C H A P T E R 21 Configuring Flex Links And The Mac Address-Table Move Update Feature; Understanding Flex Links And The Mac Address-Table Move Update; Flex Links - Cisco 3750G - Catalyst Integrated Wireless LAN Controller Configuration Manual

Chapter 21 Configuring Flex Links and the MAC Address-Table Move Update Feature
If the MAC address-table move update feature is configured and enabled on the switches in
and port 1 goes down, port 2 starts forwarding traffic from the PC to the server. The switch sends a MAC
address-table move update packet from port 2. Switch C gets this packet on port 4 and immediately
learns the MAC address of the PC on port 4, which reduces the reconvergence time.
You can configure the access switch, switch A, to send MAC address-table move update messages. You
can also configure the uplink switches B, C, and D to get and process the MAC address-table move
update messages. When switch C gets a MAC address-table move update message from switch A,
switch C learns the MAC address of the PC on port 4. Switch C updates the MAC address table,
including the forwarding table entry for the PC. The switch then starts forwarding traffic from the server
to the PC through port 4, which reduces the loss of traffic from the server to the PC.
Figure 21-2
Switch B
OL-8550-02
MAC Address-Table Move Update Example
Switch C
Port 3 Port 4
Port 1 Port 2
Switch A

Understanding Flex Links and the MAC Address-Table Move Update

Server
Switch D
PC
Catalyst 3750 Switch Software Configuration Guide
Figure 21-2
21-3