RE: [Rmt] Should FLUTE File Aggregation I-D be a working group item?
Rod.Walsh@nokia.com Tue, 22 November 2005 09:43 UTC
Received: from localhost.cnri.reston.va.us ([127.0.0.1] helo=megatron.ietf.org) by megatron.ietf.org with esmtp (Exim 4.32) id 1EeUgX-0000Of-UN; Tue, 22 Nov 2005 04:43:33 -0500
Received: from odin.ietf.org ([132.151.1.176] helo=ietf.org) by megatron.ietf.org with esmtp (Exim 4.32) id 1EeUgW-0000Nv-4u for rmt@megatron.ietf.org; Tue, 22 Nov 2005 04:43:32 -0500
Received: from ietf-mx.ietf.org (ietf-mx [132.151.6.1]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id EAA23661 for <rmt@ietf.org>; Tue, 22 Nov 2005 04:42:52 -0500 (EST)
From: Rod.Walsh@nokia.com
Received: from mgw-ext03.nokia.com ([131.228.20.95]) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1EeUz6-0000KH-RJ for rmt@ietf.org; Tue, 22 Nov 2005 05:02:45 -0500
Received: from esebh107.NOE.Nokia.com (esebh107.ntc.nokia.com [172.21.143.143]) by mgw-ext03.nokia.com (Switch-3.1.7/Switch-3.1.7) with ESMTP id jAM9eIUX020503; Tue, 22 Nov 2005 11:40:22 +0200
Received: from esebh103.NOE.Nokia.com ([172.21.143.33]) by esebh107.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 22 Nov 2005 11:43:21 +0200
Received: from trebe101.NOE.Nokia.com ([172.22.124.61]) by esebh103.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 22 Nov 2005 11:43:20 +0200
x-mimeole: Produced By Microsoft Exchange V6.5.7233.31
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Subject: RE: [Rmt] Should FLUTE File Aggregation I-D be a working group item?
Date: Tue, 22 Nov 2005 11:43:19 +0200
Message-ID: <7222D14EF47E0840AD88EC7BCBAD851301556BBB@trebe101.NOE.Nokia.com>
Thread-Topic: [Rmt] Should FLUTE File Aggregation I-D be a working group item?
Thread-Index: AcXuhtdhs5T2UkajRdyP3uqk1/CH/QAvopCw
To: magnus.westerlund@ericsson.com, christoph.neumann@inrialpes.fr
X-OriginalArrivalTime: 22 Nov 2005 09:43:20.0709 (UTC) FILETIME=[2C6F9B50:01C5EF49]
X-Spam-Score: 0.3 (/)
X-Scan-Signature: 20f22c03b5c66958bff5ef54fcda6e48
Content-Transfer-Encoding: quoted-printable
Cc: vincent.roca@inrialpes.fr, rmt@ietf.org
X-BeenThere: rmt@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Reliable Multicast Transport <rmt.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/rmt>, <mailto:rmt-request@ietf.org?subject=unsubscribe>
List-Post: <mailto:rmt@ietf.org>
List-Help: <mailto:rmt-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/rmt>, <mailto:rmt-request@ietf.org?subject=subscribe>
Sender: rmt-bounces@ietf.org
Errors-To: rmt-bounces@ietf.org
Hi All If you haven't read the document yet there are two things as play which may be confused: Group of files into: - logical groups OR physically one transmission object Extened-FLUTE-FDT signalling of files in physically aggregated objects: - using FLUTE normally (e.g. TOI 0) OR embedding the aggregated files' FDT in the object Magnus, correct me if I misunderstood - you're talking about the second issue. (i.e. you are questioning the placement of the file transport data - but are happy with the files going into multipart MIME?) Yes, unfortunately it will not be backwards compatible >with the normal FDT, but it could have a number of benefit: Well you could give the extended FDT a new MIME type and put it on "other than TOI=0" and then it's backwards compatible. Also, you can extend the FDT with "aggregated file" elements (instead of using the "file" element and so you'd be able to change semantics for aggregated files without gamaging "not-enhnaced" FLUTE receiveres. Is there something I missed about backward compatability onthis? >- The possibility to externally before receiving the object >determine if all files already has been received or if some >has. This is quite important to minimize the connection time >when doing repeated transmission to repair/complete unfinished >sessions. This seems to confirm it's about where to signal the file details of objects. Doing this as an "index FDT" in the multipart MIME assumes that the kind of use case mentioned is not significant. i.e. that it's highly unlikely that clients will have all the data of an object before it gets sent, and it's highly unlikely that objects with different fileURIs but the same files will get sent. If these are not good assumptions, extending the FDT is indeed a better method: but not without cost as bloated FDTs start to require their own FEC and reliability techniques and (unlike embedding in the aggregated object) there is no garuntee that all FDT instances will be received even though all files of an aggregated object are. So do we need to allow both methods, or is there a way to limit to just one? (To me it seems both, but with advisory text as to when each is better and some recommendations). >- Possibility to extract data from an partially decoded block. >With small files and large FEC blocks this becomes highly >interesting. Thus the data offset and length needs to be >available from external source. >Special data integrity mechanisms to make this reliable may >also need to be considered. There are two partically reveived deocding aspects: - partially received AOs, but some fully