Terminology for Constrained-Node Networks
draft-ietf-lwig-terminology-07

[Ballot comment]
Thanks to the authors for a long road to addressing my Discuss.

I am left with one point that I will not hold the document on.

There is a statement that constrained nodes do not have the characteristics of network nodes to which we have become accustomed.
I see a distinction between "constraints" and "characteristics".
It is quite clear to me that a constraint might limit the behavior and that might remove a characteristic that we have previously been used to. But that does not mean they are the same thing.
Characteristics (I am guessing) would be things like "ability to process messages at line speed" or "ability to buffer messages" etc.
It would be really nice if the document gave a few examples of the characteristics that constrained nodes might not have.

[Ballot comment]
Thanks to th authors for a long road to addressing my Discuss.

I am left with one point that I will not hold the document on.

There is a statement that constrained nodes do not have the characteristics of network nodes to which we have become accustomed.
I see a distinction between "constraints" and "characteristics".
It is quite clear to me that a constraint might limit the behavior and that might remove a characteristic that we have previously been used to. But that does not mean they are the same thing.
Characteristics (I am guessing) would be things like "ability to process messages at line speed" or "ability to buffer messages" etc.
It would be really nice if the document gave a few examples of the characteristics that constrained nodes might not have.

[Ballot comment]

I'm abstaining because I think there's a missed opportunity
here to define terms that would last significantly longer
if they were not based on absolutes, which seems short
sighted to me.

write-up: I slightly dislike being told that "experts from
companies x, y & z" think something. Much better would be
to have been told that "Fred Bloggs, Joe Blow and
A.N.Other" read it and said on the list that they were ok
with it.  I've worked for large companies and some of our
company "experts" were not. And even if they were, they
were sometimes more intersted in achieving company goals
and not in objectively applying their expertise. (And just
in case, for a protocol spec, it would be fine to say that
company x have implemented since that's something one could
in principle check. So I'm not saying that write-ups ought
never mention comapanies.)

abstract: Devices years ago were arguably far more
constrained in some ways than the ones you mean here. The
tendency to forget what happened a decade or more ago is a
real one, and it'd be good if some lwig document reflected
that.  That's not really actionable, but if you wanted, you
could remove the first sentence of the abstract and still
be ok.

intro: all devices have limited CPU etc. (Except maybe some
in THHGTTG:-) That's not entirely a nit - all the
terminology here needs to be relative, and relative to what
we consider today's "standard candle" which could be a
typical laptop. If you re-cast the discussion here in to
only use relative terms, (except for examples) then perhaps
this terminology could be current for far longer?

intro: sigh. The Internet has always been made of things.
The IoT is of course a new marketing term, but doesn't
reflect any new reality really. And "becomes a reality" is
just pure marketing which'd be better omitted.

section 2: why is 5x10^10 an interesting number? That's
just 7 devices per person.

section 2: I don't understand the 2nd bullet at all. What
is it meant to say?

section 2: I disagree with the last sentence - there will
always be "constrained" nodes (relative to some standard
candle) and both the practical definition of constrained
and standard will move as technology develops. I don't see
how that *has to* to relate to scaling at all. (There are
relationships, but I don't think "scaling down" is
causitive.)

2.1: I assert that mentioning 2013 in the definition is a
mistake.

2.1: A definition that does not consider a smartphone a
constrained node seems wrong. Those are differently
constrained compared to a tension sensor, but both should
be considered constrained IMO. ("My problems are worse than
your problems" doesn't seem like a good basis for
terminology.)

2.1, bullet list: I would argue that you ought include
"constrained user interfaces" here. (A LED is a user
interface as is a factory-reset button, or even a
replacable battery arguably.)

2.1: bullet list: I think you're again making the mistake
of not being relative, e.g. "maximum node complexity" isn't
even really understandable (why's it a max? can't I just
add more? yes, I can!  but of course then its a different
device). Again the right approach (I claim:-) would be to
cast all this in relative terms.

