End-to-End Session Identification in IP-Based Multimedia Communication Networks
draft-ietf-insipid-session-id-27

Thanks for addressing my DISCUSS, leaving my comments below for posterity.

== General ==

I do not think RFC 7206 needs to be a normative reference, but I'm also fine with the downref.

== Section 6 ==

"It should be noted that messages received by an endpoint might
   contain a "local-uuid" value that does not match what the endpoint
   expected its peer's UUID to be.  It is also possible for an endpoint
   to receive a "remote-uuid" value that does not match its generated
   UUID for the session.  Either might happen as a result of service
   interactions by intermediaries and MUST NOT affect the communication
   session."

The MUST NOT at the end there is vague and also seems a bit contradictory to the statement in Section 4.2 that "How a device acting on Session Identifiers processes or utilizes the Session Identifier is outside the scope of this document." Could you clarify what the intent of the last sentence is, and how it squares with the idea that actions taken (or not taken) based on session identifiers are not being specified here?

== Section 7 ==

"The Session-ID header field value included in a CANCEL request MUST
   be identical to the Session-ID header field value included in the
   corresponding request."

Does "corresponding request" mean original request, as in Section 6? I think it would be clearer if the text said "original INVITE request" both here and in Section 6.

== Section 11 ==

'altering the nil "remote-uuid"' seems like it could be phrased less awkwardly.

"Standard implementations SHOULD NOT expect pre-standard implementations to be consistent in their implementation" -- I don't think this needs normative language.

== Section 12 ==

I think the note about billing purposes is outside the scope of the document and should be removed. Or if not, it needs further motivation -- if someone wanted to bill based on the number of sessions a UA initiated, why would using the session identifier be an inappropriate way of counting those?

The IESG discussed the downref issue in the telechat. The consensus is to allow the downref.

I'm a Yes, anticipating that Alissa's Discuss and Suresh's Discuss are resolved, and I appreciate the effort required to produce this specification. It meets an important need.