At 10:09 AM -0500 3/11/03, Peter van Oene wrote: >Hi all, > >Here is a quick post from Dave Katz on ISIS vs OSPF in large >networks dealing with the issue of which protocol inherently scales >better. This is from a thread in the IETF OSPF WG mailing list for >those looking for the full thread. Dave has participated >significantly in the development of routing protocol software for >both Cisco and Juniper. > >Thought some folks might find it interesting > >Pete
As far as the "implementations of ISIS from various vendors," Dave wrote all of the ISIS code involved. There was turnover in Cisco's early OSPF developers. > > >>Date: Sun, 9 Mar 2003 21:05:14 -0800 >>Reply-To: Mailing List >>Sender: Mailing List >>From: Dave Katz >>Subject: Re: ospf limits... >>To: [EMAIL PROTECTED] >>X-RAVMilter-Version: 8.4.1(snapshot 20020919) (usermail.com) >>X-Spam-Status: No, hits=-8.5 required=9.1 >> tests=FORGED_RCVD_TRAIL,IN_REP_TO,REFERENCES >> version=2.50 >>X-Spam-Level: >>X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) >> >>For all practical purposes, the designs of the OSPF and ISIS protocols >>will not be the limiting factor in the size of an area, unless (a) you >>have a really good implementation, and (b) you feel the need to dump >>excessive numbers (many thousands) of external and stub routes into >>the protocol. >> >>Most implementations will crash and burn before the topology gets >>big enough to become an issue, and most people don't dump externals >>into their IGPs (they use BGP instead.) >> >>Architecturally, OSPF limits the inter-router topology and stub routes >>due to the 64KB limit on the Router LSA, and ISIS limits the total amount >>of information due to the 256 LSP "fragment" limit. One could come up >>with various hacks for either protocol if these limits were actually, >>well, limiting, but this has never been the case in (sane) practice. >> >>Historically, the ISIS implementation from a particular major vendor has >>had better scaling characteristics than the OSPF implementation of that >>particular major vendor, but this this isn't really the case for another >>major vendor. ;-) >> >>--Dave Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65078&t=65078 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