2.1: batterys vs. harvesting is not a real dichotomy, afaik
almost all harvesting nodes have a battery or charge up a
capacitor. There are vanishingly few nodes with no energy
storage or accumulation mechanism and if they did become
popular I suspect they ought be a class of their own. Or am
I wrong there?

2.2: again 2013 in the definition is an error IMO.

2.2: constrained n/w definition also seems wrong in that
there are networks today that are high speed that fit this
definition e.g. fibre based networks doing quantum key
distribution.

2.2.1: I don't think this is really a useful section at
all, unless the goal is simply to say that DTN protocols
are out of scope, which they are, since all protocols are
out of scope. I'd say just delete this section (if you fix
the definitions).

2.3: Just to note that this defintion is fine!

2.3.x: again you seem to be just dealing with territory
here but I guess this could be useful

3 - I bet you some beers you live to regret using absolute
numbers here. I don't find this table that useful. The text
definitions saying what the nodes in various classes can
and cannot do however is good and should be used in the
definitions.

4.1 says you're not defining classes, but then 4.2 seems to
do exactly that, which I find confusing.

4.2: I'd suggest s/E3/Einf/ so you could introduce new
classes when you find out that E0..2 aren't sufficiently
descriptive of interesting classes of device. For example,
this section doesn't seem to consider duty-cycles which IMO
can siginifcantly influence designs and which also provide
a handy way to talk about device power requirements and
capabilities in a n/w.

- table 4: Sn as classes is a terrible choice since it
conflicts with existing sleep state terminology for ACPI.

- I agree with the secdir reviewer's suggestion [1] that
it'd be good to note the security characteristics of the
various classes defined (even if the current classes are
kept). A table could usefully do that. (The exercise of
generating that table might also help to see if the current
class definitions are meaningful.)

  [1] http://www.ietf.org/mail-archive/web/secdir/current/msg03964.html

[Ballot comment]
write-up: I slightly dislike being told that "experts from
companies x, y & z" think something. Much better would be
to have been told that "Fred Bloggs, Joe Blow and
A.N.Other" read it and said on the list that they were ok
with it.  I've worked for large companies and some of our
company "experts" were not. And even if they were, they
were sometimes more intersted in achieving company goals
and not in objectively applying their expertise. (And just
in case, for a protocol spec, it would be fine to say that
company x have implemented since that's something one could
in principle check. So I'm not saying that write-ups ought
never mention comapanies.)

abstract: Devices years ago were arguably far more
constrained in some ways than the ones you mean here. The
tendency to forget what happened a decade or more ago is a
real one, and it'd be good if some lwig document reflected
that.  That's not really actionable, but if you wanted, you
could remove the first sentence of the abstract and still
be ok.

intro: all devices have limited CPU etc. (Except maybe some
in THHGTTG:-) That's not entirely a nit - all the
terminology here needs to be relative, and relative to what
we consider today's "standard candle" which could be a
typical laptop. If you re-cast the discussion here in to
only use relative terms, (except for examples) then perhaps
this terminology could be current for far longer?

intro: sigh. The Internet has always been made of things.
The IoT is of course a new marketing term, but doesn't
reflect any new reality really. And "becomes a reality" is
just pure marketing which'd be better omitted.

section 2: why is 5x10^10 an interesting number? That's
just 7 devices per person.

section 2: I don't understand the 2nd bullet at all. What
is it meant to say?

section 2: I disagree with the last sentence - there will
always be "constrained" nodes (relative to some standard
candle) and both the practical definition of constrained
and standard will move as technology develops. I don't see
how that *has to* to relate to scaling at all. (There are
relationships, but I don't think "scaling down" is
causitive.)

2.1: I assert that mentioning 2013 in the definition is a
mistake.

2.1: A definition that does not consider a smartphone a
constrained node seems wrong. Those are differently
constrained compared to a tension sensor, but both should
be considered constrained IMO. ("My problems are worse than
your problems" doesn't seem like a good basis for
terminology.)

