JP2007267249A - Data transmission device, data transmission method, and data transmission program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform retransmission processing in network communications using hardware. <P>SOLUTION: A first buffer 11 temporarily stores transmission data. A second buffer 12 is a FIFO buffer and temporarily stores transmission data sent from the first buffer 11. A data sending circuit 13 selectively sends transmission data stored in the first buffer 11 or the second buffer 12 to a network 30. A sending control circuit 14 controls the data sending circuit 13 so as to send transmission data stored in the second buffer 12 to the network 30 when a possibility is detected that transmission data sent to the network 30 may not be received based on communication information exchanged via the network 30, and controls the data sending circuit 13 so as to send transmission data stored in the first buffer 11 to the network 30 when all the transmission data stored in the second buffer 12 are sent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data transmission apparatus, a data transmission method, and a data transmission program that transmit data via a network.

  In recent years, with the rapid development of network environments and the spread of computers, information communication networks provide a wide variety of services. In an information communication network, it is necessary to reliably deliver communication data between computers to the other party. When there is data that has not arrived, the data that has not arrived is complemented by retransmitting the data from the transmission side. Many of the networks that have recently been standardized implement such a mechanism that performs this retransmission control by hardware to ensure that data arrives.

  However, among information communication networks, there are networks in which standards are created based on the conventional concept. In such a network, since it is not known whether the other party's hardware has a retransmission control function, retransmission control must be performed by software processing of the host computer. As an example of the simplest retransmission processing by software, there is one that sends data one by one and performs data communication while checking how far the data has been sent.

TCP / IP (Transmission Control Protocol / Internet Protocol) is a communication standard widely used when performing retransmission processing using such software. In addition, a data transmission device has been proposed in which a dedicated protocol is assembled on User Datagram Protocol / Internet Protocol (UDP / IP) for which retransmission processing is not specified, and a mechanism for performing retransmission processing on the protocol is created by software. (See Patent Document 1). Further, a data transmission apparatus has been proposed in which the above-described data transmission apparatus is expanded and a mechanism for performing similar retransmission processing without using UDP / IP is created by software (see Patent Document 2).
JP 2000-134263 A JP 2002-135302 A

  However, communication data for network communication has been rapidly increasing due to the recent widening of the information communication network, and the processing load on the computer due to retransmission processing using software has increased. Therefore, when resending processing is performed using software, there is a problem that resources used for processing other than resending processing such as communication processing are reduced and performance of the entire system is lowered. Furthermore, since the data is repeatedly exchanged between the hardware and software for the retransmission process, there is a problem that the retransmission process itself becomes slow.

  SUMMARY An advantage of some aspects of the invention is that it provides a data transmission device, a data transmission method, and a data transmission program that perform retransmission processing in network communication using hardware.

  In order to solve the above-described problem, the present invention provides a data transmission device that transmits data via a network, and acquires and temporarily stores transmission data generated for transmission via the network. A first buffer and the transmission data sent from the first buffer are temporarily stored, and when the storage capacity is satisfied, the previously stored transmission data is erased and new transmission data is stored. 2 buffer, a data transmission circuit for selectively transmitting the transmission data stored in the first buffer or the transmission data stored in the second buffer to the network, and the first When the transmission data is stored in the buffer, the data is transmitted so that the transmission data stored in the first buffer is transmitted to the network. The transmission data stored in the second buffer is detected by controlling the output circuit and detecting the possibility that the transmission data sent to the network based on the communication information exchanged via the network is not received. When the transmission data stored in the second buffer is all transmitted, the transmission data stored in the first buffer is transferred to the data transmission circuit. There is provided a data transmission apparatus comprising a transmission control circuit for controlling the data transmission circuit so as to transmit to a network.

