[tcpm] On TCP option codepoints

"Scharf, Michael (Michael)" <michael.scharf@alcatel-lucent.com> Tue, 08 October 2013 12:50 UTC

Return-Path: <michael.scharf@alcatel-lucent.com>
X-Original-To: tcpm@ietfa.amsl.com
Delivered-To: tcpm@ietfa.amsl.com
Received: from localhost (localhost []) by ietfa.amsl.com (Postfix) with ESMTP id F2F7721E8186 for <tcpm@ietfa.amsl.com>; Tue, 8 Oct 2013 05:50:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -10.599
X-Spam-Status: No, score=-10.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([]) by localhost (ietfa.amsl.com []) (amavisd-new, port 10024) with ESMTP id 2rcGi-DahsZV for <tcpm@ietfa.amsl.com>; Tue, 8 Oct 2013 05:49:58 -0700 (PDT)
Received: from ihemail1.lucent.com (ihemail1.lucent.com []) by ietfa.amsl.com (Postfix) with ESMTP id E808F21E819C for <tcpm@ietf.org>; Tue, 8 Oct 2013 05:49:57 -0700 (PDT)
Received: from fr712usmtp2.zeu.alcatel-lucent.com (h135-239-2-42.lucent.com []) by ihemail1.lucent.com (8.13.8/IER-o) with ESMTP id r98Cnsm2012538 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for <tcpm@ietf.org>; Tue, 8 Oct 2013 07:49:56 -0500 (CDT)
Received: from FR711WXCHHUB01.zeu.alcatel-lucent.com (fr711wxchhub01.zeu.alcatel-lucent.com []) by fr712usmtp2.zeu.alcatel-lucent.com (GMO) with ESMTP id r98CnrrH000745 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for <tcpm@ietf.org>; Tue, 8 Oct 2013 14:49:54 +0200
Received: from FR712WXCHMBA15.zeu.alcatel-lucent.com ([]) by FR711WXCHHUB01.zeu.alcatel-lucent.com ([]) with mapi id 14.02.0247.003; Tue, 8 Oct 2013 14:49:54 +0200
From: "Scharf, Michael (Michael)" <michael.scharf@alcatel-lucent.com>
To: "tcpm@ietf.org" <tcpm@ietf.org>
Thread-Topic: On TCP option codepoints
Thread-Index: Ac7EJOG470P5YCtSS/uinwT7ojflKQ==
Date: Tue, 8 Oct 2013 12:49:53 +0000
Message-ID: <655C07320163294895BBADA28372AF5D0D913F@FR712WXCHMBA15.zeu.alcatel-lucent.com>
Accept-Language: de-DE, en-US
Content-Language: de-DE
x-originating-ip: []
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-Scanned-By: MIMEDefang 2.57 on
Subject: [tcpm] On TCP option codepoints
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.12
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: <http://www.ietf.org/mail-archive/web/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: Tue, 08 Oct 2013 12:50:04 -0000

Hi all,

I've performed today a small and very nonscientific experiment:

For all TCP option codepoints N marked as "Reserved" on http://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml, I entered the term "tcp option N" in a major Internet search engine and applied a special, human ranking by post-processing the first 5 results for the exact match, if available. To ensure that only the data analysis tool is proprietary and biased, but not in the data source, I also verified the key result in a second major search engine, and I used hex values for N as well ;)

The result of this small experiment resulted in two surprising news (well, that was actually to be expected, but I wasn't aware of it):
- For N= 38 (0x26), there are several links to official product documentation

- For N= 101 (0x65), there are several product-related links, but no official product documentation

There is also a single hit for N= 171 (0xab), but the sample size seems too small even for an entirely nonscientific method ;) Also, note that I cannot verify the quality and correctness of the two data sources. The method does not work well for N= 64 and N= 128.
The good news is that the two data sources didn't find any exact match for most other values of N...