The MPLS WG Archive

["Don Fedyk" <dwfedyk@nortelnetworks.com>]

Title: RE: Any more comments on draft-ietf-mpls-te-feed-00.txt?

Dear Atsushi Iwata

Usually, we do not specify limitations that are required attributes of
the design. Numbered links are a required part of the current TE design.

Don

> -----Original Message-----
> From: Atsushi Iwata [mailto:iwata@ccm.CL.nec.co.jp]
> Sent: Thursday, April 06, 2000 9:55 PM
> To: Fedyk, Don [BL60:2001:EXCH]
> Cc: Ashwood-Smith, Peter [CAR:CS57:EXCH]; MPLS mailing list; Norihito
> Fujita
> Subject: RE: Any more comments on draft-ietf-mpls-te-feed-00.txt?
>
>
> Dear Don Fedyk,
>
> Thank you for your reponse.
>
> I understand the target of your draft.
> Could you add any sections which clarify the current
> limitation of your
> draft, such as not supporting unnumbered links, or something
> like that ?
>
> Regards,
>
> At 12:56 00/04/06 -0500, Don Fedyk wrote:
>
> >Dear Atsushi Iwata,
> >
> >The feedback draft is aimed at numbered links only. The cycle is
> >a path is selected from a topology database that is populated by
> >an IGP. Both IGPs use the same format so it does not matter which
> >IGP. The path becomes the ER MPLS LSP.
> >
> >Next the ER LSP is established and our Draft uses CR-LDP to
> accomplish
> >this. If a link that is not able to support the path is encountered,
> >the bandwidth profile (independent of the IGP for the number link) is
> >added to the failure notification. This information is generated for
> >every link along the traversed section of the path.
> >
> >This information can then be added to the topology database
> improving its
> >accuracy for all subsequent path requests.
> >
> >A crankback as you describe cannot update the database since it may
> >not have an accurate bandwidth profile. This could happen if you
> >encountered a node that did not support the feedback. So crankback
> >could be the degenerate case of feedback.
> >
> >ER paths can support un-numbered links in some cases. When
> the path is
> >loose routed, for example, but this is not the constraint based case
> >we were covering in the draft.
> >
> >Don
> >
>
> ----------------------------------------------------------------
> Atsushi Iwata
> Assistant Manager
> Network Architecture TG, Networking Research Laboratory
> C&C Media Research Laboratories, NEC Corporation
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>
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