[c-nsp] which IGRP?

[Pete Templin]

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.)

Step 1: Keep iBGP.  You'll need this to carry exterior routing 
information around your network.

Step 2: Pick up "Optimal Routing Design" from Cisco Press.  Might want 
to grab "BGP Design and Implementation" while you're at it, but it's not 
as critical.

Step 3: Avoid RIP and/or RIPv2 like the plague.  Avoid EIGRP if at all 
possible, only to make things easier if you ever add routing-capable 
equipment that's ABC (Anything But Cisco).  This can include servers 
that run OSPF to routers from Juniper or Riverstone (but don't do 
Riverstone).  EIGRP also doesn't support MPLS Traffic Engineering; you 
may find MPLS TE to be quite useful even if it's only for Fast ReRoute 
(i.e. routing around link or node failures in <1s, rather than waiting 
several seconds for your IGP to notice).  This leaves you with OSPF or 
IS-IS.

Step 4: If you can stomach it and your gear will run it, go with IS-IS. 
  Potentially better security (it runs on CLNS not IP, so outside 
hackers can't send forged packets into your network to blow up your 
routing), better MPLS TE feature support, and other benefits as folks 
have mentioned.

See the following for information and examples about IS-IS:

http://www.nanog.org/mtg-0310/gill.html
http://www.nanog.org/mtg-0202/cengiz.html
http://www.nanog.org/mtg-0405/vemulapalli.html
http://www.nanog.org/mtg-0202/shankar.html
http://www.nanog.org/mtg-0010/isis.html
http://www.nanog.org/mtg-0006/katz.html

pt