[EME] Re: transport recovery at the APP layer ?

Joe Touch <touch@ISI.EDU> Wed, 15 November 2006 17:05 UTC

Received: from [127.0.0.1] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1GkOCQ-0007aN-1l; Wed, 15 Nov 2006 12:05:22 -0500
Received: from [10.91.34.44] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1GkOCP-0007aF-4g for eme@irtf.org; Wed, 15 Nov 2006 12:05:21 -0500
Received: from vapor.isi.edu ([128.9.64.64]) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1GkOCN-0001Gj-Q2 for eme@irtf.org; Wed, 15 Nov 2006 12:05:21 -0500
Received: from [127.0.0.1] (67.sub-75-209-245.myvzw.com [75.209.245.67]) by vapor.isi.edu (8.13.8/8.13.8) with ESMTP id kAFH54aE017955; Wed, 15 Nov 2006 09:05:07 -0800 (PST)
Message-ID: <455B48BD.5050201@isi.edu>
Date: Wed, 15 Nov 2006 09:05:01 -0800
From: Joe Touch <touch@ISI.EDU>
User-Agent: Thunderbird 1.5.0.8 (Windows/20061025)
MIME-Version: 1.0
To: Rémi Després <remi.despres@wanadoo.fr>
References: <E6F7A586E0A3F94D921755964F6BE00662575C@EXCHANGE2.cs.cornell.edu> <4559FC5C.1090803@rd-iptech.com> <455A14AA.6010007@isi.edu> <455B3DDC.2060903@rd-iptech.com> <455B4094.1080400@isi.edu> <455B472A.9000303@wanadoo.fr>
In-Reply-To: <455B472A.9000303@wanadoo.fr>
X-Enigmail-Version: 0.94.0.0
X-ISI-4-43-8-MailScanner: Found to be clean
X-MailScanner-From: touch@isi.edu
X-Spam-Score: 0.0 (/)
X-Scan-Signature: d0bdc596f8dd1c226c458f0b4df27a88
Cc: eme@irtf.org
Subject: [EME] Re: transport recovery at the APP layer ?
X-BeenThere: eme@irtf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: end-middle-end research group <eme.irtf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/eme>, <mailto:eme-request@irtf.org?subject=unsubscribe>
List-Archive: <http://www1.ietf.org/pipermail/eme>
List-Post: <mailto:eme@irtf.org>
List-Help: <mailto:eme-request@irtf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/eme>, <mailto:eme-request@irtf.org?subject=subscribe>
Content-Type: multipart/mixed; boundary="===============0781569325=="
Errors-To: eme-bounces@irtf.org


Rémi Després wrote:
> Joe Touch wrote :
>> It'd be useful to decide whether recovery includes the assumption that
>> the app layer will reconnect and restore E2E context. If that's
>> _assumed_ here, it'd be a first IMO.
>>
>> Joe
> This is IMO an important question.
> 
> We agree, I believe, that forbidding middleboxes that do some transport
> relaying is unrealistic.
> (In other words, for the real world Internet,.the EME model must be
> accepted in addition to the E2E one.)

I'm not sure we agree.

I agree that we can call a proxy a middlebox, and so long as the
endpoint KNOWS it's not talking to the ultimate end, that's fine.

I don't agree that this is OK when the endpoint doesn't know about it.
I.e., if you prefer: E2E trumps EME.

> Then, there seems to be no simpler place, to recover from transport
> relay failures, than just above the transport layer..

The problem with this model is that all it does is move E2E to the
application layer. The transport layer no longer becomes an E2E service,
and all the capabilities it provides - reliable transport in particular
- must be reinvented at the app layer.

That's been a step backwards, IMO.

> It is thus not a surprise that  real applications, that had to adapt to
> the real transport world with no extra layer between transport and
> themselves, already have that recovery mechanism.
> 
>  It would indeed be a first _as an recognized model_, but AFAIK not in
> implemented code.

Right. I don't agree we should recognize it where it breaks E2E. (it
doesn't break E2E when the middle is explicitly known).

JOe


_______________________________________________
EME mailing list
EME@irtf.org
https://www1.ietf.org/mailman/listinfo/eme