Re: [CCAMP] WG Last Call on draft-ietf-ccamp-flexi-grid-fwk-03 and call for sheperd

[Ramon Casellas <[e-mail]>]

Jonas, all

Thanks for your careful review of the IM. Please see inline

El 20/05/2015 a las 14:51, Jonas Mårtensson escribió:
>
> A)<Available Central Frequency Granularity> ::= p x 6.25GHz
>
> ”A) yields 6.25, 12.5, 18.75, 25.0, 31.25, etc... a list of values 
> that are not necessarily common or deployed.”
>
> Still… I don’t really see a good reason why you would exclude those 
> values (which are compliant with G.694.1) at this point… More 
> generally, I think an information model should describe the needed 
> information, not necessarily limit values representing the information 
> (that could be done in a future encoding draft).
>

Ramon> good point. I guess we do not need to necessarily list the actual 
values themselves, and exclude compliant ones.

> Anyway, and sorry if I confuse things even more, it seems to me that 
> what you actually want to capture with the information model is 
> available center frequencies and slot widths, not the granularities 
> per se. Granularities are one way to represent available values but 
> how to represent those could be left for a future encoding draft. So a 
> more general information model could be:
>
> <Available Spectrum> ::=
>
>        <Available Frequency Range-List>
>
>        <Available Central Frequencies>
>
>        <Available Slot Widths>
>
>
> <Available Central Frequencies> ::= the subset of supported n values 
> (where n is defined as in G.694.1)
>
Ramon> It is true that I have been thinking whether the information on 
NCF granularity could be implied by its (dynamic) availability, and 
whether we were adding redundancy (e.g. those NCFs that are not 
supported by reasons of granularity would never appear as available e.g. 
in  <Available Frequency Range-List>). On a second thought, this seems 
to not be always the case (only when the choice of formats is chosen to 
be so). It seems perfectly valid to list both the available ranges e.g. 
by means of start/end and then which NCFs are possible/available, so +1 
to your suggestion. See below once integrated

> <Available Slot Widths> ::= the subset of supported m values (where m 
> is defined as in G.694.1)
>
> If you want to go one step further and limit how to represent these 
> subsets by introducing granularities (and possibly offsets but that is 
> maybe unnecessarily complex) you could have:
>
> <Available Central Frequencies> ::=
>
>         <Available Central Frequency Granularity>
>
>         <Offset>
>
> One possible representation would be to say that available center 
> frequencies are the subset of supported n values given by p x n + q 
> where p (granularity) is a positive integer and q (offset) belongs to 
> 0,..,q-1.
>
Ramon> I understand q (offset) belongs to 0,.., p-1, right? but ok.

Ramon> In order to try to complete it, Would the following be ok ?

OLD

    <Available Spectrum> ::=
        <Available Frequency Range-List>
        <Available Central Frequency Granularity >
        <Available Slot Width Granularity>
        <Minimal Slot Width>
        <Maximal Slot Width>

    <Available Frequency Range-List> ::=
        <Available Frequency Range> [<Available Frequency Range-List>]

    <Available Frequency Range> ::=
      ( <Start Spectrum Position> <End Spectrum Position> ) |
      <Sets of contiguous slices>

    <Available Central Frequency Granularity> ::= (2^n) x 6.25GHz
      where n is a non negative integer, giving rise to granularities
      such as 6.25GHz, 12.5GHz, 25GHz, 50GHz, and 100GHz

    <Available Slot Width Granularity> ::= (2^m) x 12.5GHz
      where m is positive integer

    <Minimal Slot Width> ::= j x 12.5GHz,
      j is a positive integer

    <Maximal Slot Width> ::= k x 12.5GHz,
        k is a positive integer (k >= j)

NEW

       NCF: Nominal Central Frequency

    <Available Spectrum> ::=

        <Available Frequency Range-List>

        <Available NCFs>

        <Available Slot Widths>

where

    <Available Frequency Range-List> ::=
        <Available Frequency Range> [<Available Frequency Range-List>]

    <Available Frequency Range> ::=
      ( <Start NCF> <End NCF> ) |
        <FS defined by its (n, m) and containing a set of contiguous available NCFs>

and

    <Available NCFs> ::=
         <Available NCF Granularity> [<Offset>]
    -- Subset of supported n values given by p x n + q where p is a positive integer and q (offset) belongs to 0,..,p-1.

and
    <Available Slot Widths> ::=
         <Available Slot Width Granularity>
         <Min Slot Width>
          -- value given by j x 12.5GHz, with j a positive integer
         <Max Slot Width>
          -- value given by k x 12.5, with k a positive integer (k >= j)