From: frank.yu@japan.bnpparibas.com
Date: Thu Sep 05 2002 - 10:54:18 GMT-3
Can any one shed me a light on the tunnel solution?
Thanx,
Frank
Internet
dmitry_volkov@ca.ml.com - 09/05/2002 02:33 PM
To: nshah
cc: Frank Yu, ccielab
Subject: RE: redistribute ospf to igrp again
> -----Original Message-----
> From: Nick Shah [mailto:nshah@connect.com.au]
> Sent: Thursday, September 05, 2002 1:10 AM
> To: Volkov, Dmitry (Toronto - BCE)
> Cc: frank.yu@japan.bnpparibas.com; ccielab@groupstudy.com
> Subject: Re: redistribute ospf to igrp again
>
>
> Further to what has already been discussed :
> The question to ask yourself and the proctor is what is
> allowed and what is
> not ?
>
> * Check if default network is permitted, if so, and if you can get a
> classful network to play with, nothing better.
>
> * Check for all possibilities of generating area-ranges &
> summaries (Area
> range is possible only on ABRs and summary is possible only
> on ASBR), So if
> a router is not an ABR, think if you can make it one, or if
> its not an ASBR
> can you make it one. In this case (especially one mentioned
> below) you can
> use 172.16.0.4/30 assign it to a dummy interface, do a redistribution
> (connected etc.) and make an ASBR, and then do the summary
> stuff. This would
> only work if the other subnets of 172.16.0.0/24 are not in
> use elsewhere.
>
> * Check if the topology permits creating area ranges, mostly
> it does, and
> that will save the day.
>
> * With RIP , secondary addressing work well. Because you can
> have RIP honour
> the secondary address masks, and also learn addresses with
> those masks on
> the other side. With IGRP, its ugly, you have to be careful,
> mostly if used
> on both ends it summarizes to the mask of the primary ip
> address. (I still
> have to try what Dmitry has mentioned here)
There was one mistake in my initialy proposed solution...
I forgot to say to put sec address 172.16.0.x (/xx) on R2 interface faced
to
R3.
In this case igrp being ruuning on 172.16.0.0/16 will redistr network
defined by this secondary into ospf and make LSA 5 in ospf.
After that to put "summary-address 172.16.0.0 255.255.255.0" under OSPF
process on R2
And this 172.16.0.0/24 will go to R3. This works (just repeated again).
But this is too ugly.
It's much better to assign 172.16.0.x/24 (for example) on R2 interface
(don't run ospf on it) faced to R1 and don't do anything else. (maybe to
filter it from redistr into ospf)
In both cases I meant to put only one sec address on R2. Nothing on R3 !
Dmitry
>
> * Tunnels have been suggested by Faraz Shamim, author of T'shooting IP
> routing protocols as appropriate when dealing with IGRP especially.
>
> * Then there are other 'dirty tricks', of creating second
> instance of OSPF,
> redistributing into the first one. But that is mostly done to
> create an
> ASBR.
>
> So the trick when using OSPF is to see how you can get it to cough up
> 'summaries' whether by making it ABR or ASBR or tunnels or secondary
> addressing.
>
> rgds
> Nick
>
>
> ----- Original Message -----
> From: "Volkov, Dmitry (Toronto - BCE)" <dmitry_volkov@ca.ml.com>
> To: "'Omer Ansari'" <omer@ansari.com>
> Cc: <frank.yu@japan.bnpparibas.com>; <ccielab@groupstudy.com>
> Sent: Thursday, September 05, 2002 2:03 PM
> Subject: RE: redistribute ospf to igrp again
>
>
> > > howdy,
> > >
> > > two questions:
> > >
> > > 1. amongst the VLSM/FLSM resolution techniques, i've
> > > heard/tried several
> > > options:
> > >
> > > secondary address
> > > tunnelling
> > > area X range/summary-address
> > > ip summary-address eigrp
> > > etc etc..
> > >
> > > is the touted secondary address solution the one you
> presented below?
