Chapter 21 Configuring Flex Links and the MAC Address-Table Move Update Feature

Configuring Flex Links and MAC Address-Table Move Update

Beginning in interface configuration mode, follow these steps to configure a preemption scheme for a pair of Flex Links:

 

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 48.

Step 3

 

 

switchport backup interface interface-id

Configure a physical Layer 2 interface (or port channel)

 

 

as part of a Flex Links pair with the interface. When one

 

 

link is forwarding traffic, the other interface is in standby

 

 

mode.

Step 4

 

 

switchport backup interface interface-idpreemption

Configure a preemption mechanism and delay for a Flex

 

mode [forced bandwidth off]

Link interface pair. You can configure the preemption as:

 

 

Forced—the active interface always preempts the

 

 

backup.

 

 

Bandwidth—the interface with the higher bandwidth

 

 

always acts as the active interface.

 

 

Off—no preemption happens from active to backup.

Step 5

 

 

switchport backup interface interface-idpreemption

Configure the time delay until a port preempts another

 

delay delay-time

port.

 

 

Note Setting a delay time only works with forced and

 

 

bandwidth modes.

Step 6

 

 

end

Return to privileged EXEC mode.

Step 7

 

 

show interface [interface-id]switchport backup

Verify the configuration.

Step 8

 

 

copy running-config startup config

(Optional) Save your entries in the switch startup

 

 

configuration file.

 

 

 

This example shows how to configure the preemption mode as forced 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 gigabitethernet1/0/2 preemption mode forced Switch(conf-if)#switchport backup interface gigabitethernet1/0/2 preemption delay 50 Switch(conf-if)#end

Switch# show interface switchport backup detail Active Interface Backup Interface State

------------------------------------------------------------------------

GigabitEthernet1/0/21 GigabitEthernet1/0/2 Active Up/Backup Standby Interface Pair : Gi1/0/1, Gi1/0/2

Preemption Mode : forced

Preemption Delay : 50 seconds

Bandwidth : 100000 Kbit (Gi1/0/1), 100000 Kbit (Gi1/0/2)

Mac Address Move Update Vlan : auto

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

OL-9775-02

21-7

 

 

 

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Cisco Systems 3750E Switchport backup interface interface-id preemption, Mode forced bandwidth off, Delay delay-time, 21-7