MAC Aging Time

The MAC table needs to be updated constantly because the network topology always changes. The entries automatically generated in a MAC table are not always valid. Each entry has a lifecycle. If an entry is not updated within the lifecycle, it is deleted. This lifecycle is called the aging time. If an entry is updated before its lifecycle ends, the aging timer of the entry is reset.

Context

You need to set the aging time properly. If the aging time is excessively long or short, the switch may broadcast a large number of data frames because their destination MAC addresses cannot be found in the MAC table. This degrades the performance of the switch.

If the aging time is excessively long, the switch may save a large number of useless MAC entries, and new MAC entries cannot be added because the number of MAC entries is limited. As a result, the switch cannot update the MAC table according to network changes.
If the aging time is excessively short, the switch may delete valid MAC entries, and therefore the forwarding performance is degraded.

Generally, the default aging time (300s) is recommended.

Procedure

Choose Service Management > MAC > MAC Aging Time in the navigation tree to open the MAC Aging Time page.
Table 1 describes the parameters on the MAC Aging Time page.

Table 1 MAC Aging Time

Parameter

Description

Aging Time

Indicates the aging time of MAC entries.
Set the parameters.
Click Apply to complete the configuration.