INPUT CELL BUFFER SYSTEM FOR ATM EXCHANGE

摘要

PROBLEM TO BE SOLVED: To accumulate the cells of both variable speed (VBR) and fixed speed (CBR) via a single input buffer while reducing the disuse rate of the VBR cells and also reducing the transfer delay of the CBR cells. SOLUTION: A cell type identifier 1 identifies the type of an input ATM cell, and a VBR cell counter counts the VBR cells stored in an input buffer 10. A disuse rate output table outputs the disuse rate of the non-VBR cells based on the count value of the counter 2 and the threshold of a threshold holding circuit. An accumulation enabling circuit 7 outputs a non-VBR cell accumulation enabling signal when the disuse rate of the non-VBR cells is smaller than the random number value that is generated with every input of cells. Then the circuit 7 stores the non-VBR cells in the buffer 10.