Re: [quicwg/base-drafts] Merge Crypto timeout and PTO (#2806)

ianswett <notifications@github.com> Sat, 13 July 2019 11:23 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 5380E12019F for <quic-issues@ietfa.amsl.com>; Sat, 13 Jul 2019 04:23:05 -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_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, 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 ceoMjq4YYXHi for <quic-issues@ietfa.amsl.com>; Sat, 13 Jul 2019 04:23:02 -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 6859312019C for <quic-issues@ietf.org>; Sat, 13 Jul 2019 04:23:02 -0700 (PDT)
Date: Sat, 13 Jul 2019 04:23:01 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1563016981; bh=3TfGi+W+KYGFguuR3PpCLKIwZxp06BMl4K3gaErgZtQ=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=I9wbyRNhFpm4mJmPFUaAAiJbu18mS+/q+FbynIh0X09r7aTwviBkkDPCyeJHo5/DT u3CJmMsygYjXUYhcqb2xAGBzhByDBr9lYZbuM49fGR1OL+zat5QH3TLWQevqOKBH3I xtMArvGpn8YA3AqmECqTzsnFBeZmBu6f591IQ1AE=
From: ianswett <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJK3XSGM2WCHX57ISSB53G3YZLEVBNHHBWSJPJ4@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2806/review/261537548@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2806@github.com>
References: <quicwg/base-drafts/pull/2806@github.com>
Subject: Re: [quicwg/base-drafts] Merge Crypto timeout and PTO (#2806)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5d29bf1554a9d_3b523fef412cd95c292961"; 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/K2Y0h8HILzE5XXkB_zqU1dZSkZ4>
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, 13 Jul 2019 11:23:05 -0000

ianswett commented on this pull request.

Thanks Ryan, I took your editorial suggestion, I can file an issue for the last comment.

>  ## Probe Timeout {#pto}
 
-A Probe Timeout (PTO) triggers a probe packet when ack-eliciting data is in
-flight but an acknowledgement is not received within the expected period of
-time.  A PTO enables a connection to recover from loss of tail packets or acks.
-The PTO algorithm used in QUIC implements the reliability functions of Tail Loss
-Probe {{?TLP=I-D.dukkipati-tcpm-tcp-loss-probe}} {{?RACK}}, RTO {{?RFC5681}} and
+A Probe Timeout (PTO) triggers sending one or two probe packets when

It's 1 or 2 because some impls only do 1 packet PTO(TLP).  I could recommend two packets during the handshake, in order to speed handshake completion?

It actually should be datagrams, but I'm inclined to change that in a follow-up, rather that burying it in this change?

> +data.  If no data can be sent, then the PTO alarm MUST NOT be armed until
+data has been received from the client.
+
+Because the server could be blocked until more packets are received, the client
+MUST ensure that the retransmission timer is set if the client does not yet
+have 1-RTT keys.  If the probe timer expires before the client has 1-RTT keys,
+it is possible that the client may not have any crypto data to retransmit.
+However, the client MUST send a new packet, containing only PADDING frames if
+necessary, to allow the server to continue sending data. If Handshake keys
+are available to the client, it MUST send a Handshake packet, and otherwise
+it MUST send an Initial packet in a UDP datagram of at least 1200 bytes.
+
+Because Initial packets only containing PADDING do not elicit an
+acknowledgement, they may never be acknowledged, but they are removed from
+bytes in flight when the client gets Handshake keys and the Initial keys are
+discarded.

True, we recommend that elsewhere.  I think we should change that in a follow-up though, since it's not directly related to this change?

-- 
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/2806#pullrequestreview-261537548