On Tue, 2005-06-21 at 09:04 -0500, Dan Evans wrote:

Can anyone point me to information on what the top N service providers are using for their IGP? I'm trying to build a case for switching from OSPF to IS-IS.

Why are you trying to build a case...? Would you already have operational benefit from switching and are you building a case round that and if not, why switch...? Switching IGP in a non-trivial network isn't something you'd want to do unless you've got a clear motive and it gives you some operational advantage... Cheers, -- --- Erik Haagsman Network Architect We Dare BV Tel: +31(0)10-7507008 Fax: +31(0)10-7507005 http://www.we-dare.nl

Dan Evans wrote:

All,

Can anyone point me to information on what the top N service providers are using for their IGP? I'm trying to build a case for switching from OSPF to IS-IS. Those on this list who are currently running IS-IS, do you find better scalability and stability running IS-IS than OSPF? I understand that this question is a lot more complex than a simple yes or no since factors like design and routing policy will certainly affect the protocols behavior.

Any insights or experiences that you can share would be most helpful.

Thanks,

Daniel Evans Alltel Communications

Daniel, in short, we've found ISIS to be slightly easier to maintain and run, with slightly more peace of mind in terms of securitiy than OSPF. Performance and stability wise, no major difference that was noticable. For more information, see the talk by Dave Katz at http://www.nanog.org/mtg-0006/katz.html Also, AOL's experience in switching from OSPF to ISIS is covered at http://www.nanog.org/mtg-0310/gill.html the PDF on that page is actually an older version. The full version I used at NANOG is available at http://www.vijaygill.com/oi.pdf /vijay

Hi Daniel, We wrote a draft some time back comparing the two protocols ISIS and OSPF. It should address some of your doubts and concerns. Here's a pointer to my local copy: http://geocities.com/mnvbhatia/draft-bhatia-manral-diff-isis-ospf-00.txt Thanks, Manav !> -----Original Message----- !> From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] !> On Behalf Of Dan Evans !> Sent: Tuesday, June 21, 2005 7:35 PM !> To: nanog@merit.edu !> Subject: OSPF -vs- ISIS !> !> !> All, !> !> Can anyone point me to information on what the top N service !> providers !> are using for their IGP? I'm trying to build a case for !> switching from !> OSPF to IS-IS. Those on this list who are currently running IS-IS, do !> you find better scalability and stability running IS-IS than OSPF? I !> understand that this question is a lot more complex than a simple yes !> or no since factors like design and routing policy will certainly !> affect the protocols behavior. !> !> Any insights or experiences that you can share would be most helpful. !> !> Thanks, !> !> Daniel Evans !> Alltel Communications !> !>