  Thereby, as shown in FIG. 1, the 1st buffer 11 acquires the transmission data produced | generated in order to transmit via the network 30, and memorize | stores it temporarily. The second buffer 12 temporarily stores the transmission data sent from the first buffer 11, erases the previously stored transmission data when the storage capacity is satisfied, and stores new transmission data. The data transmission circuit 13 selectively transmits the transmission data stored in the first buffer 11 or the transmission data stored in the second buffer 12 to the network 30. When the transmission data is stored in the first buffer 11, the transmission control circuit 14 controls the data transmission circuit 13 to transmit the transmission data stored in the first buffer 11 to the network 30. At the same time, based on the communication information exchanged via the network 30, whether or not there is a possibility that the transmission data sent to the network 30 may not have been received, and if it is determined that retransmission processing is necessary, When the data transmission circuit 13 is controlled to transmit the transmission data stored in the second buffer 12 to the network 30, and when all the transmission data stored in the second buffer 12 is transmitted, the first data The data transmission circuit 13 is controlled to transmit the transmission data stored in the buffer 11 to the network 30.

  According to the data transmission device of the present invention, the possibility that the transmission data sent to the network was not received by the communication partner is uniquely determined based on the communication information exchanged via the network, and the transmission data is received by the communication partner. If it is determined that there is a possibility that the data has not been transmitted, the data transmission circuit is controlled so as to transmit the transmission data stored in the second buffer to the network, thereby performing retransmission processing in the network communication using hardware. be able to. Therefore, even if a network device created based on the conventional concept that is not configured to perform retransmission control by hardware is used as a communication partner, the reliability of network communication can be improved without placing a processing load on the computer. Is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram of the invention applied to this embodiment. As shown in FIG. 1, the data transmission device 10 is a network interface for the computer 20 to transmit data via a network 30. The data transmission device 10 includes a first buffer 11, a second buffer 12, a data transmission circuit 13, and a transmission control circuit 14.

  The computer 20 performs data communication with the data transmission device 10 via the network 30. Specifically, data generated by the computer 20 and transmitted to the communication partner is temporarily stored in the first buffer 11.

  The second buffer 12 outputs the transmission data output from the first buffer 11 to the data transmission circuit 13 and transmitted to the network 30, and is simultaneously transmitted from the data transmission circuit 13 to the network 30 from the first buffer 11. Receive and store temporarily. The second buffer 12 is a first-in first-out (FIFO) buffer. When the storage area is filled with data received from the first buffer 11, the second buffer 12 is erased from the previously stored data. The received data is stored at the end.

  The data transmission circuit 13 acquires either transmission data stored in the first buffer 11 or transmission data stored in the second buffer 12 based on the control signal, and acquires the acquired transmission data. Is sent to the network 30.

  The network 30 is a network called Ethernet (registered trademark). Ethernet is a general term for networks standardized by the Institute of Electrical and Electronic Engineers (IEEE) 802.3 Committee.

  When the transmission control circuit 14 receives a notification signal indicating that transmission data is stored in the first buffer 11, the transmission control circuit 14 transmits the transmission data stored in the first buffer 11 to the network 30. Output a control signal.

  The data transmission circuit 13 acquires transmission data stored in the first buffer 11 based on the control signal, and transmits it to the network 30. At this time, the transmission data sent to the network 30 is stored in the second buffer 12.

  Further, the transmission control circuit 14 constantly monitors communication information exchanged via the network 30. When the transmission control circuit 14 detects the possibility that the transmission data transmitted to the network 30 has not been received by the communication partner from the communication information, A control signal is output to the data transmission circuit 13 so that the transmission data stored in the second buffer 12 is transmitted to the network 30.

  The data transmission circuit 13 transmits the transmission data stored in the second buffer 12 to the network 30 based on the control signal. When the transmission control circuit 14 receives from the second buffer 12 a notification signal indicating that the transmission data stored in the second buffer 12 is exhausted, the transmission control circuit 14 again transmits the data stored in the first buffer 11 to the network 30. The data transmission circuit 13 is controlled so as to transmit the data.

  In this way, the possibility that the transmission data sent to the network 30 has not been received by the communication partner is uniquely detected by monitoring the communication information exchanged via the network 30, and the necessity of retransmission is detected. By controlling the data transmission circuit 13 to transmit the transmission data stored in the second buffer 12 to the network 30, the retransmission process can be realized without using software. It is possible to improve the reliability of network communication without imposing a load on the (Central Processing Unit).

  Further, the data transmission apparatus 10 determines that there is a possibility that the transmission data has not been received by the communication partner by itself based on the determination signal, and transmits the transmission data stored in the second buffer 12 to the network 30. Since the data transmission circuit 13 is controlled, even if there is a possibility that the communication partner of the network communication does not have the function of the retransmission process, the retransmission process can be performed regardless of the function of the communication partner. Communication reliability can be improved.

