Subject: [ippm] Martin Vigoureux's No Objection on draft-ietf-ippm-stamp-07: (with COMMENT)

From: Martin Vigoureux via Datatracker <[email-masked]>
Date: Thu, 05 Sep 2019 07:05:16 -0700

Martin Vigoureux has entered the following ballot position for
draft-ietf-ippm-stamp-07: No Objection

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COMMENT:
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I support Barry's DISCUSS.

Also a few points are not clear:

   o  Stateless - STAMP Session-Reflector does not maintain test state
      and will reflect the received sequence number without
      modification.
This is not the only thing that the reflector reflects, right?

      The STAMP Session-Sender and Session-Reflector MAY use, not use,
      or set value of the Z field in accordance with the timestamp
      format in use.  This optional field is to enhance operations, but
      local configuration or defaults could be used in its place.
What do you mean by "use"and how does that differ from "set"?
Also the fact that it is described as optional here but as "MUST/SHOULD be set
to NTP" in interop with TWAMP light is confusing.

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From: Greg Mirsky <[email-masked]>
Date: Tue, 10 Sep 2019 16:36:36 -0700

Hi Martin,
thank you for your comments and questions. Will follow on to address
Barry's DISCUSS on another thread. In this reply, please find answers to
your comments in-line tagged GIM>>.

Regards,
Greg

> https://datatracker.ietf.org/doc/draft-ietf-ippm-stamp/
GIM>> Correct. A Session-Reflector reflects all the information received in
a test packet as well as the value of TTL/Hop Count field. To clarify how
the Stateless mode is different from the Stateful propose the following
update:
OLD TEXT:
      Stateless - STAMP Session-Reflector does not maintain test state
      and will reflect the received sequence number without
      modification.
NEW TEXT:
      Stateless - STAMP Session-Reflector does not maintain test state
      and will use the value in the Sequence Number field in the
      recieved packet as the value for the Sequence Number field in the
      reflected packet.  As a result, values in Sequence Number and
      Session-Sender Sequence Number fields are the same, and only
      round-trip packet loss can be calculated while the reflector is
      operating in stateless mode.

> What do you mean by "use"and how does that differ from "set"?
GIM>> Yes, it's awkward. We propose the following update:
OLD TEXT:
      The STAMP Session-Sender and Session-Reflector MAY use, not use,
      or set value of the Z field in accordance with the timestamp
      format in use.  This optional field is to enhance operations, but
      local configuration or defaults could be used in its place.
NEW TEXT:
      The STAMP Session-Sender and Session-Reflector MUST use a Z field
      value of 0, (NTP 64 bit format of a timestamp) as the default.
      The STAMP Session-Sender and Session-Reflector MAY optionally set
      the Z field to a value of 1 (PTPv2 truncated format of a
      timestamp).

Also the fact that it is described as optional here but as "MUST/SHOULD be
> set
GIM>> Thank you for pointing to these two references. After reviewing them,
we've concluded that the first is in fact unnecessary because only the
Session-Sender uses timestamp and must be aware of its format. Hence, in
the case when a Session-Reflector supports TWAMP-Light, STAMP
Session-Sender can use any format. Will remove these two sentences:
  The Session-Sender SHOULD use the default format for its timestamps -
   NTP.  And it MAY use PTPv2 timestamp format.
The second reference to the Z flag in the section:
   The Session-Reflector MUST be set to use the default format
   for its timestamps, NTP.
is in sync with the proposed above update.
Would these changes address your concern?