Subject: WSON Framework next steps...

From: Greg Bernstein <[email-masked]>
Date: Thu, 10 Jul 2008 14:27:57 -0700

Hi folks, one of the next steps for the WSON (wavelength switched 
optical networks) draft was to include wavelength converters a bit more 
rigorously.
We planed (and have tentative text) for relating the models of ITU-T 
G.872 to the current WSON work. Here is a quick summary of the issues 
and some thoughts.

1. Current ITU-T models for "optical channels" OCh tell us:
(a) G.872 OCh characteristic information (CI): maximum bandwidth and SNR 
(Section 5.3). Note that the CI doesn't include the wavelength.
Example of OCh through a wavelength converter in G.872 Appendix I, since 
the wavelength converter doesn’t change the CI this doesn’t involve 
changing layers.Or at least that was my impression.
(b) G.709 “… OCh transports a digital client signal between 3R 
regeneration points.”
2. Most (?) wavelength converters are OEO based and are also 3R 
regenerators.
Would like to handle connection through wavelength converters as a 
single LSP without stitching (RFC5150) if possible for most common cases.
3. Framework draft uses the term “Lightpath”
We didn’t define the characteristic information for this yet but 
signaling drafts are leaning towards such information as modulation, 
modulation parameters, bit rate and FEC since these are minimally needed 
to ascertain if an end system can process the signal into digital bits.
4. Could we define our Lightpath with characteristic information 
(modulation, modulation parameters, bit rate and FEC) then if a 
wavelength converter (whether optical or OEO based) preserves this CI 
then we can use a single LSP to describe. If the wavelength converter 
includes a 3R and changes some CI such as modulation parameter or FEC 
then an LSP stitching mechanism seems to be required.

We will bring this up at the Dublin meeting, but there isn't usually 
time for extended discussion, so figured it was best to kick this around 
on the list a bit.

Regards

Greg B.

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