Re: [quicwg/base-drafts] Define under-utilizing the congestion window (#2675)

Jana Iyengar <notifications@github.com> Fri, 17 May 2019 01:42 UTC

Return-Path: <noreply@github.com>
X-Original-To: quic-issues@ietfa.amsl.com
Delivered-To: quic-issues@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 68A3C120341 for <quic-issues@ietfa.amsl.com>; Thu, 16 May 2019 18:42:15 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8.01
X-Spam-Level:
X-Spam-Status: No, score=-8.01 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_IMAGE_ONLY_32=0.001, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, T_DKIMWL_WL_HIGH=-0.01] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=github.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 uVgJJajn3uRP for <quic-issues@ietfa.amsl.com>; Thu, 16 May 2019 18:42:13 -0700 (PDT)
Received: from out-5.smtp.github.com (out-5.smtp.github.com [192.30.252.196]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B12E812033D for <quic-issues@ietf.org>; Thu, 16 May 2019 18:42:12 -0700 (PDT)
Date: Thu, 16 May 2019 18:42:11 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1558057331; bh=NMqNT7q+JO1wy0e3pNHhByRa0OT+QLxuORnkmOkwpJs=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=bA0ArY83eeUCae837StrSCD2Qlz+v8Kg86MsDF287VwFoPktFc1HVWLCjaCuQkim4 8BLQIQCmaClitVNJfRmOjxhwaoNdwOsBPWEQckvRUR//MG/PiAlEE8mCzt6/X3p2R/ YsFasffMSFG3LyaKPFsgz/K/31rP/BfeOzVxJTdM=
From: Jana Iyengar <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJK4MBIY5ITMPK6ZSZZ525NB7HEVBNHHBUUHC6A@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2675/review/238707234@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2675@github.com>
References: <quicwg/base-drafts/pull/2675@github.com>
Subject: Re: [quicwg/base-drafts] Define under-utilizing the congestion window (#2675)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5cde1173983a1_3abc3f938c2cd96825393"; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: janaiyengar
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
X-GitHub-Recipient-Address: quic-issues@ietf.org
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic-issues/hrHKjsg4YLWrPwaUJmQzo3-bAP8>
X-BeenThere: quic-issues@ietf.org
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <quic-issues.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic-issues/>
List-Post: <mailto:quic-issues@ietf.org>
List-Help: <mailto:quic-issues-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 17 May 2019 01:42:15 -0000

janaiyengar commented on this pull request.



> @@ -848,9 +850,10 @@ and not fully utilize the congestion window due to this delay. A sender
 should not consider itself application limited if it would have fully
 utilized the congestion window without pacing delay.
 
-Bursting more than an intial window's worth of data into the network might
-cause short-term congestion and losses. Implemementations SHOULD either use
-pacing or reduce their congestion window to limit such bursts.
+Sending multiple packets into the network without any delay between them
+creates a burst of load that might cause short-term congestion and losses.

>  The existing text says you SHOULD not burst more than an initial window into the network(ever), with nothing specific to coming out of quiescence.

Yes, I think this is the problem. I believe the intent here was to say that a sender SHOULD NOT do more than IW as an upper limit on bursts without recommending that as the correct limit for any bursting.

We can either specify that _all_ bursts should be limited to IW, irrespective of how much data is in the network already, or that bursts coming out of quiescence should be limited to IW. While I'm not sure how to change this text here, I'm trying to steer clear of saying something overly broad. (I'll suggest some text).

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/2675#discussion_r284953524