Specifications

4-24
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 4 Administering the Switch
Managing the MAC Address Table
This section includes the following topics:
• Changing the Address Aging Time, page 4-24
• Removing Dynamic Address Entries, page 4-25
• Configuring MAC Address Change Notification Traps, page 4-25
• Configuring MAC Address Move Notification Traps, page 4-27
• Configuring MAC Threshold Notification Traps, page 4-29
• Adding and Removing Static Address Entries, page 4-30
• Configuring Unicast MAC Address Filtering, page 4-32
• Disabling MAC Address Learning on a VLAN, page 4-33
• Displaying Address Table Entries, page 4-34
Changing the Address Aging Time
Dynamic addresses are source MAC addresses that the switch learns and then ages when they are not in
use. You can change the aging time setting for all VLANs or for a specified VLAN.
Setting too short an aging time can cause addresses to be prematurely removed from the table. Then
when the switch receives a packet for an unknown destination, it floods the packet to all ports in the same
VLAN as the receiving port. This unnecessary flooding can impact performance. Setting too long an
aging time can cause the address table to be filled with unused addresses, which prevents new addresses
from being learned. Flooding results, which can impact switch performance.
BEFORE YOU BEGIN
Review the “MAC Address Table” section on page 4-4.
DETAILED STEPS
To return to the default value, use the no mac address-table aging-time global configuration command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
mac address-table aging-time [0 |
10-1000000] [vlan vlan-id]
Set the length of time that a dynamic entry remains in the
MAC address table after the entry is used or updated.
The range is 10 to 1000000 seconds. The default is 300. You
can also enter 0, which disables aging. Static address entries
are never aged or removed from the table.
For vlan-id, valid IDs are 1 to 4094. Do not enter leading
zeros.
Step 3
end Return to privileged EXEC mode.
Step 4
show mac address-table aging-time Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.