Digitized voice distribution using XTP and FDDI

Abstract

The feasibility of distributing digitized voice over FDDI using the Xpress Transfer Protocol (XTP) is examined. The requirements of such a system, the role of a communications protocol, and the overall experimental design are studied. A basic configuration is developed to measure the system throughput, latency, and jitter, and from these data the number of voice channels that a given configuration would support is computed. The basic system is then perturbed by adding up to 75 Mb/s of background synchronous load to the FDDI network, and by artificially dropping up to 10% of the transmitted packets to force retransmissions. Whether XTP's reliable transport multicast, which provides a 1-to-m transmission capability, provides a latency reduction when compared to m serial unicasts is investigated. Conclusions regarding the utility of a transport protocol for both single segment and multiple-segment LANs are presented.<>