self ] [ master ] [ router ] [
use ] [ dst IPADDR ] [ vni VNI ] [ port PORT ] [ via DEVICE ]

bridge fdb [ show ] [ dev DEV ]

bridge mdb { add | del } dev DEV port PORT grp GROUP [ permanent | temp ]
[ vid VID ]

bridge mdb show [ dev DEV ]

bridge vlan { add | del } dev DEV vid VID [ pvid ] [ untagged ] [ self ]
[ master ]

bridge vlan [ show ] [ dev DEV ]

bridge monitor [ all | neigh | link | mdb ]

OPTIONS
-V, -Version
print the version of the bridge utility and exit.

-s, -stats, -statistics

output more information. If this option is given multiple times, the
amount of information increases. As a rule,
the information is statistics or some time values.

-d, -details
print detailed information about MDB router ports.

-n, -net, -netns <NETNS>

switches bridge to the specified network namespace NETNS. Actually
it just simplifies executing of:

ip netns exec NETNS bridge [ OPTIONS ] OBJECT { COMMAND | help }

 to

bridge -n[etns] NETNS [ OPTIONS ] OBJECT { COMMAND | help }

-b, -batch <FILENAME>

Read commands from provided file or standard input and invoke them.
First failure will cause termination of bridge
command.

-force Don't terminate bridge command on errors in batch mode. If there

were any errors during execution of the commands,
the application return code will be non zero.

-json Display results in JSON format. Currently available for vlan and fdb.

BRIDGE - COMMAND SYNTAX

OBJECT
link - Bridge port.

fdb - Forwarding Database entry.

mdb - Multicast group database entry.

vlan - VLAN filter list.

COMMAND
Specifies the action to perform on the object. The set of possible actions
depends on the object type. As a rule, it is
possible to add, delete and show (or list ) objects, but some objects do not
allow all of these operations or have some
additional commands. The help command is available for all objects. It
prints out a list of available commands and argument
syntax conventions.

If no command is given, some default command is assumed. Usually it is list

or, if the objects of this class cannot be
listed, help.

bridge link - bridge port

link objects correspond to the port devices of the bridge.

The corresponding commands set and display port status and bridge specific
attributes.

bridge link set - set bridge specific attributes on a port

dev NAME
interface name of the bridge port

cost COST
the STP path cost of the specified port.

priority PRIO
the STP port priority. The priority value is an unsigned 8-bit
quantity (number between 0 and 255). This metric is
used in the designated port an droot port selectio algorithms.

state STATE
the operation state of the port. This is primarily used by user space
STP/RSTP implementation. One may enter a low‐
 ercased port state name, or one of the numbers below. Negative inputs
are ignored, and unrecognized names return an
error.

0 - port is DISABLED. Make this port completely inactive.

1 - STP LISTENING state. Only valid if STP is enabled on the bridge.

In this state the port listens for STP BPDUs
and drops all other traffic frames.

2 - STP LEARNING state. Only valid if STP is enabled on the bridge.

In this state the port will accept traffic only
for the purpose of updating MAC address tables.

3 - STP FORWARDING state. Port is fully active.

4 - STP BLOCKING state. Only valid if STP is enabled on the bridge.

This state is used during the STP election
process. In this state, port will only process STP BPDUs.

guard on or guard off

Controls whether STP BPDUs will be processed by the bridge port. By
default, the flag is turned off allowed BPDU
processing. Turning this flag on will cause the port to stop
processing STP BPDUs.

hairpin on or hairpin off

Controls whether traffic may be send back out of the port on which it
was received. By default, this flag is turned
off and the bridge will not forward traffic back out of the receiving
port.

fastleave on or fastleave off

This flag allows the bridge to immediately stop multicast traffic on
a port that receives IGMP Leave message. It is
only used with IGMP snooping is enabled on the bridge. By default the
flag is off.

root_block on or root_block off

Controls whether a given port is allowed to become root port or not.
Only used when STP is enabled on the bridge. By
default the flag is off.

learning on or learning off

Controls whether a given port will learn MAC addresses from received
traffic or not. If learning if off, the bridge
will end up flooding any traffic for which it has no FDB entry. By
default this flag is on.

learning_sync on or learning_sync off

Controls whether a given port will sync MAC addresses learned on
device port to bridge FDB.

flooding on or flooding off

Controls whether a given port will flood unicast traffic for which
there is no FDB entry. By default this flag is
on.

hwmode Some network interface cards support HW bridge functionality and they
may be configured in different modes. Cur‐
rently support modes are:

vepa - Data sent between HW ports is sent on the wire to the external
switch.

veb - bridging happens in hardware.

mcast_flood on or mcast_flood off

Controls whether a given port will be flooded with multicast traffic
for which there is no MDB entry. By default
this flag is on.

self link setting is configured on specified physical device

master link setting is configured on the software bridge (default)

-t, -timestamp
display current time when using monitor option.

bridge link show - list bridge port configuration.

This command displays the current bridge port configuration and flags.

bridge fdb - forwarding database management

fdb objects contain known Ethernet addresses on a link.

The corresponding commands display fdb entries, add new entries, append
entries, and delete old ones.

bridge fdb add - add a new fdb entry

This command creates a new fdb entry.

