Control of access through local carrier sensing for high data rate networks and control of access of synchronous messages through circulating reservation packets

摘要

A combination of two new access methods for ring and unidirectional bus networks supports high data rate integrated traffic. The first access method provides access for asynchronous traffic. When a node senses the channel idle, it can begin to transmit. When it senses an incoming signal, it must stop transmitting in order to avoid a collision. But unlike other access protocols which abort the transmission when a collision occurs or is imminent, the process truncates the message in a fashion such that it can be resumed later when the channel again is idle. The system is called Carrier Sensed Multiple Access-Ring Network (CSMA/RN). The second access method provides support for synchronous traffic. This method implements one or more circulating reservation packets which permit a node to have reserved space when the special packet returns. The media access system is called Circulating Reservation Packet (CRP) system. Both access protocols operate simultaneously on the network with minimal interference. The CRP system is preferably used with the CSMA/RN protocol but is applicable to other fixed length, non-corrupting, circulating network structures to enable the nodes in a network to reserve space for synchronous traffic and guaranteed access.