Re: [tcpm] A possible simplification for AccECN servers

Jonathan Morton <chromatix99@gmail.com> Sat, 23 November 2019 14:06 UTC

Return-Path: <chromatix99@gmail.com>
X-Original-To: tcpm@ietfa.amsl.com
Delivered-To: tcpm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E0BEF1200D8 for <tcpm@ietfa.amsl.com>; Sat, 23 Nov 2019 06:06:59 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.748
X-Spam-Level:
X-Spam-Status: No, score=-1.748 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.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 KBam8qtjae91 for <tcpm@ietfa.amsl.com>; Sat, 23 Nov 2019 06:06:56 -0800 (PST)
Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id C1372120088 for <tcpm@ietf.org>; Sat, 23 Nov 2019 06:06:56 -0800 (PST)
Received: by mail-qt1-x834.google.com with SMTP id o49so11453579qta.7 for <tcpm@ietf.org>; Sat, 23 Nov 2019 06:06:56 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=b6dL/yOr81p14tFTefGm2785sf8CmbFbjH1uChChuto=; b=fzPixsZzEJI5ieL9TOzgrAZHdXlNscNODu5zXCh1MAbsEuYjYrU3Nak9zEqogT0b2Q MTW0FM4vLyKCksUMk5sA0PZPj6T41iIXgYjqV1OHbwYBpJPdxEelP/Oq76stC5SdTZC+ dJ+Zc/OWxJAomtq58MUmy7DcI0W/UIBCYi50Ib8Ky/R1Hrwr3Kz23fS9Xov5KuQ8RZbU tKivKRC1pIc7m1DCf3se1MOsWe1u4gMYToaTOTGKgGqU/+/jzdhEgngVdb9SgOpmDpId AYB6iADuUuBuTA3F4fKNKpCMe19Xdo9MAWExYeh2x1Ibb77sNXA4KeGQkCqyrks+Pigq 64pg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=b6dL/yOr81p14tFTefGm2785sf8CmbFbjH1uChChuto=; b=CjKPqb/xGrFCXAWNTsDKl/Nkd1spEuCjzbyZ4Hig3b4nYp0/uQTNqzyLLyZiMwJOVU JdpAvMr9a6BcPSUHBk/a9+6tH9MIewdxr6MCGmlqw8m4Tc7MqnNfMj0PzONezugKEp70 FaPXmKd0sD6EaFCSrjMbyPk1hbtIxnUvzFb9ScWEWB/eFSOCRMBEt1Aw38FirhDlTrKh kYgNs6pJU5wGMG2BdJigT+AiUfoco2EuXRNP498mAZzK1SLDnYuEpe5djIGpwbcQbc/Q r8KJCwbrE/q2x0BMfCapsAeGZ1lNOtfTXIw/iUZB/E+V9uOowrv3U2W0d1lpO8XNSD+V asAw==
X-Gm-Message-State: APjAAAUPyLZLDQwI5wWxvo1bUcOxuFVhILh0iOZtGyfFSuzFMeFFOUxJ n/ZVzzJn+8FkZDZYFhT/19+T8qdhE7G5rqay7kk=
X-Google-Smtp-Source: APXvYqxUz6Jb4f0aMa16OKpE1GJyFiDM7GEKzx+1ej88FJDTOHnSoTE5Oh+yhB4QdZf+ph2n/CDn/iGlyO4zneYmQo8=
X-Received: by 2002:aed:24af:: with SMTP id t44mr5270528qtc.57.1574518015671; Sat, 23 Nov 2019 06:06:55 -0800 (PST)
MIME-Version: 1.0
Received: by 2002:a0c:e48b:0:0:0:0:0 with HTTP; Sat, 23 Nov 2019 06:06:54 -0800 (PST)
Received: by 2002:a0c:e48b:0:0:0:0:0 with HTTP; Sat, 23 Nov 2019 06:06:54 -0800 (PST)
In-Reply-To: <d35618ee-c0dc-44ee-9e22-50bdabbe026c@bobbriscoe.net>
References: <d35618ee-c0dc-44ee-9e22-50bdabbe026c@bobbriscoe.net>
From: Jonathan Morton <chromatix99@gmail.com>
Date: Sat, 23 Nov 2019 16:06:54 +0200
Message-ID: <CAJq5cE0c7TPMVD9PR9h0Q3t_p5Bg=OzGda-phZD4K3gDGJ7Rbw@mail.gmail.com>
To: Bob Briscoe <ietf@bobbriscoe.net>
Cc: Richard Scheffenegger <rscheff@gmx.at>, tcpm IETF list <tcpm@ietf.org>, Mirja Kuehlewind <ietf@kuehlewind.net>
Content-Type: multipart/alternative; boundary="0000000000000441b50598040be6"
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/12JXOoxKwx7iQOSOo3rIKUQCI08>
Subject: Re: [tcpm] A possible simplification for AccECN servers
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: TCP Maintenance and Minor Extensions Working Group <tcpm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tcpm>, <mailto:tcpm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tcpm/>
List-Post: <mailto:tcpm@ietf.org>
List-Help: <mailto:tcpm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tcpm>, <mailto:tcpm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 23 Nov 2019 14:07:00 -0000

I believe that taking advantage of such a provision would result in a
violation of RFC-3168, as seen by a server supporting that specification
but not AccECN.

If I happen to be wrong about that, could you explain how the server gets
to know that the connection has reverted to Not-ECT mode after sending a
SYN-ACK confirming RFC-3168 support in response to a valid RFC-3168 SYN?

- Jonathan Morton