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List:       ms-ospf
Subject:    Re: NSSA type-7/5 translation
From:       Sina Mirtorabi <sina () CISCO ! COM>
Date:       2001-11-06 22:51:01
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humm, actually since you have one exit the shorter path to ABR will be always the
over all shortest path. :-)
but there is no benefit of touching the body of the LSA ( 7/5 ) and you need just to
update the LSA header further should be another ABR  later and this router is still
the translator  it has to maxage / reoriginate what it has send previously without
the FA

Sina


Sina Mirtorabi wrote:

> Singh
>
> "Singh, Gurpreet" wrote:
>
> > Is there any scenario where the Forwarding address may not be copied to the
> > type-5 LSA while doing the translation. Lets say the ABR is sending the
> > type-5 LSA to the type-5 capable areas and this ABR is the only way to reach
> > inside the NSSA and subsequently to the destination described in type-5 LSA.
> > In that case for any router outside NSSA would have to send the packet
> > through this ABR.
> > Is it possible for the ABR to set the Forwarding address to itself or
> > 0.0.0.0 in the type-5 LSA in this case, even if the type-7 LSA had some
> > other forwarding address.
> >
> > Thanks
>
> altough if an ABR is the only one attached to NSSA area  traffic will go through
> it but what is the benefit of resetting the forwarding address to zero ?
>
> for example if you have 2 path to the ABR( ASBR ) by resetting the forwarding
> address to zero a router will  go through the shortest path to reach the ABR and
> the ABR will go though the best path within the NSSA area to reach the
> forwarding address * but * this shortest path to the ABR might not be the over
> all shortest path  to reach the forwarding address and if you had gone through
> the other path the over all path to reach the forwarding address would be
> shorter
>
> the only time you would reset the forwarding address to zero is when your type 5
> is an aggregation of your type 7
>
> Sina
>
> >
> > Gurpreet
> >
> > -----Original Message-----
> > From: Pat Murphy - (650)329-4044 [mailto:pmurphy@noc.usgs.net]
> > Sent: Tuesday, November 06, 2001 3:33 PM
> > To: OSPF@DISCUSS.MICROSOFT.COM
> > Cc: GURPREET.SINGH@SPIRENTCOM.COM
> > Subject: Re: NSSA type-7/5 translation
> >
> > Gurpreet,
> >
> > In RFC 1587 Section 4.1 Step 1 and the paragraphs following Section 4.1
> > Step 3, the type-5 LSA's network, network mask, metric, forwarding
> > address, external route tag and path type are all copied from the type-7
> > LSA. They are the same.
> >
> > Pat

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