Re: [quicwg/base-drafts] Do not reset pto_count on Initial ACKs (#3551)

Jana Iyengar <notifications@github.com> Thu, 09 April 2020 02:28 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 DB7B93A043A for <quic-issues@ietfa.amsl.com>; Wed, 8 Apr 2020 19:28:56 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.267
X-Spam-Level:
X-Spam-Status: No, score=-3.267 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.168, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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 cD1NjnliZ9pt for <quic-issues@ietfa.amsl.com>; Wed, 8 Apr 2020 19:28:55 -0700 (PDT)
Received: from out-27.smtp.github.com (out-27.smtp.github.com [192.30.252.210]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 556DF3A044D for <quic-issues@ietf.org>; Wed, 8 Apr 2020 19:28:55 -0700 (PDT)
Received: from github-lowworker-9bcb4a1.ac4-iad.github.net (github-lowworker-9bcb4a1.ac4-iad.github.net [10.52.25.84]) by smtp.github.com (Postfix) with ESMTP id 55A42E1612 for <quic-issues@ietf.org>; Wed, 8 Apr 2020 19:28:54 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1586399334; bh=IO9j9l/KgGOAzhGPb1EBkqAbhtfW2qI5669gIyvUOu0=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=xUwGPOXFaLBqvKo9CoEFgi2ZJLARRH25btI8d5OsU6yJQ93TMsEFJ76I+5FMKWe4V /bTi6s/diEHUuNQjhQZN2efrXinG1SPiznD4JfR5OZJo6xWwJ7gXKoh0m9e3xjBs91 GlK67Fumvq3zRBme97c6yUncqmlJMbBV+SRTlYzw=
Date: Wed, 08 Apr 2020 19:28:54 -0700
From: Jana Iyengar <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJK3JMNM5JGFT55ECQTN4TJUWNEVBNHHCGKCD2A@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/3551/review/390450027@github.com>
In-Reply-To: <quicwg/base-drafts/pull/3551@github.com>
References: <quicwg/base-drafts/pull/3551@github.com>
Subject: Re: [quicwg/base-drafts] Do not reset pto_count on Initial ACKs (#3551)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5e8e886645c7c_17553fad8d2cd95c13138e"; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: janaiyengar
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/QaeYBTqJYCu0XoFQruASUVnRJsA>
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, 09 Apr 2020 02:28:57 -0000

@janaiyengar commented on this pull request.

Thanks, Ian, a couple of comments.

> @@ -501,7 +501,13 @@ packet on a PTO expiration before confirming that the server is able to decrypt
 expiration before it has the keys to process an acknowledgement.
 
 When a PTO timer expires, the PTO period MUST be set to twice its current
-value. This exponential reduction in the sender's rate is important because
+value.  The PTO period is reset based on the latest rtt information when

```suggestion
value.  The PTO period is set based on the latest RTT information when
```

> @@ -501,7 +501,13 @@ packet on a PTO expiration before confirming that the server is able to decrypt
 expiration before it has the keys to process an acknowledgement.
 
 When a PTO timer expires, the PTO period MUST be set to twice its current
-value. This exponential reduction in the sender's rate is important because
+value.  The PTO period is reset based on the latest rtt information when
+receiving an acknowledgement if the peer has completed address validation.
+The PTO timer is not decreased while the peer is validating the

```suggestion
The PTO backoff is not decreased even on receiving an
acknowledgement as long as the peer is validating this endpoint's
```

> +address, to ensure the endpoint's anti-deadlock timer does not fire too
+aggressively when the server does not yet have handshake data to send.

```suggestion
address. Doing so ensures that the endpoint's anti-deadlock timer is not 
set too aggressively when the server seems to be slow in responding with
handshake data.
```

> @@ -1147,7 +1153,10 @@ OnAckReceived(ack, pn_space):
     OnPacketsLost(lost_packets)
   OnPacketsAcked(newly_acked_packets)
 
-  pto_count = 0
+  // Reset pto_count unless the server has not yet
+  // validated the client's address.
+  if (PeerCompletedAddressValidation()):
+    pto_count = 0
   SetLossDetectionTimer()

Should this also be done only when pto_count is set to 0? Why restart the timer here if the pto_count hasn't changed?

-- 
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/3551#pullrequestreview-390450027