Disabling MAC Address Learning on VLAN You can control MAC address learning on a VLAN to manage the available MAC address table space by controlling which VLANs can learn MAC addresses. Before you disable MAC address learning, be sure that you are familiar with the network topology. Disabling MAC address learning on VLAN could cause flooding in the network. Beginning in privileged EXEC mode, follow these steps to disable MAC address learning on a VLAN: Before you begin Follow these guidelines when disabling MAC address learning on a VLAN: • Use caution before disabling MAC address learning on a VLAN with a configured switch virtual interface (SVI).
The switch then floods all IP packets in the Layer 2 domain. • You can disable MAC address learning on a single VLAN ID from 2 - 4094 (for example, no mac address-table learning vlan 223) or a range of VLAN IDs, separated by a hyphen or comma (for example, no mac address-table learning vlan 1-10, 15). Administering the Device Disabling MAC Address Learning on VLAN Command or Action Purpose Step 6 mac address-table notification threshold [limit percentage] | [interval time] Example: Device(config)# mac address-table notification threshold interval 123 Device(config)# mac address-table notification threshold limit 78 Enters the threshold value for the MAC address threshold usage monitoring.
• (Optional) limit percentage—Specifies the percentage of the MAC address table use; valid values are from 1 to 100 percent. The default is 50 percent. • (Optional) interval time—Specifies the time between notifications; valid values are greater than or equal to 120 seconds. The default is 120 seconds. Step 7 end Example: Device(config)# end Returns to privileged EXEC mode. Step 8 show running-config Example: Device# show running-config Verifies your entries. Step 9 copy running-config startup-config Example: Device# copy running-config startup-config (Optional) Saves your entries in the configuration file. Administering the Device 32