ON THE USE OF DISPERSITY ROUTING FOR FAULT-TOLERANT REALTIME CHANNELS

This paper presents a taxonomy of dispersity routing schemes designed to provide fault-tolerant realtime communication. Our model involves t he provision of dispersity at the application level, rather than in th e physical layer as in traditional uses of dispersity. We assume a con nection oriented realtime communication service such as that provided by the Tenet Suite 1 or Asynchronous Transfer Mode (ATM) networks. We use the ideas of dispersity routing, redundancy, disjoint paths, and h ot and cold standbys to design and classify a set of schemes that can provide a range of fault-tolerant realtime services. The classificatio n provides a convenient framework, which we use to discuss the propert ies of the schemes and to conduct simulation experiments. We compare t he service provided and the costs of our schemes to other approaches t o fault-tolerant realtime communication, such as the Internet approach . We conclude that dispersity routing is a flexible approach to increa sing the fault tolerance of realtime connections, which can provide a range of improvements in service with a corresponding range of costs.