LAN Port Redundancy

You can configure the device for LAN port redundancy, where one of the ports is active while the other is the backup port (only one of them forwards packets). You can configure multiple groups of active-backup LAN ports.

Port backup operates in non-retrieve mode. The active port remains active until its link fails at which stage a switch-over to the backup port is done. When the first port link comes up again, no switch over (back) is made to this port, and it remains as the backup port.

After a device reset, if both ports have a link, the first port that was configured becomes the active port.

Port redundancy is configured as follows:

conf d
interface <first LAN port>
port-redundancy <second LAN port>

Example of two groups of LAN port redundancy pairs:

# conf d
(config-data)# interface fastethernet 1/1
(conf-if-FE 1/1)# port-redundancy fastethernet 1/2
(conf-if-FE 1/1)# ex
(config-data)# interface fastethernet 1/3
(conf-if-FE 1/3)# port-redundancy fastethernet 1/4
(conf-if-FE 1/3)# do show data port-redundancy
Port Redundancy Status
----------------------------
First Port   FastEthernet 1/1
Second Port   FastEthernet 1/2
Active Port   FastEthernet 1/1

Port Redundancy Status
----------------------------
First Port   FastEthernet 1/3
Second Port   FastEthernet 1/4
Active Port   FastEthernet 1/4