Configuring Mac Address Table Aging Time - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

Managing Source Learning

Configuring MAC Address Table Aging Time

Source learning also tracks MAC address age and removes addresses from the MAC address table that
have aged beyond the aging timer value. When a device stops sending packets, source learning keeps track
of how much time has passed since the last packet was received on the device's switch port. When this
amount of time exceeds the aging time value, the MAC is aged out of the MAC address table. Source
learning always starts tracking MAC address age from the time since the last packet was received.
By default, the aging time is set to 300 seconds (5 minutes) and is configured on a global basis using the
mac-address-table aging-time
to 1200 seconds (20 minutes):
-> mac-address-table aging-time 1200
A MAC address learned on any VLAN port will age out if the time since a packet with that address was
last seen on the port exceeds 1200 seconds.
Note. An inactive MAC address may take up to twice as long as the aging time value specified to age out
of the MAC address table. For example, if an aging time of 60 seconds is specified, the MAC will age out
any time between 60 and 120 seconds of inactivity.
When using the mac-address-table aging-time command in a switch configuration file (e.g., boot.cfg),
include an instance of this command specifying the VLAN ID for each VLAN configured on the switch.
This is necessary even though all VLANs will have the same aging time value.
To set the aging time back to the default value, use the no form of the mac-address-table aging-time
command. For example, the following sets the aging time for all VLANs back to the default of 300
seconds:
-> no mac-address-table aging-time
Note. The MAC address table aging time is also used as the timeout value for the Address Resolution
Protocol (ARP) table. This timeout value determines how long the switch retains dynamically learned
ARP table entries. See
To display the aging time value for one or all VLANs, use the
command. For more information about this command, see the OmniSwitch CLI Reference Guide.
OmniSwitch AOS Release 6 Network Configuration Guide
command. For example, the following sets the aging time for all VLANs
Chapter 24, "Configuring IP,"
Configuring MAC Address Table Aging Time
for more information.
show mac-address-table aging-time
September 2009 page 2-9