Hi Greg,
Sorry for the delay in replying. I'm working on this topic since a while so
yes, it's interesting. Before going on specific issue I would have some
question/clarification regarding the draft itself.
* Within Abstract and the following.
You don't talk about Optical Cross Connects (OXC) is something missing or
understated somewhere?
* Section 3.1 where you state:
"A fixed mapping between the
GMPLS label space and these ITU-T WDM grids as proposed in [Otani] "
Does it implies a sort of network level label space? How relate with usual
local label significance?
* Section 3.4 Wavelength Converters
"Current or envisioned contexts for wavelength converters are : ..."
Could we think to a description/model for wavelength converter that is
technology agnostic? Simply something like: full conversion capability, partial
conversion capability with some constrains, and may be others.
* Section 3.4. the following:
"4. Wavelength converters that are O-E-O based will have a restriction
based on the modulation format and transmission speed"
Not clear to me the type of restriction here when OEO happens... probably I'm
missing what you mean here.
* Section 4.1 when you talk about Lightpath temporal characteristics:
"Lightpath connection duration has typically been thought of as
approximately three time frames: "
and the following you define: dynamics, pseudo-static, static.
Why there's a need of this classification? When you us Short/long is compared
to what?
minor typo on your mail below: point (c) rfc4328 (not 4238) right?
Thanks,
Giovanni
________________________________
From: Greg Bernstein [mailto:[EMAIL PROTECTED]
Sent: giovedì 27 settembre 2007 1.42
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-switched-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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