A TIME-EFFICIENT ARCHITECTURE FOR MULTIMEDIA APPLICATIONS

This paper presents an architecture that enforces time requirements an d gives minimal end-to-end delays for multimedia applications, The lay ers and mechanisms allowing the system to fulfill the selected synchro nization, i.e., the logical relationships and timed interval semantics , are presented, The proposed approach relies on the use of a formal m odel based on extended time Petri nets, i.e., the time stream Petri ne t model (TStreamPN), that allows the user to completely specify the ti me requirements of a given application, The architecture implements, i n the application layer and on top of asynchronous environments, the r equested quality of service (perceived by the user) with respect to ti me, At the transport layer, the use of a partial order transport servi ce improves the reactive response of the communication transfers, Its principles are presented together with a presynchronization sublayer t hat makes the partial order transport service match the applicative sy nchronization requirements, Moreover, measurements on the implementati on of a videoconference system show that the requirements of the quali ty of ser,ice are fulfilled.