C H A P T E R 50 Configuring Fallback Bridging; Fallback Bridging And Switch Stacks; Default Fallback Bridging Configuration - Cisco Catalyst 3750-X Software Configuration Manual

Chapter 50 Configuring Fallback Bridging

Fallback Bridging and Switch Stacks

When the stack master fails, a stack member becomes the new stack master by using the election process
described in
spanning-tree instance, which temporarily puts the spanning-tree ports used for fallback bridging into a
nonforwarding state. A momentary traffic disruption occurs until the spanning-tree states transition to
the forwarding state. All MAC addresses must be relearned in the bridge group.
If a stack master running the IP services feature set fails and if the newly elected stack master is running
Note
the IP base feature set, the switch stack loses its fallback bridging capability.
If stacks merge or if a switch is added to the stack, any new VLANs that are part of a bridge group and
become active are included in the VLAN-bridge STP.
When a stack member fails, the addresses learned from this member are deleted from the bridge group
MAC address table.
For more information about switch stacks, see
Configuring Fallback Bridging
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Default Fallback Bridging Configuration

Table 50-1
Feature
Bridge groups
Switch forwards frames for stations that it has
dynamically learned
Spanning tree parameters:
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OL-21521-01
Chapter 5, "Managing Switch Stacks."
Default Fallback Bridging Configuration, page 50-3
Fallback Bridging Configuration Guidelines, page 50-4
Creating a Bridge Group, page 50-4
Adjusting Spanning-Tree Parameters, page 50-5
Default Fallback Bridging Configuration
Switch priority
Port priority
Port path cost
Hello BPDU interval
Forward-delay interval
Maximum idle interval
The new stack master creates new VLAN-bridge
Chapter 5, "Managing Switch Stacks."
(required)
(optional)
Default Setting
None are defined or assigned to a port. No
VLAN-bridge STP is defined.
Enabled.
32768.
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128.
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10 Mb/s: 100.
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100 Mb/s: 19.
1000 Mb/s: 4.
2 seconds.
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20 seconds.
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30 seconds.
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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
Configuring Fallback Bridging
50-3