Hi Young,
I had a quick look at the draft, pretty nice !
A comment on Ch. 4.1 Frequency-Slot Selection TLV is on the sentence:
”” 1: First-Fit. All the feasible frequency slots are numbered
(based on "n" parameter), and this SA method chooses the
available frequency-slot with the lowest index, where "n" is
the parameter in f = 193.1 THz + n x 0.00625 THz where 193.1
THz is the ITU-T "anchor frequency" and "n" is a positive
integer including 0
“””
The “n” value is actually a positive AND NEGATIVE integer including 0
A second comment on Ch. 4.1 Frequency-Slot Selection TLV:
It could be interesting to have also a new Method starting from the C-band
higher end …
Like first fit starting from higher “n” values and decrementing it, so I’d add:
”” 2: First-Fit-reverse. All the feasible frequency slots are numbered
(based on "n" parameter), and this SA method chooses the
available frequency-slot with the HIGHEST index, where "n" is
the parameter in f = 193.1 THz + n x 0.00625 THz where 193.1
THz is the ITU-T "anchor frequency" and "n" is a positive AND NEGATIVE
integer including 0
“””
Best Regards,
Gabriele
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Gabriele Galimberti
Principal Engineer
Cisco Photonics Srl
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From: Pce <[email protected]> on behalf of Leeyoung <[email protected]>
Date: Tuesday, 12 March 2019 at 00:57
To: "[email protected]" <[email protected]>, "[email protected]" <[email protected]>
Cc: "[email protected]"
<[email protected]>
Subject: Re: [Pce] Chair review of draft-lee-pce-flexible-grid
Hi Adrian,
Thanks for your chair's review. Please see inline for my comment. 01 version
has been uploaded (please see the attachment).
Note: I might have made mistakes as I was rush to meet the deadline :)
Best regards,
Young
-----Original Message-----
From: Adrian Farrel [mailto:[email protected]]
Sent: Monday, February 18, 2019 4:10 PM
To: [email protected]<mailto:[email protected]>
Cc:
[email protected]<mailto:[email protected]>
Subject: Chair review of draft-lee-pce-flexible-grid
Hi,
As this document is being polled for adoption, I thought I should review it..
There are a considerable number of nits, but nothing that prevents adoption in
my view. In the event that this document is adopted, I think the authors would
do well to address the changes shortly afterwards. If the document is not
adopted but the authors want to continue with the work, they should pick up
these nits.
Thanks,
Adrian
---
Please fix the RFC 2119 boilerplate to use the latest form...
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
....You'll need to add a reference to RFC 8174
---
idnits shows a lot of issues with references. It is not hard to run idnits so
please get into the habit of running it before you ask for WG adoption.
For your convenience, here are all of the issues
== Missing Reference: 'RFC3209' is mentioned on line 318, but not
defined
== Unused Reference: 'RFC2863' is defined on line 654, but no explicit
reference was found in the text
== Unused Reference: 'RFC6566' is defined on line 683, but no explicit
reference was found in the text
== Unused Reference: 'RFC7420' is defined on line 687, but no explicit
reference was found in the text
== Unused Reference: 'RFC7446' is defined on line 692, but no explicit
reference was found in the text
== Unused Reference: 'RFC5521' is defined on line 708, but no explicit
reference was found in the text
== Unused Reference: 'RFC6205' is defined on line 712, but no explicit
reference was found in the text
== Unused Reference: 'RFC7689' is defined on line 719, but no explicit
reference was found in the text
== Unused Reference: 'RFC7688' is defined on line 722, but no explicit
reference was found in the text
== Unused Reference: 'RFC7581' is defined on line 731, but no explicit
reference was found in the text
** Downref: Normative reference to an Informational RFC: RFC 7698
The last issue is a warning, and you can keep the downwards reference if you
think it is the right thing to do.
---
Please check that all abbreviations are expanded on first use.
I see:
ERO
PCE
---
Move the first sentence of paragraph 4 of Section 3 down to the end of that
paragraph so that the use of the term "flexi-grid" comes after it has been
explained.
---
Section 3 has
This document provides PCEP extensions to support Routing and
Spectrum Assignment (RSA) in in Spectrum Switched Optical Networks
(SSON)[RFC7698].
s/in in/
s/(SSON)[RFC7698]/(SSON} [RFC7698]/
The terms RSA and SSON are, of course, defined in RFC 7698. But the terms come
as a surprise in this document. Perhaps you could insert a short paragraph
above this one to say...
The terms "Routing and Spectrum Assignment" (RSA) is introduced in
[RFC7698] to refer to blah blah. The term "Spectrum Switched
Optical Networks" is also introduced in [RFC7698] and indicates a
network that is blah blah blah.
That would leave you with
This document provides PCEP extensions to support RSA in SSONs.
---
Section 3
s/extensions are going to be specified/extensions are specified/
---
Section 4
Bullet b) has a second sentence (beginning "This document aligns...") that
doesn't seem specific to that bullet. Maybe it belongs at the top of the
section.
---
Section 4 has
Additionally, given a range of potential spectrums to allocate, the
request SHOULD convey the heuristic / mechanism to the allocation.
The reader is left wondering how to meet that "SHOULD" and also why to vary
that "SHOULD".
---
Section 4 needs a reference to RFC 5511 to explain the notation.
---
Section 4
If the SA object is present in the request, it MUST be encoded after
the ENDPOINTS object.
I think that should be 'GENERALIZED ENDPOINTS object'
---
Section 4 has
The following new flags SHOULD be set
But I think you are equally happy for the bit to be set or cleared.
