From: Joseph D. Phillips (josephdphillips@fastmail.us)
Date: Wed Jul 14 2004 - 22:14:07 GMT-3
Bingo.
----- Original message -----
From: "Kenneth Wygand" <KWygand@customonline.com>
To: ccielab@groupstudy.com
Date: Wed, 14 Jul 2004 20:57:34 -0400
Subject: Suboptimal Routing?
I have a generic question regarding suboptimal routing on the CCIE lab.
Suppose I have both RIP and OSPF running in my network. I have two
routers that are running both RIP and OSPF (on the RIP/OSPF border).
One of these routers is mutually redistributing RIP and OSPF (let's call
this "Router 1"). Without changing distances or filtering, routes that
originate in RIP and are redistributed by "Router 1" into OSPF will be
received by "Router 2" in OSPF. So now Router 2 will know of routes
from the RIP domain through both it's own RIP routes and also through
the OSPF routes. Of course, the distance of OSPF is less than RIP, so
it will default to choose the routes that "go all the way around the
world" to get back into the RIP domain.
This is a clear case of "suboptimal routing" but still provides full IP
connectivity. Every single practice lab I've ever come across has
always "treated" this situation by using some mechanism (filtering,
distance, etc) to cause the native RIP routes to be preferred through
RIP as opposed to the "all the way around the world" OSPF routes.
However, none of these labs ever say "ensure you avoid suboptimal
routing". I've also heard many times that the lab is "not testing
real-world best practices, only that you meet the requirements of the
question". Well, if the question states I must have IP reachability,
then why should I bother fixing suboptimal routing. Sure, it will
display to the proctor that I understand it and I know what I'm doing,
but why -specifically- do I have to do it to get points on my exam? If
it doesn't say to avoid this, why should I waste my time?
Thanks in advance, as I really look forward to your responses.
Ken
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