Optical star network protocol and system with minimised delay between consecutive packets

摘要

A system to allow a network of stations (100) such as computers arranged in a star formation, to communicate with each other. The system has a protocol whereby stations (100) are granted access to the network, the protocol being tailored to star networks. Each station (100) may send a packet of data in each cycle of operation, provided that it indicated in a corresponding reservation slot (112), that it wishes to transmit. By examining the reservation slots (112) associated with stations (100) earlier in the cycle, each station (100) can determine the station (100) which is immediately preceding the one station amongst the stations which are to transmit data (i.e. have indicated in the corresponding reservation slot). On the basis of that determination the one station (100) transmits its data packet promptly after that preceding station (100) has transmitted its data packet; at least in certain cases, the station initiates transmission prior to having finished receiving the packet transmitted by the preceding station but with a timing to avoid data collision. Arrangements are shown whereby a data receiving station (100) can acknowledge receipt in a suitable acknowledgement slot (114) and wherein a busy station (100) can automatically reserve space. A variation to the protocol is given wherein reservations are note necessary, thereby speeding up operation in certain operating conditions.