Re: [tcpm] Fwd: New Version Notification for draft-yang-tcpm-ets-00.txt

Hi,
Thanks for preparing the draft. I basically like the idea in the docs and
have several comments.

1: I am wondering if we really need to have 32 bits TSval and TSecr in ETS
option in SYN when TSopt is also sent?
    For example, If TSopt has 1 ms granularity, I think ETS option will
need to carry only small fractions of timestamp.

2: "To prevent a false positive PAWS rejection of a valid segment, an ETS
receiver MUST skip the PAWS check"
    -> This is one possible approach, but just skipping PAWS doesn't sound
very good to me.
         How about discarding the segment while updating TS.recent as an
alternative? If the segment is not an old one, it will be retransmitted and
accepted.
         I think this is a bit more conservative.

3: It is not very clear for me how measuring NetworkRTT can contribute to
improving RTO.
    Or, are there some other ways to utilize NetworkRTT?

4: Just out of curiosity, is intended status standard track or
experimental? ExID is usually used for exp or info docs.

Thanks,
--
Yoshi

On Mon, Nov 2, 2020 at 4:26 PM Yuchung Cheng <ycheng=
40google.com@dmarc.ietf.org> wrote:

> Hi tcpm & iccrg,
>
> We are proposing a new TCP timestamp option to measure the network delay
> more precisely (e.g. excluding delayed ACK effects) for congestion control,
> e.g. Swift published SIGCOMM 2020. The precision of the measurements can
> potentially be further enhanced by NIC hardware timestamps. We are working
> on a reference implementation for Linux as well.
>
> We'll also present it in the upcoming tcpm meeting. Feedbacks are very
> welcome.
>
> ---------- Forwarded message ---------
> From: <internet-drafts@ietf.org>
> Date: Mon, Nov 2, 2020 at 3:29 PM
> Subject: New Version Notification for draft-yang-tcpm-ets-00.txt
> To: Eric Dumazet <edumazet@google.com>, Yuchung Cheng <ycheng@google.com>,
> Neal Cardwell <ncardwell@google.com>, Kevin Yang (Yudong) <yyd@google.com>
>
>
>
> A new version of I-D, draft-yang-tcpm-ets-00.txt
> has been successfully submitted by Kevin (Yudong) Yang and posted to the
> IETF repository.
>
> Name:           draft-yang-tcpm-ets
> Revision:       00
> Title:          TCP ETS: Extensible Timestamp Options
> Document date:  2020-11-02
> Group:          Individual Submission
> Pages:          13
> URL:            https://www.ietf.org/archive/id/draft-yang-tcpm-ets-00.txt
> Status:         https://datatracker.ietf.org/doc/draft-yang-tcpm-ets/
> Htmlized:       https://datatracker.ietf.org/doc/html/draft-yang-tcpm-ets
> Htmlized:       https://tools.ietf.org/html/draft-yang-tcpm-ets-00
>
>
> Abstract:
>    This document presents ETS: an Extensible TimeStamps option for TCP.
>    It allows hosts to use microseconds as the unit for timestamps to
>    improve the precision of timestamps, and advertise the maximum ACK
>    delay for its own delayed ACK mechanism.  Furthermore, it extends the
>    information provided in the [RFC7323] TCP Timestamps Option by
>    including the receiver delay in the TSecr echoing, so that the
>    receiver of the ACK is able to more accurately estimate the portion
>    of the RTT that resulted from time traveling through the network.
>    The ETS option format is extensible, so that future extensions can
>    add further information without the overhead of extra TCP option kind
>    and length fields.
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
>
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