An investigation of packetised voice on the FDDI token ring

The aim of the study is to verify that the fiber distributed data interface (FDDI), a proposed American National Standard for a 100 Mb/s token ring network using a fiber-optic medium that can support packetized voice while providing a reasonable service for asynchronous traffic. The authors begin by analyzing the maximum number of voice conversations the can be supported by a 100 Mbs/s FDDI token-ring network. The constraints imposed by FDDI ensure that no packets are lost, even under worst-case conditions. Simulation results indicate that a much greater number of calls can be supported by relaxing these constraints while still providing a suitable level of service. For example, using 10 ms voice packets, and FDDI network can support up to 734 conversations as compared with the analytical value of 376. A 10 km ring with 100 stations allows 600 conversations while leaving 30 Mb/s of bandwidth for asynchronous traffic