NAME

       interfaces-bridge - Bridge extensions for the interfaces(5) file format

DESCRIPTION

       Linux has support for Ethernet bridging interfaces which act like an Ethernet switch
       within the Linux Kernel. The following options allow to set up Ethernet bridges and adding
       configured interfaces to bridges.

       See ip-link(8) for more details about the options listed below.

BRIDGE-RELATED OPTIONS

       bridge-ports list of interfaces
           A space separated list of interfaces which should be configured as member interfaces
           of this bridge. This option must be set for the bridge to be configured.

       bridge-hw MAC address
           Denotes the MAC address the bridge should use.

       bridge-ageing seconds
           Denotes the time in seconds after which a MAC address will be removed from the
           Forwarding DataBase (FDB) after not having seen a frame with this source address.

       bridge-vlan-aware bool
           Denotes wether or not the bridge should be aware of 802.1q VLANs. bool can be given as
           yes/no or 0/1.  The defaul is no. See related options for configuring vlan-aware
           bridges, below.

SPANNING TREE RELATED BRIDGE OPTIONS

       bridge-stp state
           Activates or deactivates IEEE 802.1d Spanning Tree Protocol (STP) support of the
           bridge. Valid values are on/off.

       bridge-bridgeprio priority
           Sets the bridge's priority to priority. The priority value is a number between 0 and
           65535. Lower priority values are better. The bridge with the lowest priority will be
           elected root bridge.

       bridge-fd seconds
           Denotes the bridge forward delay in seconds. Valid values are between 2 and 30.

       bridge-hello seconds
           Denotes the bridge hello time in seconds. Valid values are between 1 and 10.

       bridge-maxage seconds
           Denotes the seconds until another bridge is considerd dead after reception of its last
           STP hello message. Valid values are between 6 and 40.

OPTIONS FOR VLAN-AWARE-BRIDGES

       The following options only have an effect on vlan-aware bridges and their ports.

       All settings can be applied on the bridge interface itself and all member port iface
       stanzas.  If applied on the bridge interface they take effect for the bridge interface
       itself and might be inherited to bridge-ports depending on the compatibility settings
       configured in ifupdown-ng.conf(5).

       Configuring VLAN options on the bridge interface might be required for setting up a VLAN
       interface to one of the VLANs carried within the bridge. See the EXAMPLES section for an
       example for this scenario.

       See ifupdown-ng.conf(5) for more information about compatiblity settings mentioned below.

       bridge-access vlan ID
           Configure the given vlan ID for untagged ingress and egress on this interface.  The
           common description for this kind of configuration is called "access port".

       bridge-pvid vlan ID
           Denotes the vlan ID to considered a PVID at ingress. Any untagged frames received on
           this interface will be assigned to this vlan ID.  The default PVID is 1.

           If compatibility to ifupdown2 bridge port inheritance is active a bridge-pvid set on
           the bridge will be inherited to any interface configured in bridge-ports without a
           bridge-pvid set.

       bridge-vids list of vlan IDs
           Denotes the space separated list of VLANs to be allowed tagged ingress/egress on this
           interface.

           If compatibility to ifupdown2 bridge port inheritance is active a bridge-vids set on
           the bridge will be inherited to any interface configured in bridge-ports without
           bridge-vids set.

       bridge-allow-untagged bool
           Denotes wether or not the bridge should allow untagged frames on ingress as well as
           egress. If set to no untagged frames will be droppped on ingress and none will be
           sent. bool can be given as yes/no or 0/1.  The defaul is yes.

EXAMPLES

       A simple layer 2 only bridge:

           auto br0
           iface br0
                bridge-ports eth0 veth-vm1 tap0
                bridge-fd 0
                bridge-stp off

       A bridge with layer 3 configuration:

           auto br0
           iface br0
                bridge-ports eth0 veth-vm1 tap0
                bridge-fd 0
                bridge-stp off
                #
                address 192.0.2.42/24
                address 2001:db8::42/64

       A layer 2 only vlan-aware bridge:

           auto bond0
           iface bond0
                bond-members eth0 eth1
                bridge-vids 23 42 84 1337

           auto br0
           iface br0
                bridge-ports bond0

       A vlan-aware bridge with a VLAN interface on top:

           auto eth0
           iface eth0
                bridge-vids 23 42 84 1337

           auto br0
           iface br0
                bridge-ports eth0
                bridge-vlan-aware yes
                bridge-vids 42

           auto vlan42
           iface vlan42
                vlan-raw-device br0
                #
                address 192.0.2.42/24
                address 2001:db8::42/64

SEE ALSO

       interfaces(5) ifupdown-ng.conf(5) ip-link(8) bridge(8)

AUTHORS

       Maximilian Wilhelm <max@sdn.clinic>

                                            2022-02-16                       interfaces-bridge(5)