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RE: Label Set Object

At 01:07 PM 5/8/2002 -0700, John Drake wrote:
Label Set and Explicit Label Control are used for different purposes, and as I understand it, Explicit Label Control is more natural  for establishing SONET/SDH LSPs, while Label Set is more natural for establishing wavelength LSPs. 
You could, however, use Label Set for SONET/SDH LSPs and Explicit Label Control for wavelength LSPs.

Hi John,

While I agree with the last statement, I didn't understand why you mentioned that explicit label control is more natural for SONET/ SDH. IMHO the label set is a more natural way of constraining labels in all scenarios.

Any way, this is a non-debate, in the light of the email sent by Suresh in which he suggested that the constraints are implied by the nature of the TDM circuits. I agree with Suresh that there is no point of copying the same parameters using the other means, if they can be implied.

Thanks

Regards... Zafar
-----Original Message-----
From: Juneja, Manoj [mailto:m_juneja@trillium.com]
Sent: Wednesday, May 08, 2002 11:57 AM
To: John Drake; Juneja, Manoj; 'Zafar Ali'; Vinay Vernekar; Manoj Agiwal; 'Ccamp (E-mail)
Cc: mpls@UU. NET (E-mail)
Subject: RE: Label Set Object
Hi Jonh,
              Sorry for creating the confusion. Should the label set be used for establishing the SDH/SONET LSPs ?
 
Regards,
manoj.
-----Original Message-----
From: John Drake [mailto:jdrake@calient.net]
Sent: Wednesday, May 08, 2002 11:50 AM
To: 'Juneja, Manoj'; 'Zafar Ali'; Vinay Vernekar; Manoj Agiwal; 'Ccamp (E-mail)
Cc: mpls@UU. NET (E-mail)
Subject: RE: Label Set Object
I didn't say that.
-----Original Message-----
From: Juneja, Manoj [mailto:m_juneja@trillium.com]
Sent: Wednesday, May 08, 2002 11:48 AM
To: John Drake; 'Zafar Ali'; Vinay Vernekar; Manoj Agiwal; 'Ccamp (E-mail)
Cc: mpls@UU. NET (E-mail)
Subject: RE: Label Set Object
Hi John,
               Did u mean Explicit label control is used only for SDH/SONET case  and is not used for FSC/LSC LSPs ? If this is the case then it should be clearly mentioned in the draft. Furthermore, it should also be mentioned that label set is not used for SDH/SONET LSPs.
 
Regards,
manoj.
-----Original Message-----
From: John Drake [mailto:jdrake@calient.net]
Sent: Wednesday, May 08, 2002 11:26 AM
To: 'Zafar Ali'; Vinay Vernekar; Manoj Agiwal; 'Ccamp (E-mail)
Cc: mpls@UU. NET (E-mail)
Subject: RE: Label Set Object
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

===============
Zafar Ali
Cisco Systems
(734) 276-2459
100 S Main St. #200
Ann Arbor, MI 48104.
email: zali@cisco.com