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:[email protected]]
Sent: 05 August 2015 12:51
To: Black, David; [email protected]; [email protected];
[email protected]; [email protected]; 'General Area Review
Team'
Cc: [email protected]; [email protected]
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:[email protected]]
Sent: Wednesday, August 05, 2015 9:34 AM
To: Fatai Zhang; [email protected]; [email protected];
[email protected]; [email protected]; 'General Area Review
Team'
Cc: [email protected]; [email protected]
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:[email protected]]
Sent: Tuesday, August 04, 2015 9:08 PM
To: Black, David; [email protected]; [email protected];
[email protected]; [email protected]; 'General Area Review
Team'
Cc: [email protected]; [email protected]
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:[email protected]]
Sent: Tuesday, August 04, 2015 10:30 PM
To: [email protected]; Fatai Zhang; [email protected];
[email protected]; [email protected]; 'General Area Review
Team'
Cc: [email protected]; [email protected]; 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:[email protected]> mailto:[email protected]]
> Sent: Monday, August 03, 2015 1:38 PM
> To: Black, David; <mailto:[email protected]> [email protected];
<mailto:[email protected]> [email protected];
> <mailto:[email protected]> [email protected];
<mailto:[email protected]> [email protected]; 'General Area Review
> Team'
> Cc: <mailto:[email protected]> [email protected]; <mailto:[email protected]>
[email protected]
> 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
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