Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring Fallback Bridging
Configuring Fallback Bridging
Fallback Bridging Configuration Guidelines
Up to 32 bridge groups can be configured on the switch.
An interface (an SVI or routed port) can be a member of only one bridge group.
Use a bridge group for each separately bridged (topologically distinct) network connected to the switch.
Do not configure fallback bridging on a switch configured with private VLANs.
All protocols except IP (Version 4 and Version 6), Address Resolution Protocol (ARP), reverse ARP
(RARP), LOOPBACK, Frame Relay ARP, and shared STP packets are fallback bridged.
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.
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 to assign an
interface to it. This procedure is required.
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 32 bridge groups.
Frames are bridged only among interfaces in the same group.
Step 3
interface interface-id Specify the interface on which you want to assign the bridge group, and
enter interface configuration mode.
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.