From: Darby Weaver (darbyweaver@yahoo.com)
Date: Thu Nov 01 2007 - 23:59:05 ART
Is optimal routing even the goal of the lab in
question?
--- Carlos Trujillo Jimenez <nergal888@hotmail.com>
wrote:
> The same, redistribution is killin me also...
> Noticed in some (not all)
> toplogies at internetworkexpert labs, that there is
> no way to have optimal
> routing I hace tried changing distances, metrics,
> taggig, but there is no
> way sometimes.
>
>
>
>
> >From: <hadek.el-ayachi@nsn.com>
> >Return-Path: ccielab-owner@groupstudy.com
> >
> >I had many problems trying to avoid suboptimal
> routing and loops in such
> >a topology. My advices are :
> >- Don't try to avoid suboptimal routing if it is
> not asked for, only
> >loops are indesirable
> >- there is always a straightforward, a very simple
> solution for each
> >senario instead of changing AD,tagging here and
> there and creat some
> >mind loops
> >- redistribution is a manual process. Put your
> self, in a round robin
> >style, in one routing protocol and see what can
> happen to you internal
> >routes as well as you external routes seperatly
> when coming back to you.
> >- use metric instead of AD or tags.
> >- pay more attention to external routes for each
> protocol
> >BR
> >
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> >ext Xiao Li
> >Sent: jeudi 1 novembre 2007 10:47
> >To: ccielab@groupstudy.com
> >Subject: redistributing.. again..
> >
> >Hi, I was doing core work book lab 6 this
> afternoon and the
> >redistribution really got me hard. I thought of
> using distance to limit
> >route feed back is convenient and reliable.. it
> proves me wrong.
> >OSPF, RIP , EIGRP are mutually redistributed on R3,
> R4 and R5.. so I
> >apply the golden rules: from lower ad to higher
> ad, no worries, routes
> >will never get feed back to the lower ad domain
> because the higher ad
> >route will not get in the routing table at the
> other redistribution
> >point... checked from higher ad to lower ad, use
> distances command to
> >lower down the ad for the redistributed routes..
> checked I thought
> >that should more or less has done the magic
> automatically.. but I keep
> >getting routing loops for routes coming from the
> rip domain.. after some
> >time i realized that whenever a route is added in
> the rip domain, the
> >route is looping between r3, r4, r5.. further i
> realized that the route
> >propagation in RIP is much slower than
> redistributing from
> >rip->eigrp100->eig!
> > rp200->rip.. so when the route is ready to be
> redistributed from
> >eigrp200->rip at R4, the higher ad rip route (as
> compared to eigrp
> >external) did not reach R4 yet to stop it.. and I
> was careless enough
> >to put "redistribute eigrp 200 metric 1" under rip,
> which make it a
> >prefer rip route from R3 since metric is low. The
> solution guide does
> >use metric 10 on R4 and R5, but on R3, it uses
> metric 1 also. I am
> >thinking that this can also cause a problem when
> bb2 advertise new rip
> >routes or reload, as
> r5->rip->ospf->eigrp200->eigrp100->r3 could still
> >go faster than R5->rip->R3. I did not have a time
> to test this out
> >though.. will try that later..
> >
> > Changing the metric to a higher value when
> redistributing to rip will
> >work around this issue, but it does not seem to be
> a complete solution.
> >The fact is: for a short period of time, the routes
> are feed back to rip
> >domain where is originates. Another problem is:
> the rip metric can't
> >really go too high.
> >
> > I can't think of a way to use tag either..
> tags are overridden, and
> >in this lab there is so many point of
> redistribution. Is there a way to
> >append the tag like the AS path does in bgp? Or
> any other way to better
> >address this problem? Thanks for the advise.
> >
> >Best regards,
> >Li Xiao
>
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This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:27 ART