RE: GRSVP-TE and MSSPRING

["Vishal Sharma" <v.sharma@ieee.org>]

Diego, Adrian,

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org]On
> Behalf Of Adrian Farrel
> Sent: Tuesday, November 25, 2003 1:45 PM
> To: ccamp@ops.ietf.org; Diego Caviglia
> Subject: Re: GRSVP-TE and MSSPRING
>
>
> Diego,
>
> I believe that if you use Label Set and Acceptable Label Set you
> will arrive at the right
> result.
> It may take a few messages backwards and forwards to sort it out.

Or, alternatively, enhance the routing protocol to appropriately convey
information about time slot availability to nodes in the MS-SPRING
(and beyond, if the ring is embedded in a general mesh network),
so that no trial and error (in searching for the right "label")
is required.

Note that this may not be easy to do for legacy BLSR/MS-SPRINGs.

-Vishal

PS: There are ways to signal LSPs for UPSRs, and one such solution is
documented in a Journal of Optical Networking paper, "On the
IP-Centric Control of UPSR-based Transport Networks, JON, March
2003, a copy of which is available at:
http://www.metanoia-inc.com/Publications/UPSR_JON_March03.pdf


> ----- Original Message -----
> From: "Diego Caviglia" <Diego.Caviglia@marconi.com>
> To: <ccamp@ops.ietf.org>
> Sent: Tuesday, November 25, 2003 3:00 PM
> Subject: GRSVP-TE and MSSPRING
>
>
> > Hi all,
> >               MSSPRING has been defined in ITU-T G.841 and is
> widely used
> > as inherent protection scheme in transport network (SDH).
> >
> > MSSPRING introduces some constraints to Label selection due to the
> > impossibility to change TimeSlot (a.k.a. Label) inside a MSSPRING ring.
> >
> > In case of bi-directional LSP Upstream TNE has to choose the Label and
> > signal it by means of the UPSTREAM Label obj but if the TNE is inside a
> > MSSPRING ring it MUST choose a Label that is free on all the
> TNE traversed
> > by the LSP that are part of the MSSPRING ring.
> >
> > Of course the problem is that it does not have that information.
> >
> > My question is how can I signal, with GRSVP-TE, a bidirectional LSP that
> > traverses an MSSPRING ring?
> >
> > My impression is that I can not.
> >
> > Any answer is welcome.
> >
> > Regards
> >
> > Diego
> >
> >
> >
> > ------------------------------------------
> > Diego Caviglia
> > Marconi - Optical Networks
> > ASTN/GMPLS - System Design Manager
> > Via A. Negrone 1/A
> > 16153 Genoa - Italy
> > Phone: +390106003736
> >
> >
> >
> >
> >
> >
>