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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter26 Configuring Fallback Bri dging Configuring Fallback Bridging
This example shows how to create bridge group 10, specify the VLAN-bridge STP t o r un in th e br idge
group, and assign an interface to the bridge group:
Switch(config)# bridge 10 protocol vlan-bridge
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# no switchport
Switch(config-if)# bridge-group 10
Preventing the Forwarding of Dynamically Learned Stations
By default, the switch forwards any frames for stations that it has dynamically learned. By disabling this
activity, the switch only forwards frames whose addresses have been statically configured into the
forwarding cache.
Beginning in privileged EXEC mode, follow these steps to prevent the switch from forwarding frames
for stations that it has dynamically learned:
To cause the switch to forward frames to stations that it has dynamically l ear ne d, use th e bridge
bridge-group acquire global configuration command.
This example shows how to prevent the switch from forwarding frames for stations that it has
dynamically learned in bridge group 10:
Switch(config)# no bridge 10 acquire
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 no bridge bridge-group acquire Enable the switch to stop forwarding any frames for stations that it has
dynamically learned through the discovery process and to limit frame
forwarding to statically configured stations.
The switch filters all frames except those whose destined-to addresses
have been statically configured into the forwarding ca che. To configure
a static address, use the bridge bridge-group address mac-address
{forward | discard} global configuration command.
For bridge-group, specify the bridge group number. The range is 1
to 255.
Step3 end Return to privileged EXEC mode.
Step4 show running-config Verify your entry.
Step5 copy running-config startup-config (Optional) Save your entry in the configuration file.