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Re: Generalizing WSON information...



Hi Julien, interesting point. It did seem like older SDH equipment did have a "time-slot continuity constraint", but I never directly dealt with those systems. There was some work a while ago on MS-SPRing (Diego?). Maybe we need to think up a level, as you said in the usual GMPLS, MPLS cases full label swapping is a typical capability. Should we be explicit in the WSON case (maybe with the connectivity matrix) in indicating that this may or may not be the case? Right now we are being implicit about this lack of wavelength (label) conversion capability.

The notion of the shared wavelength converter pools and the accompanying details seem very WSON specific. But the fact that a switch or mux can't perform label exchange seems a fairly general notion that we could group with other generalizable information...

Best Regards

Greg

julien.meuric@orange-ftgroup.com wrote:
Hi Greg.

Just a small comment on Wavelength Converter Pool in section 3.2. In some other GMPLS contexts, this may be modelled as a label swapping capability, which is a common enough to be considered as "Generalizable" (it's even a typical case that becomes an exception due to our label continuity constraint). However, as for several other parameters, I don't think there is an actual need for it (this is already the default); but maybe we could imagine some MS-SPRing operations in SONET/SDH.

Regards,

Julien

-----Original Message-----
From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On Behalf Of Greg Bernstein
Sent: Tuesday, April 14, 2009 6:32 PM
To: ccamp
Subject: Generalizing WSON information...

Hello fellow CCAMPers, at the 74th IETF meeting in San Francisco the question came up as to what if any of the WSON path computation information model would be useful in other technologies. Below is a first attempt at such an assesment based on the current version of draft-ietf-ccamp-rwa-info-02.txt. Existing GMPLS
standard information is not included.

 From section 3.2 Node Information:

Switched Connectivity Matrix: Generalizable:Yes. This can be used to model any type of asymetrical switch in any technology. Caveat: Besides optical is there
any current products that can make use of this?

Fixed Connectivity Matrix: Generalizable: Yes. This can be used to model fixed
connectivity between ports. Caveat: Is there any need outside optical?

Wavelength Converter Pool: Generally useful: No. This is very application
specific to optical switching systems.

 From section 3.3 Link Information:

Switched and Fixed Port Wavelength (label) Restrictions: Generally useful: I
don't think so but open to examples. These constraints must be shared in the
WSON case for two reasons: (a) the wavelength continuity constraint requires
global label assignment, (b) WSON devices present many different types of
wavelength constraints. Note that without requirement (a) then (b) doesn't need
to be shared since local label (wavelength) assignment would suffice.

 From section 3.4  Dynamic Link information

Available Wavelengths (labels): Generally useful? We need detailed wavelength availability information due to the wavelength continuity constraint. Way back in the old days many of us implemented bit maps to track SONET/SDH time slots
but this never made it into the standards. Any interest in that now? Other
examples?

Shared Backup Wavelengths (labels): Similar to the above but used in efficient
shared mesh backup path computation.

 From section 3.5 Dynamic Node Information

Wavelength Converter Pool Status: Not generally applicable. Too application
specific.

Comments appreciated

Greg


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Dr Greg Bernstein, Grotto Networking (510) 573-2237