3Com 10014298 Setting MAC Address Aging Time, Displaying and Debugging the MAC Address Table

252CHAPTER 11: SYSTEM MANAGEMENT

By default, the MAC address learning function is enabled.

Setting MAC Address Aging Time

Setting an appropriate aging time implements MAC address aging. Too long or too short an aging time set by subscribers will cause the Ethernet switch to flood a large amount of data packets. This affects the switch operation performance.

If aging time is set too long, the Ethernet switch stores a great number of out-of-date MAC address tables. This consumes MAC address table resources and the switch will not be able to update the MAC address table according to the network change.

If aging time is set too short, the Ethernet switch may delete valid MAC address table entries.

You can use the following commands to set the MAC address aging time for the system.

Perform the following configuration in system view.

Table 274 Setting the MAC Address Aging Time for the System

Operation	Command
Set the dynamic MAC address aging time	mac-address timer { aging age
	no-aging }
Restore the default MAC address aging time	undo mac-address timer aging-time

In addition, this command takes effect on all the ports. However, the address aging only functions on the dynamic addresses (the learned or configured as age entries by the user).

By default, the aging-time is 300 seconds. With the no-aging parameter, the command performs no aging on the MAC address entries.

Displaying and Debugging the MAC Address Table

Execute the display command in all views to display the MAC address table configuration, and to verify the effect of the configuration.

Execute the debugging command in user view to debug MAC address table configuration.

Table 275 Displaying and Debugging MAC Address Table

Operation	Command
Display the information in the address table	display mac-address [ static
	dynamic ] [ [ interface {
	interface-name interface-type
	interface-num } ] [ vlan vlan-id ]
	]

Display the aging time of dynamic address table entries

Display the dynamic MAC address learning capability of the system and ports

display mac-address aging-time

display mac-address learning [ interface-typeinterface-num interface-name ]