CHAPT ER
21-1
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
21
Configuring Flex Links and the MAC Address-Table Move Update Feature
This chapter describes how to configure Flex Links, a pair of interfaces on the Catalyst3750 switch that
provide a mutual backup. It also describes how to configure the MAC address-table move update feature,
also referred to as the Flex Links bidirectional fast convergence feature. Unless otherwise noted, the term
switch refers to a standalone switch and to a switch stack.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
The chapter consists of these sections:
Understanding Flex Links and the MAC Address-Table MoveUpdate, page 21-1
Configuring Flex Links and the MAC Address-Table Move Update, page21-7
Monitoring Flex Links and the MAC Address-Table MoveUpdate, page 21-14

Understanding Flex Links and the MAC Address-Table

Move Update

This section contains this information:
Flex Links, page 21-1
VLAN Flex Link Load Balancing and Support, page21-3
Flex Link Multicast Fast Convergence, page21-3
MAC Address-Table Move Update, page21-6

Flex Links

Flex Links are a pair of a Layer 2 interfaces (switch ports or port channels) where one interface is
configured to act as a backup to the other. The feature provides an alternative solution to the Spanning
Tree Protocol (STP). Users can disable STP and still retain basic link redundancy. Flex Links are