CHAPT ER
23-1
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
23
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 Catalyst 3750-X
or 3560-X 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 Catalyst 3750-X or 3560-X standalone switch
and to a Catalyst 3750-X 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 Move Update, page 23-1
Configuring Flex Links and MAC Address-Table Move Update, page 23-7
Monitoring Flex Links and the MAC Address-Table Move Update, page 23-14

Understanding Flex Links and the MAC Address-Table Move

Update

This section contains this information:
Flex Links, page 23-1
VLAN Flex Link Load Balancing and Support, page 23-2
Flex Link Multicast Fast Convergence, page 23-3
MAC Address-Table Move Update, page 23-6

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