RE: [mpls] One LDP Implementation specific question of receive labelmapping for prefix FECs

Hi Bob,

> Hi Bruno,
> 
> > Hi Pranjal, all,
> >
> > That's a good question; thanks for asking ;-)
> >
> > Currently, as per RFC 3036 section 3.5.7.1, Ru should perform a
longest =
> > match.
> 
> I think you meant exact match.

[Bruno D:] Indeed. Thanks for the rectification.

>   draft-ietf-mpls-rfc3036bis-03.txt:
> 
>    An LSR receiving a Label Mapping message from a downstream LSR for
a
>    Prefix SHOULD NOT use the label for forwarding unless its routing
ta-
>    ble contains an entry that exactly matches the FEC Element.
>                               ***************
> 
> 
> Bob
> 
> 
> > But we believe that in some situation (eg use of IGP areas), we
could =
> > benefit from doing a longest match as this would relax the need for
=
> > leaking in the IGP all the /32 prefixes across area boundaries. To =
> > initiate discussion on this point, we've written =
> > draft-decraene-mpls-ldp-interarea-01.txt and presented it in
Vancouver ( =
> > http://www3.ietf.org/proceedings/05nov/slides/mpls-4.pdf )
> >
> > Right after this presentation, it was suggested to gather feed-back
on =
> > the usefulness of this ID before moving forward.=20
> >
> > Pranjal, all, could you please tell us whether you think that it is
=
> > worth being pursed?
> >
> >
> > Best regards,
> > Bruno
> >
> >
> >
> > ________________________________________
> > From: Dutta, Pranjal [mailto:pdutta@riverstonenet.com]=20
> > Sent: Saturday, April 08, 2006 10:11 PM
> > To: mpls@ietf.org
> > Subject: [mpls] One LDP Implementation specific question of receive
=
> > labelmapping for prefix FECs
> >
> > Hi,
> > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 I have a basic confusion
on =
> > the "Label Mapping Receive Procedure" explained in the appendix of
RFC =
> > 3036. One step says "Find the FEC next hop". When Ru receives a
label =
> > mapping for a FEC of type IPv4/v6 prefix from Rd, the next hop for
the =
> > FEC can be determined after route lookup. Now here, for looking up
the =
> > FEC at Ru do we need to do exact match or Longest prefix match? It
is =
> > quite possible that the prefix as FEC mapped by Rd may be within a =
> > supernetted =A0prefix at Ru. The reason why I am asking is I guess
the =
> > implications could be different based on whether LSR is merge
capable or =
> > non-merge capable.
> >
> > Thanks in advance,
> > Pranjal
> >
> >
> > _______________________________________________
> > mpls mailing list
> > mpls@lists.ietf.org
> > https://www1.ietf.org/mailman/listinfo/mpls
> >

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