IETF Logo Mail Archive

Re: [quicwg/base-drafts] Reduce restrictions on valid RTT samples (#2568)

Nick Banks <notifications@github.com> Sat, 30 March 2019 23:52 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 7C68812006F for <quic-issues@ietfa.amsl.com>; Sat, 30 Mar 2019 16:52:17 -0700 (PDT)
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 e6g64ECFHmjW for <quic-issues@ietfa.amsl.com>; Sat, 30 Mar 2019 16:52:15 -0700 (PDT)
Received: from out-4.smtp.github.com (out-4.smtp.github.com [192.30.252.195]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A871F120044 for <quic-issues@ietf.org>; Sat, 30 Mar 2019 16:52:15 -0700 (PDT)
Date: Sat, 30 Mar 2019 16:52:14 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1553989934; bh=FmuuttCmxutsmPjftZ4AtNVajU3yYK5DG4u01or5JjU=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=MN4YC4G8ahlV1/J8vpMIOBykDs/3bZ1iHu57o70yplrpT2LhS2SeeexjL9tKnj01F CJxQO4fHEJqef1ZhcjkfyAj4EcWCbZvfT0XSmI9eEnmC2Ix8Jq8AOmofL84+68HtaT KV2Y2wcLPVvjCBkXeabPXF7vlnkRQyZ7Z9hZakB4=
From: Nick Banks <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab903884b949cf5df697ef9fd9548a60517d67b4b492cf0000000118b7c32e92a169ce19787a10@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/issues/2568/478299319@github.com>
In-Reply-To: <quicwg/base-drafts/issues/2568@github.com>
References: <quicwg/base-drafts/issues/2568@github.com>
Subject: Re: [quicwg/base-drafts] Reduce restrictions on valid RTT samples (#2568)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5ca0012e3fe86_7ad73fc4d80d45bc16316d9"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: nibanks
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/R-offQP8Gk9-JSJA5Tkw_g5ga-k>
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: Sat, 30 Mar 2019 23:52:18 -0000

It just seems like a bad idea to always ignore RTT measurements if ack_delay is larger than max_ack_delay. For instance, what about one of the following scenarios:

1. Sheer CPU load on the peer prevents it from ACK'ing a packet within max_ack_delay.
2. An implementation that literally sets a max_ack_delay timer on receipt of a packet, then when the timer fires, queues a send packet work item. When that work item is processed, the ack_delay is calculated and it ends up being just over max_ack_delay.

-- 
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/issues/2568#issuecomment-478299319

v2.23.0 | Report a Bug | By Email