YL>> OLD: The following new flag SHOULD be set
NEW: One flag bit is allocated as follows:
---
4.1
This TLV
MUST NOT be used when the M bit is cleared.
I think you may mean...
SHOULD NOT be present and MUST be ignored
YL>> Yes.
OLD: This TLV MUST NOT be used when the M bit is cleared.
NEW: This TLV SHOULD not be present and MUST be ignored when the M bit is
cleared.
---
I think you are going to need an IANA registry for the Frequency-Slot
Assignment (FSA) Method.
YL>> Yes, added.
NEW:
IANA is to allocate a new PCEP TLV type, Frequency-Slot Selection TLV (TBD2) in
the "PCEP TLV Type Indicators" subregistry
(http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type-indicators).
---
4.1 is going to need an explanation of what the 'n' parameter is.
YL>> Yes. Added:
where "n" is the parameter in f = 193.1 THz + n x 0.00625 THz where 193.1 THz
is the ITU-T "anchor frequency" and "n" is a positive integer including 0
[RFC7698].
---
4.1
- S bit not supported: a PathErr MUST be generated with the
Error Code "Routing Problem" (24) with error sub-code
"Unsupported Frequency slot Selection Symmetry value" (TDB).
This is a bit unclear. Presumably the issue is "S bit clear not supported".
You might consider reversing the meaning of the S bit and then this would be a
lot clearer.
YL>> Done.
---
Please distinguish the different TBDs as TBD1, TBD2, etc.
(And note you have several cases of "TDB")
YL>> yes. Added TBDX (where X=1,2,...)
---
4.1
As defined in
[RFC7570], the R bit reflects the LSP_REQUIRED_ATTRIBUTE and
LSP_ATTRIBUTE semantic defined in [RFC5420], and it SHOULD be set
accordingly.
It is not clear what R bit you are referring to.
YL>> This paragraph was removed as this is an irrelevant discussion.
---
4.1
A Frequency Slot Selection TLV can be constructed by a node and
added to an ERO Hop Attributes subobject in order to be processed
by downstream nodes (transit and egress). As defined in
[RFC7570], the R bit reflects the LSP_REQUIRED_ATTRIBUTE and
LSP_ATTRIBUTE semantic defined in [RFC5420], and it SHOULD be set
accordingly.
Once a node properly parses the Spectrum Selection sub-TLV
received in an ERO Hop Attributes subobject, the node use the
indicated spectrum assignment method (at that hop) for the LSP.
In addition, the node SHOULD report compliance by adding an RRO
Hop Attributes subobject with the WSON Processing Hop Attribute
TLV (and its sub-TLVs) that indicate the utilized method.
Frequency-Slot Selection TLVs carried in an RRO Hop Attributes
subobject are subject to [RFC7570] and standard RRO processing;
see [RFC3209].
There's something odd here.
- Doesn't this section say/imply that the Frequency-Slot Selection TLV
belongs in the Spectrum Assignment object? Why are you talking about
TLVs in the Hop Attribute TLV and the ERO Hop Attributes subobject?
Maybe the first paragraph here should read...
A Frequency Slot Selection TLV can also be constructed by a node...
- Why are you talking about the Spectrum Selection sub-TLV? Doesn't that
belong in Section 5?
YL>> Thanks for pointing this out. You are correct. These two paragraphs do not
belong here. Deleted.
---
4.2
For any request that contains a Frequency-slot assignment, the
requester (PCC) MUST be able to specify a restriction on the
frequency-slots to be used.
I think you can s/MUST/must/
YL>> Yes. Corrected.
---
4.2
<Frequency-lot Restriction Constraint> ::=
<Action> <Count> <Reserved>
(<Link Identifiers> <Freq-slot Restriction>)...
I don't think you need to list every field of the frequency slot TLV in the
RBNF, and in particular you should not list the reserved field.
YL>> Actually the following is the right RBNF:
NEW
<Frequency-lot Restriction Constraint> ::=
( <Action> <Count> <Reserved>
<Link Identifiers> <Freq-slot Restriction>)...
With this correction, I think I can further reduce it as follows:
<Frequency-lot Restriction Constraint> ::=
( <Action> <Link Identifiers> <Freq-slot Restriction>)...
Is this OK with you?
---
4.2
Note that a PCC MAY add a spectrum restriction that applies to all
links by setting the Count field to zero and specifying just a set
of spectrums.
I think s/spectrum/frequency slot/ twice
YL>> Agreed and corrected.
---
4.2
and Section 3.3.1 for the Spectrum Restriction Field encoding,
respectively.
Why do you point us at the definition of this field?
YL>> Yes, it is not necessary; removed.
---
4.2.1 broken reference
YL>> It is corrected to point to Section 4.2
---
5.
The Spectrum Allocation TLV type is TBD, recommended value is TBD.
No need to recommend a value of TBD :-)
YL>> "recommended value is TBD" delete.
---
5.
The type
value of the Spectrum Restriction Constraint TLV is TBD by IANA.
This seems out of place and is the first mention of this TLV.
YL>> Deleted. Instead before Figure 4, added "IANA is to allocate a new PCEP
TLV type, the Spectrum Allocation TLV Type (TBD).
---
Section 7 could use some external references.
Added: G.694.1 and G.872.
---
Section 8
IANA maintains a registry of PCEP parameters. IANA has made
allocations from the sub-registries as described in the following
sections.
Hmmm, I think IANA has not actually made these allocations. You should say
"IANA is requested to make allocations..."
---
I think the titles of 9.1 and 9.2 may be reversed.
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