Re: [tcpm] On allocating reserved bits in the TCP header

"Scharf, Michael" <Michael.Scharf@hs-esslingen.de> Sun, 03 November 2019 14:51 UTC

Return-Path: <Michael.Scharf@hs-esslingen.de>
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 EBA3D120059 for <tcpm@ietfa.amsl.com>; Sun, 3 Nov 2019 06:51:32 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.998
X-Spam-Level:
X-Spam-Status: No, score=-1.998 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=hs-esslingen.de
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 CQSVPBIAzwsQ for <tcpm@ietfa.amsl.com>; Sun, 3 Nov 2019 06:51:31 -0800 (PST)
Received: from mail.hs-esslingen.de (mail.hs-esslingen.de [134.108.32.78]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id F16EA120033 for <tcpm@ietf.org>; Sun, 3 Nov 2019 06:51:30 -0800 (PST)
Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.hs-esslingen.de (Postfix) with ESMTP id 75A1125A17; Sun, 3 Nov 2019 15:51:29 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hs-esslingen.de; s=mail; t=1572792689; bh=NCOU6gCCSR/43fdgJrqKbI46s69PWuntMZWwkCGebEs=; h=From:To:CC:Subject:Date:References:In-Reply-To:From; b=zccDS9VEvHmRh9+GuQuJXjIH8PAKKtLye2oacRkoejafHlBe47GcRWoeFm1Ny9l/n PYDa6MeJpPwRRYtIw1FiYJn00VBxxuSj3wKVXtCcrKhvhb3omh6C27vjThhOEshWrm ImWYqVmVP05Xf5UQAkgT3WBWbW0AR5/O0wzGkYPs=
X-Virus-Scanned: by amavisd-new-2.7.1 (20120429) (Debian) at hs-esslingen.de
Received: from mail.hs-esslingen.de ([127.0.0.1]) by localhost (hs-esslingen.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id o2dBGGoheZv1; Sun, 3 Nov 2019 15:51:28 +0100 (CET)
Received: from rznt8102.rznt.rzdir.fht-esslingen.de (rznt8102.rznt.rzdir.fht-esslingen.de [134.108.29.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.hs-esslingen.de (Postfix) with ESMTPS; Sun, 3 Nov 2019 15:51:28 +0100 (CET)
Received: from RZNT8114.rznt.rzdir.fht-esslingen.de ([169.254.3.61]) by rznt8102.rznt.rzdir.fht-esslingen.de ([fe80::f977:d5e6:6b09:56ac%10]) with mapi id 14.03.0468.000; Sun, 3 Nov 2019 15:51:28 +0100
From: "Scharf, Michael" <Michael.Scharf@hs-esslingen.de>
To: "Rodney W. Grimes" <4bone@gndrsh.dnsmgr.net>
CC: "tcpm@ietf.org" <tcpm@ietf.org>
Thread-Topic: [tcpm] On allocating reserved bits in the TCP header
Thread-Index: AdVmj1xabgQDGeLVSb628zuZMsyT0ArLD1IAACWg15A=
Date: Sun, 3 Nov 2019 14:51:27 +0000
Message-ID: <6EC6417807D9754DA64F3087E2E2E03E2D4D8D80@rznt8114.rznt.rzdir.fht-esslingen.de>
References: <6EC6417807D9754DA64F3087E2E2E03E2D437915@rznt8114.rznt.rzdir.fht-esslingen.de> <201911022125.xA2LP0N0093157@gndrsh.dnsmgr.net>
In-Reply-To: <201911022125.xA2LP0N0093157@gndrsh.dnsmgr.net>
Accept-Language: de-DE, en-US
Content-Language: de-DE
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [134.108.48.165]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/4luZWVpUr-6kOjPIh8WFBt8i1Ho>
Subject: Re: [tcpm] On allocating reserved bits in the TCP header
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: Sun, 03 Nov 2019 14:51:33 -0000

> As author of draft-grimes-tcpm-tcpsce, which is also requesting use of a TCP bit
> for experimental purpose, ask what the next steps are?

The usual dos and don'ts apply: Socialize the idea, get feedback, consider the feedback, update the document, convince the working group, etc.

We have 4 reserved bits left in the TCP header. There has been a past and completed experiments with bit 7. The past use could be considered a precedent when publishing a standards track document that allows new experiments with reserved bits. The precedent only exist for bit 7.

I am aware of at least 4 different ideas that have been posted recently to this list regarding use of a reserved bit. If the TCPM working group (well, actually the IETF) reached consensus that more than one experiment was useful, we may have to think about a way of negotiating what experiment is in use on a connection. Or find another solution.

As an individual contributor to TCPM, my current thinking is that one bit (i.e., bit 7) would be enough for experimentation - for the time being.

This is my personal view. The last change to the main TCP header was done in 2001. It is hard to predict what the IETF consensus would be these days.

Michael