| 摘要 |
Access protection and priority control is performed in a network with distributed queueing by the use of counters (119-123) and a memory (106). The counters (119-123) accumulate a number of passing request bits, the number of packets waiting in a queue, request bits generated, busy bits changed by station, and the numbers of free packets which have passed the station on the communication medium (100, 110). These request bits indicate that another station wishes to issue a data packet. The counters decrement when a free cell passes the station. The counters indicate a queue placing. The memory (106) stores upper and lower threshold values (124). These threshold values (124) are compared to the counter values (119-123) to control (105) the issuing of data packets from each station onto the medium. The imposed thresholds ensure that the bandwidth available to each station is maintained despite traffic load conditions, transmission rates, or length of the medium. This mechanism is applicable to the static and dynamic control of bandwidth usage of stations and nodes used in the I.E.E.E. 802.6 Draft Standard for Distributed Queue Dual Bus Metropolitan Area Networks. |
