The MPLS WG Archive

[Atsushi Iwata <iwata@ccm.CL.nec.co.jp>]

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
>
> > -----Original Message-----
> > From: Atsushi Iwata 
> [<mailto:iwata@ccm.CL.nec.co.jp>mailto:iwata@ccm.CL.nec.co.jp]
> > Sent: Wednesday, April 05, 2000 8:30 PM
> > To: Ashwood-Smith, Peter [CAR:CS57:EXCH]
> > Cc: MPLS mailing list; Norihito Fujita
> > Subject: Re: Any more comments on draft-ietf-mpls-te-feed-00.txt?
> >
> >
> > Hi, Peter,
> >
> > I have one comment.
> >
> > At 10:17 00/04/05 -0400, Peter Ashwood-Smith wrote:
> > >RE: draft-ietf-mpls-te-feed-00
> > >
> > >   Still looking for feedback on the feedback draft ... pun
> > >intended.
> > >
> > >   I will be asking the WG chairs for a last call on this in the
> > >next few days unless somebody has some issues with it.
> >
> > As I explained our draft,
> > draft-fujita-mpls-crldp-crankback-00.txt, in the
> > last IETF, there are several possibilities of indicating of
> > links or nodes.
> > If you use unnumbered point-to-point links between routers,
> > you cannot
> > specify IPv4 address of interfaces for IPV4 specificed link
> > feedback TLV
> > and IPV6 specified link feedback TLV. In that case, you have to use a
> > routing protocol (OSPF etc) dependent TLV to indicate links or nodes.
> >
> > Our draft specifies protocol independent TLV (using ER-HOPS
> > information)
> > and routing protocol dependent TLV (OSPF, ISIS-specific
> > information). I
> > guess that our draft could be an one of possible solution to
> > indicate such
> > links or nodes.
> >
> > What do you think ?
> >
> > Best regards,
> > ----------------------------------------------------------------
> > Atsushi Iwata
> > Assistant Manager
> > Network Architecture TG, Networking Research Laboratory
> > C&C Media Research Laboratories
> > NEC Corporation
> > 4-1-1 Miyazaki Miyamae-ku, Kawasaki, Japan 216-8555
> > TEL: +81-44-856-2123 (Direct), Fax: +81-44-856-2230 (Direct)
> > NEC-internal TEL: 8-272-3281, NEC-internal FAX: 8-272-3299
> > E-mail: a-iwata@ah.jp.nec.com
> >
> > ** New organization has started since Apr.1, 2000. ***
> >
> >

----------------------------------------------------------------
Atsushi Iwata
Assistant Manager
Network Architecture TG, Networking Research Laboratory
C&C Media Research Laboratories, NEC Corporation
4-1-1 Miyazaki Miyamae-ku, Kawasaki, Japan 216-8555
TEL: +81-44-856-2123 (Direct), Fax: +81-44-856-2230 (Direct)
NEC-internal TEL: 8-272-3281, NEC-internal FAX: 8-272-3299
Internet E-mail:     a-iwata@ah.jp.nec.com
NEC-internal E-mail: iwata@ccm.CL.nec.co.jp

** New organization has started since Apr.1, 2000. ***