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From: ccci!tcs@uunet.UU.NET (Terry Slattery)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: RIP vs IGRP
Message-ID: <34815@boulder.Colorado.EDU>
Date: 7 May 91 19:07:39 GMT
Sender: daemon@boulder.Colorado.EDU
Lines: 40

> I was all set to implement my wide-area network using IGRP; now that Novell has
>released NetWare 386 v3.11, which uses RIP in its TCP/IP implementation, I fear
>I have to revisit the routing issue.  The problem, for me, is that Novell just
>dumped about a dozen RIP-based routers onto my network; I need a way to deal
>with them.  My choices seem to be: (1) run IGRP on the WAN, and force the Net-
>Ware routers to use their local cisco box for a default route; or (2) run RIP
>everywhere.  Option (2) appears easier to deal with, since there are no static
>routes to deal with; it is also more consistent.  However, IGRP (and OSPF) is
>a better routing protocol than RIP.  My network is simple enough now that I
>would probably have no trouble running as a RIP-based net; that may change,
>though, so I don't want to shoot myself in the foot by choosing RIP.  (Does any-
>one know of an IGRP or OSPF implementation for NetWare v3.11....)
> Anyway, I'd appreciate any comments on or solutions to this dilemma; thanks in
>advance for any and all helpful input.
>
>- Andrew E. Birner, Zenith Electronics Corporation -

Andrew,
  There's no magic bullet to solve your problem.  With either IGRP or OSPF,
you must use RIP as the intermediate system (ie router) to end system (ie
host) routing protocol.  With either of these protocols, you'll need to
import RIP routes learned from the Novell routers and redistribute IGRP
(OSPF) routes via RIP to the Novell routers.  Your option (2) is certainly
the simplest thing for the time being, then you can use one router as a test
system for designing the redistribution mechanism you'll need for OSPF or
IGRP.

The redistribution mechanism will pick up IGRP (OSPF) routes, and convert
them into RIP routes with a fixed metric (probably 1 or 2).  Similarly, the
RIP information you receive from the Novell routers will need to be
redistributed via IGRP (OSPF).  If the Novell routers don't do split horizon
in their RIP implementation, you'll need to build some filters to discard
your IGRP (OSPF) routes from the Novell RIP updates.

There are a couple of alternatives.  You can use static routes in IGRP
(OSPF) for the appropriate Novell routers for each network they service.
And you can have the cisco's source a RIP default route so that the Novell
routers dynamically learn of their default router.

	-tcs