Reviewer: Zitao Wang (Michael) Review result: Has Nits I have reviewed this document as part of the Operational directorate’s ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. Document reviewed: draft-weis-gdoi-rekey-ack-05 Summary: The Group Domain of Interpretation (GDOI) includes the ability for a Group Controller/Key Server (GCKS) to provide a set of current Group Member (GM) devices with additional security associations (e.g., to rekey expiring security associations). This memo adds the ability of a GCKS to request the GM devices to return an acknowledgement of receipt of its rekey message, and specifies the acknowledgement method. I think the document make sense and is written very clear, except some small nits: Page 2: The second paragraph of introduction-- “A GDOI GCKS uses a GROUPKEY-PUSH message to alert...”. I suggest adding a reference that the reader can easy refer to this message. Page 7: 3.1 HDR -- "Next Payload identifies a Hash payload (8)." I suggest mollifying (8) to (value 8), and adding a reference like "section 5 of [rfc6407]" Page 10: “A GM MAY introduce a jitter to the timing of its Acknowledgement message to help the GCKS better manage replies from group members. The jitter SHOULD be no more than a few seconds.” How to measure this jitter? How to know if the 'jitter' satisfy the requirement? A run of idnits revealed there were 1 error, 1 warning and 2 comments: == Outdated reference: draft-weis-gdoi-iec62351-9 has been published as RFC 8052 ** Obsolete normative reference: RFC 5226 -- Obsolete informational reference (is this intentional?): RFC 2408 (Obsoleted by RFC 4306) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 2 comments (--).