Re: [Pce] New draft on wavelength switched optical networks

[Greg Bernstein <gregb@grotto-networking.com>]

Hi Julien, good questions.  See comments below. 

Regards

Greg B.

MEURIC Julien RD-CORE-LAN wrote:
> Hi Greg.
>
> I'm really interested in this topic, but I think I've missed some points when reading your ID.
>
> For instance, I don't get why you consider the signal modulation format. I don't believe a single-vendor environment would require a negociation on modulation for a specific bandwidth, 
--> In the optical case as it is currently implemented I tend to agree 
with you here.  However in other systems negotiation of modulation 
format and such is more common.
> and I don't think modulation information would be enough for 2 different implementations to interwork on (analog) optical line.
>   
I was thinking along the lines of the relatively new ITU-T optical 
signal designations such as NRZ 2.5G, and RZ 40G defined in G.959.1.
I'm also, like most of the ITU-T recommendations, restricting the focus 
to digital signals over fiber. Not including impairment information for 
now, this should give us adequate information to understand the signals 
spectral characteristics for compatibility with wavelength selective 
switching elements and such.  At least this was the part of the point of 
the physical layers interfaces defined G.959.1. 

One thing that we might have not hit well enough is the compatibility of 
the end systems where the optical signals are demodulated. Its one thing 
to be able to switch the lambdas its another to demodulate them. Would 
we need more information or would this be covered in the PID?  For 
example if the PID indicates that the carried signal is a particular 
flavor of10G Ethernet that would be sufficient.  I'll review the current 
PID stuff as applied to lambda switching.
> Anyway, this work is a good start to highlight GMPLS and PCE lack to handle the different kinds of optical networks.
>
> Regards,
>
> Julien
>
>
> -----Original Message-----
> From: Greg Bernstein [mailto:gregb@grotto-networking.com] 
>
> Hi CCAMPer's and PCEr's, we have just published a new draft on the 
> "Applicability of GMPLS and PCE to Wavelength Switched Optical 
> Networks"  
> http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wavelength-switched-00.txt 
> .
>
> This draft looks at optical networks that include tunable lasers and 
> ROADM (reconfigurable optical add/drop multiplexers) with no or limited 
> wavelength conversion capability (these components are defined in the 
> draft). 
> These limitations lead to the RWA (routing and wavelength assignment) 
> problem which is a bit more demanding in terms of input information and 
> computation than other constrained path computation problems.  In the 
> draft we look at the implications for GMPLS signaling, GMPLS routing, 
> and PCE protocols and suggest some potential extensions to better 
> accommodate this application.
>
> We'd appreciate feedback/collaboration on (a) overall interest in this 
> application, (b) requirements discussions, and (c) solution/extension 
> discussions.
>
> Cheers
>
> Greg B.
>
>   

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