Performance and Guaranteed Quality of Service for AT&T Multimedia Communications Systems

Abstract

In this paper, we model and analyze the performance of ATM based AT&T multimedia (MM) communication server for server-centric and peer-to-peer scenarios. We present data structures and algorithms and a way to ship the needed MM data from the database to clients in a timely manner avoiding both starvation and overflow. The system level capacity and performance metrics we use are the maximum number of simultaneous video streams of given bit rate supported and the response time for a typical user command respectively. By modeling the processing scenarios using queuing network and accounting for the parallelism within the architectures, we show that the system supports 14, 8 Megabit per second streams in the server-centric case and over 45, streams in the peer-to-peer case. The delays experienced by the data packets at the disk subsystem, bus complexes, and server CPU limit the capacity in the former case and the delays that occur when data packet moves from the disk to ATM adapter via the bus complexes limit the number of streams in the later case. The methodology is general, and is useful in designing, prototyping and configuring servers and provides a basis for realizing guaranteed quality of service in MM communication context.