just what I was looking for :) Thanks, Dave On Wednesday 14 March 2001 23:34, Howard C. Berkowitz wrote: > >Hey all, > > > > I've been reading into BSCN here lately with Cisco press > >books. In the book > >there is a fairly detailed discussion of OSPF. I'm not in the least > > opposed to learning it. One thing I would like to understand is why an > > organization would use it. Is this used in ISP's? What are the advantages > > of it over say, EIGRP? I always see it compared to RIPv1 but I find it > > silly for advanced routing protocols to be compared with ripV1. > > I'll preface my remarks with the observation that all three advanced > IGPs: OSPF, EIGRP, and ISIS, all work well. ISIS is more a niche > protocol for ISPs. There are pros and cons for each one. > > OSPF and ISIS require structured network topology from the very > beginning, while EIGRP is much more tolerant -- up to a point. For > me, the definitive comment came over a few beers shared with a > distinguished Cisco engineer. He observed, "to build a really big > network, you absolutely have to have clue." He burped loudly, and > then went on. "EIGRP has the advantage of letting you stay clueless > for longer." > > The biggest argument against EIGRP is that it is Cisco proprietary. > Being proprietary has implications beyond the multivendor question. > Because some of the EIGRP mechanisms have not been published by > Cisco, there isn't the external knowledge base about EIGRP that there > is about OSPF and ISIS. Protocol and network architects have a very > deep understanding how OSPF and ISIS will behave and what their > strengths and weaknesses are, but no one who hasn't been a Cisco > employee can have the same sort of insight. > > For similar topologies, EIGRP generally needs less processing than > OSPF. On the other hand, with ever-faster processors, this may not be > a significant constraint. In a fair test, with equivalent timers set > to equivalent values, both converge very fast, and convergence time > should not be an issue with any protocol (assuming reasonable network > topology). EIGRP may be able to find an alternate path faster when > that path goes through a neighbor, but OSPF is faster if the > alternate path might be several hops away. > > If you run Appletalk or IPX routing, there is a definite advantage to > using EIGRP. EIGRP also can bring incremental updating to a Netware > 3.x environment that can't be upgraded. > > A few things to consider. > > >Please forgive me if this is shortsighted of me. > > > >Thanks in advance, > >Dave > > > >_________________________________ > >FAQ, list archives, and subscription info: > >http://www.groupstudy.com/list/cisco.html > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > _________________________________ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html Report misconduct and > Nondisclosure violations to [EMAIL PROTECTED] _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