2.1, bullet list: I would argue that you ought include
"constrained user interfaces" here. (A LED is a user
interface as is a factory-reset button, or even a
replacable battery arguably.)

2.1: bullet list: I think you're again making the mistake
of not being relative, e.g. "maximum node complexity" isn't
even really understandable (why's it a max? can't I just
add more? yes, I can!  but of course then its a different
device). Again the right approach (I claim:-) would be to
cast all this in relative terms.

2.1: batterys vs. harvesting is not a real dichotomy, afaik
almost all harvesting nodes have a battery or charge up a
capacitor. There are vanishingly few nodes with no energy
storage or accumulation mechanism and if they did become
popular I suspect they ought be a class of their own. Or am
I wrong there?

2.2: again 2013 in the definition is an error IMO.

2.2: constrained n/w definition also seems wrong in that
there are networks today that are high speed that fit this
definition e.g. fibre based networks doing quantum key
distribution.

2.2.1: I don't think this is really a useful section at
all, unless the goal is simply to say that DTN protocols
are out of scope, which they are, since all protocols are
out of scope. I'd say just delete this section (if you fix
the definitions).

2.3: Just to note that this defintion is fine!

2.3.x: again you seem to be just dealing with territory
here but I guess this could be useful

3 - I bet you some beers you live to regret using absolute
numbers here. I don't find this table that useful. The text
definitions saying what the nodes in various classes can
and cannot do however is good and should be used in the
definitions.

4.1 says you're not defining classes, but then 4.2 seems to
do exactly that, which I find confusing.

4.2: I'd suggest s/E3/Einf/ so you could introduce new
classes when you find out that E0..2 aren't sufficiently
descriptive of interesting classes of device. For example,
this section doesn't seem to consider duty-cycles which IMO
can siginifcantly influence designs and which also provide
a handy way to talk about device power requirements and
capabilities in a n/w.

- table 4: Sn as classes is a terrible choice since it
conflicts with existing sleep state terminology for ACPI.

- I agree with the secdir reviewer's suggestion [1] that
it'd be good to note the security characteristics of the
various classes defined (even if the current classes are
kept). A table could usefully do that. (The exercise of
generating that table might also help to see if the current
class definitions are meaningful.)

  [1] http://www.ietf.org/mail-archive/web/secdir/current/msg03964.html

[Ballot discuss]

I have one discuss point, that I'll probably quickly clear
when told the wg could rather not, and then I'll move to
abstain. My discuss is:

I think we're missing an opportunity here to do much better
than this and could do so if this document were re-worked
with the goal of making the text be such that it would
likely still be useful in 5 years time. Would the WG like
to do that?

Assuming the answer will be "no, thanks" then I'll move to
an abstain since I think that's unfortunate, and very
little, but some, harm will ensue, in terms of confusion
when these terms are used in the not too distant future.

I'm happy discuss my comments of course, in any case, but
really handling many of them would only make sense if the
wg wanted to re-do this, so if I do end up abstaining,
it'll be entirely fine to pretty much ignore my comments:-)

[Ballot comment]

write-up: I slightly dislike being told that "experts from
companies x, y & z" think something. Much better would be
to have been told that "Fred Bloggs, Joe Blow and
A.N.Other" read it and said on the list that they were ok
with it.  I've worked for large companies and some of our
company "experts" were not. And even if they were, they
were sometimes more intersted in achieving company goals
and not in objectively applying their expertise. (And just
in case, for a protocol spec, it would be fine to say that
company x have implemented since that's something one could
in principle check. So I'm not saying that write-ups ought
never mention comapanies.)

abstract: Devices years ago were arguably far more
constrained in some ways than the ones you mean here. The
tendency to forget what happened a decade or more ago is a
real one, and it'd be good if some lwig document reflected
that.  That's not really actionable, but if you wanted, you
could remove the first sentence of the abstract and still
be ok.

