Re: Label Set and Suggested Label

["manoj juneja" <manojkumarjuneja@hotmail.com>]

Hi All,
       Is label set realy useful in TDM domain ? I think if the
upstream node wants to select only one label in the label set, it can
very well use the explicit label control procedure. What are other
benefits of having label set in TDM domain ? I can very understand the
use of label set for LSC and FSC interfaces where label ranges make
sense.

Regards,
manoj.


>From: Eric Gray <eric.gray@sandburst.com>
>To: Suresh Katukam <skatukam@cisco.com>
>CC: ccamp@ops.ietf.org
>Subject: Re: Label Set and Suggested Label
>Date: Mon, 02 Jul 2001 09:44:00 -0400
>
>Suresh,
>
>     Unfortunately, the current wording is:
>
>"There are four cases where a Label Set is useful in the optical domain."
>
>It is arguable that your examples are more properly in the TDM  domain,
>but section 3.5 of "draft-ietf-mpls-generalized-signaling-04" does not
>seem to leave much room for generalizing the label set in this way.  It
>should probably say either that these are examples that apply to the
>optical domain (other uses may exist for other domains) or - better -
>still it should simply state these as a few examples and leave it at that.
>
>     There is nothing to be gained by guessing what the authors meant -
>they must make it clear.
>
>--
>Eric Gray
>
>You wrote:
>
> > Manoj,
> >
> > >         In the GMPLS drafts, it is mentioned that the use of label set
> > > is in the following cases :
> > >
> > >            a) End equipment is only capable of transmitting and
> > >               receiving on a small set of wavelengths.
> > >            b) There are sequence of interfaces which can't support
> > >               wavelength conversion.
> > >            c) It is desireable to limit the amount of wavelength
> > >               conversion to reduce the distortion on the optical
> > >               signals.
> > >            d) Two ends of a link support different sets of 
>wavelengths.
> > >
> > > All the above four points are valid only in case LSP encoding type is
> > > lambda. Does this mean if a label set is received in cases where LSP
> > > encoding type is other than Lambda, it should be ignored or considered
> > > protocol error ?
> >
> > I am not sure whether it is the intention of GMPLS authors to list
> > all possible scenerios under which a label set is used. There are
> > other scenerios under which label set can be used. In TDM, for example,
> > one may want to use same time slot (for BLSRs) assigned along the
> > entire BLSR segment. In such a scenerio, BLSR headend lists all 
>available
> > labels and forwards the PATH message. Each node in BLSR knows what
> > label to use when it receives a RESV message.
> >
> > There may be other reasons too. In anycase, you should not consider
> > that to be a protocol error.
> >
> > Thanks,
> > Suresh
> > >
> > > What about the suggested Label ? Is it also defined to take care of
> > > specific LSP encoding type ?
> > >
> > > Please Clarify.
> > >
> > > Regards,
> > > manoj.
> > >
> > > _________________________________________________________________
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>


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