Configuring The Bridge Table Aging Time - Cisco Catalyst 3550 series Software Configuration Manual

Configuring Fallback Bridging
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

Configuring the Bridge Table Aging Time

A switch forwards, floods, or drops packets based on the bridge table. The bridge table maintains both
static and dynamic entries. Static entries are entered by you or learned by the switch. Dynamic entries
are entered by the bridge learning process. A dynamic entry is automatically removed after a specified
length of time, known as aging time, from the time the entry was created or last updated.
If you are likely to move hosts on a switched network, decrease the aging-time to enable the switch to
quickly adapt to the change. If hosts on a switched network do not continuously send packets, increase
the aging time to keep the dynamic entries for a longer time and thus reduce the possibility of flooding
when the hosts send again.
Beginning in privileged EXEC mode, follow these steps to configure the aging time:
Command
Step 1
configure terminal
Step 2
bridge bridge-group aging-time seconds
Step 3
end
Step 4 show running-config
Step 5
copy running-config startup-config
To return to the default aging-time interval, use the no bridge bridge-group aging-time global
configuration command.
This example shows how to change the bridge table aging time to 200 seconds for bridge group 10:
Switch(config)# bridge 10 aging-time 200
Filtering Frames by a Specific MAC Address
A switch examines frames and sends them through the internetwork according to the destination address;
a switch does not forward a frame back to its originating network segment. You can use the software to
configure specific administrative filters that filter frames based on information other than the paths to
their destinations.
You can filter frames with a particular MAC-layer station destination address. You can configure any
number of addresses in the system without a performance penalty.
Catalyst 3550 Multilayer Switch Software Configuration Guide
36-6
Purpose
Enter global configuration mode.
Specify the length of time that a dynamic entry remains in the bridge
table from the time the entry was created or last updated.
For bridge-group, specify the bridge group number. The range is 1
•
to 255.
• For seconds, enter a number from 0 to 1000000. The default is 300
seconds.
Return to privileged EXEC mode.
Verify your entry.
(Optional) Save your entry in the configuration file.
Chapter 36 Configuring Fallback Bridging
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