From: Scott Morris (smorris@ipexpert.com)
Date: Sun Nov 11 2007 - 13:56:07 ART
It's not so much a limitation of having one TE-capable IGP in service, but a
single LSP doesn't like to cross the IGP boundaries there. So you can have
separate IGPs, just terminate/stitch/recreate your LSPs if necessary.
Or, as Pete mentions, just do it all in a single ISIS area are don't worry
about it! Think about what gains you are, or are not, getting from your
multi-area OSPF design and use that you guide yourself towards your ISIS
deployment model.
In the end, as long as you know what's going on in your network and can
think this stuff through ahead of time, there are not any magical problems
that occur.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Pete
Templin
Sent: Sunday, November 11, 2007 11:47 AM
To: Tarun Pahuja
Cc: Dishan Gamage; Cisco certification; Cisco certification
Subject: Re: ospf muti-area to isis
Tarun Pahuja wrote:
> Dishan,
> There a lot of consideration a company has to make before
> moving from one protocol or another. Since I do not know anything
> about your network and the motivation behind moving to ISIS from OSPF.
> I can only give you a couple of tips to get started thinking about a
> few things. You will have to master ospf and isis in order to do the
> migration(unless you want to get a consultant in). The size of the
> network, link speeds, type of routers, etc would play a very important
> role in migration phase as well as the overall final design.
Honestly, I didn't have to learn much about ISIS to make the switch, though
we did switch from multi-area OSPF to single-area ISIS (the areas weren't
doing anything for us). The migration was incredibly seamless; I planned to
roll one POP per night, almost for the fun of watching the migration go
across the network. However, the only glitch we ran into was with MPLS
Traffic Engineering: it's been a while, but I think TE only likes to have
one TE-capable IGP in service. This forced us to make the switch in one
night, which was no big deal anyway.
> On Nov 11, 2007 9:25 AM, Pete Templin <petelists@templin.org
> <mailto:petelists@templin.org>> wrote:
>
> http://www.nanog.org/mtg-0310/gill.html
Again, this was all I needed. Granted, we were a service provider network
with a topology much like ATDN (though with only five POPs).
The basic premise is simple: roll out ISIS across the network, prefer ISIS
across the network, remove OSPF across the network. Done.
pt
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