Configuring Vlan Load Balancing On Flex Links - Cisco Catalyst 4500 Series Software Configuration Manual

Configuring Flex Links

Configuring VLAN Load Balancing on Flex Links

To configure VLAN load balancing on Flex Links, perform this task:
Command
Step 1
Switch# configure terminal
Step 2
Switch(conf)# interface interface-id
Step 3
Switch(conf-if)# switchport backup interface
interface-id prefer vlan vlan-range
Step 4
Switch(conf-if)# end
Step 5
Switch# show interfaces [interface-id] switchport
backup
Step 6
Switch# copy running-config startup config
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
When both interfaces are up, Fast Ethernet port 1/0/8 forwards traffic for VLANs 60 and 100 to 120 and
Fast Ethernet port 1/0/6 forwards traffic for VLANs 1 to 50.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
FastEthernet1/6
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
When a Flex Links interface shuts down, VLANs preferred on this interface are moved to the peer
interface of the Flex Links pair. In this example, if interface 1/6 shuts down, interface 1/8 carries all
VLANs of the Flex Links pair.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
FastEthernet1/6 FastEthernet1/8
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
24-8
Chapter 24
Purpose
Enters global configuration mode.
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.
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.
Returns to privileged EXEC mode.
Verifies the configuration.
(Optional) Saves your entries in the switch startup
configuration file.
Backup Interface
FastEthernet1/8 Active Up/Backup Standby
Backup Interface
Active Down/Backup VLB all
Configuring Flex Links and MAC Address-Table Move Update
State
State