backup interface

kon_salev · ‎02-09-2008

Is it possible to have a fastethernet interface as a backup of more than one serial lines on a 7507 router ?

Goutam Sanyal · ‎02-09-2008

Hi,

If I assume that you want FastEthernet as a backup interface of Serial so it is possible. Also its depends how your network is designed.

i.e.

Router(config)#inty ser 0/0/0

Router(config-if)#backup interface fastEthernet ?

<0-0> FastEthernet interface number

Thanks

Goutam

pls rate if it works.

kon_salev · ‎02-09-2008

I use a 7507 with 15 serial lines and a second 7507 with 5 adsl-vpn lines. The two routers are connected together with fastethernet. I want to use the fastethenet for backup of all 15 seials.

Goutam Sanyal · ‎02-09-2008

Hi,

Not clear to me. Can u post the diagram?

Thanks

Goutam

Richard Burts · ‎02-09-2008

konstantinos

While it may work for one interface I believe that trying to use any interface as backup for more than 1 interface is a problem. This is because the backup interface is put into a special state while the primary is up and the backup only becomes active when the primary is down. So if the FastEthernet is backup for serial 1 and 2 and serial 1 goes down I believe that the FastEthernet will not activate until both interfaces go down.

Perhaps an alternative might be to create a trunk on the FastEthernet with VLAN subinterfaces going over the trunk. Then you could use a subinterface as backup for the serial.

HTH

Rick

HTH

Rick

carl_townshend · ‎02-11-2008

for what benifit does the backup interface command have to us ?