Kawasaki Steel Corporation

Sony Corporation

Hiroshi Yoshizawa

Masato Yoneda

Yoshihiro Ishida

Hideo Nakano

Each CAM of a retrieving device according to the present invention has one output terminal and four input terminals. One of the four input terminals is pulled down to input a logical value 0 at all times. The other three of the input terminals are connected to output terminals of other CAMs. Prior to starting auto-store processing, each CAM recognizes a terminal that inputs an output from a CAM having a higher priority than the CAM itself on the basis of an input signal [ABCD] including initial signals and the logical value 0 from the input terminals. On the basis of a result of the recognition, each CAM performs auto-store processing. Thereby auto-store processing can be readily performed by a plurality of CAMs.

Retrieving device and method, recording medium, and program for enabling a plurality of associative memories for retrieval and auto-storing

The invention relates to a network interface apparatus called a router or the like which is provided in a network system and relays the transmission of a data packet as a bundle of information. In order to know the permission or inhibition of communication of the data packet at a high speed while suppressing an increase in memory capacity, there is provided a coupling management table in which one VLAN ID is allocated to each terminal (each MAC address) and coupling information showing whether the communication from the terminal having a transmitting side VLAN ID to the terminal having a receiving side VLAN ID is permitted (logic &ldquo;1&rdquo;) or inhibited (logic &ldquo;0&rdquo;) has been stored at each of the coordinate points using the VLAN ID on the transmitting side and the VLAN ID on the receiving side as coordinates.

Network interface apparatus for transmitting a data packet

An associative memory device having a high speed and good performance is provided without degrading the simple design of a peripheral circuit of a conventional associative memory. The associative memory device has an N-bit first buffer and an M-bit second buffer in which W-bit data is stored through a data input port, detection device for detecting that the W-bit data is input to the first buffer k times or to the second buffer r times, a switch for alternately switching buffers in which the W-bit data is stored, and a search control for performing a search operation for a memory region by using data in the first or second buffer. By using data in the first or second buffer, during the search operation for the memory region of the associative memory, the W-bit data for the next search operation is input to the second or first buffer.

Associative memory device

The present invention provides a network frame switch and a content addressable memory (CAM). The CAM includes a plurality of word memories which store a plurality of data pieces in such a way that those data pieces can be rewritten and registers which corresponding to the plurality of word memories respectively. The registers store information indicating whether valid target data is stored in the corresponding word memories, so that when retrieval data is input, the system retrieves word memories that store target data having a data part whose position corresponds to a prescribed first data part extracted from the input retrieval data. The CAM further includes a retrieval result correspondence write-in device which performs retrieval of word memories which store target data comprising a data part whose position corresponds to the first data part. Depending on whether any word memories are detected, the data part whose position corresponds to a second data part that is different from the first data part and which is extracted from the input retrieval data out of the target data stored in one or more word memories selected from the detected word memories, is overwritten by the same information as the second data part or the input retrieval data is written in one word memory selected from one or more word memories other than the word memory storing valid target data using the retrieval result correspondence write-in device.

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Chiba, Japan

Hiroshi Yoshizawa