RTT sampling on retransmissions
Arvid Picciani <aep@exys.org> Sat, 21 July 2018 14:20 UTC
Return-Path: <aep@exys.org>
X-Original-To: quic@ietfa.amsl.com
Delivered-To: quic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 14E7C124D68 for <quic@ietfa.amsl.com>; Sat, 21 Jul 2018 07:20:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.911
X-Spam-Level:
X-Spam-Status: No, score=-1.911 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, T_DKIMWL_WL_MED=-0.01] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=exys-org.20150623.gappssmtp.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bEU6XTMwJN2C for <quic@ietfa.amsl.com>; Sat, 21 Jul 2018 07:20:32 -0700 (PDT)
Received: from mail-oi0-x236.google.com (mail-oi0-x236.google.com [IPv6:2607:f8b0:4003:c06::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A9B99130DBE for <quic@ietf.org>; Sat, 21 Jul 2018 07:20:32 -0700 (PDT)
Received: by mail-oi0-x236.google.com with SMTP id i12-v6so26236645oik.2 for <quic@ietf.org>; Sat, 21 Jul 2018 07:20:32 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=exys-org.20150623.gappssmtp.com; s=20150623; h=mime-version:from:date:message-id:subject:to; bh=+cBUUVEZaKLNqhFvVXBUHs7Yf2dKFzlg0xPJtwRvhwg=; b=XoYKiGfC1muDa+IrWo8sSqJ1FjoQt2auMPKJPbikwCVOQjZLSRy02WR8i0i+kWaNDv 3J5jTWELH05YzF98st8zkDrVe2mFo6LefW2qKaBpnWptIsOcbG3uWbHY25U2nbzDtfl9 c64/LD6bkyaym0fb0Y0/Z57KzqXDC34gPUJLWNRrKybvH8T1Jr5dkMdXK2956cUzW5YY ujbw9QUoQu0HfxWqxGDAGTSS5rOiXgujIvh428OK4E/CrNzqI6u3md7UL/L97gI/iNz7 0WYS7S5uah/ma1vzCV5m7K9fWY5ThDpfmjG/MQEpjbOfGbTfuQvX5HqLRqvx08omW0qA NLbQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=+cBUUVEZaKLNqhFvVXBUHs7Yf2dKFzlg0xPJtwRvhwg=; b=pL+LAdYkweaDYVjOy6RyzTSxv9t+fZrvTH1uG3OWUa9GApdpHna9efLzLfBzTaBI01 ccLcoZTL324kZm4pPRg2C7nVPNKw6VuXbtz5ekhvy1I+6VcP9j3148HhJR5c+riyfZd3 neJGxTD/zm7YUhb1VTOktWE9WxgiVVjx6GdZaJArAP1mEUE35GPdOpchMlnCEpW7b+DH WQgHP6wT9/4e5PgXYzK4074OoylU7Vn/jfOQLsIP02KSi1AF5mAURTiHIA69eHV0Ib5c qCOyJCEnzKutCgXWOxqaf0m/ozAVP/gd4NDSde+Vn1MSS9V+ethol0NjcpHhJLjaspVf rUPQ==
X-Gm-Message-State: AOUpUlEz71YQQmFGT6kc47IjlYHxDq59BcL3WkNj3NGRrLELkBmH9buR IVExCC5eIiPZ/SICEYywTF3F9MIKZ25vsCwkxW+M7PJs8po=
X-Google-Smtp-Source: AAOMgpfg0CaC57xLFgJY4/vZAFoMGb2qLnudJsxIfyO1rOgYvpiK/J/SOL6hwSMZ60wcCfDnd+3/Mv87zxgqvxFq5iU=
X-Received: by 2002:aca:5354:: with SMTP id h81-v6mr1792687oib.299.1532182831196; Sat, 21 Jul 2018 07:20:31 -0700 (PDT)
MIME-Version: 1.0
Received: by 2002:ac9:5dd0:0:0:0:0:0 with HTTP; Sat, 21 Jul 2018 07:20:30 -0700 (PDT)
X-Originating-IP: [77.180.150.202]
From: Arvid Picciani <aep@exys.org>
Date: Sat, 21 Jul 2018 16:20:30 +0200
Message-ID: <CACD9L=AnVqsLjoifoz-qyKQS+MKKh=V5BjWVOE38zEO+rd9jiw@mail.gmail.com>
Subject: RTT sampling on retransmissions
To: quic@ietf.org
Content-Type: text/plain; charset="UTF-8"
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic/Upvo-xGnaGUc5kKz6lrRDOa0KwA>
X-BeenThere: quic@ietf.org
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: Main mailing list of the IETF QUIC working group <quic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic>, <mailto:quic-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic/>
List-Post: <mailto:quic@ietf.org>
List-Help: <mailto:quic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic>, <mailto:quic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 21 Jul 2018 14:23:20 -0000
Hi, UpdateRtt in https://tools.ietf.org/html/draft-ietf-quic-recovery-13#section-3.5.5 does seem to calculate the RTT from an ack on any packet, even if the packet was resent. 1. In a TLP event The oldest packet is resent and the sent_time reset to the current time. 2. Eventually that packet is acked, because the network was just slow. 3. RTT is calculated from the last sent_time (which was the time it was resent). 4. RTT is way too small now, leading to lots of timeouts. what am i missing here? https://tools.ietf.org/html/rfc6298 section 2 specifically says that RTT must NOT be calculated from retransmissions. Is a "retransmitted" bit in the quic-recovery left as exercise to the reader or should retransmissions actually never be passed to OnPacketSent? /b/
- RTT sampling on retransmissions Arvid Picciani
- Re: RTT sampling on retransmissions Ian Swett