Input buffer controller using back-pressure signals in atm switches and a method for determining the logical queue size

Abstract

A controller for the logical buffer depth in ATM switching system and a method for determining the logical queue depth, using the back-pressure signal and the occupied buffer depth information and supporting the P classes, are disclosed. The controller includes Routing Table Element making tag for routing of input cell; Input Buffer storing the cell that a tag is attached to in said routing table element; Switch fabric that reads the cell from said input buffer and then switches it to the output port; and Input buffer controller controlling the logical queue size in said input buffer. And the method for determining the logical queue depth includes the steps of calculating the back-pressure signal occurrence rate b,of the ith class; calculating the back-pressure signal occurrence threshold rate b,of the ith class; calculating the buffer depth T,of the logical queue of the ith class; calculating threshold values T,T,of the two buffer depths of the ith class; calculating the buffer size L,of the logical queue of the ith class; calculating the empty area size D,(j=1, 2, 3, L, P) of logical queues for the number of p classes.