OSPF to RIP to OSPF again

[koued]

Hello,

I'm having trouble with a network that I had to implement. In OSPFv2, let's say we have the area 0, this area is supposed to have an other area, area 2, directly connected. Everything works fine but then we put an other subnet that is configured in RIP between the area 0 and 2 so the connexion is broken. Is there still a way to make it work somehow? Does it have something to do with "Not So Stubby Area" ? I am not so sure if there is a way the area 2 can still send its traffic to the backbone, I suppose not...
I've never seen something like that but I'm still curious if there is still a way but I don't have a lot of experience in this domain...

[MHM Cisco World · Accepted solution]

You need gre tunnel between two area, this make area 2 connect to area 0 through tunnel interfacr

[koued]

thanks for the quick answer, so the trick is to keep a Border Router on the backbone and encapsulate with GRE through rip, so an interface of the Border Router is in area 2 ?

[Joseph W. Doherty]

Using a GRE tunnel is one way, but although simple, it can have a few issues.  The first of which is, if your L3 device is a (smaller older) L3 switch it may not support GRE.  Another issue, GRE often leads to packet fragmentation.

Another approach might be for your OSPF routers to run RIP or for the RIP router to run OSPF and pass routes between the two OSPF areas.

There are more variations of routing, all more complicated to configure than GRE, but all avoiding GRE issues.

[MHM Cisco World]

Yes correct

[koued]

thanks, I appreciate !