backup up line over a second GRE Tunnel

[fmitev]

Hi,

i have a 2621 with a WIC-E1 for the leased line connection, FE0/0 for LAN and FE0/1 is the second WAN link.

Have a tunnel running over the E1 link, now I need a backup solution if the E1 goes down over the FE0/1 interface

[spremkumar]

Hi

would suggest to create a GRE tunnel over ur FE0/1 taking source as ur FE0/1 and destination as ur remote router network.

do remember to enable keepalive on both the sides on the GRE tunnels otherwise the tunnels will stay up though ur link is down..

once the tunnel config is thru do add the static routes if ur already using statics in ur network with hig admin distance so that ur primary tunnel will be used in normal idle conditions..

regds

[Richard Burts]

I have implemented a project at a customer site that is very close to what the original post asked about. We support a number of remote sites. Each remote site is configured with two GRE tunnels. Each GRE tunnel terminates on a different router at Headquarters so that we have redundancy. We run EIGRP over the tunnels so that we get very quick convergence and do not require the GRE tunnel keepalive (which had not yet been introduced when I started the design of this project). We configure the remote routers as EIGRP stubs and only advertise a default route to the remote router. The customer wanted a primary tunnel/backup operation rather than a load sharing operation so we configure an offset list for the backup tunnel so the metrics are not equal and all traffic uses the primary tunnel if it is availabe.

HTH

Rick

[mgracias]

HI,

I suggest create a LOOPBACK interface. Use the Tunnel Source as the Loopback IP. By making loopback as the tunnel source you can only use one tunnel all your routing needs. Make the backup of the E1 as the FE0/1 interface which will also ensure that the primary is E1 all times.

Condition for the tunnel to work is that the Loopback is available across both the WAN links

[a-malin]

Using Tunnel interfaces seems to be proccessor

intensive for the traffic going through it.