An integrated video/voice/data protocol using distributed priority change

As a media access control (MAC) protocol for integrated services on a high-speed LAN, the distributed priority change (DPC) protocol is proposed. DPC supports synchronous voice/video service and asynchronous data service. To support synchronous service, it is necessary to guarantee periodic access to the network with a small delay variation. This requirement is met by alternating between the synchronous mode and the asynchronous mode. In DPC, there is not central controller and there is no special bit in the token for reservation to realize fair asynchronous data transmission. Performance comparisons with other token ring protocols are presented. It is shown that DPC can achieve higher maximum throughput than other priority protocols using a central controller. DPC can transmit long size data more effectively than the timed token protocol used in FDDI