Re: [quicwg/base-drafts] Persistent Congestion Time Threshold (#2365)

Marten Seemann <notifications@github.com> Tue, 12 February 2019 01:59 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 7E8E71277D2 for <quic-issues@ietfa.amsl.com>; Mon, 11 Feb 2019 17:59:04 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8
X-Spam-Level:
X-Spam-Status: No, score=-8 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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 q_a7KhzF22tl for <quic-issues@ietfa.amsl.com>; Mon, 11 Feb 2019 17:59:02 -0800 (PST)
Received: from out-2.smtp.github.com (out-2.smtp.github.com [192.30.252.193]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 5FB571276D0 for <quic-issues@ietf.org>; Mon, 11 Feb 2019 17:59:02 -0800 (PST)
Date: Mon, 11 Feb 2019 17:59:01 -0800
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1549936741; bh=f9hHt8oluh5o01PCXm8B6NKFpEv6whZmINldOvtSsdY=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=jUFPCf6rNKUi10Om6KrXnmqk0dLOesZvHTpL9zjeWtRpbqDCkd+coIjvZc2SHoDOx yA7UueMzEfBXJXtewwR8Vcd06SJFIWQnFyKa8vLfbpNfFpRIIMSthEgJP6un2ifGDC qaYKrfbleOdn/YxjPxzuC9HD96fITWw1CKRoG9wo=
From: Marten Seemann <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab8058e7d6f331e9a69c943cc5657e4881c93232f192cf000000011879ea6592a169ce17fab1f6@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2365/review/202447083@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2365@github.com>
References: <quicwg/base-drafts/pull/2365@github.com>
Subject: Re: [quicwg/base-drafts] Persistent Congestion Time Threshold (#2365)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5c62286546d3e_33e43fe4844d45c41492bf"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: marten-seemann
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/fLLFldlvHALjDGuzuL8ZMmuv8NE>
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: Tue, 12 Feb 2019 01:59:05 -0000

marten-seemann commented on this pull request.



> +  max_ack_delay = 0
+  kPersistentCongestionThreshold = 2
+
+If an eck-eliciting packet is sent at time = 0, the following scenario would
+illustrate persistent congestion:
+
+  t=0 | Send Pkt #1 (App Data)
+  t=1 | Send Pkt #2 (PTO 1)
+  t=3 | Send Pkt #3 (PTO 2)
+  t=7 | Send Pkt #4 (PTO 3)
+  t=8 | Recv ACK of Pkt #4
+
+The first three packets are determined to be lost when the ACK of packet 4 is
+received at t=8.  The congestion period is calculated as the time between the
+oldest and newest lost packets: (3 - 0) = 3.  The duration for persistent
+congestion is equal to: (1 * ((2 ^ 2) - 1)) = 3.  Because the threshold was

Just saying, this was my experience when reading this paragraph for the first time. Would be interesting to hear what other people reading this text for the first time think.

-- 
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/2365#discussion_r255773610