Re: OSPF vs IS-IS

["Justin M. Streiner" <streiner () cluebyfour org>]

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>