From: Chua, Parry (Parry.Chua@xxxxxxxxxx)
Date: Tue Nov 27 2001 - 05:38:40 GMT-3
I think it is depenent on the given topology, if you spot that there are
multiple mutual distribution, for sure we need to apply the technique to
prevent suboptimal
path and routing loop. If there are other dynamic routes inject or
learn, it may need
to be redistribute into other routing protocol. In most case, I think
filter your network from inject by other routing protocol should be OK.
I would like to know other comments.
Parry Chua
-----Original Message-----
From: Wayne Lewis [mailto:lewisway@hcc.hawaii.edu]
Sent: Tuesday, November 27, 2001 3:55 PM
To: ccielab@groupstudy.com
Subject: RE: flsm to vlsm
Sorry for the confusion. Hansang, I agree with your statement
about using
route-maps with redistribution. But my question wasn't whether or not
to
use them, but if a prescriptive route-map for IGRP to OSPF
redistribution is
acceptable on the exam. What I like to do is create a route-map
specifying
the exact IGRP routes I want to redistribute into OSPF. But I'm
wondering
if the powers that be might prefer that the redistribution is more
dynamic
in that it would be designed to allow for 'other' IGRP routes to be
redistributed should more be added later - it's really a design
question.
Considering that the scenarios in the lab exam are typically far from
practical/real-life, I'm assuming that we don't need to be especially
concerned with following design principles, as long as our method is
functional. I'd like to hear one or two people say, yeah, that's right,
you're OK with just redistributing a list of routes and denying all
others.
Thanks,
Wayne
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Hansang Bae
Sent: Monday, November 26, 2001 9:08 PM
To: ccielab@groupstudy.com
Subject: RE: flsm to vlsm
At 02:26 PM 11/27/2001 +1100, Albert Lu wrote:
>[snip]
>I'm pondering this question as well, as I see from examples in Doyle
that
>redistribution between IGPs should be done carefully, so filtering via
>route-maps or distribute-list is required. That means you have to use
>route-maps and distribute-lists for all routers that are doing
>redistribution between two protocols. But Heck!!! I've seen examples
that
>don't use filtering, and it still works!!
>My thoughts are that the filtering is there for precautionary measures,
just
>in case routes do feed back into the routing protocol it originated
from.
>There's also the admin distance that has to be taken into account of.
>If anyone has any suggestions of the proper way of doing this, please
let
me
>know
Folks,
While I understand that people are fretting about the smallest detail of
the lab (e.g. what's consider superfluous command...) there are some
definite engineering standards that should be used in the real world.
One
of these is "if you redistribute, you need to route-map/distribute-list
what your redistributing." If you don't... sooner or later, you'll
experience rolling blackouts. Just about every book on IGP has
examples
of route feedback causing temporary/rolling blackouts. This won't
happen
every single time as it's a function of topology and routing protocols
in
use. But sooner or later, you will be bitten by this.
So you should ALWAYS use route-maps (I prefer them to distribute-lists)
to
control redistribution.
hsb
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