Nec Corporation

Kazuhiro Ushiyama

Kenji Matsumura

Suminori Yoshikawa

A back-pressure type ATM switch wherein a variety of high-quality and flexible services can be served with high hardware/software efficiency. A resource manager provided to each input buffer, performs rejection control of cells according to RTQL (Rejection Threshold Queue Length) of each of s&times;n input queues, RTQL of each of s QoS-class virtual resources and a minimum guaranteed resource of each of the s&times;n input queues referring to RTQL of a common resource. A shaper accompanying each of the s&times;n input buffers shifts cells into a virtual queue at a speed obtained by (minimum guaranteed speed)&plus;(rate information)&times;(active VC number of the input queue). A rate controller calculates the rate information as a function of the sum of the virtual queue of each of the s&times;n input queues of every of the input buffers. A back-pressure connector provided to the input queue read controller of each input buffer defines correspondence between back-pressures generated by output buffers and back-pressures referred to by the input queue read controller.

Back-pressure type ATM switch

An ATM system including a switch unit having a plurality of input/output ports and a plurality of interface units connected to the respective input/output ports of the switch unit, each of the interface units mutually generating an internal communication cell with information necessary for rate control of an ATM traffic added thereto, inserting the cell into a free band of a user traffic and sending the same to all the interface units through the switch unit to interchange rate control information between the respective interface units, thereby conducting rate control of an ATM traffic by which equal throughputs can be obtained among connections.

Growing community of inventors

Tokyo, Japan

Kazuhiro Ushiyama