From: Chuck Larrieu (chuck@xxxxxxxxxxxxx)
Date: Thu Aug 09 2001 - 12:43:31 GMT-3
as with anything, the answer is "it depends"
the design guide that I referred to appears to have been written more than a
couple of years ago. the recommendations there came from extensive field
experience with large customers, if my sources are correct.
that said, yes, the mitigating factors are processor, memory, stability of
the network links throughout the ospf domain, whether or not good design
practice has been followed, and effective summarization is in place. the
killer in OSPF is the running of the Djikstra algorithm, and not necessarily
the number of routes, the number of routers, the number of links, or the
number of areas to which a router is connected.
we recently had a discussion along these lines on the regular groupstudy
list. I walked away from that discussion questioning a couple of things that
Cisco and the study materials preach as gospel, including the issue of
scalability of static routing. It occurred to me that under certain designs,
static routing / on demand routing could actually involve far less work and
provide far greater stability than configuring any routing protocol.
as with everything Cisco, "it depends"
Chuck
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Matt Wagner
Sent: Thursday, August 09, 2001 8:17 AM
To: ccielab@groupstudy.com
Cc: strongbow71@gmx.at
Subject: Re: OSPF Limits
Hey (group), let me know if I'm wrong about this, but the "50" rule is a
generic rule. Whether you can support more or less than that depends on a
few things, like whether you are set up entirely hierarchically or whether
you are looping all over the place, the number of ASBRs, etc. I also am
pretty sure that it has less to do with the horsepower of the routers you
are using and more to do with the protocol itself handling a database with a
certain degree of complexity well, which is the main reason you shouldn't
redistribute BGP into OSSPF.
With proper design, you can probably handle more that 50 routers, and with
poor design, probably fewer. That's just what I have always thought,
though. Any comments would be appreciated.
Matt
A man said to the Universe, "Sir, I exist".
The Universe replied, "The fact may be,
but it inspires in me no sense of obligation."
----Original Message Follows----
From: "Dietmar Gaar" <strongbow71@gmx.at>
Reply-To: "Dietmar Gaar" <strongbow71@gmx.at>
To: <ccielab@groupstudy.com>
Subject: OSPF Limits
Date: Thu, 9 Aug 2001 11:59:12 +0200
Hi,
I4m playing around with OSPF last Days preparing for the Lab Exam.
So in practice, when you have not a perfect but a good Design - how "big"
can an OSPF Interwork grow up ? Exist there some practical based Limits ?
I already know that there a many unknown Parameters to take a care of - but
maybe you can give me some scales...
kind regards,
Dietmar
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