intro: all devices have limited CPU etc. (Except maybe some
in THHGTTG:-) That's not entirely a nit - all the
terminology here needs to be relative, and relative to what
we consider today's "standard candle" which could be a
typical laptop. If you re-cast the discussion here in to
only use relative terms, (except for examples) then perhaps
this terminology could be current for far longer?

intro: sigh. The Internet has always been made of things.
The IoT is of course a new marketing term, but doesn't
reflect any new reality really. And "becomes a reality" is
just pure marketing which'd be better omitted.

section 2: why is 5x10^10 an interesting number? That's
just 7 devices per person.

section 2: I don't understand the 2nd bullet at all. What
is it meant to say?

section 2: I disagree with the last sentence - there will
always be "constrained" nodes (relative to some standard
candle) and both the practical definition of constrained
and standard will move as technology develops. I don't see
how that *has to* to relate to scaling at all. (There are
relationships, but I don't think "scaling down" is
causitive.)

2.1: I assert that mentioning 2013 in the definition is a
mistake.

2.1: A definition that does not consider a smartphone a
constrained node seems wrong. Those are differently
constrained compared to a tension sensor, but both should
be considered constrained IMO. ("My problems are worse than
your problems" doesn't seem like a good basis for
terminology.)

2.1, bullet list: I would argue that you ought include
"constrained user interfaces" here. (A LED is a user
interface as is a factory-reset button, or even a
replacable battery arguably.)

2.1: bullet list: I think you're again making the mistake
of not being relative, e.g. "maximum node complexity" isn't
even really understandable (why's it a max? can't I just
add more? yes, I can!  but of course then its a different
device). Again the right approach (I claim:-) would be to
cast all this in relative terms.

2.1: batterys vs. harvesting is not a real dichotomy, afaik
almost all harvesting nodes have a battery or charge up a
capacitor. There are vanishingly few nodes with no energy
storage or accumulation mechanism and if they did become
popular I suspect they ought be a class of their own. Or am
I wrong there?

2.2: again 2013 in the definition is an error IMO.

2.2: constrained n/w definition also seems wrong in that
there are networks today that are high speed that fit this
definition e.g. fibre based networks doing quantum key
distribution.

2.2.1: I don't think this is really a useful section at
all, unless the goal is simply to say that DTN protocols
are out of scope, which they are, since all protocols are
out of scope. I'd say just delete this section (if you fix
the definitions).

2.3: Just to note that this defintion is fine!

2.3.x: again you seem to be just dealing with territory
here but I guess this could be useful

3 - I bet you some beers you live to regret using absolute
numbers here. I don't find this table that useful. The text
definitions saying what the nodes in various classes can
and cannot do however is good and should be used in the
definitions.

4.1 says you're not defining classes, but then 4.2 seems to
do exactly that, which I find confusing.

4.2: I'd suggest s/E3/Einf/ so you could introduce new
classes when you find out that E0..2 aren't sufficiently
descriptive of interesting classes of device. For example,
this section doesn't seem to consider duty-cycles which IMO
can siginifcantly influence designs and which also provide
a handy way to talk about device power requirements and
capabilities in a n/w.

- table 4: Sn as classes is a terrible choice since it
conflicts with existing sleep state terminology for ACPI.

- I agree with the secdir reviewer's suggestion [1] that
it'd be good to note the security characteristics of the
various classes defined (even if the current classes are
kept). A table could usefully do that. (The exercise of
generating that table might also help to see if the current
class definitions are meaningful.)

  [1] http://www.ietf.org/mail-archive/web/secdir/current/msg03964.html

[Ballot comment]
  Maybe the term is
  best read as "Low-Power Wireless Area Networks" (LoWPANs) [WEI].

This doesn't actually make sense—why does "area" belong in this sentence, given that no statement as to the size of the area is given?  I would suggest deleting this sentence.

In Table 1, are the column's or'd or anded?  That is, for example, is a C0 device a device that either has <<10k of RAM or <<100k of code?  Or a device that has both <<10k or RAM _and_ <<100k of code?  Is a device with 10k of RAM and 10k of code a C0 or a C1 device?

