Multiple Routing Protocols

bermovick

Greetings again everyone!

I've been working with OSPF and EIGRP in my GNS3 labs lately. I've bridged my PC so my V-topologies are accessible from my physical network, but my physical network can only do RIP, thanks to my DSL router. (To be honest I was pleased when I saw I could enable RIP on it though). Anyway, I had thought I could just enable both RIP and the other routing protocol being used on the router closest to my physical network, and it would send what it received via eigrp out the rip interfaces and vice-versa, but it doesn't seem to be doing that.

Rip only seems to be sending out updates for networks directly connected to it, as far as I can tell. I haven't actually looked at any debugs yet, as it's after midnight and I'm ready for bed, but my dsl router only lists the middle-man router's 2 directly-connected networks as being received. I know rip's configuration specifies what networks it advertises & what interfaces it would advertise them out of, but even adding the commands for the other 2 networks doesn't make it advertise those. On one hand it sortof makes sense that it wouldn't, but on the other it makes it not do what I want it to do!

I suppose it's really not a big deal, more of a 'hmm, why didn't that work?' thing when I was doing various pings to make sure I set up tonight's VLSM lab, but sometimes I just want to make everything work, even when it's beyond what I know / should know. (I'm sure there's a way to do it)

kalebksp

You'll want to look into redistribution, which can become a complex topic. For that specific situation entering 'redistribute eigrp [as number]' in the RIP config should do what you want.

TesseracT

yep you'll need to look into route redistribution which can be a huge topic. For what you need it for it's simple enough though.

On the router with the EIGRP routes that you want 'sent' to RIP you will also have to enable RIP (So the router has both 'router eigrp' and 'router rip' commands).

the command for redistribution if your eigrp is autonomous system 1 is

router rip
redistribute eigrp metric 5

This will redistribute all the routes in eigrp to the rip process with a hop count of 5. The metric command is needed for RIP because it has no idea what the hell the EIGRP metric is (remember the DUAL algorithm?), so the EIGRP metric needs to be converted into something that the RIP protocol understands... and that is the good old hop count.

It's the same with OSPF... I don't think the CCNA touches on route redistribution but it gets into it in the CCNP (BSCI,ROUTE) and even more-so in the CCIE.

burbankmarc

An important thing to remember is that RIP and EIGRP will NOT redistribute routes unless you set a default metric within the redistribution.

bermovick

Yeah what you're saying makes sense. It wouldn't automatically be able to include routes learned from the other protocol just because of the differences in how the metrics are calculated. Thanks