22-11
Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
Chapter 22 Configuring Flex Links and the MAC Address-Table Move Update Feature
Configuring Flex Links and the MAC Address-Table Move Update
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:
Switch(config)#
interface gigabitEthernet 1/2
Switch(config-if)#
switchport backup interface gigabitEthernet 1/2 prefer vlan 60,100-120
When both interfaces are up, Gi1/1 forwards traffic for VLANs 60 and 100 to 120, and Gi1/2 forwards
traffic for VLANs 1 to 50.
Switch#
show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet1/1 GigabitEthernet1/2 Active Up/Backup Up
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 interface Gi1/1 goes down, Gi1/2 carries
all VLANs of the Flex Link pair.
Switch#
show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet1/1 GigabitEthernet1/2 Active Down/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.