In Table 3, "mains powered" is a regional name, which likely will not be understood by all readers.  I notice that "mains power" is used elsewhere in the document; it might be good to define it somewhere.  I realize that this may sound very nit-picky, but you never know who is going to be reading the document.  I think it would be obvious to me in context, even if I hadn't heard the term before, what the term means, but I am unsure enough that it would be obvious to any reader that I think it's worth defining the term.

Other than that, the document looks good.  I think a lot of IETFers could benefit from reading this document, because these terms have been coming up in conversation quite a bit recently.  For example, I heard "LLN" a lot long before I learned what it stood for, and I have since used it on people who responded by saying "what's an LLN."  :)

[Ballot comment]
mostly this is an observation, I am however curious how this is addressed?

I have a lot of trouble with section 2 discussion of scaling... imho there are no problems associated with scaling the internet to 50 billion devices that are actually addressed or described in this document.

As a network operator I don't see the considerations for hosts to be dramatically different with merely an order  of magnitude more devices then we have at present.

another observation

section 2.2

network technologies associated associated with limited resource devices exist today, whether these are cdma schemes running on rs485, 802.15.4, ongoing work in 802.11ah, bluetooth 4.0 low energy and so on.  while these technologies will be more present in the future then they are today some aren't that rare (zigbee in particular) and that seems like an odd thing to omit from that particular dicussion, only to be mentioned later in other places.

[Ballot comment]
mostly this is an observation, I am however curious how this is addressed?

I have a lot of trouble with section 2 discussion of scaling... imho there are no problems associated with scaling the internet to 50 billion devices that are actually addressed or described in this document.

As a network operator I don't see the considerations for hosts to be dramatically different with merely an order  of magnitude more devices then we have at present.

another observation

section 2.2

network technologies associated associated with limited resource devices exist today, whether these are cdma schemes running on rs485, 802.15.4, ongoing work in 802.11ah, bluetooth 4.0 low energy and so on.  while these technologies will be more present in the future then they are today some aren't that rare (zigbee in particular) and that seems like an odd thing to omit from that particular dicussion, only to be mentione dlate in otehr places.

[Ballot comment]
mostly this is an observation, I am however curious how this is addressed?

I have a lot of trouble with section 2 discussion of scaling... imho there are no problems associated with scaling the internet to 50 billion devices that are actually addressed or described in this document.

As a network operator I don't see the considerations for hosts to be dramatically different with merely an order  of magnitude more devices then we have at present.

another observation

section 2.2

network technologies associated associated with limited resource devices exist today, whether these are cdma schemes running on rs485, 802.15.4, ongoing work in 802.11ah, bluetooth 4.0 low energy and so on.  while these technologies will be more present in the future then they are today some aren't that rare (zigbee in particular) and that seems like an odd thing to omit.

[Ballot discuss]
I have struggled hard in my review of this document, and Brian
Habermann has helped me a lot with understanding the value and
purpose of the work.  In my Discuss, below, I have tried to list
actionable work that I feel is necessary for the publication of
this document as a definition of terminology, and I have pushed
out to my Comment other issues that I think would be good to fix
but which are not blocking.

Before reading and attempting to resolve the Discuss issues, the
authors might like to consider whether this document could be re-
positioned as "A Discussion of Some Concept in Constrained Networks".
I believe that this re-branding complete with a few minor tweaks to
the text to be consistent would pretty much defuse most of my
Discuss comments (except, perhaps some on the Abstract and Section
2.3.1).

---

The Abstract is confusing in that it introduces a "small device with
severe constraints" and uses it to define a "constrained node network",
but never says what a "constraint" is. It then goes on to use the term
"constrained environment" without explaining what this means.

I think that the Abstract could give several examples of constraint for
a node (memory, CPU, power). It could also replace "constrained
environment" (which is not used in the rest of the document - except in
a similar paragraph in the Introduction) with "constrained network"
together with a mention that links may also be constrained, and some
examples of link constraints.

