Re: [multipathtcp] Consensus call on potential MPTCP proxy work

Olivier Bonaventure <Olivier.Bonaventure@uclouvain.be> Wed, 19 April 2017 08:19 UTC

Return-Path: <olivier.bonaventure@uclouvain.be>
X-Original-To: multipathtcp@ietfa.amsl.com
Delivered-To: multipathtcp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8DBED13156E for <multipathtcp@ietfa.amsl.com>; Wed, 19 Apr 2017 01:19:15 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.321
X-Spam-Level:
X-Spam-Status: No, score=-4.321 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_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=uclouvain.be
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 d7EYT_jZ_xVW for <multipathtcp@ietfa.amsl.com>; Wed, 19 Apr 2017 01:19:14 -0700 (PDT)
Received: from smtp6.sgsi.ucl.ac.be (smtp.sgsi.ucl.ac.be [130.104.5.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 250B313156C for <multipathtcp@ietf.org>; Wed, 19 Apr 2017 01:19:14 -0700 (PDT)
Received: from [192.168.1.6] (unknown [87.66.240.251]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: obonaventure@smtp6.sgsi.ucl.ac.be) by smtp6.sgsi.ucl.ac.be (Postfix) with ESMTPSA id A1D4867DB04; Wed, 19 Apr 2017 10:19:04 +0200 (CEST)
DKIM-Filter: OpenDKIM Filter v2.9.2 smtp6.sgsi.ucl.ac.be A1D4867DB04
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=uclouvain.be; s=selucl; t=1492589945; bh=Hrn8OTr52WPCZUoBQR71vltp5vYkSN43+BHWQCP/dIE=; h=Reply-To:Subject:References:To:Cc:From:Date:In-Reply-To; b=qt9xoznTsbYCxPMG4B1AzkmvM8p0kW4OOJnQ+VbgyUFoS4LKPPP1N5MtH8LTH/nsY X056BqRd4FJcoFQOqr3ss5jbcfnUoOiApeVo/sBKG2fMOCGCw631t+Pvj0pt0ecS7B pHIu0zidvLpu8hxP1XxcQ6tvDZDbTQ6VPO3Op0QE=
X-Virus-Status: Clean
X-Virus-Scanned: clamav-milter 0.99.2 at smtp-6
Reply-To: Olivier.Bonaventure@uclouvain.be
References: <8c5ffa879686472594bfd3db2fa06076@rew09926dag03b.domain1.systemhost.net> <beacce37-1e58-5844-1ffc-786890a0ef35@uclouvain.be> <262C92B8-A35E-4C46-B2F6-C0A82BEE21AF@cs.pub.ro>
To: Costin Raiciu <costin.raiciu@cs.pub.ro>
Cc: philip.eardley@bt.com, multipathtcp@ietf.org
From: Olivier Bonaventure <Olivier.Bonaventure@uclouvain.be>
Message-ID: <231d1dd6-9d9f-4a5f-d1c6-bf8b33607430@uclouvain.be>
Date: Wed, 19 Apr 2017 10:19:04 +0200
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.8.0
MIME-Version: 1.0
In-Reply-To: <262C92B8-A35E-4C46-B2F6-C0A82BEE21AF@cs.pub.ro>
Content-Type: text/plain; charset="windows-1252"; format="flowed"
Content-Transfer-Encoding: 7bit
X-Sgsi-Spamcheck: SASL authenticated,
X-SGSI-Information:
X-SGSI-MailScanner-ID: A1D4867DB04.A5213
X-SGSI-MailScanner: Found to be clean
X-SGSI-From: olivier.bonaventure@uclouvain.be
X-SGSI-Spam-Status: No
Archived-At: <https://mailarchive.ietf.org/arch/msg/multipathtcp/iSADbsb902gv3LQI1zAkQexjgUk>
Subject: Re: [multipathtcp] Consensus call on potential MPTCP proxy work
X-BeenThere: multipathtcp@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Multi-path extensions for TCP <multipathtcp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/multipathtcp>, <mailto:multipathtcp-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/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: Wed, 19 Apr 2017 08:19:15 -0000

Costin,

>> I fully support the work on MPTCP proxies. I would not focus on the current use case (how gateway and two proxies) but more on the importance of :
>>
>> - being able to terminate Multipath TCP connections on a proxy somewhere in the network to bond different access networks when the server is not MPTCP capable
>> - using 0-rtt, i.e. the proposed solution should not require an additional rtt to create a connection
>
> + 1.
>
> Also, the solution should be future proof - if the server does support MPTCP, the proxy should simply relay the traffic, and not terminate the connection, allowing the client to directly connect to the server with other subflows.

Since the proxy is explict, the client creates an MPTCP connection to 
the proxy and the proxy creates another MPTCP connection to the final 
server. Since the proxy was the destination of the SYN, it cannot simply 
relay the traffic, but it should indicate to the client that the server 
supports MPTCP so that the next connection established by the client 
towards this server can directly bypass the proxy. This information 
about the MPTCP support on the final server could be part of the 
signalling information contained in the payload of the SYN+ACK



Olivier