Hitachi, Ltd.

Akio Makimoto

Norihiko Moriwaki

Akihiko Takase

Kenichi Sakamoto

Kazumasa Yanagisawa

Takahiko Kozaki

Atsushi Kiuchi

Takayuki Kanno

Masami Takahashi

Mitsuhiro Wada

Yusho Futami

Masumi Fukano

Kaori Nakayama

Yasuo Oginuma

A packet switch having a structure of writing a variable length packet received from each of input lines into a shared buffer memory on a fixed length data block unit basis, wherein a buffer controller forms an input queue for each input line and, when the last data block of a variable length packet is registered in the input queue, links a linked address list for the input queue to one or a plurality of output queues corresponding to one or a plurality of packet destination output lines.

Shared buffer type variable length packet switch

Provided is a high-throughput large-capacity ATM switch in which variation in memory access time and data output delay time generated in the case where a DRAM is used as a cell buffer of the ATM switch is absorbed. To realize this, the ATM switch comprises a first memory using a DRAM for storing cells, a second memory using an SRAM for switching and temporarily storing the cells before transferring the cells to the first memory, and a controller for generating write/read address and timing signals for the first and second memories. The controller generates read address and timing signals for the second memory and write address and timing signals for the first memory taking variation in access time or delay time based on access address of the first memory into account, so that the cells are output on destination output lines after the cells are switched and stored in the second memory and then stored in the first memory.

ATM switch

Cell buffer memory for a large capacity and high throughput ATM switch

An ATM cell processing apparatus including a DRAM for a frame producing buffer of a frame producing unit. In order to absorb the anisotropy of the access rate of the DRAM access, the random access mode of the DRAM access is always used. To compensate a drop in access rate in this case, the DRAM is arranged is an array form and each cell is divided. Resultant partial cell data are written into and read from respective DRAM banks in order. As a result, a fast cell buffer having a large capacity can be formed. The present cell buffer can be applied to a FIFO and the like as well.

ATM cell processing apparatus

Growing community of inventors

Yokohama, Japan

Akio Makimoto