Universidade Federal do Rio de Janeiro
Projeto de Cooperação Internacional CAPES/COFECUB
Grupo de Teleinformática e Automação
From multimedia models to multimedia protocols
Prof. Michel Diaz - LAAS-CNRS
13 de julho de 1998 - Sala H312 - 9:00 / 12:00 h, 13:30 / 16:30 h
Michel Diaz is Directeur de Recherche at the Centre National de la Recherche Scientifique
(CNRS) and leads the Research Group ``Communications Software'' at the LAAS du CNRS,
Toulouse. In 1989 and 1990, he spent a year as a visiting professor and staff at the University of
Delaware at Newark and the University of California at Berkeley.
He is been working on the development of methodologies, techniques and tools for the
design of high speed multimedia cooperative distributed systems.
He has written one book, more than 120 technical publications and is the editor of a North
Holland volume on Protocol Specification, Testing and Verification, 1985, co-editor of three
North Holland volumes on developing and using Formal Description Techniques for the
Specification, Testing, Verification and Implementation of Protocols (on Estelle, LOTOS and the
FORTE conference), co-editor of a LNCS volume on ``Application and Theory of Petri nets'',
1995, and co-editor of a World Scientific volume on Multimedia Modeling, 1996.
This talk presents a new general architecture and a new transport layer
for multimedia systems. It will show how this architecture has been
deduced from a formal model of the synchronization requirements inherent
to multimedia objects. The global design methodology follows a three step
process. The purpose of the first step was to well understand what multimedia
requirements are; this has been done by defining general formal models of
multimedia objects. Then a deep analysis of the present protocols was
conducted and an extension of them was proposed in coherence with these
models. The last phase led to the general multimedia architecture that has
been designed to minimize the network and end-system communications resources,
the end-to-end delay, and to fulfill the multimedia temporal requirements.
This new architecture includes a new communication transport layer to transfer
complex multimedia objects. This new transport protocol, based on the concept
of Partial Order Connection, is a partially reliable and partially order ed
protocol. The resulting protocol leads to the definition of a new, generic
and application-dep endent service and to a set of related protocols that
will be shown to be able to integrate the different flows and media. The
proposed new connection, is a direct extension of the usual concepts of
connection used in existing connection oriented -CO- (e.g. TCP) and
connectionless -CL- (e.g. UDP) protocols. These ideas were implemented in
the context of a generic teleconferencing system and the related general
architecture will finally be discussed.