Cisco Catalyst 2975 Software Configuration Manual page 506

Configuring Flex Links and the MAC Address-Table Move Update
Beginning in privileged EXEC mode, follow these steps to configure a preemption scheme for a pair of
Flex Links:
Command
Step 1 configure terminal
Step 2
interface interface-id
Step 3 switchport backup interface interface-id
Step 4 switchport backup interface interface-id preemption
mode [forced | bandwidth | off]
Step 5 switchport backup interface interface-id preemption
delay delay-time
Step 6
end
Step 7 show interfaces [interface-id] switchport backup
Step 8 copy running-config startup config
To remove a preemption scheme, use the no switchport backup interface interface-id preemption
mode interface configuration command. To reset the delay time to the default, use the no switchport
backup interface interface-id preemption delay interface configuration command.
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 interfaces 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 2975 Switch Software Configuration Guide
19-10
Chapter 19 Configuring Flex Links and the MAC Address-Table Move Update Feature
Purpose
Enter global configuration mode.
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.
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.
Configure a preemption mechanism and delay for a Flex
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.
Configure the time delay until a port preempts another
port.
Setting a delay time only works with forced and
Note
bandwidth modes.
Return to privileged EXEC mode.
Verify the configuration.
(Optional) Save your entries in the switch startup
configuration file.
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