[c-nsp] which IGRP?

Mark Tinka mtinka at africaonline.co.sz
Fri Jul 15 08:30:28 EDT 2005


On Friday 15 July 2005 13:02, Jeff Chan wrote:

> Instead of iBGP, should we use a routing protocol
> optimized specifically for interior use such as EIGRP,
> OSPF, etc.? Or can it be done satisfactorily with iBGP
> and a route reflector setup?  (Naturally we're talking
> eBGP to our external peers.)
>
> Is there a standard practice for this?

I wouldn't say it's a standard practice, per se, but most 
providers now do what you're doing, use iBGP as the IGP, 
but different from what you are doing, use a "real" IGP, 
e.g., OSPF or IS-IS, to create an infrastructure atop 
which iBGP can create it's sessions. iBGP isn't 
link-state, so it needs another routing protocol to tell 
it how to get to its neighbors.

In your case, although you don't mention it, it sounds 
like you create your infrastructure with static routes, 
which is how iBGP then creates its relationships. This 
fine, for a small, beginning network, but as you grow 
(which is what you are doing with a third router), 
moving your static routing to something like OSPF or 
IS-IS is the way to go.

Keeping iBGP as your interior routing protocol would 
still be personally recommended. As an IGP to begin 
with, I'd recommend OSPF.

Mark.

> IOS is 
> 12.3(13) mainline everywhere.
>
> Jeff C.
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