Cisco Catalyst 4500 Series - Configuring VLAN Load Balancing on Flex Links

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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
OL_28731-01
Chapter 23 Configuring Flex Links and MAC Address-Table Move Update
Configuring Flex Links
To remove a preemption scheme, enter the no switchport backup interface interface-id preemption
mode interface configuration command. To reset the delay time to the default, enter the
no switchport backup interface interface-id preemption delay interface configuration command.
This example shows how to configure preemption mode as bandwidth for a backup interface pair and to
verify the configuration:
Switch# configure terminal
Switch(conf)# interface gigabitethernet1/0/1
Switch(conf-if)# switchport backup interface gigabitethernet1/2
Switch(conf-if)# switchport backup interface gigabitethernet1/2 preemption mode forced
Switch(conf-if)# switchport backup interface gigabitethernet1/2 preemption delay 50
Switch(conf-if)# end
Switch# show interface switchport backup detail
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet1/21 GigabitEthernet1/2 Active Down/Backup Down
Interface Pair : Gi1/21, Gi1/2
Preemption Mode : forced
Preemption Delay : 50 seconds
Bandwidth : 10000 Kbit (Gi1/1), 10000 Kbit (Gi1/2)
Mac Address Move Update Vlan : auto
<output truncated>
Configuring VLAN Load Balancing on Flex Links
To configure VLAN load balancing on Flex Links, perform this task:
To disable the VLAN load balancing feature, enter the no switchport backup interface prefer vlan
interface configuration command.
In this example, VLANs 1 to 50, 60, and 100 to 120 are configured on the switch:
Switch(config)# interface fastethernet 1/6
Switch(config-if)# switchport backup interface fastethernet 1/0/8 prefer vlan 60,100-120
Command Purpose
Step 1
Switch# configure terminal
Enters global configuration mode.
Step 2
Switch(conf)# interface interface-id
Specifies the interface, and enters interface configuration
mode. The interface might be a physical Layer 2 interface
or a port channel (logical interface). The port channel
range is 1 to 48.
Step 3
Switch(conf-if)# switchport backup interface
interface-id prefer vlan vlan-range
Configures a physical Layer 2 interface (or port channel)
as part of a Flex Links pair with the interface, and
specifies the VLANs carried on the interface. The VLAN
ID range is 1 to 4094.
Step 4
Switch(conf-if)# end
Returns to privileged EXEC mode.
Step 5
Switch# show interfaces [interface-id] switchport
backup
Verifies the configuration.
Step 6
Switch# copy running-config startup config
(Optional) Saves your entries in the switch startup
configuration file.