[Gen-art] Genart telechat review of draft-ietf-6lo-rfc6775-update-14

[Peter Yee <[e-mail]>]

Reviewer: Peter Yee
Review result: Ready with Issues

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair. Please wait for direction from your
document shepherd or AD before posting a new version of the draft.

For more information, please see the FAQ at

<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.

Document: draft-ietf-6lo-rfc6775-update-14
Reviewer: Peter Yee
Review Date: 2018-03-07
IETF LC End Date: 2018-03-06
IESG Telechat date: 2018-04-05

Summary: This document updates RFC 6775 with an Extend Address Registration
Option and various changes/simplifications.  There are some questions I have
that should be addressed along with a list of nits. [Ready with issues.]

I am aware that this is a review against draft -14.  Unfortunately, I started
the review before -15 was released and I lack the time to go back and start
with draft -15.  I hope that most of my comments remain relevant and useful.

Major issues:  None

Minor issues:

Page 6, 2nd paragraph: why is the capability for multiple registrations only
"RECOMMENDED"?  It's not entirely clear why one would not want to follow this
recommendation.  The second sentence says "It is also RECOMMENDED to provide
new mechanisms..."  To whom is this recommendation made - the working group? 
It's not clear why this recommendation is here and stated in RFC 2119 form.

Page 11, Section 4.6, 5th paragraph, last sentence: it's not clear to me how
the 6LN knows this is the case.

Page 19, Section 7.1.2, 4th paragraph, last sentence: the sentence reads: "Once
the 6LR is known to support this specification, the 6LN MUST obey this
specification."  Isn't that only true with respect to that 6LR, not necessarily
all 6LRs with which the 6LN may be communicating?  If so, perhaps that point
should be clarified in the text.

Page 20, Section 7.3, 3rd paragraph: what's the definition of "reasonable".  If
guidance on what reasonable can't be given other than to say it's device and
deployment dependent, is the guidance useful?  Or are there known guidelines
that are easily derived from the device type and perhaps less so from the
deployment parameters?

Page 21, Section 8, 2nd paragraph: the paragraph notes an expectation of a
secure MAC in order to work.  Is that a realistic assumption?  Or is that a
requirement and the whole scheme (potentially) falls apart if a secure MAC is
not being used?

Page 22, 1st partial bullet item, last sentence: I may be confused, but why
would a larger lifetime be appropriate for a node that moves compared to one
that is relatively static?  Wouldn't the mobile node do better with a smaller
lifetime so its registration doesn't linger on a 6LR that is simply not aware
that the node has moved (and probably failed to deregister from it)?

Page 36, Req5.3: the requirement reads: "6LoWPAN ND security mechanisms SHOULD
lead to small packet sizes".  Should that really say that their use SHOULD NOT
lead to large packets?  I can't imagine a security mechanism that makes a
packet smaller.

Page 36, Req5.6: You may wish to expand this beyond CCM* as IEEE 802.15.4y is
being spun up to make IEEE 802.15.4 algorithm agile.  At a minimum, this will
likely add 256-bit key sizes and allow the use of GCM as a peer to CCM*.

Nits/editorial comments:

General:

I mark these nits in order to save the RFC Editor a bit of work later on in the
process and to make comprehension easier for all readers.  Take these as you
will.

General:

Throughout the document, change "a NA" to "an NA".  Change "a NS" to "an NS". 
Change "a LLN" to "an LLN".  Change "a RPL" to "an RPL" unless RPL is typically
spoken as "ripple" and not spelled out.  Change "a EARO" to "an EARO".  Change
"a EDAR" to "an EDAR".  Change "a RUID" to "an RUID" unless it pronounced like
"druid" without the leading 'd'.

Change "ARO option" to "ARO".  Change "EARO option" to "EARO".  Change "SLLAO
option" to "SLLAO".

Change any use of "IEEE Std." to "IEEE Std" and leave a space after "Std". 
Yes, the IEEE is aware that it would be more grammatical to use "Std.", but
they don't.

Make sure each use of "i.e." and "e.g." is followed by a comma.

Change "replacement to" to "replacement for".

Replace "BLUETOOTH" with "Bluetooth".  And if you're going to use "(R)" for
Bluetooth, consider that IEEE says, "The term EUI-64 is trademarked by IEEE and
should be so identified."

Change "TimeSlotted" to "Timeslotted" to match IEEE Std 802.15.4 usage.

Change "Dependant" to "Dependent".

Specific:

Page 1, Authors: change "cisco" to "Cisco" or "Cisco Systems" to reflect the
official name of the company.

Page 1, Abstract: change "low power" to "low-power".

Page 3, Section 1, 1st paragraph, 1st sentence: change "Low Power" to
"Low-Power".

