Samsung Electronics Co., Ltd.

Electronics and Telecommunications Research Institute

Korea Telecom

Jeong-Won Heo

Ju-Yong Lee

Sung-Hyuk Byun

Jae-Jin Shin

Jin-Woo Yang

Dan-keun Sung

Kyung-geun Lee

Dan-Keun Sung

Kyeong-Ho Lee

Soo-Jong Lee

Kyung-Geun Lee

Tae-Won Kim

An ATM switch having the buffer threshold controller to control the cell input into the switching element using the back-pressure signal and a method for determining the buffer threshold according to the buffer threshold controller are disclosed. The ATM switch includes buffer pool storing the cell input to the switch; buffer pool control part storing the buffer pool occupancy information per input port of the buffer pool; threshold control part receiving the buffer pool occupancy information from the buffer pool control part and calculating the threshold per input port periodically and then sending it to the buffer pool control part; input crosspoint control part controlling the cells input to the buffer pool by receiving the control signal from the buffer pool control part; and output crosspoint control part controlling the cells output from the buffer pool by receiving the control signal from the buffer pool control part. The method includes the steps of calculating r , the buffer pool occupancy rate of the ith input port (i&equals;1, 2, 3, . . . , N); calculating r , the threshold of the buffer pool occupancy rate of the ith input port; calculating L , the number of occupation of the cells in the buffer pool of the ith input port; calculating the difference, D &equals;t &minus;L (k&equals;1, 2, 3, N . . . , N) between t , the threshold of the jth input port and L , the number of cells stored in the buffer pool, where i&ne;j (j&equals;1, 2, 3, . . . , N); calculating t , the threshold in case where the t &minus;L is the kth value in descending order from the N input ports; calculating b , minimum threshold to guarantee the minimum cell input; and comparing &Dgr;, the minimum unit of increase or decrease of the threshold and the value of t &minus;b .

ATM switch and a method for determining buffer threshold

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&equals;1, 2, 3, L, P) of logical queues for the number of p classes.

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

An idle address controller for a shared buffer type ATM switch controls the addresses of output cells in a common memory to be stored directly in an idle address buffer without passing through the conventional idle address delay controller, by improving the idle address control scheme of a unit switch. The idle address controller includes an idle address control signal generator for generating idle address control signals based on the buffer length information from counters, idle address control signal buffers for storing the idle address control signals, and an idle address control signal multiplexer. Therefore, the idle addresses can be efficiently provided, and this mechanism lowers cell loss and reduces required memory capacity.

Idle address controller for shared buffer type ATM switch

Growing community of inventors

Daejon, South Korea

Jeong-Won Heo