Re: [multipathtcp] Two proxy scenario (network proxy off path) - far end connection initiation?

Yoshifumi Nishida <nishida@sfc.wide.ad.jp> Thu, 30 March 2017 17:59 UTC

Return-Path: <nishida@sfc.wide.ad.jp>
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 9C45E126557 for <multipathtcp@ietfa.amsl.com>; Thu, 30 Mar 2017 10:59:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.401
X-Spam-Level:
X-Spam-Status: No, score=-1.401 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_SORBS_SPAM=0.5, RP_MATCHES_RCVD=-0.001, SPF_PASS=-0.001] autolearn=no autolearn_force=no
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 TgIUY3TPEElC for <multipathtcp@ietfa.amsl.com>; Thu, 30 Mar 2017 10:59:01 -0700 (PDT)
Received: from mail.sfc.wide.ad.jp (shonan.sfc.wide.ad.jp [IPv6:2001:200:0:8803::53]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2442C128D19 for <multipathtcp@ietf.org>; Thu, 30 Mar 2017 10:59:01 -0700 (PDT)
Received: from mail-oi0-f52.google.com (mail-oi0-f52.google.com [209.85.218.52]) by mail.sfc.wide.ad.jp (Postfix) with ESMTPSA id 7610929CEB9 for <multipathtcp@ietf.org>; Fri, 31 Mar 2017 02:58:59 +0900 (JST)
Received: by mail-oi0-f52.google.com with SMTP id o67so38796558oib.1 for <multipathtcp@ietf.org>; Thu, 30 Mar 2017 10:58:59 -0700 (PDT)
X-Gm-Message-State: AFeK/H0ZIufpgQCtF97laH5p/FA5cuOvOE8MwG2X0gI5PTPaqSQOWTnqq+0fARzcsoXBUMj52jKVarMA9hGHGA==
X-Received: by 10.202.92.138 with SMTP id q132mr628612oib.168.1490896737893; Thu, 30 Mar 2017 10:58:57 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.157.41.137 with HTTP; Thu, 30 Mar 2017 10:58:57 -0700 (PDT)
In-Reply-To: <5e11095d-3498-8a59-da5a-77e9288d33d8@uclouvain.be>
References: <6d6cd823acc9416a83801684c73cb22c@rew09926dag03b.domain1.systemhost.net> <787AE7BB302AE849A7480A190F8B933009E431BF@OPEXCLILMA3.corporate.adroot.infra.ftgroup> <627564a6096f425eb9010ad3f9e011e1@rew09926dag03b.domain1.systemhost.net> <5e11095d-3498-8a59-da5a-77e9288d33d8@uclouvain.be>
From: Yoshifumi Nishida <nishida@sfc.wide.ad.jp>
Date: Thu, 30 Mar 2017 10:58:57 -0700
X-Gmail-Original-Message-ID: <CAO249ydNLAGMmDTXAqafi1NTaz_+dxmkjiig+Uhmr32dT_-PfA@mail.gmail.com>
Message-ID: <CAO249ydNLAGMmDTXAqafi1NTaz_+dxmkjiig+Uhmr32dT_-PfA@mail.gmail.com>
To: "Olivier.Bonaventure@uclouvain.be" <Olivier.Bonaventure@uclouvain.be>
Cc: "philip.eardley" <philip.eardley@bt.com>, mohamed.boucadair@orange.com, multipathtcp <multipathtcp@ietf.org>
Content-Type: multipart/alternative; boundary=001a113c141875a9d9054bf67257
Archived-At: <https://mailarchive.ietf.org/arch/msg/multipathtcp/AlbQisMTUijKwLegrI4X5ZufQvI>
Subject: Re: [multipathtcp] Two proxy scenario (network proxy off path) - far end connection initiation?
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: Thu, 30 Mar 2017 17:59:04 -0000

Hmm.  But, I am not very sure if we really need to think about this case at
this moment.
It seems to me there are too many assumptions to make this work and it
doesn't look very scalable (I'm not sure how to maintain such public IP
address table)
If we don't see strong demands to support this case, I think it might be
better put aside it for the time being.
--
Yoshi


On Thu, Mar 30, 2017 at 8:19 AM, Olivier Bonaventure <
Olivier.Bonaventure@uclouvain.be> wrote:

> On 30/03/17 17:03, philip.eardley@bt.com wrote:
>
>> If I get it right, the assumption here is that for a TCP connection
>> initiated from the remote end point , the remote network proxy is on path.
>> (in the other direction we're assuming the remote proxy is off path, so
>> seems a bit odd?)
>>
>
> This is related to the fact that if the downstream MCP operates in
> explicit mode, then it performs NAT. Typically, the MCP has a block of
> public IP addresses that it uses for the clients that it serves. All
> external packets destined to any of these addresses are routed to the MCP.
>
> I think there's also the assumption that the local endpoint (in the home)
>> has previously made a connection out which has instantiated state in the
>> remote proxy. So in this scenario, when the TCP SYN from the remote end
>> point hits the remote proxy, then the remote proxy knows which home gateway
>> the other end is on. Or something like that - to be honest, I couldn't
>> understand the slide /section of the draft.
>>
>
> There is an assumption that either there is a one-to-one mapping between
> the client addresses and the public addresses used by the MCP or the client
> has configured some port mapping rules, e.g. with PCP on the dMCP and the
> uMCP
>
>
> Olivier
>
>
> _______________________________________________
> multipathtcp mailing list
> multipathtcp@ietf.org
> https://www.ietf.org/mailman/listinfo/multipathtcp
>