2020-11-29 21:52:28 +01:00

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.. _bridge-interface:
######
Bridge
######
A Bridge is a way to connect two Ethernet segments together in a
protocol independent way. Packets are forwarded based on Ethernet
address, rather than IP address (like a router). Since forwarding is
done at Layer 2, all protocols can go transparently through a bridge.
The Linux bridge code implements a subset of the ANSI/IEEE 802.1d
standard.
.. note:: Spanning Tree Protocol is not enabled by default in VyOS.
:ref:`stp` can be easily enabled if needed.
*************
Configuration
*************
Common interface configuration
==============================
.. cmdinclude:: ../_include/interface-common-with-dhcp.txt
:var0: bridge
:var1: br0
Member Interfaces
=================
.. cfgcmd:: set interfaces bridge <interface> member interface <member>
Assign `<member>` interface to bridge `<interface>`. A completion
helper will help you with all allowed interfaces which can be
bridged. This includes :ref:`ethernet-interface`,
:ref:`bond-interface`, :ref:`l2tpv3-interface`, :ref:`openvpn`,
:ref:`vxlan-interface`, :ref:`wireless-interface`,
:ref:`tunnel-interface` and :ref:`geneve-interface`.
.. cfgcmd:: set interfaces bridge <interface> member interface <member>
priority <priority>
Configure individual bridge port `<priority>`.
Each bridge has a relative priority and cost. Each interface is
associated with a port (number) in the STP code. Each has a priority
and a cost, that is used to decide which is the shortest path to
forward a packet. The lowest cost path is always used unless the
other path is down. If you have multiple bridges and interfaces then
you may need to adjust the priorities to achieve optimium
performance.
.. cfgcmd:: set interfaces bridge <interface> member interface <member>
cost <cost>
Path `<cost>` value for Spanning Tree Protocol. Each interface in a
bridge could have a different speed and this value is used when
deciding which link to use. Faster interfaces should have lower
costs.
Bridge Options
==============
.. cfgcmd:: set interfaces bridge <interface> aging <time>
MAC address aging `<time`> in seconds (default: 300).
.. cfgcmd:: set interfaces bridge <interface> max-age <time>
Bridge maximum aging `<time>` in seconds (default: 20).
If a another bridge in the spanning tree does not send out a hello
packet for a long period of time, it is assumed to be dead.
.. cfgcmd:: set interfaces bridge <interface> igmp querier
Enable IGMP querier
.. _stp:
STP Parameter
-------------
:abbr:`STP (Spanning Tree Protocol)` is a network protocol that builds a
loop-free logical topology for Ethernet networks. The basic function of
STP is to prevent bridge loops and the broadcast radiation that results
from them. Spanning tree also allows a network design to include backup
links providing fault tolerance if an active link fails.
.. cfgcmd:: set interfaces bridge <interface> stp
Enable spanning tree protocol. STP is disabled by default.
.. cfgcmd:: set interfaces bridge <interface> forwarding-delay <delay>
Spanning Tree Protocol forwarding `<delay>` in seconds (default: 15).
Forwarding delay time is the time spent in each of the Listening and
Learning states before the Forwarding state is entered. This delay is
so that when a new bridge comes onto a busy network it looks at some
traffic before participating.
.. cfgcmd:: set interfaces bridge <interface> hello-time <interval>
Spanning Tree Protocol hello advertisement `<interval>` in seconds
(default: 2).
Periodically, a hello packet is sent out by the Root Bridge and the
Designated Bridges. Hello packets are used to communicate information
about the topology throughout the entire Bridged Local Area Network.
VLAN
====
.. cmdinclude:: ../_include/interface-vlan-8021q.txt
:var0: bridge
:var1: br0
.. cfgcmd:: set interfaces bridge <interface> member interface <member>
native-vlan <vlan-id>
Set the native VLAN ID flag of the interface. When a data packet without a
VLAN tag enters the port, the data packet will be forced to add a tag of a
specific vlan id. When the vlan id flag flows out, the tag of the vlan id
will be stripped
.. cfgcmd:: set interfaces bridge <interface> member interface <member>
allowed-vlan <vlan-id>
Allows specific VLAN IDs to pass through the bridge member interface. This
can either be an individual VLAN id or a range of VLAN ids delimited by a
hyphen.
*******
Example
*******
Creating a bridge interface is very simple. In this example we will
have:
* A bridge named `br100`
* Member interfaces `eth1` and VLAN 10 on interface `eth2`
* Enable STP
* Bridge answers on IP address 192.0.2.1/24 and 2001:db8::ffff/64
.. code-block:: none
set interfaces bridge br100 address 192.0.2.1/24
set interfaces bridge br100 address 2001:db8::ffff/64
set interfaces bridge br100 member interface eth1
set interfaces bridge br100 member interface eth2.10
set interfaces bridge br100 stp
This results in the active configuration:
.. code-block:: none
vyos@vyos# show interfaces bridge br100
address 192.0.2.1/24
address 2001:db8::ffff/64
member {
interface eth1 {
}
interface eth2.10 {
}
}
stp
*******
Example
*******
An example of creating a VLAN-aware bridge is as follows:
* A bridge named `br100`
* The member interface `eth1` is a trunk that allows VLAN 10 to pass
* VLAN 10 on member interface `eth2` (ACCESS mode)
* Enable STP
* Bridge answers on IP address 192.0.2.1/24 and 2001:db8::ffff/64
.. code-block:: none
set interfaces bridge br100 member interface eth1 allowed-vlan 10
set interfaces bridge br100 member interface eth2 native-vlan 10
set interfaces bridge br100 vif 10 address 192.0.2.1/24
set interfaces bridge br100 vif 10 address 2001:db8::ffff/64
set interfaces bridge br100 stp
This results in the active configuration:
.. code-block:: none
vyos@vyos# show interfaces bridge br100
member {
interface eth1 {
allowed-vlan 10
}
interface eth2 {
native-vlan 10
}
}
stp
vif 10 {
address 192.0.2.1/24
address 2001:db8::ffff/64
}
*******
Example
*******
.. opcmd:: show bridge
The `show bridge` operational command can be used to display
configured bridges:
.. code-block:: none
vyos@vyos:~$ show bridge
bridge name bridge id STP enabled interfaces
br100 8000.0050569d11df yes eth1
eth2.10
.. opcmd:: show bridge <name> spanning-tree
Show bridge `<name>` STP configuration.
.. code-block:: none
vyos@vyos:~$ show bridge br100 spanning-tree
br100
bridge id 8000.0050569d11df
designated root 8000.0050569d11df
root port 0 path cost 0
max age 20.00 bridge max age 20.00
hello time 2.00 bridge hello time 2.00
forward delay 14.00 bridge forward delay 14.00
ageing time 300.00
hello timer 0.06 tcn timer 0.00
topology change timer 0.00 gc timer 242.02
flags
eth1 (1)
port id 8001 state disabled
designated root 8000.0050569d11df path cost 100
designated bridge 8000.0050569d11df message age timer 0.00
designated port 8001 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags
eth2.10 (2)
port id 8002 state disabled
designated root 8000.0050569d11df path cost 100
designated bridge 8000.0050569d11df message age timer 0.00
designated port 8002 forward delay timer 0.00
designated cost 0 hold timer 0.00
.. opcmd: show bridge <name> macs
Show bridge Media Access Control (MAC) address table
.. code-block:: none
vyos@vyos:~$ show bridge br100 macs
port no mac addr is local? ageing timer
1 00:53:29:44:3b:19 yes 0.00