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Catalyst 2960 and 2960-S Switch Software Configuration Guide
OL-8603-09
Chapter 19 Configuring Flex Links and the MAC Address-Table Move Update Feature
Configuring Flex Links and the MAC Address-Table Move Update
Switch# show interfaces switchport backup detail
Active Interface Backup Interface State
------------------------------------------------------------------------
Catalyst 2960 switch:
GigabitEthernet0/21 GigabitEthernet0/2 Active Up/Backup Standby
Interface Pair : Gi0/1, Gi0/2
Preemption Mode : forced
Preemption Delay : 50 seconds
Bandwidth : 100000 Kbit (Gi0/1), 100000 Kbit (Gi0/2)
Mac Address Move Update Vlan : auto
Configuring VLAN Load Balancing on Flex Links
Beginning in privileged EXEC mode, follow these steps to configure VLAN load balancing on Flex
Links:
To disable the VLAN load balancing feature, use the no switchport backup interface interface-id
prefer vlan vlan-range interface configuration command.
In the following example, VLANs 1 to 50, 60, and 100 to 120 are configured on the switch:
Catalyst 2960-S switch:
Catalyst 2960 switch:
Switch(config)#interface gigabitethernet 0/6
Switch(config-if)#switchport backup interface gigabitethernet 0/8 prefer vlan 60,100-120
When both interfaces are up, Gi2/0/8 forwards traffic for VLANs 60 and 100 to 120, and Gi0/6 forwards
traffic for VLANs 1 to 50.
Switch#show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet0/6 GigabitEthernet0/8 Active Up/Backup Up
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the interface, and enter interface configuration
mode. The interface can be a physical Layer 2 interface or
a port channel (logical interface). The port-channel range
is 1 to 6.
Step 3 switchport backup interface interface-id prefer vlan
vlan-range
Configure a physical Layer 2 interface (or port channel)
as part of a Flex Links pair with the interface, and specify
the VLANs carried on the interface. The VLAN ID range
is 1 to 4094.
Step 4 end Return to privileged EXEC mode.
Step 5 show interfaces [interface-id] switchport backup Verify the configuration.
Step 6 copy running-config startup config (Optional) Save your entries in the switch startup
configuration file.