Low-Power Wide Area Network (LPWAN) Overview
draft-ietf-lpwan-overview-10

Overall I liked this document -- I do however have some suggestions/nits which I think would improve the document.

1: I think it would be helpful to explain in the introduction how an LPWAN is different (other than the obvious "it's bigger") than a low power LAN / PAN -- after reading the document I'm still not quite sure if there is a fundamental difference.

2: A few examples of the sorts of devices that might be LPWAN devices would be helpful as well - this document is an overview - this means that many of the readers will be unfamiliar with the concepts; I ended up searching for some of the technologies discussed and found things like railway track monitors and parking sensors, and having these sorts of things as example devices helped me understand why the technologies are useful.

Nits:
1: Section 2.1.2: 
O:   o  - Join Server: The Join Server (JS) is a server on the Internet 
C: stray '-'

O: o  Uplink message: refers to communications from end-device to
      network server or application via one or more gateways.
C: I think 'from an end-device' (or possibly 'end-devices') - same for server, etc.

O:  o  Downlink message: refers to communications from network server or
C: Same as above.


I found Section 2.2 much harder to read - the document says that it assumes familiarity with numerous 3GPP terms -- perhaps if I were familiar with there it would have made more sense, but I basically just skipped over it.

Section 2.3. SIGFOX
   Text here is largely from [I-D.zuniga-lpwan-sigfox-system-description] which may have been updated since this was published.

A comma after the bracket, or putting the "which may..." would improve readability. (Hey, I did say these were nits!).

Section 2.4.2.  Characteristics
O: o  Coverage The range of 
C: Missing colon after "Coverage".

What's the relation of this document to draft-ietf-lwig-energy-efficient-08?

Some minor, mostly editorial comments:

1) While this document provides a good overview, I find section 2 more extensive than needed for the gap analysis; on the other hand section 2.2 (NB-IoT) does not really talk about security functions/encryption while the other sections do that.

2) "Text here is largely from [I-D.farrell-lpwan-lora-overview]" and " Text here is largely from [I-D.ratilainen-lpwan-nb-iot]" and so one
I would suggest to remove these sentences with references to expired drafts (given the contributions are listed in sec 7 again).

3) In sec 2.2.2 there is this fragment that can potentially be removed: "User plane protocol stack"

4) Section 2.4.2: "The Transport service is based on User Datagram Protocol (UDP)
   defined in RFC768 or Transmission Control Protocol (TCP) defined in
   RFC793."
  Does this mean one can only use UDP or TCP over IPv6 over 6LoWPAN over FAN but no other transport protocols? I assume that's not the case and would recommend to just remove this sentence (and the reference in the table).

5) Seems slightly weird to me that TLS is mentioned in a section called "4.1.  Naive application of IPv6"

6) I guess another challenge regarding security might be to update/upgrade such devices over a low bandwidth network, but that might a topic on its own...