Why IS-IS?

Posted by stretch in Resources on Thursday, 22 May 2008 at 5:33 a.m. GMT

Every once in a while I find myself referring to a brilliant little piece on the advantages of IS-IS over OSPF, entitled Why IS-IS?. The author lists ten reasons to prefer IS-IS, each somewhat debatable but certainly noteworthy. I especially like #3, a point which highlights a subtle operational characteristic of OSPF:

3. Link state basis. OSPF uses a distance vector scheme for computing interarea routes; it's only a link state protocol within an area. IS-IS maintains separate link state databases for L1 and L2 topologies and uses SPF to compute routes in both.

Unfortunately, I've long since forgotten how this article found its way into my bookmarks. Even Google seems to have forgotten about it. Does anyone know the identity of the author?

UPDATE: Ivan Pepelnjak of IOS Hints has a great explanation of OSPF's inter-area distance-vector behavior.

Brandon Carroll commented on 23 May 2008 at 5:27 a.m.

Doesn't IS-IS use the same metric for every interface? Sure it can be changed but isn't that basically RIP? It's late though so maybe I'm wrong. I love the list though. It now lives in my bookmarks.

Ivan Pepelnjak commented on 31 May 2008 at 1:26 p.m.

Would you happen to have the original text? The link you've provided doesn't work any longer.

stretch commented on 31 May 2008 at 2:56 p.m.

Crap. It seems the author (still don't know his/her proper name) has taken it offline. Did referrals from my humble blog really cause that much fuss? I'm sorry if they did!

I suppose I should have saved the article before I referenced it just in case.

nicholas commented on 1 Jun 2008 at 7:38 a.m.

Hi, If my memory serves me right the original author is Catfive. He can be usually found in #cisco on freenode although he's not particularly active lately. I believe he is/was a Cisco Systems employee but don't quote me on this one. Postel or Nemith may have more information on this. They can be also found on freenode.

Keep it up and don't let the desert scorpions bite too much.

nick

Wbm commented on 3 Aug 2008 at 8:20 p.m.

Use the force (altavista archive) Luke! ;-)

Leave a comment

(optional, will not be published)
(optional)

Comment Tips

  • You can use Markdown syntax for decoration. (Cheat sheet)
  • Links: [Google](http://google.com) or <http://google.com>
  • Use backticks around commands: `ip address 127.0.0.1`
  • Use indentations (tabs) for preformatted text (code blocks)