Experimental evaluation of real-time support on the Mercuri wide area ATM testbed

ATM has been widely accepted as the key enabling technology for emerging multimedia applications. We at the Honeywell Technology Center are investigating the application of this technology to real-time control systems. The Mercuri wide area ATM testbed is a collaborative research effort in this direction. In this paper we describe our experiences from a series of performance evaluation experiments on the Mercuri testbed. Besides measuring application level throughput and round-trip delay, we investigated the support for real-time provisions like priority and deadline guarantees, which are especially important for control applications. We also measured delay and jitter for remote video transfer under no-load and loaded conditions. The major conclusion of our experiments is that the end systems remain a major bottleneck for high speed communications. We point out possible causes of performance degradation in this paper and outline some issues that need to be resolved for ATM to become a viable alternative for real-time multimedia based control applications.