14 Performance Trade-offs for a Multimedia Distributed Application Kurt Maly, C.M. Overstreet, Hussein Abdel- Wahab, A.K. Gupta, Muthu Kumar and Rahul Srivastava Old Dominion University Department of Computer Science Norfolk, Virginia 23529, U.S.A Phone: 804-683-3915, Fax: 804-683-4900 E-Mail: (maly, cmo, wahab, ajay, rethi_m, sriva_r)@cs.odu.edu Abstract We have developed an Interactive Remote Instruction (IRI) system to support university- level instruction in a networked environment. The IRI system creates a virtual classroom where all participants have similar experiences independent of their location (separated by up to order of 100 km). Participants interact with audio, video, and collaborative tool operation using a multimedia workstation. We describe an IRI testbed consisting of Sun Sparcstations 5 running Solaris 2.4 implemented over a local area network. We discuss the performance trade-offs and the scalability of the IRI system by analyzing results obtained during the execution of a test suite. The most important conclusion of this work is that, though some improvements are required, we are able to achieve an acceptable performance within the goals we had established for IRI-required functionalities using moderately priced hardware. Feasibility means that response time for user commands is no more than twice in the worst case (Mosaic running on a single workstation by itself versus Mosaic running collaboratively on the testbed with multiple video streams and audio added). Results from this experimentation are being used to design dynamic resource management scheme which will regulate the demand on the IRI system resources to improve user perception of the quality of the virtual classroom. Keywords Networking, multimedia, remote instruction, performance evaluation 1 INTRODUCTION While several multimedia teleconferencing systems are available which support collaborative work, none have the ability to support more than a few simultaneous users and none automate the handling of video and audio streams. We present a performance study on the tradeoff's R. Puigjaner (ed.), High Performance Networking © Springer Science+Business Media Dordrecht 1995