Re: [Gen-art] [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05 - Nits/editorial items

["Adrian Farrel" <[e-mail]>]

Right, thanks Fatai. You have put us right.
 
But David and I both got confused by Figure 3, and perhaps by the difference
between n and m.
 
I suggest
 
OLD
         Slot width = 25 GHz     Slot width = 37.5 GHz
NEW
         Slot width = 25 GHz     Slot width = 37.5 GHz
             n = 4,   m = 2          n = 6,  m = 3      
END
 
OLD
      *  The '--' represents the nominal central frequency granularity
NEW
      *  The '--' represents the nominal central frequency granularity in units
of 6.25 GHz
END
 
Cheers,
Adrian
 
From: Fatai Zhang [mailto:[e-mail]] 
Sent: 05 August 2015 12:51
To: Black, David; [e-mail]; [e-mail];
[e-mail]; [e-mail]; 'General Area Review
Team'
Cc: [e-mail]; [e-mail]
Subject: RE: [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05 -
Nits/editorial items
 
Hi David,
 
I am not sure if it needs the formula or not, but I think you can get more
information from Section 3.2.1. 
 
It can be seen that a slot width is constrained to be m x SWG..,  Slot Width
Granularity (SWG) is  12.5 GHz, and Nominal Central Frequency Granularity is
6.25GHz.
 
Take Figure 3 as an example. 
 
Note that the '--' represents the Nominal Central Frequency Granularity (NOT
Slot Width Granularity)!!  i.e., a couple of '--' forms the size of one SWG.
 
Frequency Slot 1: slot width = 2*SWG=2*12.5=25GHz.
Frequency Slot 2: slot width = 3*SWG=3*12.5=37.5GHz.
 
 
 
Best Regards
 
Fatai
 
From: Black, David [mailto:[e-mail]] 
Sent: Wednesday, August 05, 2015 9:34 AM
To: Fatai Zhang; [e-mail]; [e-mail];
[e-mail]; [e-mail]; 'General Area Review
Team'
Cc: [e-mail]; [e-mail]
Subject: RE: [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05 -
Nits/editorial items
 
Hi Fatai,
 
> I think the amount of frequency in use is exactly the same value of the slot
width (ie., m*SWG). Please see the formula:
> 
> Frequency slot = [(central frequency) - (slot width)/2] ~[(central frequency)
+ (slot width)/2]
 
That was not obvious to me in reading the draft.
 
As an alternative to Adrian's new sentence, could you add that formula to the
draft?
 
Thanks,
--David
 
From: Fatai Zhang [mailto:[e-mail]] 
Sent: Tuesday, August 04, 2015 9:08 PM
To: Black, David; [e-mail]; [e-mail];
[e-mail]; [e-mail]; 'General Area Review
Team'
Cc: [e-mail]; [e-mail]
Subject: RE: [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05 -
Nits/editorial items
 
Hi Adrian and David,
 
Thanks for your comments.
 
I just have one comment for clarification on the following proposal:
 
I think the original text is correct, so it is not necessary to add the last
sentence in the "NEW'. 
 
I think the amount of frequency in use is exactly the same value of the slot
width (ie., m*SWG). Please see the formula:
 
Frequency slot = [(central frequency) - (slot width)/2] ~[(central frequency) +
(slot width)/2]
 
In addition, I think some people might be confused by Nominal Central Frequency
Granularity (which is 6.25) and Slot Width Granularity (which is 12.5).
 
 
================================================================================
================
> OLD
>>    o  Slot Width: The slot width determines the "amount" of optical
>>       spectrum regardless of its actual "position" in the frequency
>>       axis.  A slot width is constrained to be m x SWG (that is, m x
>>       12.5 GHz), where m is an integer greater than or equal to 1.
> >NEW
>>    o  Slot Width: The slot width determines the "amount" of optical
>>       spectrum regardless of its actual "position" in the frequency
>>       axis.  A slot width is constrained to be m x SWG (that is, m x
> >      12.5 GHz), where m is an integer greater than or equal to 1.
>>       The slot width defines the amount of spectrum in use on
>>       each side of the central frequency, thus the amount of
>>       frequency in use is actually twice the value of the slot width.
 
>That definitely helps.
 
 
 
 
Best Regards
 
Fatai
 
 
-----Original Message-----
From: Black, David [mailto:[e-mail]] 
Sent: Tuesday, August 04, 2015 10:30 PM
To: [e-mail]; Fatai Zhang; [e-mail];
[e-mail]; [e-mail]; 'General Area Review
Team'
Cc: [e-mail]; [e-mail]; Black, David
Subject: RE: [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05 -
Nits/editorial items
 
Adrian,
 
Thanks for the response - this note contains the follow-ups on nits/editorial
items.  All of these are nits or editorial, and hence I defer to the editors'
discretion on what (if anything) to do about them.  The two suggestions for
text revisions in your response will definitely improve the draft, IMHO.
 
Thanks,
--David
 
> -----Original Message-----
> From: Adrian Farrel [ <mailto:[e-mail]> mailto:[e-mail]]
> Sent: Monday, August 03, 2015 1:38 PM
> To: Black, David;  <mailto:[e-mail]> [e-mail];
<mailto:[e-mail]> [e-mail];
>  <mailto:[e-mail]> [e-mail];
<mailto:[e-mail]> [e-mail]; 'General Area Review
> Team'
> Cc:  <mailto:[e-mail]> [e-mail];  <mailto:[e-mail]>
[e-mail]
> Subject: RE: [CCAMP] Gen-ART review of draft-ietf-ccamp-flexi-grid-fwk-05
> 
> Hello David,
> 
> Responding as a contributing author who wants to see this work move forward
> promptly...
> 
> Many thanks for taking the time to review.
 
[... snip ...]
 
