CURRENT_MEETING_REPORT_ Reported by Sam Wilson/The University of Edinburgh Networking Multimedia Applications BOF (MULTIAPP) Chris Adie introduced himself as the leader of the RARE Multimedia Information Services Task Force and described the scope of the MULTIAPP BOF, namely covering networked access to multimedia (MM) resources from both the user's and provider's points of view. In particular it was not intended to cover MM conferencing, which was being addressed elsewhere. Three developments suggested the need for work in this area: o Users were using MM authoring tools (e.g. Guide, Toolbook) to produce MM applications; o Existing client/server tools such as Gopher, WAIS and WWW are being extended to cope with MM; and o Various MM-related network tools and projects have emerged: MICE (in the conferencing field), RTP (Real Time Protocol), ST2 and multicast (though multicast was currently being used largely in the conferencing area: person-to-person rather than machine-to-person). Chris then gave a short presentation covering the probable application categories, the requirements, the existing systems and standards and the aims he saw for the BOF. The slides from his presentation follow these minutes. A couple of points of interest to go with the slides: 1. Chris is the editor of RARE Technical Report 5 ``A Survey of Distributed Multimedia: Research, Standards and Products'' available on paper and in various forms for anonymous FTP on ftp.ed.ac.uk in the directory pub/mmsurvey; and 2. Many projects seem to use SGML in one form or another. A list of relevant issues that might be suitable areas of work was then solicited from the floor. The discussion arising from this was wide ranging and it took some time before suitable areas for IETF involvement was agreed upon. The list eventually comprised: o Responsiveness o Reliability o Isochronism o Reverse Control Flow o Hypermedia Linking o Presentation Topics covered and points made in the discussion included: - The first three items in the list fall into the 'Quality of Service' area; the third item, 'Reverse Control Flow' might fall into either QoS or into 'user requirements' since it might refer to low level control ("I'm a slow display, send me fewer frames per second") or to the users navigation through the MM application ("send frames 36 to 90 at 1 frame per second"). - In the QoS area questions arose about whether 'responsiveness' (for instance) was a 'lower layer' problem and should therefore be tackled by the network providers; it was noted that caching strategies can help there. - Also in the QoS area there was a lot of talk about how to handle the syncing of data, both in the 'isochronicity' area and also in the realm of synchronising different parts of a MM presentation; RTP provides time stamping and sequencing but requires higher level stuff to actually use this information. - Handling of 'out-of-sync' conditions need to be handled in consistent ways - Apple's Quicktime seems to do it impressively and so may other architectures (Microsoft's "ClockWorks" was mentioned). - What can the IETF contribute to an area where there are already so many competing products, some being pushed heavily by the big manufacturers? Some answers to this covered the areas of interworking and platform independence - the ability to play back and control MM applications across the network and onto a different platform from that for which it was written. - In the area of 'Hypermedia linking' it was pointed out that what is needed is more than hyperTEXT linking - we need to be able to define, say, active areas of graphics as well as active words or phrases. At this point Tim Berners-Lee was invited to give a short description of HTML and HTML+, the description languages underlying WWW, and compared it particularly to HyTime. Tim was less than encouraging about HTML+ as a contender for a generalised MM presentation language or interchange format, but Chris Adie was more hopeful. At this point the group seemed to be inclining towards the view that there was nothing obvious that the IETF could be doing except perhaps to encourage a pilot project to mount a MM application across a network. Discussion re-focussed on the description of interchange formats and `Multimedia X.' Carsten Bormann of Technische Universitaet Berlin revitalised the meeting by suggesting the following `taxonomy' for the problem: o Remote Access to MM Applications Needs MM analogue of X Window System (note that RTP provides some of the necessary functionality but higher level integration is needed along with some kind of session control). o Global Hyperlinking - URI/URL - searching - ``location address'' (this is a HyTime term) o MM Document/Application Interchange Format This is already being tackled by, for example, HyTime, MHEG, and HyperODA. The major area of work here is in the ``MM X'' area, though there is some work needed in interchange formats. It was decided that some members of the group (which members seemed to be decided informally later) should: 1. Take one or more existing applications; 2. Try to mount them for access across a network; 3. Decide whether it is currently possible to achieve this; and 4. Come back to the IETF within a year or so to see if there was any standardisation effort that should be followed up or whether the existing tools and techniques were sufficient. Looking further at the X analogy brought Carsten to the overhead projector again to describe the possible structure of ``MM X'' (or perhaps just ``M'' a Multimedia X analogue. "monomedium X" | "MultiMedia X" ------------------------|------------------------ | Events | Drawing requests | Video and audio clips Windows | | Window Manager(s) | QoS Mgr, Time Mgr, | Schedule Mgr, etc. ------------------------------------------------- | TCP | RTP | Between the two layers in ``MM X'' would be specifications for synchronisation and playout. Some people (SunSoft, DEC, others that people vaguely recalled but couldn't name) are already working in this area. Discussion followed on the details of what work should be done, how the tasks should be limited (need achievable goals), and how to liaise with other groups. The meeting eventually settled on the following items: o Attempting some pilot work in mounting (at least) one MM application across the network; o Working up a draft charter for a proposed IETF working group; o Looking at ways of linking existing or emerging standards (RTP, HTML+, etc.) to define a MM access protocol somewhat analogous to X; and o Study of prior art and liaison with other groups (SunSoft, DEC, Apple, Microsoft, Bellcore and various other groups and consortia). Minute-Taker's Disclaimer: In the tradition of BOFs, the discussion in this one was varied and wide ranging. Trying to make coherent minutes that reflect the feel of the meeting is a tricky task and has no doubt been influenced by what the minute-taker happened to be concentrating on (or not) at any particular moment. I therefore take full responsibility for any errors of fact, substance or emphasis, whilst denying any liability in that regard! Attendees Chris Adie C.J.Adie@edinburgh.ac.uk Axel Belinfante Axel.Belinfante@cs.utwente.nl Carsten Bormann cabo@cs.tu-berlin.de Steve Buchko stevebu@newbridge.com Jill Foster Jill.Foster@newcastle.ac.uk Kevin Gamiel kgamiel@cnidr.org Joan Gargano jcgargano@ucdavis.edu Terry Gray gray@cac.washington.edu Maria Heijne maria.heijne@surfnet.nl Rune Hjelsvold Rune.Hjelsvold@idt.unit.no Xinli Hou xinli@cs.utwente.nl Sascha Ignjatovic sascha@veda.co.at Xander Jansen xander.jansen@surfnet.nl Ola Johansson ojn@se.ubn.net John Johnston john@berlioz.nsc.com Thomas Kaeppner kaeppner%heidelbg.vnet@ibmpa.ibm.com Jim Knowles jknowles@binky.arc.nasa.gov Steen Linden steen.linden@uni-c.dk John Martin John.Martin@newcastle.ac.uk Paul Milazzo milazzo@bbn.com Ronny Nilsen Ronny.Nilsen@usit.uio.no Lars-Gunnar Olsson Lars-Gunnar.Olsson@data.slu.se Geir Pedersen Geir.Pedersen@usit.uio.no Dan Romascanu dan@lannet.com A. Velu Sinha avsinha@attmail.com Simon Spero simon_spero@unc.edu Guido van Rossum guido@cwi.nl Ton Verschuren Ton.Verschuren@SURFnet.nl Chris Weider clw@merit.edu Sam Wilson sam.wilson@ed.ac.uk