IPv6: IS-IS or OSPFv3

devang patel devangnp at gmail.com
Fri Dec 26 22:56:39 CST 2008


Kevin,

Thanks for pointing out other good part of having CLNS as a transport for
ISIS as a security point!

regards
Devang Patel


On Fri, Dec 26, 2008 at 9:37 PM, Kevin Oberman <oberman at es.net> wrote:

> > Date: Fri, 26 Dec 2008 19:47:21 -0700
> > From: "devang patel" <devangnp at gmail.com>
> >
> > Hello,
> >
> > I do have some confusion about which one is better for IPv6 in Service
> > Provider networks as far as IP routing and MPLS application is concern!
> >
> > 1. Which protocol should i use to support the IPv6 in network: ISIS or
> > OSPFv3?
> >     As ISIS has multi-topology feature that can give us capability to run
> > IPv4 network separate from IPv6 right! and same thing with OSPF: OSPFv2
> will
> > be used for IPv4 routing and OSPFv3 will be used for IPv6 routing! again
> Its
> > look like resource    utilization for both the protocol will be same as
> they
> > are going to use separate database for storing the routing or topology
> > information. ISIS still has advantage over OSPF as it does use the TLV
> > structure which can help in expanding network to support the new feature!
> >
> > 2. MPLS is not distributing label for IPv6 protocol so again there will
> not
> > be any IGP best path calcuated for any MPLS related application for IPv6!
> >
> > 3. what if i have already running OSPFv2 for IPv4 in the network then
> should
> > i think for migrating to ISIS?
> >    if yes then what are the advantages that I can look at for migrating
> my
> > network to IS-IS?
>
> FWIW, we run OSPF for IPv4 and ISIS for IPv6. We started with ISIS for
> v6 because we were routing IPv6 before OSPFv3 was available.
>
> The main reason I prefer ISIS is that it uses CLNS packets for
> communications and we don't route CLNS. (I don't think ANYONE is routing
> CLNS today.) That makes it pretty secure.
>
> I would hope you have a backbone well enough secured that you don't need
> to rely on this, but it does make me a bit more relaxed and makes me
> wish we were using ISIS for IPv4, as well. The time and disruption
> involved in converting is something that will keep us running OSPF for
> IPv4 for a long time, though. I remember the 'fun' of converting from
> IGRP to OSPF about 13 years ago and I'd prefer to retire before a
> repeat.
>
> The real issue is that you need to run something you understand and can
> manage effectively. It that is OSPF, it will certainly do the job. If it
> is ISIS, it will, too. The real differences are few and not significant for
> most.
> --
> R. Kevin Oberman, Network Engineer
> Energy Sciences Network (ESnet)
> Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
> E-mail: oberman at es.net                  Phone: +1 510 486-8634
> Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
>



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