Subject: New draft on optical impairments signaling

From: "Giovanni Martinelli (giomarti)" <[email-masked]>
Date: Fri, 9 Nov 2007 10:11:43 +0100

Hi all,

we submitted a new draft proposing lightpath setup through signaling
extensions that take into account optical impairments. This allow asses
optical feasibility in the context of wavelength switched optical
networks.

http://www.ietf.org/internet-drafts/draft-martinelli-ccamp-optical-imp-s
ignaling-00.txt

comments/suggestion are highly appreciated!

Regards,
Giovanni

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From: Greg Bernstein <[email-masked]>
Date: Fri, 09 Nov 2007 11:50:37 -0800

Hi Giovanni, this looks very interesting.  I noticed we both hit some 
similar issues ( see our draft 
http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wson-signaling-00.txt 
), i.e., we both think there is a need for modulation type and FEC 
information. Since, in our draft we weren't looking at impairments we 
were using these more for end system compatibility and 
regenerator/wavelength converter compatibility.  We looked at these more 
as "optical traffic parameters" so placed them in a Tspec object and 
used the attributes stuff for other information associated with 
wavelength assignment.

I noticed you expressed a concern on the amount of space used per 
lambda. Isn't it true that for wavelengths close to each other that the 
impairment (CD, PMD) parameters should be roughly the same so that we 
could group these with a "wavelength set"? We looked at a bit map 
encoding of a label set in both
http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wson-signaling-00.txt 
and 
http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wson-info-00.txt 
such a mechanism could be helpful to reduce the space needed in the 
messages.

Regards

Greg B.

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

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From: Giovanni Martinelli <[email-masked]>
Date: Tue, 13 Nov 2007 23:06:06 +0100

Hi Greg,

thanks for your comments, please see inline some initial considerations...

Greg Bernstein wrote:
> Hi Giovanni, this looks very interesting.
thx!
> I noticed we both hit some similar issues ( see our draft 
> regenerator/wavelength converter compatibility.  We looked at these 
> more as "optical traffic parameters" so placed them in a Tspec object 
> and used the attributes stuff for other information associated with 
> wavelength assignment.
>
Correct and the tspec was a solution we evaluate as well. In this case 
we preferred a newly defined (sub)TLV to have the possibility to signal 
more than one tuple (fec, modulation).

> lambda. Isn't it true that for wavelengths close to each other that 
> the impairment (CD, PMD) parameters should be roughly the same so that 
> we could group these with a "wavelength set"? We looked at a bit map 
The short answer is yes but probably not true in general. Using 
"wavelength set"(s) can leads to some approximation in evaluating your 
optical impairments while having parameters for each lambda is the 
general case.
Another consideration,  I'm wondering if even using "wavelength set" you 
might risk fragmentation in case your spectrum require too many sets.

Regards,
G