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Re: [tcpm] Disabling PAWS when possible

Yoshifumi Nishida <nishida@sfc.wide.ad.jp> Wed, 27 June 2018 04:02 UTC

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From: Yoshifumi Nishida <nishida@sfc.wide.ad.jp>
Date: Tue, 26 Jun 2018 21:01:53 -0700
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To: Yuchung Cheng <ycheng@google.com>
Cc: Yoshifumi Nishida <nishida@sfc.wide.ad.jp>, Neal Cardwell <ncardwell@google.com>, "tcpm@ietf.org" <tcpm@ietf.org>, Eric Dumazet <edumazet@google.com>, Wei Wang <weiwan@google.com>, Van Jacobson <vanj@google.com>
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Subject: Re: [tcpm] Disabling PAWS when possible
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Hi Yuchung,

On Mon, Jun 25, 2018 at 1:28 PM, Yuchung Cheng <ycheng@google.com> wrote:

> > Do you still need TS option even when you have records of transmission
> time, or this feature is not used in the datacenter?
>
> RACK's packet sent time and TS options are orthogonal. but yes we do
> use both. In particular, the TS-opt val in Google DCs is in
> microsecond unit, which we negotiated internally using a private
> option like what Neal proposed. We do have to relax the PAWs check for
> that, so your proposal would make this feature standardize-able for
> public Internet :-)
>
> RACK's packet sent time is essential to RACK. But TS-opt is a nice to
> have feature to measure RTT on retransmitted packets.
>

Thanks for the useful info. It seems that people still want to keep TS.

Just to be clear, the main point of the draft is to disable PAWS as the
title indicates.
I guess I should focus on this point more explicitly in the next version.
--
Yoshi

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