Standby/Failover on router with 2 Ethernet Interfaces

sdawson35 · ‎01-12-2009

Hi,

Trying to work out the best method for a small problem we have.

There is a single 2800 series router with 2 ethernet interfaces, each one goes to a 6500 series switch.

The router has a bunch of isdn's attached for our FOIP environment.

What we want is to provide redundancy in that if one switch fails our FOIP environment will keep working.

I cannot use HSRP as there is only one router with 2 interfaces so what else can I use ?

Scott.

John Blakley · ‎01-12-2009

deleted.

HTH, John *** Please rate all useful posts ***

chris.grammer · ‎01-12-2009

Scott,

One solution is using a backup interface command on the primary interface and make the secondary the backup. This will cause the secondary interface to stay down unless the primary interface goes down at which time the secondary will come up.

The config looks like this:

interface FastEthernet0/0

backup interface FastEthernet0/1

ip address 1.1.1.1 255.255.255.0

no ip route-cache

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 1.1.1.1 255.255.255.0

no ip route-cache

duplex auto

speed auto

FastEthernet0/0 1.1.1.1 YES manual up up

FastEthernet0/1 1.1.1.1 YES manual standby mode down

Notice that the secondary interface F0/1 is in "standby". If the primary interface goes down/down, the secondary interface will come up.