From: Mohamed, Liban [NTK] (Liban.Mohamed@sprint.com)
Date: Sun Nov 11 2007 - 14:00:49 ART
Pete,
You will find ISIS is more stable and requires VERY minimum changes (if
designed well), and less headache ( no more types, LSA's). and that is
the one of the reason's large ISP's run ISIS as IGP. If one understands
OSPF, it will take very little time to understand IS-IS, Do you plan to
use ISIS, just for reach ability and use I-BGP as internal protocol? As
Tarun mentioned advertise passive-only comes in handy to reduce the
routing table. Unicast me if you have any specific question,
www.geant.net/upload/pdf/NEP-02-087.pdf
this Link is has juniper samples, but you will get the picture.
Thanks,
Liban Mohamed
NTAC-IP
Sprint/Nextel
www.sprint.net
liban.mohamed@sprint.com
(W) 678-291-3438
(PCS) 404-441-9701
-----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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