Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

2 WAN Links on router

Hello,I have client that wants to set up a new router that has 2 wan links. The idea is that the first link will handle most/all of the workload and the second link will only be used if the 1 link is down, or when traffic is to much for the first link.

My question is, would the 1721 router with 2 wan wic's work for this setup? and how would you recommend the links be configured?

Thanks for any ideas/insight.



Re: 2 WAN Links on router

That should work fine. I would still recommend using something like a 1800 series router as the price difference is not a lot and your money will be well invested as, these routers will be in support from Cisco for the next 5 - 10 yrs.

New Member

Re: 2 WAN Links on router

That is very useful, how would you handle setting up the backup interface? Could I implement a Dial on Demand routing configuration, even if they are 2 wan links that are each connected to an always on internet link? 1 is to the databahn network, 2 is to a slower satellite connection.

Re: 2 WAN Links on router

You can use backup interface command to specify when to bring up the backup interface.

Check this link.

Or else, you can set up two floating static routes and get redundancy.

ip route serial 0 <----primary

ip route serial 1 150 <---secondary

150 is admin distance. By default , static routes have admin distance of 1, so your primary wan will be used and when it fails, secondary link will be used.

New Member

Re: 2 WAN Links on router

I think this is exactly what I was looking for. Thanks.


New Member

Re: 2 WAN Links on router


i have a question about the backup interface method.

lets say we have se0 as the primary interface and se1 is supposed to backup for se0 should se0 fail.

you go into interface se0 and do the foll.

inter se0

backup inter se1

ip addr x.x.x.x y.y.y.0

no shut


Do we need to do anything at all on the se1 interface ?

Do we need to set it up with a separate ip address or it will invoke all the configs from the se0 primary interface ?

if it picks up the config from the primary s0 interface, then how do is the other end of the backup interface se1 configured ?

Can you please explain ?

Thanks in advance !


Hall of Fame Super Silver

Re: 2 WAN Links on router


When you set up se1 as backup of se0, you need to configure an IP address and any other appropriate prarmeters on se1. It does not invoke any configs from se0. The other end of the backup link will also need to be configured with a corresponding IP address and any other parameters.