Last Call Review of draft-ietf-dnsop-session-signal-10
review-ietf-dnsop-session-signal-10-genart-lc-halpern-2018-06-15-00

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Document: draft-ietf-dnsop-session-signal-10
Reviewer: Joel Halpern
Review Date: 2018-06-15
IETF LC End Date: 2018-06-25
IESG Telechat date: Not scheduled for a telechat

Summary: This document is ready for publication as a Proposed Standard.
    Also, the document is well-written and clear.

Major issues:

Minor issues:
    Section 5.1.3 places some requirements on application level middleboxes,
    and includes a very clear explanation of why it places these requirements. 
    While it may be "obvious" to one who lives and breathes DNS, I think it
    would help to explain why the usual operation of an existing middlebox will
    (typically? always?  inherently?) meet this requirement.

    The third and fourth paragraphs of section 5.2.2 do not talk about optional
    additional TLVs.  It would be helpful if the document stated that in
    addition to those additional TLVs required by the primary TLV, other TLVs
    may be included based on their individual definition, independent of the
    definition of the primary TLV.  (Both the Encryption padding and the delay
    retry TLVs may be included in suitable messages without being called out in
    the definition of the primary TLVs.)

Nits/editorial comments:
    Section 5.4 talks about by default the TCP data ack and the DSO reply
    message being combined.  Doesn't this depend upon the responsiveness of the
    DSO engine?  Is there an implicit assumption about such timeliness (sub 200
    ms)?

    In section 7.1, the description of the Keepalive message seems to be
    missing the explicit sentence that a keepalive response MUST contain a
    Keepalive TLV.  I realize this is implicit in much of the description, but
    it seems a good practice to be clear about the requriement, and we should
    establish that practice in this document.  (This would seem to belong in
    the next-to-last paragraph of section 7.1.)