[core] RFC7252 - 5.4.1 Critical/Elective

[Achim Kraus <[e-mail]>]

Hi list,

I have some detail questions about:

RFC7252 - 5.4.1 Critical/Elective

Point 3:

 > Unrecognized options of class "critical" that occur in a
 > Confirmable response, or piggybacked in an Acknowledgement, MUST
 > cause the response to be rejected (Section 4.2).

"or piggybacked" "MUST" "rejected"

I have my doubts about rejecting a ACK. Is that really intended?
In my opinion, that violates the usual message sequences.

Point 2 and 4:

 > Unrecognized options of class "critical" that occur in a
 > Confirmable request MUST cause the return of a 4.02 (Bad Option)
 > response. This response SHOULD include a diagnostic payload
 > describing the unrecognized option(s) (see Section 5.5.2).

 > Unrecognized options of class "critical" that occur in a Non-
 > confirmable message MUST cause the message to be rejected
 > (Section 4.3).

My interpretation:
Point 2 addresses CON requests
Point 4 NON messages

A NON request would therefore match point 4. But why should the outcome
(response 4.02 or rejected) depend on the message type CON/NON?
Was there a reason for that? Or is my interpretation wrong?

best regards
Achim