Last Call Review of draft-ietf-ntp-packet-timestamps-07
review-ietf-ntp-packet-timestamps-07-genart-lc-housley-2020-02-07-00

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Document: draft-ietf-ntp-packet-timestamps-07
Reviewer: Russ Housley
Review Date: 2020-02-07
IETF LC End Date: 2020-02-20
IESG Telechat date: Unknown


Summary: Almost Ready

Major Concerns: None


Minor Concerns:

Abstract: It is too long.  In my opinion, the second paragraph should
be moved to the Introduction.


Section 2.1: Please use:

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.


Section 2.3, paragraph 1: I think it would be better to define timestamp
error without using the phrase "device under test".  If you disagree,
please add a definition for "device under test".


Section 3, Synchronization aspects: The paragraph should also say that
there might not be any synchronization considerations.  For example, an
epoch since the device was powered up does not have any.


Section 9:  Please say "such as Message Authentication Codes (MAC)".
HMAC is one instance of a MAC, and you are not trying to name a specific
algorithm here.


Section 11.2:  RFC 1323 has been obsoleted by RFC 7323.  Is there a
reason that it is better ot reference the older document here?


Nits:

General: Some places this Internet-Draft refers to itself as "this memo"
and other places if refers to itself as "this document".  Please pick.


Section 1, paragraph 1: Nonces often have a timestamp embedded in them.
For example, TLS 1.2 [RFC5246] defined the nonce as:

         struct {
             uint32 gmt_unix_time;
             opaque random_bytes[28];
         } Random;

So, I think the paragraph should include something about using time to
create an unlikely to repeat value.


Section 3: I do not find the "+" improves readability.


Section 3 says:

      The structure of the timestamp field consists of:

      + Size: The number of bits (or octets) used to represent the
      packet timestamp field.  If the timestamp is comprised of more
      than one field, the size of each field is specified.

Since there is only one item, I suggest:

      Size: The structure of the timestamp field consists of the number
      of bits (or octets) used to represent the packet timestamp field.
      If the timestamp is comprised of more than one field, the size of
      each field is specified.


Questions:

Should RFC 6019 be included in the table in Section 6?