Greg,
I believe the draft is very useful. I have a couple of questions comments: 1. Section : 4.4. Traffic Grooming: Combining WSON and Higher Layer Network Optimization How the problem of grooming of higher layer network traffic over optical trails is any different from the problem of traffic grooming in TDM (e.g. VC12 over VC4)? I mean this is a general problem of inter-layer relationship. I suggest moving all higher layer network considerations out of scope of the draft and focusing on specifics of the OCh layer. 2. Considering wavelength conversion inevitably brings to the problem of looped paths, which is a completely new ball game in path computation, and I am surprised that the issue was never mentioned in the draft. Cheers, Igor ________________________________ From: Greg Bernstein [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 26, 2007 7:42 PM To: ccamp; [EMAIL PROTECTED] Subject: [Pce] Some key issues with Wavelength Switched Optical Networks... Hi folks, I haven't seen too many comments on our draft "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks" ( http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wavelength-swi tched-01.txt). So I figured I'd point out some potentially controversial issues that the draft brings up. (a) The draft brings up models for the following WDM network elements: 1. WDM links 2. Optical transmitters 3. Wavelength Converters and OEO regenerators 4. ROADMs, FOADMs, optical splitters and combiners. For items (3) and (4) we are taking the modeling lead rather than some other SDO. And for ROADMs, in particular, we going beyond the classic ITU-T "fabric" model (M.3100) which has been the mainstay of any connection oriented switch (TDM, ATM, MPLS). (b) The draft brings up three (not one, not two, but three) different computational models for RWA which can impact GMPLS and PCE protocols: 1. A single PCE computing both the path and wavelength 2. Two distinct PCEs, where one computes the path, and a different PCE computes the wavelength assignment 3. A PCE computes the path and wavelength assignment is accomplished in a distributed fashion via signaling (e.g., using label set objects) Do we really need all three models? (c) G.709 includes the Optical Multiplex Section and Optical Channels. RFC4238 was aimed at GMPLS extensions for G.709 (Optical Transport Network) control. Weren't we finished with all this optical stuff years ago? I'd like to think the draft answers some of these questions. I also think that network element models and the process models are important enough to warrant this separate framework document. Your opinions are solicited. Regards Greg B. -- =================================================== Dr Greg Bernstein, Grotto Networking (510) 573-2237
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