> > >
> > > also, my reasoning behind its working:
> > > note that the /30 route is in the IGRP db also on the
> ASBR, however,
> > > when it gets redist'ed to OSPF, ospf rejects it because it
> > > already sees
> > > this route as connected..however a secondary address on which
> > > ospf is not
> > > running, would then get redist'ed into ospf, seen as an
> External LSA.
> > > and then the summary-address would do its magic.
> > >
> > > in other words if we had
> > > router ospf X
> > > network 172.16.0.0 0.0.255.255 area X
> > >
> > > this solution would not work. correct?
> >
> > heh, buddy, too complex. It's too late in Toronto already :)
> > Everything much easier:
> > I meant assign sec address 172.16.0.1/24 (for example) on
> R2 interface
> > (don't run ospf on it)
> > faced to R1 (to avoid split hor issues). It's the same
> major net, hence
> it's
> > just known by IGRP without any redistribution, the same
> mask, the same
> major
> > - what else do we need ?
> > Net 172.16.0.0/24 will be in R3.
> >
> >
> > > 2. remember we once discussed this, when you and I were
> learning this
> > > method, and i mentioned using a loopback interface for
> > > 172.16.0.1/24 but
> > > the idea was shot down.
> >
> > The same stuff as secondary. It depends what is allowed (if any ;)
> >
> > Dmitry
> >
> >
> > > just want to make sure why that would be a bad idea, b/c
> i still like
> > > using it :)
> > >
> > > regards,
> > > Omer
> > >
> > > On Wed, 4 Sep 2002, Volkov, Dmitry (Toronto - BCE) wrote:
> > >
> > > > Hello,
> > > >
> > > > Since R2 is not ABR but ASBR we can not use area range command.
> > > > I case if You are doing redistr between OSPF and IGRP You
> > > can just put
> > > > "summary-address 172.16.0.0 255.255.255.0" under OSPF
> process on R2
> > > > It will create automatically route to Null
> > > > This route will be propagated into IGRP.
> > > > You can also just put secondary address (like
> > > 172.16.0.1/24) on R2 interface
> > > > faced to R1
> > > >
> > > > Dmitry
> > > >
> > > > > -----Original Message-----
> > > > > From: elping [mailto:elpingu@acedsl.com]
> > > > > Sent: Tuesday, September 03, 2002 12:37 AM
> > > > > To: frank.yu@japan.bnpparibas.com
> > > > > Cc: ccielab@groupstudy.com
> > > > > Subject: Re: redistribute ospf to igrp again
> > > > >
> > > > >
> > > > > do an area range command for the /30
> > > > >
> > > > > frank.yu@japan.bnpparibas.com wrote:
> > > > >
> > > > > > Group,
> > > > > >
> > > > > > As you can see the following diagram, R2 is ospf
> > > > > ASBR and running
> > > > > > igrp too.
> > > > > > My question is how can R3 reach ospf area0, except
> > > > > R2 advertising a
> > > > > > default route to igrp?
> > > > > > Is there a way for R2 to summary the ospf backbone
> > > > > into 24bit route
> > > > > > and redistribute it to igrp domain?
> > > > > > Thanks!
> > > > > >
> > > > > > 172.16.0.0/30 172.16.1.0/24
> > > > > > R1-------------------R2--------------------R3
> > > > > > ospf area0 igrp
> > > > > >
> > > > > > Frank
> > > > > >
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This message and any attachments (the "message") is
intended solely for the addressees and is confidential.
If you receive this message in error, please delete it and
immediately notify the sender. Any use not in accord with
its purpose, any dissemination or disclosure, either whole
or partial, is prohibited except formal approval. The internet
can not guarantee the integrity of this message.
BNP PARIBAS (and its subsidiaries) shall (will) not
therefore be liable for the message if modified.
---------------------------------------------
Ce message et toutes les pieces jointes (ci-apres le
"message") sont etablis a l'intention exclusive de ses
destinataires et sont confidentiels. Si vous recevez ce
message par erreur, merci de le detruire et d'en avertir
immediatement l'expediteur. Toute utilisation de ce
message non conforme a sa destination, toute diffusion
ou toute publication, totale ou partielle, est interdite, sauf
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