Cisco Catalyst 3550 Series User Manual

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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 36 Configuring Fallback Bridging
Configuring Fallback Bridging
Creating a Bridge Group
To configure fallback bridging for a set of SVIs or routed ports, these interfaces must be assigned to
bridge groups. All interfaces in the same group belong to the same bridge domain. Each SVI or routed
port can be assigned to only one bridge group. A maximum of 31 bridge groups can be configured on
the switch.
Note The protected port feature is not compatible with fallback bridging. When fallback bridging is enabled,
it is possible for packets to be forwarded from one protected port on a switch to another protected port
on the same switch if the ports are in different VLANs.
Beginning in privileged EXEC mode, follow these steps to create a bridge group and assign an interface
to it:
To remove a bridge group, use the no bridge bridge-group global configuration command. To remove
an interface from a bridge group and to remove the bridge group, use the no bridge-group bridge-group
interface configuration command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
bridge bridge-group protocol
vlan-bridge
Assign a bridge group number, and specify the VLAN-bridge
spanning-tree protocol to run in the bridge group. The ibm and dec
keywords are not supported.
For bridge-group, specify the bridge group number. The range is 1
to 255. You can create up to 31 bridge groups.
Frames are bridged only among interfaces in the same group.
Step 3
interface interface-id Enter interface configuration mode, and specify the interface on which
you want to assign the bridge group.
The specified interface must be one of these:
• A routed port: a physical port that you have configured as a Layer 3
port by entering the no switchport interface configuration
command.
• An SVI: a VLAN interface that you created by using the interface
vlan vlan-id global configuration command.
Note You can assign an IP address to the routed port or to the SVI,
but it is not required.
Step 4
bridge-group bridge-group Assign the interface to the bridge group created in Step 2.
By default, the interface is not assigned to any bridge group. An
interface can be assigned to only one bridge group.
Step 5
end Return to privileged EXEC mode.
Step 6
show running-config Verify your entries.
Step 7
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco Catalyst 3550 Series Specifications

General

Brand	Cisco
Model	Catalyst 3550 Series
Category	Network Router
Language	English