[Dots] Alissa Cooper's Discuss on draft-ietf-dots-signal-channel-31: (with DISCUSS and COMMENT)

[Alissa Cooper via Datatracker <[e-mail]>]

Alissa Cooper has entered the following ballot position for
draft-ietf-dots-signal-channel-31: Discuss

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DISCUSS:
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= Section 3 =

"By default, a DOTS signal channel MUST run over port number TBD as
   defined in Section 9.1, for both UDP and TCP, unless the DOTS server
   has a mutual agreement with its DOTS clients to use a different port
   number.  DOTS clients MAY alternatively support means to dynamically
   discover the ports used by their DOTS servers (e.g.,
   [I-D.boucadair-dots-server-discovery])."

MUST implies an absolute requirement, so "MUST ... unless" is a problematic
construction. Furthermore, it doesn't make sense together with "MAY
alternatively," which indicates that port number discovery is an alternative to
the fixed to-be-assigned port.

I didn't have time to get very far into draft-boucadair-dots-server-discovery,
but it appears that it does not mandate support for any single discovery
mechanism for clients and servers to support. If so, that "alternatively" seems
like more of a problem, since it allows for there to be no interoperable
mechanism for clients to discover server ports. I think maybe what was intended
here was:

s/MUST/SHOULD/
s/MAY alternatively/MAY additionally/

= Section 4.4.1 =

(1)
"In deployments where server-domain DOTS gateways are enabled,
   identity information about the origin source client domain SHOULD be
   propagated to the DOTS server.  That information is meant to assist
   the DOTS server to enforce some policies such as grouping DOTS
   clients that belong to the same DOTS domain, limiting the number of
   DOTS requests, and identifying the mitigation scope.  These policies
   can be enforced per-client, per-client domain, or both.  Also, the
   identity information may be used for auditing and debugging purposes."

Does "identity information" just refer to cdid, or something else?

(2) The constructions "MUST ... (absent explicit policy/configuration
otherwise)" are problematic. I'm assuming these are meant to be SHOULDs.

= Section 13.1 =

I don't understand why RFC 7951 is a normative reference but
draft-ietf-core-yang-cbor is an informative reference.


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COMMENT:
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= Section 4.4.1 =

"The 'cuid' is intended to be stable when communicating with a
      given DOTS server, i.e., the 'cuid' used by a DOTS client SHOULD
      NOT change over time. "

Why is this the recommended behavior?