Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
OL-8566-01
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
switchport backup interface
switchport backup interface
Use the switchport backup interface interface configuration command on a Layer 2 interface to
configure Flex Links, a pair of interfaces that provide backup to each other. Use the no form of this
command to remove the Flex Links configuration.
switchport backup interface {interface-id} mmu primary vlan vlan-id
switchport backup interface {interface-id} preemption [forced | bandwidth | off] | [delay
delay-time]
no switchport backup interface {interface-id} mmu primary vlan vlan-id
no switchport backup interface {interface-id} preemption [forced | bandwidth | off] | [delay]
Syntax Description
Note Though visible in the command-line help, VLAN interfaces are not supported.
Defaults The default is to have no Flex Links defined.
Preemption mode is off. No preemption occurs.
Preemption delay is set to 35 seconds.
Command Modes Interface configuration
Command History
interface-id Specify the Layer 2 interface to act as a backup link to the interface being
configured. The interface can be a physical interface or port channel. The
port-channel range is 1 to 48.
mmu Specifies configuring the mac move update (MMU) for a backup interface
pair.
primary vlan vlan-id The VLAN ID of the private-VLAN primary VLAN; valid range is 1 to 4094.
preemption Specifies configuring a preemption scheme for a backup interface pair.
forced (Optional) Specifies the interface always preempts the backup.
bandwidth (Optional) Specifies the interface with the higher available bandwidth
always preempts the backup.
off (Optional) Specifies no preemption occurs from backup to active.
delay delay-time (Optional) Specifies a preemption delay; valid values are 1 to 300 seconds.
Release Modification
12.2(25)SEE This command was introduced.