IETF Logo Mail Archive

Re: [tcpm] ftp IP TOS Usage

<toby.moncaster@bt.com> Wed, 27 January 2010 15:35 UTC

Return-Path: <toby.moncaster@bt.com>
X-Original-To: tcpm@core3.amsl.com
Delivered-To: tcpm@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id B6DC63A6AB5 for <tcpm@core3.amsl.com>; Wed, 27 Jan 2010 07:35:30 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.599
X-Spam-Level:
X-Spam-Status: No, score=-3.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mWcMBwrrH6bh for <tcpm@core3.amsl.com>; Wed, 27 Jan 2010 07:35:29 -0800 (PST)
Received: from smtp1.smtp.bt.com (smtp1.smtp.bt.com [217.32.164.137]) by core3.amsl.com (Postfix) with ESMTP id 9C87F3A6950 for <tcpm@ietf.org>; Wed, 27 Jan 2010 07:35:29 -0800 (PST)
Received: from E03MVZ1-UKDY.domain1.systemhost.net ([193.113.30.62]) by smtp1.smtp.bt.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 27 Jan 2010 15:35:43 +0000
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Date: Wed, 27 Jan 2010 15:35:40 -0000
Message-ID: <AEDCAF87EEC94F49BA92EBDD49854CC70EB416DA@E03MVZ1-UKDY.domain1.systemhost.net>
In-Reply-To: <0B0A20D0B3ECD742AA2514C8DDA3B0650318D65B@VGAEXCH01.hq.corp.viasat.com>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: [tcpm] ftp IP TOS Usage
Thread-Index: Acqb1N2RUo9a45sCRYm0Gmf2V9ORxgDjsrCg
References: <0B0A20D0B3ECD742AA2514C8DDA3B0650318D65B@VGAEXCH01.hq.corp.viasat.com>
From: toby.moncaster@bt.com
To: Anil.Agarwal@viasat.com, tcpm@ietf.org
X-OriginalArrivalTime: 27 Jan 2010 15:35:43.0025 (UTC) FILETIME=[63054210:01CA9F66]
Subject: Re: [tcpm] ftp IP TOS Usage
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: TCP Maintenance and Minor Extensions Working Group <tcpm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/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: Wed, 27 Jan 2010 15:35:30 -0000

The ToS field has been redefined several times and now consists of the 6 bit Diffserv codepoint field and the 2 bit ECN field. 

Have a look at: http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51B_HTML/MAN/MAN4/0055____.HTM

And p.21 of RFC1060 which might explain why telnet uses 0x100. 0x08 implies that the segments are being sent with the "reliability" flag in the parlance of RFC1349.

Not sure if that helps at all...

Toby

____________________________________________________________________ 
Toby Moncaster, Senior Researcher, BT Network Infrastructure Practice
B54/70 Adastral Park, Ipswich, IP53RE, UK.  +44 7918 901170 



> -----Original Message-----
> From: tcpm-bounces@ietf.org [mailto:tcpm-bounces@ietf.org] On Behalf Of
> Agarwal, Anil
> Sent: 23 January 2010 02:36
> To: tcpm@ietf.org
> Subject: [tcpm] ftp IP TOS Usage
> 
> 
> Can someone please describe (or point to a document) why ftp uses non-
> zero IP TOS values (0x10 and 0x08) for non-SYN TCP segments of the
> control and data TCP connections, but uses IP TOS = 0 in TCP SYN
> segments?
> 
> telnet seems to use TOS = 0x10 in all TCP segments.
> 
> ssh and sftp seem to use TOS = 0 for SYN and the first few data
> segments, then switch to a non-zero TOS value (0x08).
> 
> (Above observations are based on Linux).
> 
> Thanks,
> Anil
> 
> Anil Agarwal
> ViaSat Inc.
> Germantown, MD 20876
> 
> 
> _______________________________________________
> tcpm mailing list
> tcpm@ietf.org
> https://www.ietf.org/mailman/listinfo/tcpm

v2.23.0 | Report a Bug | By Email