[Anima] Genart last call review of draft-ietf-anima-constrained-join-proxy-09

[Ines Robles via Datatracker <[e-mail]>]

Reviewer: Ines Robles
Review result: On the Right Track

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 treat these comments just
like any other last call comments.

For more information, please see the FAQ at

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

Document: draft-ietf-anima-constrained-join-proxy-09
Reviewer: Ines Robles
Review Date: 2022-04-08
IETF LC End Date: 2022-04-08
IESG Telechat date: Not scheduled for a telechat

Summary:

The document defines a mechanism to assign a Device (Pledge) to a (anima)
domain, represented by a Registrar, using an intermediate node (e.g. 6LR)
called constrained Joint Proxy.  Once that the Pledge is enrolled to the
network, it can take the role of a Joint Proxy.

I understand that the document is going currently under modifications, new text
is being proposed into the Mailing List (e.g. updates on section 4, etc.), and
the open issues are being tracked into github
[https://github.com/anima-wg/constrained-join-proxy/issues/]

Additional Comments/Questions:

1- Which are the differences between a "Circuit-proxy" and a "stateful
constrained join Proxy"? I understand that both are stateful join proxy
entities, right? (Maybe the difference is in the constrained level?). In the
abstract states that they replace each other. Maybe a better description could
be: "instead of having only stateful join proxy (Circuit-proxy) mode, this spec
also include the stateless join proxy mode", is this correct?

2- Terminology Section:

2.1- It mentions JCR, but in the text is used "Registrar", thus, it could be
mentioned here that both refers to the same. 2.2- Other terms such as TOFU,
MASA and imprint  are never used through the document [Maybe it should be
described (in SEC. section?) how these terms are related in this document (if
applicable)]. 2.3- Additionally, it would be nice to include the definition of
the: a) "constrained Joint Proxy" [smth similar what RFC9030 defines?]; b)
"Stateful and Stateless mode" (the text from the introduction could be moved to
this section); c) circuit-proxy (refer to RFC8995?)

3- What happens when a joint-proxy restart in a stateful mode during a joining
message flow?

4- Just for better understanding: E.g. If a Pledge participates in two
different use cases, meaning two different domains, then is it possible that
the Pledge become Stateful and Stateless Join Proxy (in different domains)?. I
understand that this is possible, but not useful, since the device will include
the specification complexity of both modes. Thus, I could think that it is
recommended to select the same mode for all the domains that a device join?
This could be a decision point whether to become or not a joint proxy?
(Although, at the end of the day it could be defined by the use case
requirements/available network resources).

5- Section 5, Page 6: "..A Join Proxy MAY implement both, with an unspecified
mechanism to switch between the two modes." I understand that it refers to one
single domain, I do not understand the meaning of "unspecified mechanism".
Maybe it should read: "the mechanism to switch between modes is not in the
scope of this document" ?

6- Section 5.1, Page 6: "...The Join Proxy maintains a 4-tuple array to
translate the DTLS messages received from the Registrar and forwards it back to
the
   Pledge..."  Translate the DTLS message to what? Please clarify.

7- Page 11: I understand that when the Pledge is one hop from the Registrar, it
does not need the join proxy, right?

Nit (Pag. 11): "...Step 2 in implementation dependent..." -> "...Step 2 is
implementation dependent..."

Thanks for this document,

Ines.