Page 3, Section 1, "Registration" bullet item: change "a IPv6" to "an IPv6".

Page 4, "Extended LLN" definition: change "MultiLink" to "Multilink" or
"Multi-Link" or "Multi-link", depending on which original use of the term you
wish to align with.

Page 4, "updated" definition: append a comma after "6LR".

Page 6, first paragraph, 1st sentence: delete comma after "messages".

Page 8, Section 4.2.1, 1st paragraph, 1st sentence: change the first "the" to
"an", change "of" to "for", and delete "specification".  I'm not entirely sure
I like "operation" since a counter doesn't by itself have an "operation", but
I'm not sure "use" is the right substitute either.

Page 8, Section 4.2.1, 2nd paragraph: put '"Sequence Counter Operation"' in
parentheses.

Page 9, Section 4,3, 1st paragraph, 2nd sentence: change "to identify" to
"identifying".  I'm also not sure what "tentative" modifies in that sentence,
but it could use a noun.  Maybe "attempt"?

Page 10, 1st paragraph, 2nd sentence: consider changing "memory" to "state".

Page 10, Section 4.4, 1st paragraph: change "a" before "Reserved" to "the". 
I'm not sure how support for the TID transports the "T" flag.  Perhaps this
sentence could be reworded?

Page 10, Section 4.4, 2nd paragraph: change ", and though" to "although". 
Delete the comma after "body".

Page 10, Section 4.4, 3rd paragraph: change "for" to "with".

Page 10, Section 4.5, 1st paragraph, 2nd sentence: delete the comma after
"addresses".

Page 10, Section 4.5, 3rd paragraph, last sentence: delete the comma after
"device".

Page 11, Section 4.6, 2nd paragraph, 1st sentence: change "is" to "be".

Page 11, Section 4.6, 2nd paragraph, 2nd sentence: delete the comma after
"addresses".

Page 12, 2nd full paragraph, 1st sentence: delete the second "IPv6".

Page 12, 3rd full paragraph, 2nd sentence: delete "as".

Page 12, Section 4.7, 1st paragraph, 1st sentence: append a comma after "6LR".

Page 13, 1st full paragraph, 2nd sentence: put "Table 1" in parentheses.

Page 13, 4th full paragraph, 3rd sentence: delete the comma after "6BBR".

Page 13, 4th full paragraph, last sentence: move "do so" to after "could". 
Delete "the" before "said".

Page 14, 2nd paragraph, 1st sentence: move "yet" before "reach".

Page 14, Section 5, 1st paragraph: delete "The".

Page 14, Section 5, 2nd paragraph: delete the comma after "EARO".  Add a comma
after "6LBR".

Page 14, Section 5, 3rd paragraph, 2nd sentence:  delete "Neighbor
Solicitation" and "Neighbor Advertisement" along with their associated
parentheses.

Page 14, Section 6 title: change "And" to "and".

Page 14, Section 6.1, 2nd paragraph, 2nd sentence: consider changing "On the
other hand" to "In contrast".

Page 15, 1st paragraph, 2nd sentence: insert "is" before "also".

Page 15, 3rd paragraph, 2nd sentence: insert "being" before "set".

Page 15, 2nd partial table, "0..2" entry: put "Duplicate Address" in
parentheses.

Page 16, Table 1, "4" entry: delete the comma.  Maybe add "sent" after "or". 
I'm not sure that rejections are "placed".

Page 16, Table 1, "5" entry, 2nd sentence: append a comma after "instance".

Page 16, T bit definition: change "One bit" to "One-bit".

Page 17, TID definition: change "id" to "ID".

Page 17, RUID definition: change "IDentifier" to "Identifier".  I think most
people are comfortable with the two letter "ID" being derived from
"Identifier".  Change "EUI-64 derived" to "EUI-64-derived".  Change "IID" to
"Interface Identifier (IID)".

Page 18, Code definition: change "odd" to "odd-numbered".  Totally pedantic, I
know.

Page 18, RUID definition: change "IDentifier" to "Identifier".

Page 18, 2nd paragraph, 2nd sentence: append a comma after "6LBR" and '"B"'.

Page 18, 2nd paragraph, 3rd sentence: insert "of a" before "6LR" and insert "a"
before "6LBR".

Page 18, option field L definition: change the comma to a semicolon.

Page 19, Section 7.1.2, 1st paragraph, 2nd sentence: bracket "for instance"
with commas.

Page 20, Section 7.2, 1st paragraph, 1st sentence: change "an" to "An".  Insert
"the" before "source".  Append "address in the ARO" after "source".

Page 20, Section 7.3, 1st paragraph, 1st sentence: insert "the" before "source"
and append "address" after "source".

