From: Joe Rinehart (jjrinehart@hotmail.com)
Date: Thu Aug 23 2007 - 12:55:23 ART
Personally I would avoid ISIS, its not that it's a bad protocol, it just has
some peculiarities that make it tricker to work with...
OSPF is what AT&T (and many other service providers) uses in its core
network, its easily scaled and also does a bang-up job with MPLS. Planning
out the area structure is pretty important...
BGP should only run at the edge routers where peering is taking place and
such. The clean part about a label-switched core is that it has no
knowledge of edge routes at all...keeps the switching paths simple and clear
and efficient...
I modeled a service provider setup in my lab rack and it worked exactly that
way...I can send you a copy of whcy I mocked up if you like...
Joe Rinehart
CCNP, CCDP, CCIE #14256
Unified Communications Systems Engineer
Netversant Solutions
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gregory Gombas
Sent: Thursday, August 23, 2007 8:37 AM
To: Cisco certification
Subject: Question for you ISP guys
For those of you with ISP experience, can you tell me what routing protocols
do service providers typicall run within their AS?
Do you have every single router running BGP? I can't imagine redistributing
225k+ routes into an IGP, so how do you pass these routes withing your AS?
If you are using iBGP what are you using to transmit next hop information
(as iBGP does not normally update the next hop of the external AS)?
Can someone point me to some documentation showing typical ISP routing
design?
Thanks,
Greg
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