Re: Label Set Object

[Zafar Ali <zali@cisco.com>]

Dear Vinay, 

Please see comments in-lined. 

Thanks

Regards... Zafar 
At 07:56 PM 5/8/2002 +0530, Vinay Vernekar wrote:
> Hi
> Zafar,
> The Label Set Object can't be sent to constrain
> the downstream label when the LSP encoding type is Sonet/SDH. Consider
> the example where a request is sent to downstream with SONET/SDH traffic
> parameters as NVC=n and MT=m. The label expected from the downstream
> would be 'm' set of labels each set consisting of 'n' labels further that
> identify each of the virtual concatenated components. So a Label Set in
> this scenario would consist of say 'p' sets each consisting of 'm' sets
> of 'n' labels. Such a Label Set cannot be encoded using the object/TLV
> structure of Label Set as in "Generalized MPLS - Signalling
> Functional Description -
> draft-ietf-mpls-generalized-signaling-08.txt".

I think, this would be a second level question/ issue. IMO, we should be
able to build on the concept of a label set to incorporate technologies
other than WDM. Can we, in principle, agree on this or you are aware of
an alternative for the case you mentioned above? 

> Label Set Object can
> be sent only in WDM scenario where a single wavelength is requested as a
> label and the upstream has a restriction on the usable
> wavelengths.

IMHO this would be an undesirable restriction. Why its cannot cover the
single label case in SONET? 

> Correct me if I am
> going wrong anywhere.
>  
> Regards
> Vinay    
> > ----- Original Message ----- 
> > From: Zafar Ali 
> > To: Manoj Agiwal ;
> > 'Ccamp (E-mail) 
> > Cc: mpls@UU. NET
> > (E-mail) 
> > Sent: Wednesday, May 08, 2002 11:04 AM
> > Subject: Re: Label Set Object
> >
> > At 10:00 AM 5/8/2002 +0530, Manoj Agiwal wrote:
> > > Hi ,
> > >        In gmpls signaling extensionsions
> > > for RSVP-TE , ccamp architecture on
> > > gmpls has described Label Set object usage
> > >     only for the "optical" domain viz. for
> > > carrying wavelengths ( Section
> > > 9.9 draft-ietf-ccamp-gmpls-architecture-02.txt) . 
> > >
> > >        Do we require to send Label set(i.e.
> > > time slots) for TDM switching as
> > > well . In what way it can be useful . 
> >
> > Dear Manoj, 
> >
> > Yes, label set object is also useful in TDM case. E.g., SONET poses an
> > additional requirement that the two interfaces of a bidirectional LSP
> > SHOULD traverse the exact same link with the same SUKLM values for the
> > two directions.
> >  The label set object can be used to constrain the downstream label
> > to the same as the upstream label. 
> >
> > Thanks
> >
> > Regards... Zafar 
> >
> >
> >
> > > Regards ,
> > > Manoj
> >
> > ===============
> > Zafar Ali
> > Cisco Systems
> > (734) 276-2459
> > 100 S Main St. #200
> > Ann Arbor, MI 48104.
> > email:
> > zali@cisco.com