11.Distributed Multimedia Platforms

by Paul Mueller (Universität Kaiserslautern, Germany)

Link to the SOTA Chapter

Ongoing Research

For dependable and high quality continuous media handling the provisioning of Quality of Service (QoS) by the networks and the end-systems is essential. But QoS is still an unanswered question in the internet. This yields true also for the next generation Internet based on IPv6. When different levels of Service are available (per flow or per class) then it is inevitable to use mechanism for authentication, authorization and accounting (aaa). Otherwise users will tend to always request the best service level. So that resources are blocked uselessly. Several research groups and the IETF are currently improving mechanisms for aaa. Distributed Multimedia Platforms should offer support for the integration of different media types. Several XML based solutions have been introduced and are still a current research topic. Media that is protected by copyright must be protected against unregulated duplication and usage. Therefore Digital Rights Management (DRM) a security mechanisms are essential parts for multimedia platforms.Future Directions

Future Directions

Beside QoS an adequate middleware is one of the most important issues in distributed multimedia systems. Like CORBA, COM and DCOM, the Web-Service approach can be seen as a new middleware architecture - especially for distributed multimedia systems. In order to emerge this new technology, different questions have to be answered. Scalability and security are the two significant topics as well as automatic service discovery and assembly. Therefore, the semantics of a web service and the semantics of its parameters have to be clear (semantic web). Additionally, network technologies like Peer2Peer and Ad-hoc-Networking must be taken into account to accomplish secure dynamic web service compositions.

In future most multimedia devices will be mobile and highly specialized. Therefore the existing multimedia platforms must be adapted to the requirements of mobile computing. The specialized devices will offer different environments. Multimedia platforms should be independent from the hardware, the operating systems and the network connectivity. It is necessary to develop middleware that is able to abstract from these environmental conditions.

CaberNet Related Activities

The "At Home Anywhere" (@HA) project's focus is on in-home digital networking and its applications. @HA integrates home appliances, devices, sensors and actuators in one coherent distributed architecture, based on a
common integrated network. This network supports different types of traffic (real-time and non-real-time) with different characteristics, such as entertainment, 'normal' data traffic, and sensing and control. Additionally, @HA researches the use of resource-lean embedded systems, so that even inexpensive small devices can be integrated. Main application area is ambient intelligence (or ubiquitous computing), specifically integrated home systems and health care ubiquitous computing.

The COMIT (Convergence of MHEG with Internet Technologies) project is funded by the Engineering and Physical Science Research Council under its Multimedia and Networks Architectures program. The COMIT project intends to research models and mechanisms for the integration of the MHEG-5 component of the DAVIC specification for Digital TV with current WWW technologies, such as HTML and with emerging ones, such as XML, SMIL, etc. We propose firstly to develop and compare, by means of simulation, models of an integrated service; and secondly to investigate extensions to MHEG and to the various WWW systems by means of which the two may be interfaced.

Today one can see a fast development of internet applications. The number of applications for different communication tasks is continuously increasing. There are applications for simple data transfer as well as for complex interactive multimedia applications. These different applications have different requirements for the communication. Nevertheless most applications have to use very simple communication services. New and specialized service are not used, just as Quality of Servcie (QoS) capabilities of networks. This is because applications are constituted to use a specific protocol during the development of the application. Therefore only simple protocols which are available everywhere are used.
The aim of this project is to develop and realize a concept for the dynamic switching of communication service for applications. First applications and communication services must be decoupled by an appropiate API. This is a precondition for the dynamic assignment of communication service at runtime. Then the selection of an appropriate communication service based on the application requirements and the knowledge about the services must be realized. This makes applications independent of the available communication software. It will be possible that applications profit of new technologies without adapting the application, whereby the same application is still compatible to already existing technologies.

Best effort networks typically are not able to satisfy any quality of service (QoS) guarantees regarding (minimum) packet throughput, (maximum) packet delay or delay jitter. Therefore, these networks have to be modified in order to be able to support real-time communications. In this project we elaborate new techniques for fault-tolerance which allow one to accept some deficiencies in network quality (e.g. packet losses). The techniques we investigated and analyzed are either part of some dedicated middleware or they are directly supported by the distributed applications. In case of audio / video communications, which has been the focus of our studies up to now, we are analyzing, in detail, techniques such as FEC, adaptive video encoding, information dispersal, traffic smoothing as well as combinations of these techniques [Richter 2001], [Wolfinger 2001]. Both, quantitative and qualitative assessments of the improvement in video quality are focal points of our research [Heidtmann 2001].

The GOPI project is building a distributed object-based middleware platform, or object request broker, that is intended to support soft real-time/ multimedia applications in a distributed environment. A key principle of the GOPI approach is that media-streams should be treated as first-class entities in the object-based distributed environment. For example, they should be visible in IDL definitions and handled in the same resource management environment as standard object invocations.

This project aims to improve the media quality provided by H.323 communication. This includes the usage of Quality of Service (QoS) capabilities of networks as well as the improved media processing within the endsystems. Especially the number of dropped media frames and end to end delay is aimed at being reduced.

