A Variation on CSMA/CD That Yields Movable TDM Slots in Integrated Voice/Data Local Networks

There are basic differences between the requirements for data and voice transmission. There are also differences between the capabilities of local networks and the functions that should be performed on these networks, and general global networks. A protocol is described for integrating data and voice in a local-area, random-access broadcast network. It enables a single system, with similar interfaces for voice and data, to be used for both. The protocol satisfies the transmission 1527 requirements of both media, and takes advantage of the characteristics of local networks. This protocol can be applied to any system with periodic and aperiodic sources, as long as all of the periodic sources have the same transmission requirements. In general, transmission capacity is less expensive in a local environment than in the global environment. This has resulted in significant differences in the types of networks implemented for data transmission in the two situations. In global networks, expensive access and switching techniques have been used to minimize the network capacity required to effect communications, whereas in local networks simpler switching techniques and less costly access nodes have been used. Several global networks, which use store-and-forward and packetswitching techniques to reduce the transmission requirements, are described in Chapters 1 and 2 of Ref. 1. A survey of techniques used in local networks, and an extensive bibliography is given in Ref. 2. Many of these local networks are configured as loops or random-access channels.