---

Section 2.1

I agree that the definition of Constrained Node "is less than
satisfying."  Indeed, I think that the definition you provide is useless
as a definition.

I find it odd that the definition includes the reasons why the node is
different, but not a list of the ways it might be different.

      some of the characteristics that are
      otherwise pretty much taken for granted for Internet nodes in 2013

...is so vague and unscoped. Of course, the text that follows does
list some of the constraints and these are helpful to an understanding
of the definition.

Probably the best way to handle this is to turn the whole section into
prose and dispense with the formal definition that isn't.

The same problem exists in Section 2.2.

[These concerns are consistent with my suggestion to back away from
providing definitions, and to offer a discussion of concepts instead.]

---

Section 2.3.1 is full of issues.

  In common usage, LLN often stands for "the network characteristics
  that RPL has been designed for".

Asides from being cryptic (or possibly sarcastic), that definition is so
clearly circular as to be of no value. You could, instead stop after the
quote from draft-ietf-roll-terminology.

Also, please expand RPL and give a reference.

  LLNs do appear to have significant loss at the
  physical layer

How do you mean "appear"? Do they or don't they?

  Actual "low power" does not seem to be
  required for an LLN [I-D.hui-vasseur-roll-rpl-deployment], and the
  positions on scaling of LLNs appear to vary widely
  [I-D.clausen-lln-rpl-experiences].

Again "seem to be". If you cannot provide a definition in this document
then probably best to not try.

The reference to [I-D.clausen-lln-rpl-experiences] in the discussion of
scaling LLNs is curious.  That document talks about experiences trying
to scale RPL. It does not, as far as I can tell, discuss the size or
scalability of a LLN.

  The ROLL terminology document states that LLNs typically are composed
  of constrained nodes; this is also supported by the design of
  operation modes such as RPL's "non-storing mode".  So, in the
  terminology of the present document, an LLN seems to be a constrained
  node network with certain network characteristics, which include
  constraints on the network as well.

What do you mean "is also supported by"? Are you saying that the
composition of a network is defined by the widgits built into a protocol
that runs over it?

What do you mean "an LLN seems to be..." Can you not write a clear
definition?

---

Section 2.3.2

I don't see a definition in this section of either LoWPAN or 6LoWPAN. I
only find a discussion of the expansion of the acronym.

[Again, if the document is not seeking or claiming to provide
definitions this is not a problem.]

---

In Section 3, the description of a Class 0 node seems to be prejudging
the work of LWIG. It is mixing what the physical capabilities of the
node are (memory, CPU, power) with what the node will be capable of
doing (using security).  That is surely interesting and equally surely
not part of the definition of the node class.

Similar issues apply to the discussion of Class 1 and Class 2 nodes.

[Yet again, if you are not defining but only discussing then this
issue is much less pronounced.]

---

Section 5 is missing some thoughts about the availability of security
mechanisms in constrained devices. Since these are mentioned in Section
3, you can't duck them in Section 5.

[Ballot comment]
In pulling terms and ideas from non-consensus documents, this document
assigns the terms more weight than they actually have. For example, in
2.3.2...

  Originally focused on IEEE 802.15.4, "LoWPAN" (or when used for IPv6,
  "6LoWPAN") is now also being used for networks built from similarly
  constrained link layer technologies [I-D.ietf-6lowpan-btle]
  [I-D.mariager-6lowpan-v6over-dect-ule] [I-D.brandt-6man-lowpanz].

...is undoubtedly correct, but implies that there is acceptance of this
use of the term.

I don't believe this document is supposed to be a survey of the way terms
are used in works in progress, but is supposed to be a set of
definitions to help future work.

This can be handled by a small change in wording so that "is now also
being used for" is replaced with "also refers to".