Next, an embodiment in which the data transmitting apparatus is applied to the data transmitting / receiving apparatus will be described in detail with reference to the drawings.
FIG. 2 is a diagram illustrating a system configuration example according to the present embodiment. As shown in FIG. 2, a computer 200 and a computer 201 are connected via a switch 300. The computer 200 includes a data transmission / reception device 100a. The computer 201 includes a data transmission / reception device 100b. The switch 300 is, for example, a 6-port switch, and includes data transmission / reception devices 100c, 100d, 100e, 100f, 100g, and 100h in each port. In addition, a selector 310 that controls which port transmits data to which port is provided.

  For example, when data is transmitted from the computer 200 to the computer 201, the data generated by the computer 200 is output to the switch 300 via the data transmission / reception device 100a. In the switch 300, the data transmission / reception device 100c receives the data output from the data transmission / reception device 100a, and outputs the data to the computer 201 via the selector 310 and the data transmission / reception device 100e. In the computer 201, the data transmitter / receiver 100b receives data output from the data transmitter / receiver 100e.

  That is, the data transmission / reception apparatuses 100a, 100b, 100c, 100d, 100e, 100f, 100g, and 100h (hereinafter collectively referred to as “data transmission / reception apparatus 100”) transmit / receive data between nodes in the information communication network. It is a device to do. Hereinafter, the case where the data transmitting / receiving apparatus 100 is applied as a network interface of the computer 200 will be described in detail as an example.

  FIG. 3 is a diagram illustrating processing functions of the data transmitting / receiving apparatus. As shown in FIG. 3, the data transmission / reception device 100 is a network interface for the computer 200 to transmit and receive data via the network 400.

  The data transmitting / receiving apparatus 100 includes a transmission buffer 110, a selector 120, a retransmission buffer 130, a reception buffer 140, a transmission buffer control circuit 150, a selector control circuit 160, and a pause detection circuit 170.

  The computer 200 performs data communication with the computer 201 via the data transmission / reception device 100 and the network 400. Specifically, data generated by the computer 200 and transmitted to the computer 201 is temporarily stored in the transmission buffer 110.

  The retransmission buffer 130 receives the transmission data output from the transmission buffer 110 to the selector 120 and transmitted to the network 400 from the transmission buffer 110 and temporarily stores the transmission data transmitted from the selector 120 to the network 400. The retransmission buffer 130 is a FIFO buffer. When the storage area is filled with data received from the transmission buffer 110, the retransmission buffer 130 erases the previously stored data and stores the newly received data at the end.

  The selector 120 acquires either transmission data stored in the transmission buffer 110 or transmission data stored in the retransmission buffer 130 based on the control signal, and transmits it to the computer 201 via the network 400.

  Data transmitted to the computer 200 is temporarily stored in the reception buffer 140 via the network 400 and transmitted to the computer 200. The reception buffer 140 outputs the data received via the network 400 to the computer 200 and simultaneously outputs it to the pause detection circuit 170.

The network 400 is a network called Ethernet. Ethernet is a generic term for networks standardized by the IEEE 802.3 committee.
When the transmission buffer control circuit 150 detects the amount of transmission data stored in the transmission buffer 110 and detects that the transmission data is stored in the transmission buffer 110, the transmission buffer control circuit 150 sends a notification signal indicating that the transmission data has been detected to the selector control circuit 160. Output to.

  When the selector control circuit 160 receives a notification signal indicating that transmission data has been stored in the transmission buffer 110, the selector control circuit 160 causes the selector 120 to transmit the transmission data stored in the transmission buffer 110 to the network 400. Control.

  The transmission buffer control circuit 150 detects the amount of transmission data stored in the transmission buffer 110 and controls the amount of transmission data output from the computer 200 to the transmission buffer 110. For example, when it is detected that the amount of transmission data stored in the transmission buffer 110 exceeds a certain amount, the amount of data output to the transmission buffer 110 to the computer 200 is reduced or the transmission data Is instructed to stop the output to the transmission buffer 110. Further, when it is detected that the amount of transmission data stored in the transmission buffer 110 is below a certain amount, the amount of data output to the transmission buffer 110 is increased with respect to the computer 200, or transmission is performed. An instruction is given to start outputting data to the transmission buffer 110.

