Re: [quicwg/base-drafts] DPLPMTU merge tweaks (#3702)

msvoelker <notifications@github.com> Thu, 28 May 2020 15:45 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 297643A0FD1 for <quic-issues@ietfa.amsl.com>; Thu, 28 May 2020 08:45:59 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.696
X-Spam-Level:
X-Spam-Status: No, score=-1.696 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, DKIM_VALID_EF=-0.1, HTML_IMAGE_ONLY_28=1.404, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, SPF_HELO_NONE=0.001, 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 4bJqw6wZRE52 for <quic-issues@ietfa.amsl.com>; Thu, 28 May 2020 08:45:57 -0700 (PDT)
Received: from out-20.smtp.github.com (out-20.smtp.github.com [192.30.252.203]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B10ED3A0FD0 for <quic-issues@ietf.org>; Thu, 28 May 2020 08:45:57 -0700 (PDT)
Received: from github-lowworker-56fcc46.va3-iad.github.net (github-lowworker-56fcc46.va3-iad.github.net [10.48.102.32]) by smtp.github.com (Postfix) with ESMTP id 9C5608C1DAC for <quic-issues@ietf.org>; Thu, 28 May 2020 08:45:56 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1590680756; bh=VYWuN8BWdjTi6T2a0kBcAn6RkJ6F3Fsc32TD26DqnpQ=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=IfLbY2mTo12mXN4rbSpnYb4hyDoxP0tMZua3tMXDmrUFIsh1NciJ7h7My0vZA0b4C 7SrpHhSW/ZS6mbpm94cwUU9VrGzSa31HRTV+lQ56SvFJFlAYvgfG9yXy315+IsaIMf Gf96RzPsFGQFHNWLlkz/JwXPEEBoI3+xBGwVDUjg=
Date: Thu, 28 May 2020 08:45:56 -0700
From: msvoelker <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJK6QJS577JYIMXZXSEV43O63JEVBNHHCKRI54E@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/3702/review/420247600@github.com>
In-Reply-To: <quicwg/base-drafts/pull/3702@github.com>
References: <quicwg/base-drafts/pull/3702@github.com>
Subject: Re: [quicwg/base-drafts] DPLPMTU merge tweaks (#3702)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5ecfdcb48d3f4_77593fc33c4cd968496ce"; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: msvoelker
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/kNz1Dhq17WsuZ6QW2h8pTeDHE3g>
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: Thu, 28 May 2020 15:45:59 -0000

@msvoelker commented on this pull request.



> +
+From the perspective of DPLPMTUD, QUIC transport is an acknowledged
+packetization layer (PL). A sender can therefore enter the DPLPMTUD BASE state
+when the QUIC connection handshake has been completed.
+
+
+### Sending QUIC DPLPMTUD Probe Packets
+
+DPLPMTU probe packets are ack-eliciting packets.  Probe packets that use the
+PADDING frame implement "Probing using padding data", as defined in
+Section 4.1 of {{!DPLPMTUD}}.  Endpoints could limit the content of probe
+packets to PING and PADDING frames as packets that are larger than the current
+maximum packet size are more likely to be dropped by the network.
+
+DPLPMTU probe packets consume congestion window, which could delay subsequent
+transmission by an application.

I think here is more to consider. QUIC's loss detection will trigger on a lost probe packet. Even tough this does not lead to a retransmission, since PING and PAD frames won't be retransmitted, one could misinterpret the loss as a congestion signal. It might worth to note that a lost probe packet should not be treated as a congestion signal by the congestion control.

-- 
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/3702#pullrequestreview-420247600