---

Section 1

  Small devices with limited CPU, memory, and power resources, so
  called constrained devices (also known as sensor, smart object, or
  smart device) can constitute a network, becoming "constrained nodes"
  in that network.  Such a network may itself exhibit constraints, e.g.
  with unreliable or lossy channels, limited and unpredictable
  bandwidth, and a highly dynamic topology.

I question "also known as..." A sensor, smart object, or smart device
does not need to be constrained. A constrained device does not need to
be a sensor, smart object, or smart device. It might be reasonable to
say that "...many sensors, smart objects, and smart devices are
constrained devices..."

I think "constitute a network" is wrong. These constrained nodes may be
included in a network, but do they constitute the network?

Are the elements of constrained connectivity between nodes (nodes which
may or may not themselves be constrained nodes) relevant to the work of
LWIG? It is possible that the behavior of the data channels has an
impact on the code and buffering needed in a node. If so, perhaps this
could be drawn out more in the Introduction.

---

Section 2 might be better named "Core Terminology" otherwise we wonder
why other sections are not just subsections of section 2.

---

I don't like "this field of work" (which field?) and "appears to be"
(appears to whom?) in Section 2. Maybe you could give:

  There are two important aspects to scaling within the IoT:

BTW, is underbar _really_ necessary?

---

Section 4.1

  Instead of defining classes or clusters, we propose simply stating,
  in SI units, an approximate value for one or both of the quantities
  listed in Table 2:

You "propose"? You have moved beyond that. Now you "do".

---

I am surprised that Ps is a useful measure. In my experience devices
often operate power availability on a curve (usually a series of steps)
as a function of remaining energy in the store. Thus devices that are
running short of energy reduce the available power to try to eke out
what is left.  That would, of course, make the average an ambiguous
measure.

---

Section 4.3

I was amused by he term "Always Off". "Always" as in "except for the
exceptions"? :-)

---

In section 4.3 it would be useful to align with (or at least mention)
the terms "sleepy node" and "non-sleepy node" as presented in
draft-ietf-roll-terminology.

[Ballot comment]
Thanks for writing this useful document. A couple of comments that you may consider:

1) In my experience, power/memory/cpu are important considerations, but equally often user interface and deployment considerations are the cause of even more constraints or challenges. E.g., ability to set keys, update software, etc. Perhaps these kinds of limitations could be listed as well.

2) I agree with other ADs that tying the definitions to 2013 state of the world may not be useful.

3) I found the below comments from Suresh Krishnan's Gen-ART review useful. In particular, I'd not limit constrained devices to sensors.

---

I have been selected as the General Area Review Team (Gen-ART)
reviewer for this draft (for background on Gen-ART, please see
http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html).

Please wait for direction from your document shepherd
or AD before posting a new version of the draft.

Document: draft-ietf-lwig-terminology-05.txt
Reviewer: Suresh Krishnan
Review Date: 2013/08/12
IESG Telechat date: 2013/08/15

Summary: This draft is ready for publication as an Informational RFC but
I do have a few comments that the authors may wish to consider.

Minor
=====

* Section 1

Aren't actuators also one class of constrained devices? The section
talks about gathering information but does not talk about constrained
devices acting on information.

* Section 2.1

When speaking about the multiple facets of constraints on the nodes
shouldn't processing power be included as well? There is an item for
power but it is unclear if that means energy/power or processing power.
In either case one of them probably needs to be added.

* Section 2.2

Would it be worth mentioning the asymmetric nature of some of these link
as a constraint?

* Section 2.3.1

This sentence does not read right. Suggest rewording.

OLD:
In its terminology document, the ROLL working group is saying
[I-D.ietf-roll-terminology]:

NEW:
The ROLL terminology document [I-D.ietf-roll-terminology] defines LLNs
as follows:


* Section 3

Please add a reference to the CoAP draft at first use of CoAP.


* Section 4.3

Should this section also talk a bit about the term "duty cycle" since
this term is used frequently in the constrained device context?

Thanks
Suresh

[Ballot comment]
I'm a Yes, and think this document is in good shape and worth publishing at version -05.