LLADDR the Ethernet MAC address.

dev DEV
the interface to which this address is associated.

local - is a local permanent fdb entry

static - is a static (no arp) fdb entry

dynamic - is a dynamic reachable age-able fdb entry

self - the address is associated with the port drivers fdb. Usually
hardware.

master - the address is associated with master devices fdb. Usually

software (default).

router - the destination address is associated with a router. Valid

if the referenced device is a VXLAN type device
and has route shortcircuit enabled.

use - the address is in use. User space can use this option to
indicate to the kernel that the fdb entry is in use.

The next command line parameters apply only when the specified device DEV is
of type VXLAN.
 dst IPADDR
the IP address of the destination VXLAN tunnel endpoint where the
Ethernet MAC ADDRESS resides.

vni VNI
the VXLAN VNI Network Identifier (or VXLAN Segment ID) to use to
connect to the remote VXLAN tunnel endpoint. If
omitted the value specified at vxlan device creation will be used.

port PORT
the UDP destination PORT number to use to connect to the remote VXLAN
tunnel endpoint. If omitted the default value
is used.

via DEVICE
device name of the outgoing interface for the VXLAN device driver to
reach the remote VXLAN tunnel endpoint.

bridge fdb append - append a forwarding database entry

This command adds a new fdb entry with an already known LLADDR. Valid only
for multicast link layer addresses. The com‐
mand adds support for broadcast and multicast Ethernet MAC addresses. The
Ethernet MAC address is added multiple times
into the forwarding database and the vxlan device driver sends a copy of the
data packet to each entry found.

The arguments are the same as with bridge fdb add.

bridge fdb delete - delete a forwarding database entry

This command removes an existing fdb entry.

The arguments are the same as with bridge fdb add.

bridge fdb replace - replace a forwarding database entry

If no matching entry is found, a new one will be created instead.

The arguments are the same as with bridge fdb add.

bridge fdb show - list forwarding entries.

This command displays the current forwarding table.

With the -statistics option, the command becomes verbose. It prints out the
last updated and last used time for each entry.

bridge mdb - multicast group database management

mdb objects contain known IP multicast group addresses on a link.

The corresponding commands display mdb entries, add new entries, and delete
old ones.

bridge mdb add - add a new multicast group database entry

This command creates a new mdb entry.

dev DEV
the interface where this group address is associated.

port PORT
the port whose link is known to have members of this multicast group.
 grp GROUP
the IP multicast group address whose members reside on the link
connected to the port.

permanent - the mdb entry is permanent

temp - the mdb entry is temporary (default)

vid VID
the VLAN ID which is known to have members of this multicast group.

bridge mdb delete - delete a multicast group database entry

This command removes an existing mdb entry.

The arguments are the same as with bridge mdb add.

bridge mdb show - list multicast group database entries

This command displays the current multicast group membership table. The
table is populated by IGMP and MLD snooping in the
bridge driver automatically. It can be altered by bridge mdb add and bridge
mdb del commands manually too.

dev DEV
the interface only whose entries should be listed. Default is to list
all bridge interfaces.

With the -details option, the command becomes verbose. It prints out the
ports known to have a connected router.

With the -statistics option, the command displays timer values for mdb and
router port entries.

bridge vlan - VLAN filter list

vlan objects contain known VLAN IDs for a link.

The corresponding commands display vlan filter entries, add new entries, and
delete old ones.

bridge vlan add - add a new vlan filter entry

This command creates a new vlan filter entry.

dev NAME
the interface with which this vlan is associated.

vid VID
the VLAN ID that identifies the vlan.

pvid the vlan specified is to be considered a PVID at ingress. Any

untagged frames will be assigned to this VLAN.

untagged
the vlan specified is to be treated as untagged on egress.

self the vlan is configured on the specified physical device. Required if

the device is the bridge device.

master the vlan is configured on the software bridge (default).

bridge vlan delete - delete a vlan filter entry

 This command removes an existing vlan filter entry.

The arguments are the same as with bridge vlan add. The pvid and untagged
flags are ignored.

bridge vlan show - list vlan configuration.

This command displays the current VLAN filter table.

With the -statistics option, the command displays per-vlan traffic

statistics.

bridge monitor - state monitoring

The bridge utility can monitor the state of devices and addresses
continuously. This option has a slightly different for‐
mat. Namely, the monitor command is the first in the command line and then
the object list follows:

bridge monitor [ all | OBJECT-LIST ]

OBJECT-LIST is the list of object types that we want to monitor. It may

contain link, fdb, and mdb. If no file argument
is given, bridge opens RTNETLINK, listens on it and dumps state changes in
the format described in previous sections.

If a file name is given, it does not listen on RTNETLINK, but opens the file
containing RTNETLINK messages saved in binary
format and dumps them.

NOTES
This command uses facilities added in Linux 3.0.

Although the forwarding table is maintained on a per-bridge device basis the

bridge device is not part of the syntax. This
is a limitation of the underlying netlink neighbour message protocol. When
displaying the forwarding table, entries for all
bridges are displayed. Add/delete/modify commands determine the underlying
bridge device based on the bridge to which the
corresponding ethernet device is attached.

SEE ALSO
ip(8)

BUGS
Please direct bugreports and patches to: <netdev@vger.kernel.org>

AUTHOR
Original Manpage by Stephen Hemminger

iproute2 1 August 2012

BRIDGE(8)