RE: Label Set Object

[John Drake <jdrake@calient.net>]

Explicit Label Control is used to handle the SONET/SDH case.  Its semantics are different than Label Set, in the sense that there is one and only one value, rather than a set that is manipulated end-end 

 

Thanks,

 

John

 

-----Original Message-----
From: Zafar Ali [mailto:zali@cisco.com]
Sent: Wednesday, May 08, 2002 10:31 AM
To: Vinay Vernekar; Manoj Agiwal; 'Ccamp (E-mail)
Cc: mpls@UU. NET (E-mail)
Subject: Re: Label Set Object

> 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 
> > >