  The selector control circuit 160 detects a data transmission stop signal called a pause frame defined as an IEEE 802.3x option from the data received by the pause detection circuit 170 via the network 400 by the pause detection circuit 170, and pauses. When a notification signal indicating that a pause frame has been detected is received from the detection circuit 170, an instruction signal is output to the selector 120 so as not to send data to the network 400.

  When the pause detection circuit 170 outputs a notification signal indicating that a pause frame has been detected to the selector control circuit 160, the pause detection circuit 170 measures the interruption time set in the detected pause frame to interrupt the data transmission. When the interruption time elapses, the selector control circuit 160 is notified accordingly.

  When the selector control circuit 160 receives notification from the pause detection circuit 170 that the interruption time has elapsed, the selector control circuit 160 controls the selector 120 to transmit the data stored in the retransmission buffer 130 to the computer 201. Then, the amount of data stored in the retransmission buffer 130 is detected, and when there is no more data stored in the retransmission buffer 130, the data stored in the transmission buffer 110 is transmitted again to the computer 201. The selector 120 is controlled as follows.

The following processing is performed by the data transmitting / receiving apparatus 100 having the above functions.
FIG. 4 is a flowchart showing a procedure of data transmission control processing by the data transmitting / receiving apparatus. In the following, the process illustrated in FIG. 4 will be described in order of step number.

  [Step S11] When transmission of transmission data stored in the transmission buffer 110 to the network 400 is started, the pause detection circuit 170 determines whether a pause frame has been received. If a pause frame has been received, the process proceeds to step S12. If no pause frame has been received, the process proceeds to step S16.

  [Step S12] The pause detection circuit 170 outputs a data transmission stop signal to the selector control circuit 160. Upon receiving the data transmission stop signal, the selector control circuit 160 controls the selector 120 so that data is not transmitted to the network 400.

  [Step S13] The pause detection circuit 170 reads the interruption time set in the pause frame. Further, the elapsed time after receiving the pause frame is counted, and when the interruption time read from the pause frame has elapsed, a data transmission restart signal is output to the selector control circuit 160.

[Step S14] The selector control circuit 160 controls the selector 120 so that the data stored in the retransmission buffer 130 is transmitted to the network 400.
[Step S15] The selector control circuit 160 detects the amount of data stored in the retransmission buffer 130, and determines whether or not the data in the retransmission buffer 130 has become empty. When the retransmission buffer 130 becomes empty, the transmission buffer control circuit 150 is notified that it has become empty, and the process proceeds to step S16. If the retransmission buffer 130 is not empty, the process proceeds to step S14.

  [Step S16] The transmission buffer control circuit 150 detects the amount of data stored in the transmission buffer 110, and determines whether there is data in the transmission buffer control circuit 150. If there is data in transmission buffer 110, the process proceeds to step S17. If there is no data in transmission buffer 110, the process proceeds to step S11.

  [Step S17] The transmission buffer control circuit 150 instructs the selector control circuit 160 to control the selector 120 to send the data stored in the transmission buffer 110 to the network 400. Upon receiving the instruction, the selector control circuit 160 controls the selector 120 so that the data stored in the transmission buffer 110 is transmitted to the network 400.

  As described above, when the pause frame is received, the transmission data stored in the retransmission buffer 130 is retransmitted, so that the cause of the output of the pause frame is an overflow on the receiving side and is received when the overflow occurs. When the side fails to receive the transmission data, it is possible to supplement the transmission data that was missed by the transmission data retransmitted from the transmission source.

  In addition, the data transmission / reception apparatus 100 determines that there is a possibility that the transmission data is not received by the communication partner by the pause frame existing in the network standard, and the transmission data stored in the retransmission buffer 130 is transmitted to the network 400. Since the selector 120 is controlled to transmit, even if there is a possibility that the communication partner of the network communication does not have the function of the retransmission process, the retransmission process can be performed regardless of the function of the communication partner. Therefore, it is possible to improve the reliability of network communication with an inexpensive device.

  In addition, by performing retransmission processing by hardware, it is possible to perform retransmission processing without increasing the processing load on the computer in data communication transmitted and received via a high-speed network.

