Re: [quicwg/base-drafts] Unify TLP and RTO into Probe Timeout (#2114)

ianswett <notifications@github.com> Fri, 14 December 2018 14:31 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 82221127133 for <quic-issues@ietfa.amsl.com>; Fri, 14 Dec 2018 06:31:46 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.459
X-Spam-Level:
X-Spam-Status: No, score=-9.459 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.46, 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, SPF_PASS=-0.001] 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 9DxeIRlQZDcE for <quic-issues@ietfa.amsl.com>; Fri, 14 Dec 2018 06:31:44 -0800 (PST)
Received: from out-1.smtp.github.com (out-1.smtp.github.com [192.30.252.192]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 95A1A124BE5 for <quic-issues@ietf.org>; Fri, 14 Dec 2018 06:31:44 -0800 (PST)
Date: Fri, 14 Dec 2018 06:31:42 -0800
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1544797902; bh=B4+qGaWU3lod/xIRJFrwAPxZeWz97Dl4X4e6X0QNtdw=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=YE7VpAcKU/1OvJRjTldni0wN+3qF0soi/YcEkCqRRgD+mG4tVN9UNOFZ36xH/F7xz oZE7bw/OsKgjor+3kerWwKQRrAFdXehQXw+GbvCdT0+IgLCvKTqHZTMj1L5+23gJJM hZ3tzQqNrtoL4M60cKXM7KsSgENA0ShTJ6qpgdTM=
From: ianswett <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4abcea95bcd16226bfc004a36c2e7cc029ac45378d992cf00000001182b80ce92a169ce173c5dcf@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2114/review/185132070@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2114@github.com>
References: <quicwg/base-drafts/pull/2114@github.com>
Subject: Re: [quicwg/base-drafts] Unify TLP and RTO into Probe Timeout (#2114)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5c13bece840c0_51653f83008d45c4125879"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: ianswett
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/laCO-JLGMAEUtoAgwB3EREjgILw>
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, 14 Dec 2018 14:31:46 -0000

ianswett commented on this pull request.



> @@ -1065,6 +1004,16 @@ kLossReductionFactor:
 : Reduction in congestion window when a new loss event is detected.
   The RECOMMENDED value is 0.5.
 
+kPersistentCongestion:
+: Number of consecutive PTOs after which network is considered to be
+  experiencing persistent congestion.  The rationale for this threshold is to
+  enable a sender to use initial PTOs for aggressive probing, similar to Tail
+  Loss Probe (TLP) in TCP {{TLP}} {{RACK}}.  Once the number of consecutive PTOs
+  reaches this threshold - that is, persistent congestion is established - the
+  sender responds by collapsing its congestion window, similar to a
+  Retransmission Timeout (RTO) in TCP {{RFC5681}}.  The RECOMMENDED value is 3,

The pseudocode below decreases CWND to kMinimumWindow, which is 2 packets.  I think sticking with that makes sense, at least for now.  It also requires less text to justify.

-- 
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/2114#pullrequestreview-185132070