Re: Thoughts on draft-otani-ccamp-gmpls-lambda-labels-00.txt

[Tomohiro Otani <otani@kddilabs.jp>]

Hi Adrian, Greg and Dan,

Thank you very much for your comments and feedback.
We will update the draft and distribute it for reviewing.

I basically agree with more wavelength channels. At this moment,
how many wavelengths should we support ? 1024 ?
(I was a guy of transmission, but at that time, it was 8 to 16...)

With best regards,

Tomo


Dan Li さんは書きました:
> Hi,
>
> If the wavelength label only has the local significance, then the routing 
> problem needs to be addressed only at the level of the TE link choice, 
> and wavelength assignment can be resolved locally by the switches on 
> a hop-by-hop basis.
>
> But if we can have the "global semantic" labels, we can run into the 
> wavelength level to choose the path.
>
> I also agree with Adrian on the definition of the "global semantic" label,
> current the 160 wavelengths per fiber WDM system is deployed by 
> some carriers, and the 320 wavelengths per fiber is under developed. 
> The 640 wavelengths per fiber is expected in the near future. So the
> "n" field is better to be expanded, and leave some room for the new 
> technologies. 
>
> Regards,
>
> Dan
>
> ----- Original Message ----- 
> From: "Greg Bernstein" <gregb@grotto-networking.com>
> To: "Adrian Farrel" <adrian@olddog.co.uk>
> Cc: <ccamp@ops.ietf.org>; "Tomohiro Otani" <otani@kddilabs.jp>; <ho-guo@kddilabs.jp>; "K. Miyazaki" <miyazaki.keiji@jp.fujitsu.com>; "Diego Caviglia (GO/MCI)" <diego.caviglia@ericsson.com>
> Sent: Thursday, October 04, 2007 1:46 AM
> Subject: Re: Thoughts on draft-otani-ccamp-gmpls-lambda-labels-00.txt
>
>
>   
>> Hi folks, I agree with Adrian that this draft is very valuable for LSC 
>> networks. In addition, it seems that  these "global semantic" labels can 
>> be very useful in characterizing optical subsystems and that information 
>> can feed into a PCE performing the routing and wavelength assignment 
>> problem.
>>
>> For example a single wavelength drop port on a ROADM may be either a 
>> fixed lambda, or a range of lambda. So I'd like to characterize  this 
>> port with either one of your globally defined labels or via a range 
>> specified by by two of your nicely defined lambdas.
>>
>> Note that in ultra high capacity systems multiple optical bands could be 
>> used. In 
>> http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wavelength-switched-01.txt 
>> we estimated that to cover a wide band fiber at the narrowest channel 
>> spacing currently defined (12.5GHz) would require 4800 labels. Hence 
>> with advances in modulation formats and narrower channel spacing 
>> Adrian's suggestion of 16 bits for the "n" field below allows us to 
>> fully characterize a wide band fiber with room to grow.
>>
>> Regards
>>
>> Greg B.
>>
>> Adrian Farrel wrote:
>>     
>>> Hi,
>>>
>>> I think this draft is introducing a useful feature for LSC networks by 
>>> allowing lambda labels to have a global semantic.
>>>
>>> Although this work is functionally not an absolute requirement (it is 
>>> always possible to map lambdas on a hop-by-hop basis) it is clearly a 
>>> simplification to have a common semantic just as in the TDM label case.
>>>       
>> ---snip---
>>     
>>> ===
>>> Section 5.2
>>> It looks like you have already almost run out of Channel Spacing bits 
>>> in the CS field. Given that technology developments are likely to find 
>>> ways of decreasing the channel spacing, I would suggest allocating 
>>> another bit to the CS field.
>>> Similarly, n is limited to 511 (if my bit counting is right), and it 
>>> seems to me that the potential for more than 500 lambdas on a fiber is 
>>> not so improbable.
>>> So, how about...
>>>       0                   1                   2                   3
>>>       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>>>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>      |Grid |  C.S. |S|    Reserved   |               n               |
>>>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>> ===
>>>
>>>       
>> --snip--
>>     
>>> The two things you do need in this section are:
>>> 1. How do I use a new Lambda Label?
>>>   Answer: in all of the places that an existing Generalized
>>>   Label can be used.
>>> 2. How do I tell when a new Lambda Label is being used
>>>   and when an existing Generalized Label is being used?
>>>   Does this remain a link local issue (as it always has done)
>>>   or do you propose to define a new field value in the
>>>   Generalized label Request or a new C-Type for the
>>>   Generalized Label Object?
>>> ===
>>> Section 6.2
>>> As mentioned before, I think that discussion of advertising lambda 
>>> availability is best removed from this I-D.
>>> ===
>>> Section 7
>>> You might like to consider that the use of a global semantic makes the 
>>> control plane signaling information slightly more vulnerable to 
>>> snooping and external control. I don't think this changes the security 
>>> model, but you should mention the fact.
>>> ===
>>> Section 10
>>> I think [G.694.1] and [G.694.2] are probably normative references.
>>> ===
>>>
>>> Cheers,
>>> Adrian
>>>
>>>
>>>
>>>       
>> -- 
>> ===================================================
>> Dr Greg Bernstein, Grotto Networking (510) 573-2237
>>
>>
>>
>>     
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