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Re: OSPF vs IS-IS
From: "Justin M. Streiner" <streiner () cluebyfour org>
Date: Thu, 11 Aug 2011 10:04:09 -0400 (EDT)

On Thu, 11 Aug 2011, jim deleskie wrote:

Having run both on some good sized networks, I can tell you to run
what your ops folks know best.  We can debate all day the technical
merits of one v another, but end of day, it always comes down to your
most jr ops eng having to make a change at 2 am, you need to design
for this case, if your using OSPF today and they know OSPF I'd say
stick with it to reduce the chance of things blowing up at 2am when
someone tries to 'fix' something else.

Agreed. I did an OSPFv3 vs. IS-IS bake-off in my lab several months ago as part of an IPv6 rollout, and one of the key deciding factors in going with OSPFv3 over IS-IS was that our ops folks are much more familiar with OSPFv2. While there are difference between OSPFv2 and OSPFv3 in how they work, the learning curve is a lot less steep than going from OSPFv2 to IS-IS.

jms

On Thu, Aug 11, 2011 at 10:29 AM, William Cooper <wcooper02 () gmail com> wrote:
I'm totally in concurrence with Stephan's point.

Couple of things to consider: a) deciding to migrate to either ISIS or
OSPFv3 from another protocol is still migrating to a new protocol
and b) even in the case of migrating to OSPFv3, there are fairly
significant changes in behavior from OSPFv2 to be aware of (most
notably
authentication, but that's fodder for another conversation).

-Tony

On Thu, Aug 11, 2011 at 9:06 AM, Stefan Fouant
<sfouant () shortestpathfirst net> wrote:
Well up until not too long ago, to support IPv6 you would run OSPFv3 and for IPv4 you would run OSPFv2, making IS-IS 
more attractive, but that is no longer the case with support for IPv4 NLRI in OSPFv3.

The only reason in my opinion to run IS-IS rather than OSPF today is due to the fact that IS-IS is decoupled from IP 
making it less vulnerable to attacks.

Stefan Fouant
JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI
Technical Trainer, Juniper Networks
http://www.shortestpathfirst.net
http://www.twitter.com/sfouant

Sent from my iPad

On Aug 11, 2011, at 8:57 AM, CJ <cjinfantino () gmail com> wrote:

Hey all,
Is there any reason to run IS-IS over OSPF in the SP core? Currently, we
are running IS-IS but we are redesigning our core and now would be a good
time to switch. I would like to switch to OSPF, mostly because of
familiarity with OSPF over IS-IS.
What does everyone think?

--
CJ

http://convergingontheedge.com <http://www.convergingontheedge.com>








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