Users Guide

To ensure that existing network applications see no difference when a primary interface in a redundant pair
transitions to the backup interface, be sure to apply identical configurations of other traffic parameters to
each interface.
If you remove an interface in a redundant link (remove the line card of a physical interface or delete a port
channel with the no interface port-channel command), the redundant pair configuration is also
removed.
Important Points about Configuring Redundant
Pairs
• You may not configure any interface to be a backup for more than one interface, no interface can have
more than one backup, and a backup interface may not have a backup interface.
• The active or backup interface may not be a member of a LAG.
• The active and standby do not have to be of the same type (1G, 10G, and so on).
• You may not enable any Layer 2 protocol on any interface of a redundant pair or to ports connected to
them.
As shown in the previous illustration, interface 1/11/1 is a backup interface for 1/11/2, and 1/11/2 is in the Down
state. If 1/11/1 fails, 1/11/2 transitions to the Up state, which makes the backup link active. A message similar to
the following message appears whenever you configure a backup port.
02:28:04: %RPM0-P:CP %IFMGR-5-L2BKUP_WARN: Do not run any Layer2 protocols on Te
1/1/1/1 and Te 1/1/2/1
02:28:04: %RPM0-P:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te
1/1/1/2
02:28:04: %RPM0-P:CP %IFMGR-5-STATE_ACT_STBY: Changed interface state to standby:
te 1/1/1/2
02:28:04: %RPM0-P:CP %IFMGR-5-L2BKUP_WARN: Do not run any Layer2 protocols on Te
1/11/1 and Te 1/11/1
02:28:04: %RPM0-P:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/12/1
02:28:04: %RPM0-P:CP %IFMGR-5-STATE_ACT_STBY: Changed interface state to standby:
te 1/13/1
Example of Configuring Redundant Layer 2 Pairs
Dell(conf-if-range-te-1/11/1-1/11/2)#switchport backup interface
TenGigabitEthernet 1/11/1
Dell(conf-if-range-te-1/11/1-1/11/2)#show config
!
interface TenGigabitEthernet 1/11/1
no ip address
switchport
switchport backup interface TenGigabitEthernet 1/11/2
no shutdown
!
interface TenGigabitEthernet 1/11/2
no ip address
switchport
no shutdown
Dell(conf-if-range-te-1/11/1-1/11/2)#
Dell(conf-if-range-te-1/11/1-1/11/2)#do show ip int brief | find 1/11/1
TenGigabitEthernet 1/11/1 unassigned YES Manual up up
TenGigabitEthernet 1/11/2 unassigned NO Manual up down
[output omitted]
Dell(conf-if-range-te-1/11/1-1/11/2)#interface TenGigabitEthernet 1/11/1
Layer 2 564