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