Packet communication apparatus

Abstract

A packet communication apparatus, which includes a CPU, a memory, and a packet communication circuit, acts as an interface between a network-connected controlled object and a network terminal that remotely monitors and controls the controlled object, and transmits and receives a packet between the controlled object and the network terminal, further includes a copy and operation unit that is a hardware unit for executing the checksum calculation to check for a packet error and the copy operation. The copy and operation unit performs the packet data copy operation and the checksum calculation simultaneously between a sending buffer / receiving buffer, formed in the memory and used by the packet communication circuit, and a work area used by a communication processing program, thus reducing the load of the CPU and increasing the communication processing speed.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a packet communication apparatus that transmits and receives data that is divided into packets, and more particularly to packet data copy means and checksum calculation means used for transmitting and receiving packet data.[0002]Most communications via the Internet and LANs are packet communications based on the TCP / IP protocol.[0003]TCP / IP consists of a hierarchy of programs for protocol processing. For example, a packet received by a communication circuit, which works as the network interface, is processed sequentially by a hierarchy of programs. That is, the packet is passed to the Ethernet (registered trademark) driver, received by IP, received by TCP or UDP (User Datagram Protocol), and then processed by application software programs.[0004]In a packet transmission, a packet is transmitted from the communication circuit by performing the above processing in a reverse order.[0005]In addition, the IP or UDP software...

AI Technical Summary

Benefits of technology

[0009]A high-speed CPU, if used to meet the requirement for increasing the speed of the transmission processing, increases the network terminal cost.

[0010]It is an object of the present invention to provide a packet communication apparatus that has means for reducing the CPU processing load and increasing the transmission / reception speed even when a low-cost, low-speed CPU is used.

[0017]The packet communication apparatus using the memory copy method according to the present invention, has a hardware unit for performing the copy operation and the checksum calculation, which increase the CPU load, during the TCP / IP communication processing, enables the copy operation and the checksum calculation to be executed simultaneously, and increases the communication processing performance.

[0018]The memory copy method according to the present invention can increase the speed of the copy operation and the checksum calculation not only in the packet reception processing but also in the transmission processing and therefore make the transmission / reception processing faster.

[0019]As a result, even when a web server required to perform the transmission / reception processing frequently is installed in a network terminal, a relatively slow existing CPU can be used with the conventional software asset inherited unchanged.

Problems solved by technology

A high-speed CPU, if used to meet the requirement for increasing the speed of the transmission processing, increases the network terminal cost.

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