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ifcfg-bridge

NAME

ifcfg-bridge - ethernet bridge interface configuration

SYNOPSIS

/etc/sysconfig/network/ifcfg-br*

CONFIGURATION

To setup a bridge interface you need a configuration file ifcfg-<interface-name> with the usual network settings. But you must add additional variables:

BRIDGE <yes|no>

This option must be set to 'yes' to identify this interface as a bridge interface.

BRIDGE_PORTS <interface1 interface2 ... interfaceN>

This variable contains a space-separated list of N interfaces which take part in the bridging. You may use the usual hardware descriptions (see ifup (8)).

OPTIONAL VARIABLES

BRIDGE_AGEINGTIME <time>

This option sets the ethernet address ageing time, in seconds. After <time> seconds of not having seen a frame coming from a certain address, the bridge will delete that address from the forwarding database. Setting ageing time to zero makes all entries permanent.

BRIDGE_FORWARDDELAY <time>

Forwarding delay time is the time in seconds 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.

BRIDGE_HELLOTIME <time>

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.

BRIDGE_MAXAGE <time>

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. This timeout can be set with this variable.

BRIDGE_PATHCOSTS <costs1 costs2 ... costsN>

This is a space-separated list of costs corresponding to the interfaces in BRIDGE_PORTS. Each interface in BRIDGE_PORTS could have a different speed and this value is used when deciding which link to use. Faster interfaces should have lower costs.

BRIDGE_PORTPRIORITIES <prio1 prio2 ... prioN>

This is a space-separated list of priorities corresponding to the interfaces in BRIDGE_PORTS. The priority value is an unsigned 8-bit quantity (a number between 0 and 255), and has no dimension. This metric is used in the designated port and root port selection algorithms.

BRIDGE_PRIORITY <priority>

This option sets the bridge's priority to <priority>. The priority value is an unsigned 16-bit quantity (a number between 0 and 65535), and has no dimension. Lower priority values are 'better'. The bridge with the lowest priority will be elected 'root bridge'.

BRIDGE_STP <on|off>

Multiple ethernet bridges can work together to create even larger networks of ethernets using the IEEE 802.1d spanning tree protocol. This protocol is used for finding the shortest path between two ethernets, and for eliminating loops from the topology. The spanning tree protocol can also be turned off (for those situations where it just doesn't make sense, for example when this linux box is the only bridge on the LAN, or when you know that there are no loops in the topology.)

EXAMPLE

Minimal example for a bridge interface on eth0 and eth1, the bridge interface itself is configured via dhcp:

ifcfg-br0

        STARTMODE='auto'

        BOOTPROTO='dhcp'

        BRIDGE='yes'

        BRIDGE_PORTS='eth0 eth-id-11:de:ad:be:ef:99'

        BRIDGE_PORTPRIORITIES='50 20'

ADDITIONAL INFORMATION

For additional and more general information have a look into <http://linux-net.osdl.org/index.php/Bridge>.

BUGS

Please report bugs at <https://bugzilla.novell.com/index.cgi>

AUTHOR

Stefan Scheler <sscheler@suse.de> -- ifup-bridge 

SEE ALSO

ifcfg(5), ifup(8), brctl(8).