Cisco Systems 3750E Manual De Usuario

When the stack master fails, a stack member becomes the new stack master by using the election process 
described in 

 The new stack master creates new VLAN-bridge 

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 
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 

These sections contain this configuration information:

 (required)

 (optional)

101240

Host A

Host C

SVI 1

172.20.128.1

172.20.129.1

Layer 3 switch

Routed port
172.20.130.1

SVI 2

VLAN 20

Host B

VLAN 30