Re: [multipathtcp] Options or Payload: pros and cons

"SCHARF, Michael" <Michael.Scharf@alcatel-lucent.com> Thu, 12 November 2009 01:57 UTC

Return-Path: <Michael.Scharf@alcatel-lucent.com>
X-Original-To: multipathtcp@core3.amsl.com
Delivered-To: multipathtcp@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 5784E3A689F for <multipathtcp@core3.amsl.com>; Wed, 11 Nov 2009 17:57:37 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.249
X-Spam-Level:
X-Spam-Status: No, score=-6.249 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, HELO_EQ_DE=0.35, RCVD_IN_DNSWL_MED=-4]
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 Xvbru1awe3cs for <multipathtcp@core3.amsl.com>; Wed, 11 Nov 2009 17:57:36 -0800 (PST)
Received: from mailrelay2.alcatel.de (mailrelay2.alcatel.de [194.113.59.96]) by core3.amsl.com (Postfix) with ESMTP id E59943A6859 for <multipathtcp@ietf.org>; Wed, 11 Nov 2009 17:57:35 -0800 (PST)
Received: from SLFSNX.rcs.alcatel-research.de (slfsn2.rcs.de.alcatel-lucent.com [149.204.60.99]) by mailrelay2.alcatel.de (8.13.8/8.13.8/ICT) with ESMTP id nAC1vts5004064; Thu, 12 Nov 2009 02:57:56 +0100
x-mimeole: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Date: Thu, 12 Nov 2009 02:57:53 +0100
Message-ID: <133D9897FB9C5E4E9DF2779DC91E947C01B6AD21@SLFSNX.rcs.alcatel-research.de>
In-Reply-To: <C1CDADDD-4C5E-4CEA-8548-80FA0DDDA96E@cs.ucl.ac.uk>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: [multipathtcp] Options or Payload: pros and cons
Thread-Index: AcpidbAuiuf3FDhCS16ZftfPqCghoQAxCBHA
References: <2181C5F19DD0254692452BFF3EAF1D6808D7BB51@rsys005a.comm.ad.roke.co.uk><3c3e3fca0911091838w6620d955m68074495027d7c5d@mail.gmail.com> <C1CDADDD-4C5E-4CEA-8548-80FA0DDDA96E@cs.ucl.ac.uk>
From: "SCHARF, Michael" <Michael.Scharf@alcatel-lucent.com>
To: Costin Raiciu <c.raiciu@cs.ucl.ac.uk>, multipathtcp@ietf.org
X-Scanned-By: MIMEDefang 2.57 on 149.204.45.73
Subject: Re: [multipathtcp] Options or Payload: pros and cons
X-BeenThere: multipathtcp@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Multi-path extensions for TCP <multipathtcp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/multipathtcp>, <mailto:multipathtcp-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/multipathtcp>
List-Post: <mailto:multipathtcp@ietf.org>
List-Help: <mailto:multipathtcp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/multipathtcp>, <mailto:multipathtcp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 12 Nov 2009 01:57:37 -0000

> Payload
> + option space limits no longer matter; can do funkier stuff later,
> like negotiate keys, etc.
> + easier to get reliability; retransmit of control data linked to
> data retransmit
> + easier to deal with middleboxes that resegment (it just works!) new 
> + options on syns may be allowed, but not on data (is this true)?
> - feels like a hack, not the traditional way to evolve tcp
> - implies encoding of any data sent MUST  be ASCII; 
> middleboxes (ids, traffic normalizers) that look at content 
> and see binary stuff will probably drop the data; finally, if 
> we used binary stuff, there is no guarantee for fate sharing. 
> . Text encoding is less space efficient; does it matter?

I don't understand why ASCII encoding is mandatory. An IDS that parses
the content may anyway be confused by the incomplete content inside one
MPTCP subflow, independent of the question whether options or payload
encoding is used. Or do I miss something?

Michael