Subject: Label Set Object

From: Manoj Agiwal <[email-masked]>
Date: Wed, 8 May 2002 10:00:52 +0530

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 . 

Regards ,
Manoj

---

From: Zafar Ali <[email-masked]>
Date: Wed, 08 May 2002 01:34:43 -0400

>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

>Manoj

===============
Zafar Ali
Cisco Systems
(734) 276-2459
100 S Main St. #200
Ann Arbor, MI 48104.
email: [email-masked]

---

From: "Vinay Vernekar" <[email-masked]>
Date: Wed, 8 May 2002 19:56:34 +0530

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". 
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.
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

    Hi ,

  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: [email-masked]

---

From: Zafar Ali <[email-masked]>
Date: Wed, 08 May 2002 13:31:09 -0400

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?

>>From: <mailto:[email-masked]>Zafar Ali
>>To: <mailto:[email-masked]>Manoj Agiwal ; 
>><mailto:[email-masked]>'Ccamp (E-mail)
>>Cc: <mailto:mpls@UU. NET (E-mail)>mpls@UU. NET (E-mail)
>>SHOULD traverse the exact same link with the same SUKLM values for the 
>>two directions.