Cisco Catalyst 2960 Software Configuration Manual page 522

Configuring Flex Links and the MAC Address-Table Move Update
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
When a Flex Link interface goes down (LINK_DOWN), VLANs preferred on this interface are moved
to the peer interface of the Flex Link pair. In this example, if Gigabit interface 6 goes down, Gigabit
interface 8 carries all VLANs of the Flex Link pair.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
GigabitEthernet2/0/6
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
When a Flex Link interface comes up, VLANs preferred on this interface are blocked on the peer
interface and moved to the forwarding state on the interface that has just come up. In this example, if
Gigabit interface 6 comes up, VLANs preferred on this interface are blocked on the peer Gigabit
interface 8 and forwarded on Gigabit interface 6.
Switch#show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
GigabitEthernet2/0/6
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
Switch#show interfaces switchport backup detail
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
GigabitEthernet1/0/3
Vlans Preferred on Active Interface: 1-2,5-4094
Vlans Preferred on Backup Interface: 3-4
Preemption Mode
Bandwidth : 10000 Kbit (Gi1/0/3), 100000 Kbit (Gi1/0/4)
Mac Address Move Update Vlan : auto
Configuring the MAC Address-Table Move Update Feature
This section contains this information:
•
•
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
19-12
Backup Interface
GigabitEthernet2/0/8
Backup Interface
GigabitEthernet2/0/8
Backup Interface
GigabitEthernet1/0/4
: off
Configuring a switch to send MAC address-table move updates
Configuring a switch to get MAC address-table move updates
Chapter 19 Configuring Flex Links and the MAC Address-Table Move Update Feature
State
Active Down/Backup Up
State
Active Up/Backup Up
State
Active Down/Backup Up
OL-26520-01