| 摘要 |
<p>PROBLEM TO BE SOLVED: To attain the traffic control to suppress the congestion occurring in an ATM(asynchronous transfer mode) switchboard and also to assure the throughput of the VCs(virtual channels) using the same output port. SOLUTION: A buffer occupation value measurement part 3 measures each queue length of output port buffers 2-1 to 2-n and stores these measured queue length in a buffer occupation value table. A back pressure transmission part 4 outputs a transmission resistant signal, a transmission control signal and a transmission stop signal, when the queue length stored in the buffer occupation value table is smaller than the 1st threshold, equal to a level between the 1st and 2nd threshold levels and larger than the 2nd threshold value respectively as the back pressure signals. A cell transmission control part 12 transmits an ATM cell, without comparing the transmission time and the current time as long as the back pressure signal corresponding to a destination port instructs the restart. The part 12 also transmits an ATM cell, only when the transmission time is earlier than the current time, as long as the back pressure signal instruct the control.</p> |