That said, I am sensitive to Barry's point about "constrained" not being the same as "constrained in 2013".

If I wasn't looking at this document for the first time at the end of the process, I probably would have asked how useful Table 1 really is, because what matters isn't whether you have 100 KiB of flash memory, it's what you have enough flash memory to do. So, not based on physical characteristics, but on functional characteristics - and the distinctions based on functional characteristics are well-described in the paragraphs that follow Table 1.

What I was thinking, was more like "there are three classes of devices, and you know you have a Class 0 device when it's too constrained to communicate directly with the Internet  ..."

But unless people think that's helpful ... ship it.

[Ballot comment]
Do we really want to tie the general definitions of "constrained [thing]" (in Sections 2.1 and 2.2) to 2013?  I wouldn't think so.  It makes sense to say that the numbers in Table 1 represent constraint levels in 2013, but whether something is a constrained node or not should be relative to when the evaluation is being made, not relative to 2013, no?

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-lwig-terminology-04, which is currently
in Last Call, and has the following comments:

We understand that, upon approval of this document, there are no IANA
Actions that need completion.

If this assessment is not accurate, please respond as soon as possible.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Terminology for Constrained Node Networks) to Informational RFC


The IESG has received a request from the Light-Weight Implementation
Guidance WG (lwig) to consider the following document:
- 'Terminology for Constrained Node Networks'
  as Informational RFC

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2013-06-05. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  The Internet Protocol Suite is increasingly used on small devices
  with severe constraints, creating constrained node networks.  This
  document provides a number of basic terms that have turned out to be
  useful in the standardization work for constrained environments.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-lwig-terminology/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-lwig-terminology/ballot/


No IPR declarations have been submitted directly on this I-D.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

Informational. The document supplies terminology and is not a protocol specification.

(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

  The Internet Protocol Suite is increasingly used on small devices
  with severe constraints, creating constrained node networks.  This
  document provides a number of basic terms that have turned out to be
  useful in the standardization work for constrained environments.
 
Working Group Summary

  The document originally was extracted as a stable part of the LWIG guidance document that
the WG considered to be immediately useful.  After extraction, additional terminology was
added on energy/power availability and usage.  This document was finished collectively by a
number of people who worked in the constrained network area.  The WGLC was conducted on
April 7 for two weeks. Five supports have been expressed on the mailing list, with positive
discussion. 

Document Quality

  Are there existing implementations of the protocol? Have a
  significant number of vendors indicated their plan to
  implement the specification? Are there any reviewers that
  merit special mention as having done a thorough review,
  e.g., one that resulted in important changes or a
  conclusion that the document had no substantive issues? If
  there was a MIB Doctor, Media Type or other expert review,
  what was its course (briefly)? In the case of a Media Type
  review, on what date was the request posted?
 
  This is a document that summarizes the terminologies that has been and will be used for
people and groups that are working on constrained networks. This is generally considered to be a
useful document for people to refer when they would like to find the definition of certain terms. 
Experts from Philips, Orange, Ericsson reviewed the document, from the time when it still was an
individual document. Several wording details in the draft before the WGLC had been discussed
and the draft was updated to incorporate these changes. 


Personnel

  Who is the Document Shepherd? Who is the Responsible Area
  Director?
 
  Zhen Cao (caozhen@chinamobile.com) is the Document Shepherd.
  Brian Haberman is the Responsible AD.

(3) Briefly describe the review of this document that was performed by
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The document shepherd reviewed the draft before its adoption as an IETF work. Three aspects
were reviewed. First, the definitions and descriptions of the terminologies, for example,
constrained networks and constrained node networks. Second, the classifications of different
types of contrained devices, this section has reflected the discussion on the mailing list and now
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(4) Does the document Shepherd have any concerns about the depth or
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NONE.
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YES. ALL are INFORMATIVE.

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NO.

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If so, list these downward references to support the Area Director in
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(16) Will publication of this document change the status of any
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