Page 20, Section 7.3, 5th paragraph: change "can not" to "cannot".  (Yes, both
are correct, but cannot is more common and is used in the very next paragraph.)

Page 21, Section 8, 1st paragraph, 2nd sentence: delete "a" before "rogue".

Page 21, Section 8, 3rd paragraph: delete the comma after ")" and change
"protection" to "protecting".

Page 22, 1st full bullet item, 2nd sentence: change "stringer" to "stronger".

Page 22, 1st paragraph after bullet items, 2nd sentence: delete the comma.

Page 22, Section 9, 1st paragraph, 1st sentence: change "that is" to either
"such that it is" or "that is,".  The latter form is equivalent to "i.e.,".

Page 22, Section 9, 2nd paragraph: append a comma after "[RFC3971]" and delete
the following "and".

Page 23, 1st full paragraph: change "deployment" to "deployments" and
"environment" to "environments".

Page 23, 2nd full paragraph, 3rd sentence: append a period after the first
"[RFC8064]".

Page 23, Section 10, 1st paragraph: maybe change "attributed" to "allocated"?

Page 25, Table 5, ARO status 9: change "registry" to "Registry" to match prior
use.

Page 26, Section 11, 1st sentence: append a comma after "Lovnick".

Page 25, Section 11, 2nd sentence: append a comma after "Also" and after "6LBR".

Page 31, Appendix A, 2nd paragraph: change "Network" to "network".

Page 32, 1st full paragraph: there doesn't seem to be an exact "Low-Power
Wi-Fi" definition.  Maybe you want to cite "Wi-Fi HaLow", which is the Wi-Fi
Allowance's term for this technology.  Or is this some other term?  In which
case, you should probably call it low-power IEEE 802.11 networking.  Delete the
"(R)" after "Bluetooth" as it was already used earlier in the document.  Change
"11AH" to "11ah".

Page 32, 4th full paragraph: I-D.chakrabarti-nordmark-6man-efficient-nd is no
longer active.  And its title was "IPv6 Neighbor Discovery Optimizations for
Wired and Wireless Networks".  It expired 2.5 years ago.  Does it still make a
good reference?

Page 32, Appendix B, 1st paragraph, 2nd sentence: remove the space after "B.8".

Page 32, Section B.1, 1st sentence: should the first use of "6LR-a" be
something like "6LR-b" as in a different a 6LR from 6LR-a, which can no longer
be notified?

Page 33, Section B.2, 1st paragraph, 2nd sentence: change "at" to "by".

Page 33, Section B.2, 1st paragraph, 4th sentence: does it make sense to change
"would need to" to "must"?

Page 33, Section B.2, 2nd paragraph, 1st sentence: consider changing "Next to"
to "Beyond".

Page 33, Section B.2, 2nd paragraph, 2nd sentence: append a comma after
"example".

Page 34, Req2.2: append a comma after "[RFC6550]".

Page 34, Req2.3, 1st sentence: append a comma after "instance".

Page 34, Section B.3, 1st paragraph, 1st sentence: change "Identifier" to
"identifier".

Page 34, Section B.3, 1st paragraph, 2nd sentence: insert "including" before
"ITU-T".  Change "IEEE1901.2" to "IEEE 1901.2"

Page 34, Req3.2: change "Identifier" to "identifier".

Page 35, Section B.4, 2nd paragraph: change "Addresses" to "addresses".

Page 35, Req4.1: change "Address" to "address".

Page 35, Req4.2: delete the comma and insert "SHOULD" before "enable".

Page 35, Req4.3: change "in" to "on".

Page 35, Section B.5, 1st paragraph, 1st sentence: append a comma after "6LBR".

Page 35, Section B.5, 3rd paragraph, 2nd sentence: append a comma after
"joining".

Page 36, Req5.1: append a comma after "6LBR".

Page 36, Req5.3, 2nd sentence: append a comma after "DAR".

Page 36, Req5.9: change "Node" to "node".  Delete the comma after "owner".

Page 36, Section B.6: should "DODAG" be added to the glossary in Appendix C?

Page 37, Req6.2: change "and" to "or".

Page 37, Section B.7, 1st paragraph, 1st sentence: delete the extraneous space
before the colon.

Page 37, Section B.7, 2nd paragraph: change "he" to "the administrator". 
Change "his" to "the".

Page 37, Req7.1: I'm not a fan of "provided providing".  I don't have better
wording at the moment.

Page 37, Req7.2: change "n" to "in".

Page 37, Req7.3: change the first use of "information" to "Information". 
Change "the Address" to "the address".  Append a comma after "6LR".

Page 37, Req 74: append a period to the end of the requirement.

Page 39, Table 7: for entries that don't have a document listed, should there
be something?  Where did these requirements come from?

Page 39, LLN definition: change to "Low-Power and Lossy Network".