Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide, Rel. 12.2(25)SEF1

CHAPTER
16-1
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
OL-8915-01
16
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 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.
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 16-1
• Configuring Flex Links and MAC Address-Table Move Update, page 16-4
• Monitoring Flex Links and the MAC Address-Table Move Update, page 16-8
Understanding Flex Links and the MAC Address-Table
Move Update
This section contains this information:
• Flex Links, page 16-1
• MAC Address-Table Move Update, page 16-2
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
typically configured in service provider or enterprise networks where customers do not want to run STP
on the switch. If the switch is running STP, Flex Links is not necessary because STP already provides
link-level redundancy or backup.
You configure Flex Links on one Layer 2 interface (the active link) by assigning another Layer 2
interface as the Flex Link or backup link. When one of the links is up and forwarding traffic, the other
link is in standby mode, ready to begin forwarding traffic if the other link shuts down. At any given time,