Re: [quicwg/base-drafts] Document TCP RTO vs QUIC PTO (#3441)

MikkelFJ <> Wed, 11 March 2020 13:29 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 43FBE3A18F0 for <>; Wed, 11 Mar 2020 06:29:20 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -6.696
X-Spam-Status: No, score=-6.696 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, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id o2s2tu1odK_a for <>; Wed, 11 Mar 2020 06:29:19 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id DD8813A18ED for <>; Wed, 11 Mar 2020 06:29:18 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id EF2AD5208A8 for <>; Wed, 11 Mar 2020 06:29:17 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=pf2014; t=1583933357; bh=+YRZkhgwI/9q4/fSaszW/SQd9bklUiKCOBPq7tpWA8I=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=2cIBfoDneqagnpYdQP108pvGmV9M5lW+oLZ1Cv6JLV7MG/fMH9LqlvxkxWfLPQsYZ VMHf2isxLbvMr/0itzKlpNDGBYSNXCtY+74ueuRb+o+C9MFRcTJqTwahE5K8fgnhCw 6lCf0PwEswZX6NUO1MlzdmLhcHMLkTrwLE0Ty5ss=
Date: Wed, 11 Mar 2020 06:29:17 -0700
From: MikkelFJ <>
Reply-To: quicwg/base-drafts <>
To: quicwg/base-drafts <>
Cc: Subscribed <>
Message-ID: <quicwg/base-drafts/pull/3441/review/>
In-Reply-To: <quicwg/base-drafts/pull/>
References: <quicwg/base-drafts/pull/>
Subject: Re: [quicwg/base-drafts] Document TCP RTO vs QUIC PTO (#3441)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5e68e7adde952_450a3f9f57ecd96c214565"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: mikkelfj
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
Archived-At: <>
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 11 Mar 2020 13:29:20 -0000

mikkelfj commented on this pull request.

> +### Probe Timeout Replaces RTO and TLP
+QUIC uses a probe timeout (see {{pto}}), with a timer based on TCP's RTO
+computation.  QUIC's PTO includes the peer's maximum expected acknowledgement
+delay instead of using a fixed minimum timeout. QUIC does not collapse the
+congestion window until persistent congestion ({{persistent-congestion}}) is
+declared, unlike TCP, which collapses the congestion window upon expiry of an
+RTO.  Instead of collapsing the congestion window and declaring everything
+in-flight lost, QUIC allows probe packets to temporarily exceed the congestion
+window whenever the timer expires.
+In doing this, QUIC avoids unnecessary congestion window reductions, obviating
+the need for correcting mechanisms such as F-RTO {{!RFC5682}}. Since QUIC does
+not collapse the congestion window on a PTO expiration, a QUIC sender is not
+limited from sending more in-flight packets after a PTO expiration if it still
+has available congestion window. This occurs when a sender is

sounds like a word is missing before "congestion window".

You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub: