A NETWORK LEVEL CHANNEL ABSTRACTION FOR MULTIMEDIA COMMUNICATION IN REAL-TIME NETWORKS

The main challenge in the design of an efficient distributed multimedi a system is the integration and support of a wide variety of real-time applications. These applications require considerably different quali ties of service, in terms of expected throughput, delay, acceptable le vel of errors, specific degree of packet loss, and ability to dynamica lly adjust resource requirements. The design of communication protocol s to support guarantee real-time communication for distributed multime dia systems is the focus of this paper. We propose a network level abs traction called phi-channel to support the requirements of real-time a pplications. A phi-channel represents a fractional, simplex, end-to-en d communication channel between a source and a destination. The channe l is characterized by a set of specific performance parameters associa ted with its traffic. The required performance characteristics of a ph i-channel are specified in terms of the packet maximum end-to-end dela y and the maximum number of packets that can be sent over that delay. The primary attribute supported by the phi-channel is the on-time reli ability. Based on the specified parameters, the underlying delivery sy stem verifies the feasibility of supporting such a channel. The perfor mance of an accepted phi-channel are guaranteed under any conditions, baring hardware failures. The basic scheme that our model uses to veri fy the feasibility of accepting a phi-channel and the run-time support used to guarantee its performance are described. The results of a sim ulation experiment implementing the basic functionalities of the propo sed scheme are also presented.