Important Points About Configuring Redundant Pairs - Dell S4048T Configuration Manual

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 above illustration, interface 3/41 is a backup interface for 3/42, and 3/42 is in the Down state.
If 3/41 fails, 3/42 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
3/41 and Te 3/42
02:28:04: %RPM0-P:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 3/42
02:28:04: %RPM0-P:CP %IFMGR-5-STATE_ACT_STBY: Changed interface state to standby:
te 3/42
Example of Configuring Redundant Layer 2 Pairs
Dell(conf-if-range-te-3/41-42)#switchport backup interface TenGigabitEthernet 3/42
Dell(conf-if-range-te-3/41-42)#show config
!
interface TenGigabitEthernet 3/41
no ip address
switchport
switchport backup interface TenGigabitEthernet 3/42
no shutdown
!
interface TenGigabitEthernet 3/42
no ip address
switchport
no shutdown
Dell(conf-if-range-te-3/41-42)#
Dell(conf-if-range-te-3/41-42)#do show ip int brief | find 3/41
TenGigabitEthernet 3/41
TenGigabitEthernet 3/42
[output omitted]
Dell(conf-if-range-te-3/41-42)#interface tengig 3/41
Dell(conf-if-te-3/41)#shutdown
00:24:53: %RPM0-P:CP %IFMGR-5-ASTATE_DN: Changed interface Admin state to down: Te
3/41
Dell(conf-if-te-3/41)#00:24:55: %RPM0-P:CP %IFMGR-5-OSTATE_DN: Changed interface
state to
down: Te 3/41
00:24:55: %RPM0-P:CP %IFMGR-5-INACTIVE: Changed Vlan interface state to inactive:
Vl 1
unassigned
unassigned
YES Manual up
NO Manual up
up
down
Layer 2 606