  Although it has been explained that the pause detection circuit 170 counts the pause time, it sends a pause frame to the selector control circuit 160, stops when the pause frame is received, and counts the pause time set in the pause frame. Thus, the data in the retransmission buffer 130 may be transmitted.

  In addition, when the pause frame is received, it has been explained that the receiving side may have failed to receive the transmission data, but the material for determining the possibility that the receiving side has failed to receive the transmission data is As long as there is a possibility that the receiving side has failed to receive the transmission data, it is not limited to the pause frame.

It is a conceptual diagram of the invention applied to this Embodiment. It is a figure which shows the system configuration example which concerns on this Embodiment. It is a figure which shows the processing function of a data transmitter / receiver. It is a flowchart which shows the procedure of the data transmission control process by a data transmitter / receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Data transmitter 11 1st buffer 12 2nd buffer 13 Data transmission circuit 14 Transmission control circuit 20 Computer 30 Network

Claims (5)

A data transmission device that transmits data via a network,
A first buffer for acquiring and temporarily storing transmission data generated for transmission over the network;
A second buffer for temporarily storing the transmission data transmitted from the first buffer, erasing the previously stored transmission data when a storage capacity is satisfied, and storing new transmission data;
A data transmission circuit for selectively transmitting the transmission data stored in the first buffer or the transmission data stored in the second buffer to the network;
When the transmission data is stored in the first buffer, the data transmission circuit is controlled to transmit the transmission data stored in the first buffer to the network, and exchanged via the network When detecting the possibility that the transmission data transmitted to the network based on communication information has not been received, the data transmission circuit is configured to transmit the transmission data stored in the second buffer to the network. And when the transmission data stored in the second buffer is all transmitted, the data transmission circuit is controlled so that the transmission data stored in the first buffer is transmitted to the network. A delivery control circuit;
A data transmission device comprising: The determination signal is an instruction signal instructing stop of transmission of the transmission data to the network,
The data transmission apparatus according to claim 1, wherein the transmission control circuit controls the data transmission circuit to stop transmission of the transmission data to the network when the instruction signal is received.   The data transmission circuit transmits the transmission data stored in the second buffer to the network after a transmission stop time set in the instruction signal has elapsed. Data transmission device. A first buffer for acquiring and temporarily storing transmission data generated for transmission via the network; and temporarily storing the transmission data sent from the first buffer; Is satisfied, a data transmission method in a data transmission device capable of erasing the previously stored transmission data and accessing a second buffer for storing new transmission data,
The data transmission device includes:
A first buffering step of acquiring and temporarily storing transmission data generated for transmission to the first buffer via the network;
The transmission data transmitted from the first buffer is temporarily stored in the second buffer. When the storage capacity is satisfied, the previously stored transmission data is deleted, and new transmission data is stored. A second buffering step to store;
When the transmission data is stored in the first buffer by the first buffering step, the transmission data stored in the first buffer is transmitted to the network and exchanged via the network. The transmission data stored in the second buffer is transmitted to the network when the possibility that the transmission data transmitted to the network has not been received based on the communication information is transmitted to the network, and the second buffer A transmission step of transmitting the transmission data stored in the first buffer to the network when all the transmission data stored in the network is transmitted;
The data transmission method characterized by performing. A first buffer for acquiring and temporarily storing transmission data generated for transmission via the network; and temporarily storing the transmission data sent from the first buffer; Is satisfied, the transmission data stored previously is erased, and a data transmission device that can access the second buffer storing the new transmission data,
A first buffering step of acquiring and temporarily storing transmission data generated for transmission to the first buffer via the network;
The transmission data transmitted from the first buffer is temporarily stored in the second buffer. When the storage capacity is satisfied, the previously stored transmission data is deleted, and new transmission data is stored. A second buffering step to store;
When the transmission data is stored in the first buffer by the first buffering step, the transmission data stored in the first buffer is transmitted to the network and exchanged via the network. The transmission data stored in the second buffer is transmitted to the network when the possibility that the transmission data transmitted to the network has not been received based on the communication information is transmitted to the network, and the second buffer A transmission step of transmitting the transmission data stored in the first buffer to the network when all the transmission data stored in the network is transmitted;
A data transmission program characterized in that

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