Re: [Pce] Some key issues with Wavelength Switched Optical Networks...

[Martin Vigoureux <[e-mail]>]

Hi Greg,

please see below

best regards,

martin

Greg Bernstein a écrit :
> Hi Igor, see comments below.
> 
> Igor Bryskin wrote:
>>
>> Greg,
>>
>>  
>>
>> I believe the draft is very useful.
>>
> --> Thanks!
>>
>>  
>>
>> 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.
>>
> --> Some of my co-authors agree with you on moving this section out.  
> The reason that I put it in was that the optical "Traffic Grooming" 
> problem has received a fair amount of attention in the research and 
> general technical literature and is also a driver for the use of ROADMs 
> (optical bypass).  I guess in general we've got the following 
> inter-related problems: (a) virtual network topology design, (b) lower 
> layer connection routing, (c) higher layer flow routing. In our case (b) 
> is the RWA problem, which is fairly difficult in its own right. I guess 
> I should look closely at the MLN/MRN work and see if a specific example 
> that includes RWA is mentioned.  If so then I'd feel fine removing this 
> section from the document.

Optical considerations are not explicitly covered in MRN/MLN documents
anymore, but we still talk a lot about virtual topologies in
multi-layer/region contexts.
Optical considerations were covered at the very beginning of these 
documents, at the time they were called HPN (Hybrid Photonic Networks).
http://www.tools.ietf.org/html/draft-vigoureux-ccamp-gmpls-architecture-hpn-00