> > Nits/editorial comments:
> >
> > Section: 3.2.1 - Editorial suggestion: Changing "+" -> "+/-" in the
> > formula for nominal central frequency and re-defining n as a
> > non-negative integer would be slightly clearer.
> 
> This is something you'd need to take up with the ITU-T, I think.
> We don't want to change the formulae in common use where the data plane is
> defined.
 
Ok, proof by (ITU-T) authority wins here.
 
> > p.6 - please state that slot width is +/- wrt nominal central frequency.
> 
> Ah, took me a moment to see what you mean.
> Yes, this could be clarified with
> 
> OLD
>    o  Slot Width: The slot width determines the "amount" of optical
>       spectrum regardless of its actual "position" in the frequency
>       axis.  A slot width is constrained to be m x SWG (that is, m x
>       12.5 GHz), where m is an integer greater than or equal to 1.
> NEW
>    o  Slot Width: The slot width determines the "amount" of optical
>       spectrum regardless of its actual "position" in the frequency
>       axis.  A slot width is constrained to be m x SWG (that is, m x
>       12.5 GHz), where m is an integer greater than or equal to 1.
>       The slot width defines the amount of spectrum in use on
>       each side of the central frequency, thus the amount of
>       frequency in use is actually twice the value of the slot width.
 
That definitely helps.
 
> 
> > p.8 - Fig 4 could use a bit more explanation - the two frequency
> > slots occur at different points along the path.
> 
> Maybe...
> 
> OLD
>    o  Effective Frequency Slot [G.870]: The effective frequency slot of
>       a media channel is that part of the frequency slots of the filters
>       along the media channel that is common to all of the filters'
>       frequency slots.  Note that both the Frequency Slot and Effective
>       Frequency Slot are local terms.
> NEW
>    o  Effective Frequency Slot [G.870]: The effective frequency slot of
>       a media channel is that part of the frequency slots of the filters
>       along the media channel that is common to all of the filters'
>       frequency slots.  Note that both the Frequency Slot and Effective
>       Frequency Slot are local terms.
> 
>       Figure 4 shows the effect of combining two filters along a channel.
>       The combination of frequency slot 1 and frequency slot 2 applied to
>        the media channel is effective frequency slot shown.
> END
 
That also helps.
 
> > Nit: First nominal central frequency 'X' in Fig 5 needs to move 2
> > chars left.
> 
> I think it is one char :-)
 
Touche'
 
> > Section 4 - TE link term shows up w/o acronym expansion or definition.
> > Please define it before use.
> 
> Yes. Last line of section 4.
 
   This section provides a mapping of the ITU-T G.872 architectural
   aspects to GMPLS/Control plane terms, and considers the relationship
   between the architectural concept/construct of media channel and its
   control plane representations (e.g., as a TE link).
 
I don't understand how "e.g." defines "TE link".
 
> > Sections 4.2 and 4.3 - this may be my unfamiliarity, but it would have
> > helped to have some sort of heads-up at the start of the figures that
> > the top (non-GMPLS) portion of the figures prior to Figure 12 are
> > entirely in the optical domain.  Perhaps explaining what the two
> > planes are (and how they're realized/implemented) in Figure 8 would help.
> 
> Hmmm. I think the reader should be coming at this with the concepts of TE link
> and LSR in their heads so that the mapping is clear.
 
Ok, chalk this one (and probably the previous one) up to me not being a
GMPLS expert.
 
> > Last paragraph on p.16: "trnaponders" -> "transponders".  Also, I saw
> > "transceivers" earlier - if that's the same concept, only one term
> > should be used.
> 
> While "transponder" is technically correct, using "transceiver" would be more
> consistent.
 
Ok.
 
> > p.19 - Even after expanding acronyms, I don't understand this sentence:
> >
> >    If two OTSis must be
> >    switched to different ports, it is better to carry them by different
> >    FSC channels, and the media layer switch is enough in this scenario.
> >
> > A sentence or two explaining what an "FSC channel" is earlier in that
> > paragraph would help.
> >
> > p.21, 1st para:
> >
> >    messages, and a specific frequency slot can be requeste on any
> >
> > s/requeste/requested
> >
> > p.21:
> >
> >    In GMPLS the requested effective frequency slot is represented to the
> >    TSpec present in the Path message, and the effective frequency slot
> >    is mapped to the FlowSpec carried in the Resv message.
> >
> > I believe those are RSVP-TE messages - that should be stated.
> >
> > p. 22:
> >
> >    d.  n can change, but m needs to remain the same along the path.
> >        This ensures that the effective frequency slot remains valid, but
> >        allows the frequency slot to be moved within the spectrum from
> >        hop to hop.
> >
> > In full generality, that may require the ability to shift or convert a
> > frequency slot, which is a concept that doesn't appear to occur in the
> > draft prior to this point.
> 
> Penultimate paragraph of page 21.
 
Ok.
 
> > Figures 15 and 16 need their variables (e.g., m_a, FSb) somehow
> > labelled or explained
> >
> > After Figure 16, the switch to the EFS acronym is a surprise, given
> > the extensive prior usage of the spelled-out term.  This paragraph
> > contains all uses of the EFS acronym - I suggest removing that acronym
> > and spelling out the term.
> >
> > Section 4.6: I don't understand why this sentence is in the middle of
> > the paragraph - it doesn't seem to describe an example of different
> > slot width granularities:
> >
> >    Consider a node with an application where the nominal
> >    central frequency granularity is 12.5 GHz and where slot widths are
> >    multiples of 25 GHz.
> >
> > I'd suggest removing it.
> >
> > 5.1.1. What is L-band?  This is the first time it's mentioned.
> >
> > idnits 2.13.02 didn't find anything that needs attention.
> 
> Many thanks,
> Adrian