Protocol architecture for multimedia applications over ATM networks

At the data-link layer, ATM offers a number of features, such as high-bandwidth and per-connection quality of service (QoS) guarantees, making it particularly attractive to multimedia applications. Unfortunately, many of these features are not visible to applications because of the inadequacies of existing higher-level protocol architectures. Although a considerable effort is underway to tune these protocols for ATM networks, we believe that a new ATM specific protocol stack is essential to effectively exploit all the benefits of ATM. In this paper we describe the semantics of such a protocol stack, and discuss its advantages over traditional protocol architectures from the perspective of distributed multimedia applications. The performance impact of the new protocol architecture is experimentally demonstrated on a video conferencing testbed built around IBM RS/6000s equipped with prototype hardware for video/audio processing, and connected via ATM links.