Re: Clarification in NSSA

[Vivek Dubey <[e-mail]>]

Hi Minto,
The question here is whether R2 on seeing functionally equv
Type 5 LSA from R3 (translated previously before being
stopped) should originate Type 5 (which is a result
of Type 7 translation).

There is no doubt as far as who is translator, its R2
only.

thanks,
vivek



On Sat, 28 Jun 2003 Jeyanath Minto J - CTD, Chennai. wrote :
>hi vivek,
>    In section 3.2  step (2) clearly mention this. R3 already out
> from the
>List of NSSA border Routers and , now R2's router Id is higher
>than anyone (
>Actually R2 alone in that List ). As result, R2 will translate
>LSAs.
>
>Cheers
>Minto Mascarenhas
>**********************************************************************
>*  Internet IS for everyone - but it won't be unless WE make it
>so   *
>**********************************************************************
>
>-----Original Message-----
> From: Vivek Dubey [mailto:[e-mail]]
>Sent: Saturday, June 28, 2003 1:44 PM
>To: [e-mail]
>Subject: Re: Clarification in NSSA
>
>
>Hi,
>The point krishna is trying to make:
>1) R3 goes down
>2) R2 gets elected as translator
>3) But R2 while translating Type 7 to Type 5
>     sees functionally equv Type 5 previously
>     translated by R3 (before being stopped).
>     Note R3 router id is higher.
>     So R2 doesn't originate Translated Type 5.
>4) So both R2 and R1 hold Type 5 generated by
>     R3 before it went down (no flushing was done
>     by R3 before going down).
>5) Consequently R1 will loose routes to those
>     Type 7 networks (calculated using Translated
>     Type 5 by R3).
>6) But R2 will hold routes as it is directly connected
>     to NSSA area and can use Type 7 for getting to those
>     networks.
>
>This can happen in real networks.
>Probably Pat can clarify how to handle such
>scenarios.
>
>thanks,
>vivek
>
>
>On Fri, 27 Jun 2003 Jeyanath Minto J - CTD, Chennai. wrote :
> >hi Krishna,
> >     R2 maintain a List of this area's Nssa border Routers
>and
> >ASBR.
> >Translator is Elected from this List.
> >     so , when u stopped the R3 , R2 removes the R3 from the
> >List. And R2
> >will elect itself as a Translator ( because R3 is unreachable
>)
> >and
> >translate type 7 to Type 5.
> >
> >
> >
> >Cheers
> >Minto Mascarenhas
> >**********************************************************************
> >*  Internet IS for everyone - but it won't be unless WE make
>it
> >so   *
> >**********************************************************************
> >
> >-----Original Message-----
> > From: Krishna Rao [mailto:[e-mail]]
> >Sent: Friday, June 27, 2003 11:50 AM
> >To: [e-mail]
> >Subject: Clarification in NSSA
> >
> >
> >Hi
> >
> >I am basically testing RFC 3101 NSSA implementation. I find
> >that
> >routes are missing in the Router (not in NSSA area) but is
> >conected to the Router in NSSA area through backbone area.
> >
> >
> >Topology Used in Testing
> >========================
> >   |-------------------------------|
> >   |                               |
> >   |                               |
> >   |                               |
> >R1-------------R2---------------R3
> >                  |                |
> >                  |                |
> >                  |                |
> >             --------------------------- NSSA area 0.0.0.1
> >                         |
> >                         |
> >                         |
> >                         R4
> >                         | area 0.0.0.1
> >                         |Import External Routes.
> >                         |
> >
> >There are 2 areas in this Topology -
> >NSSA area 0.0.0.1 (R2, R3 and R4)
> >Remaining all the networks are in backbone area.
> >
> >R1 is connected to R2 and R3 through backbone area. R2 and R3
> >are
> >connected through backbone area.
> >
> >RouterID of R1 10.0.0.1
> >RouterID of R2 20.0.0.1
> >RouterID of R3 30.0.0.1
> >
> >R3 is elected as Translator. Import external routes at R4. R1
> >holds the external routes.
> >
> >Now, stop the router R3. R2 takes over as Translator.
> >
> >BUT, now R1 doesnot hold the external routes.
> >
> >I expect the R1 to hold the external routes. But as per RFC
> >3101
> >since R2 holds LSA generated by R3 which is of higher
>RouterID,
> >R2
> >doesnot generate Type 5 LSAs. Is it correct. If this is the
> >case,
> >then R1 would never hold the external routes.
> >
> >Your response on this would be highly appreciated.
> >
> >Thanks & Regards
> >Krishna
> >
> >
> >
> >
> >
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