The Information Cities project models aggregation/segregation patterns in a virtual world of infohabitants (humans, virtual firms, on -line communities and software agents acting on their behalf).

MAVA is a platform independent multimedia presentation system. In contrast to present approaches MAVA focuses on the realization of the extensibility of language concepts and media items instead of developing a new document language or language concepts. The extensibility permits a later integration of existing concepts into MAVA.

The aim of the NIPON project is to enable IP accounting systems to distinguish different users. Today's accounting systems are only able to distinguish between different hosts. Therefore on multiuser hosts and PC pools it is not possible to identify the user of a network resource. With respect to the exponential growth of bandwidth consumption and of the upcoming QoS capabilities of networks, it becomes more important to identify the person who is responsible for the usage of network resources.

Ozone, an IST project whose goal is to investigate, define and implement/integrate a generic framework to enable consumer oriented ambient intelligence applications.

The R-Fieldbus project (funded by the European Commission - IST-1999-11316) aims at developing an innovative wireless communication architecture supporting industrial multimedia. Within this project the group has proposed a new hybrid wired/wireless PROFIBUS solution where most of the design options are made in order to guarantee the proper real-time behaviour of the overall network [Alves 2002]. Furthermore, the group has also participated in the development of a double stack architecture, allowing the tunnelling of TCP/IP traffic in wired/wireless PROFIBUS networks [Pacheco 2001].

The project VENICE researches the future development of VoIP associated with web services. Within the project a new model is put forward which maps VoIP functionalities on web services. Further additional capability characteristics shall be realized as web services. Advantages over other models should be:


[Alves 2002] M. Alves, E. Tovar, F. Vasques, K. Roether, G. Hammer. "Real-Time Communications over Hybrid Wired/Wireless PROFIBUS-based Networks". Proceedings of the 14th Euromicro Conference on Real-Time Systems (ECRTS'02). Vienna, Austria. June 2002.

[Heidtmann 2001] K. Heidtmann, J. Kerse, T. Suchanek, B.E. Wolfinger, M. Zaddach. “Fehlertolerante Videokommunikation über verlustbehaftete Paketvermittlungsnetze“. GI-Fachtagung "Kommunikation in Verteilten Systemen" (KiVS 2001). Hamburg, Germany. Springer-Verlag. February 2001.

[Müller 1997] P. Müller. Visualization and QoS of Networks, CODATA Euro-American Workshop on Information Visualization, Paris, 1997.

[Müller 2000] P. Müller, B. Reuther, M.Schneider. ViAA - Avirtual ATM API for Arbitrary Layer 2 Access Networks, Computer Communications 23, S. 1019-1026, 2000

[Müller 2001] P. Müller, B. Reuter, O. P. Vyas, S.Sundar. Testbed Realization of Poisson Characteristics in ATM QoS Mechanism, in Broadband Networking in the New Millennium, ATM Interact. Symposium, New Delhi, 2001.

[Pacheco 2001] F.Pacheco, E. Tovar, A. Kalogeras, N. Pereira. "Supporting Internet Protocols in Master-Slave Fieldbus Networks". Proceedings of the 4th IFAC International Conference on Fieldbus Systems and Their Applications (FET'2001). Nancy, France. November 2001. pp. 260-266.

[Reuther 2002 ] B. Reuther, A. Ebert, P. Müller, H.Hagen. A Powerful Communication Framework for Distributed Virtual Reality. IEEE Visualization 2002. Boston.

[Richter 2001] J.P.Richter. "Spezifikations- und Messmethodik für ein adaptives Dienstgütemanagement". GI-Fachtagung "Kommunikation in Verteilten Systemen" (KiVS 2001). Hamburg, Germany. Springer-Verlag. February 2001.

[van Megen 2001] F. van Megen, P. Müller. Mapping Universal Geographical Area Description (GAD) to IPv6 Geo Based Unicast Addresses, work-in-progress, draft-vanmegen-ipv6-addr-v03.txt. October 2001.

[Vyas 1999] O.P. Vyas, S. Sundar, Reuther, P.Müller. VBR mechanism in ATM: An Experimental Investigation CMSC-99, International AMSE conference on Computer Modeling, Simulation and Communication, Jaipur, India, 1999.

[Wolfinger 2001] B.E. Wolfinger, M. Zaddach. “Techniques to Improve Quality-of-Service in Video Communications via Best Effort Networks“. IEEE International Conference on Networking (ICN '01). Colmar. July 2001.

[9] Ge Zhang, B. Reuther, P.Müller. Distributed Agent Method for User Based IP Accounting, 7th CaberNet Radicals Workshop, 13-16 October 2002, Bertinoro (Forlì), Italy

[11] Ge Zhang, B. Reuther, P. Müller. User Oriented IP Accounting in Multi-user Systems, The 8th IFIP/IEEE International Symposium on Integrated Network Management 2003, Colorado Springs, US

Maintained by Rogério de Lemos (r.delemos@ukc.ac.uk)
Last updated 23 June, 2003