The ospf over vpn is ok, we could even consider any type of link just to focus on ospf. The problem is how to set the OSPF to do that, send all traffic over one link and only a specific IP over the other.

Thanks

Hi,

I already have a GRE, the VPN is not the problem, only the ospf configuration to send all traffic over one link and the traffic for a specific IP over other.

please dont worry about OSPF over VPN it's working fine.

We can consider it's 2 ethernet links between site.

Thanks

ospf will not send certain traffic over one link, etc. It route by destionation only.

For that, you need PBR. Then if you want PBR and redundancy, it's a more advanced configuration.

Thanks, but lets say i have

site 1 Site2

172.17.0.0 172.18.0.0

Two links and simple ospf

ospf 1

network 172.17.0.0 area 0

and

ospf 1

network 172.18.0.0 area 0

This way all traffic will go over one link or other depending what ospf consider better, thats ok. I just want to force ospf to send traffic for one IP over other link that is unused. what do I put in the configuration of router for that to say to others that this route for this single IP is better to come over other link?

You can't do that with ospf. Speacifying traffic _to_one IP wuld be a static route. Specifying traffic _from_ one IP would PBR.

But if i configure a static route I will have no redundancy right? That's the problem I need it going over one link but if the link goes down this IP go through the other concurring with all other traffic.

You can have static routes and redundancy. That is done with object tracking and probes.

Or, if the static is over a physical interface, once it goes down, dynamic routing ospf will take precedence.

Yea, i didn't want to use tracking and probes because I have a lot of sites in full mesh topology and it's too complicated.

I was wandering if I could use someting like route-map in the incoming interface and match this route map in an ACL with this single IP then set metric for that and ospf would see this route as better for this single IP.

Should it work?

It's not a physical link also, so when one side goes down, the other one is up.

Guilherme

With some protocols like EIGRP you do have the ability to manipulate the metric for individual routes. But you can not do that with OSPF. As a link state protocol it calculates its metric based on its map of the topology and all routes learned from a source over an interface will get the same metric.

If you want to route a specific IP address over the PPP link then I see no good alternative to static route/object tracking or PBR.

HTH

Rick

Yes, with ospf or even easier with rip, you can inject a more specific route for the IP you are interested in. Then with a distribute list you make sure it's advertised on one link only.