received blocks which enable extraction of some complete files (relatively simple) - partially revieced blocks with some fancy maths to revover parts of them (i.e. some files) (this is what Magnus said - but except for well ordered FEC, or null FEC, codes seems improbable) For well ordered FEC codes, indeed prior knowledge of byte ranges of files can be mapped to source symbols and the FEC parameters can tell the client whether it can restore the relevant source symbols for all or part of certain files (generally only all is useful, but for some applications even files with corruption may be partially renderable - e.g. corrupt images on a web page). For the extreme-FEC-dudes, putting into nomral FLUTE TOIs, instead of embedding into the multipart MIME, is much more robust for partial recovery from incomplete received blocks. Cheers, Rod. >-----Original Message----- >From: rmt-bounces@ietf.org [mailto:rmt-bounces@ietf.org] On >Behalf Of ext Magnus Westerlund >Sent: 21 November, 2005 12:24 >To: Christoph Neumann >Cc: Vincent Roca; rmt@ietf.org >Subject: Re: [Rmt] Should FLUTE File Aggregation I-D be a >working group item? > >Hi Christoph, > >See inline. > >Christoph Neumann wrote: >> Dear all, >> To start the discussion on the object aggregation draft, I >wanted to >> point out some issues that I think are in favour of having >this as an WG item. >> Physical aggregation scheme is of great advantage to avoid >the coupon >> collector problem. In the case of a large number of small files, >> physical aggregation combined with FEC is the only way to >effeciently >> transport the content. >> Therefore I think it is necessary to have some standardized solution >> for that, which could possibly be reused in several use cases with >> different FEC schemes... >> The draft exaclty addresses this problem. > >But in the process it looses a number of properties that >individual files. I think there would be a number of benefit >to NOT use multi-part mime and instead use an FDT based >scheme. Yes, unfortunately it will not be backwards compatible >with the normal FDT, but it could have a number of benefit: > >- The possibility to externally before receiving the object >determine if all files already has been received or if some >has. This is quite important to minimize the connection time >when doing repeated transmission to repair/complete unfinished >sessions. > >- Possibility to extract data from an partially decoded block. >With small files and large FEC blocks this becomes highly >interesting. Thus the data offset and length needs to be >available from external source. >Special data integrity mechanisms to make this reliable may >also need to be considered. > >I think these comments becomes extra important when >considering battery powered wireless devices. > > >> I heard that some physical aggragation scheme has also been >defined in 3GPP >> MBMS, but I'm not really following 3GPP activities and are >therefore not >> aware of that. Maybe someone has an input here? >> Beside the coupon collector issue, some FEC schemes perform >badly with >> small files, and aggregating them, seems the only solution >in this context >> (as it has been mentioned on the slides during the rmt session). > >The aggregation mechanism defined in 3GPP is to aggregate several >different UDP datagram streams used in streaming. Please see >http://www.ietf.org/internet-drafts/draft-watson-tsvwg-fec-sf-00.txt >for the outline of that solution and which is an initial proposal for >the most likely to be FECFrame WG. The actual 3GPP >specification of this >is TS 26.346: >http://www.3gpp.org/ftp/Specs/html-info/26346.htm >Select the latest version. > >Cheers > >Magnus Westerlund > >Multimedia Technologies, Ericsson Research EAB/TVA/A >---------------------------------------------------------------------- >Ericsson AB | Phone +46 8 4048287 >Torshamsgatan 23 | Fax +46 8 7575550 >S-164 80 Stockholm, Sweden | mailto: magnus.westerlund@ericsson.com > >_______________________________________________ >Rmt mailing list >Rmt@ietf.org >https://www1.ietf.org/mailman/listinfo/rmt > _______________________________________________ Rmt mailing list Rmt@ietf.org https://www1.ietf.org/mailman/listinfo/rmt
- [Rmt] Should FLUTE File Aggregation I-D be a work… Vincent Roca
- Re: [Rmt] Should FLUTE File Aggregation I-D be a … Christoph Neumann
- Re: [Rmt] Should FLUTE File Aggregation I-D be a … Magnus Westerlund
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Mark Watson
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Michael Luby
- Re: [Rmt] Should FLUTE File Aggregation I-D be a … Joerg Ott
- Re: [Rmt] Should FLUTE File Aggregation I-D be a … Magnus Westerlund
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Mark Watson
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- Re: [Rmt] Should FLUTE File Aggregation I-D be a … Christoph Neumann
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Michael Luby
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Michael Luby
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Mark Watson
- RE: [Rmt] Should FLUTE File Aggregation I-D be a … Rod.Walsh