Re: [CCAMP] Generalized Labels for the Flexi-Grid in LSC Label Switching Routers

[Loa Andersson <[e-mail]>]

All,

16 bits and deferring the specification of of dataplane specifiction to
the Recommendation seems quite reasonable.

/Loa

On 2014-02-04 19:18, Adrian Farrel wrote:
> I think I see a general set of agreements coming along.
>
> Appendix V.1 gives an example of needing 9 bits to encode m.
> Although an Appendix is not part of the normative spec, we might assume two things from this appendix:
> 1. Currently only up to 8 bits are needed
> 2. The is a trend toward more than 8 bits
>
> As Gabriele suggests, 16 bits is a lot. So I don't think we need to worry about extensibility if we go there.
>
> I will update the I-D to make m 16 bits wide, and I will (continue to) say that the definition of m is per the slot width formula defined in G.694.1. This makes no comment within the draft on the legitimate values of m, but defers the data plane specification to the ITU-T.
>
> As to describing such things in the framework, I would be opposed to an IETF document that describes the flexi-grid data plane in any detail. That is, IMNSHO, not our remit and not the scope of CCAMP. But we could ask the AD for an opinion on that ;-)
>
> A
>
>> -----Original Message-----
>> From: CCAMP [mailto:[e-mail]] On Behalf Of Huub van Helvoort
>> Sent: 03 February 2014 14:26
>> To: Ramon Casellas; Oscar González de Dios
>> Cc: CCAMP
>> Subject: Re: [CCAMP] Generalized Labels for the Flexi-Grid in LSC Label Switching
>> Routers
>>
>> Hola Ramon,
>>
>> G.694.1 does not define a maximum value for "m".
>>
>> However G.697 gives in Appendix V.1: Wavelength ID.
>> "m" = 9 bits (m is encoded as a 9-bit unsigned integer).
>>
>> Regards, Huub.
>>
>>
>>   >> I am happy if we don't need to do so. But is this not better than
>>>> defining/ extending a new label format when ITU-T changes the data plane?
>>>
>>> Dear all,
>>>
>>> I may be missing something (apologies in advance if it is the case) and
>>> since I don't have them here right now, for the sake of this discussion,
>>> maybe could anyone point to the relevant part of the document(s) e.g.
>>> G.694.1 / G.872 etc. where it is said that the value of m is bound to 256?
>>> We are aware of the concept of frequency slot, nominal central
>>> frequencies (n, and their values) and the concept of frequency slot
>>> width, but I cannot recall now such a bound.
>>>
>>> Thanks
>>> R.
>>>
>>
>>
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-- 


Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Huawei Technologies (consultant)     phone: [phone]