JP4894012B2 - DATA COMMUNICATION SYSTEM, COMMUNICATION DEVICE, DATA COMMUNICATION METHOD, AND COMMUNICATION CONTROL PROGRAM - Google Patents

Description

  The present invention relates to a data communication system, a communication device, a data communication method, and a communication control program, and more particularly, a data communication system, a communication device, a data communication method, and a data communication system capable of buffer management with excellent processing speed when performing retransmission control. The present invention relates to a communication control program.

  Ethernet (registered trademark) is used to construct a local area network and a wide area network. Ethernet is a best-effort layer 2 network, and functions for improving reliability such as bandwidth control and retransmission control are roles of higher layers such as TCP / IP (Non-patent Document 1).

As for the packet retransmission control method, for example, in Patent Document 1, a transmission exchange station and a reception exchange station are provided between a transmission terminal and a reception terminal, and the transmission exchange station has a retransmission buffer. There is a description that the transmission switching center releases the retransmission buffer when an acknowledgment packet arrives before a predetermined time (before timeout).
Toru Okuyama, TCP structure and implementation, CQ Publisher, October 2004, pages 35-39, pages 60-61 JP-A-62-299142 (page 2, upper left column, line 13 to upper right column, line 18)

  However, when data that does not pass through the TCP / IP stack is to be communicated with high reliability through Ethernet (registered trademark), a mechanism for improving reliability on the Ethernet is required. In that case, it is possible to use the TCP / IP mechanism as it is, but TCP / IP is designed to be processed by software. For this reason, when applied to hardware as it is, it is necessary to use an expensive device due to demands for circuit scale and processing speed.

  An object of the present invention is to provide a method / apparatus that solves the above-described problems with respect to a function of arrival guarantee / retransmission control for improving reliability.

In order to achieve the above object, the data communication system according to the present invention provides the transmission data in the retransmission buffer separately from the retransmission buffer for storing transmission data and a sequence number that is identification information for identifying the transmission data. Storage position insertion means for inserting storage position information that is a storage position of the storage position into the transmission data, the first communication device that transmits the transmission data with the storage position information inserted to a destination, and the storage position An arrival confirmation unit for confirming arrival of transmission data into which information is inserted; and arrival confirmation information generating means for generating arrival confirmation information including the storage location information when arrival is confirmed by the arrival confirmation unit. And a second communication device that returns the arrival confirmation information including the storage location information to the communication device on the transmission side, and the first communication device is transmitted from the second communication device. Based on the serial storage location information, the control means for deleting the transmission data arrival is confirmed from the retransmission buffer, characterized in that it comprises further.

The communication device according to the present invention provides storage location information that is a storage location of the transmission data in the retransmission buffer separately from the retransmission buffer that stores the transmission data and a sequence number that is identification information for identifying the transmission data. Based on the storage position inserting means for inserting into the transmission data and transmitting to the receiving side communication device, and the storage position information included in the arrival confirmation information received from the receiving side communication device, the arrival from the retransmission buffer And a control means for deleting the transmission data for which confirmation has been confirmed.

In the data communication method of the present invention, in the first communication device on the transmission side, the transmission data is stored in the retransmission buffer, and separately from the sequence number which is identification information for identifying the transmission data, Inserting the storage location information, which is the storage location of the transmission data, into the transmission data, transmitting the transmission data in which the storage location information is inserted; and in the second communication device on the receiving side, the storage location information When the arrival of the inserted transmission data is confirmed and arrival of the transmission data is confirmed by the arrival confirmation unit, the arrival confirmation information including the storage position information is generated, and the arrival confirmation information including the storage position information is A step of returning to the first communication device, and, on the first communication device side, the retransmission buffer based on the storage location information transmitted from the second communication device Characterized by a step of deleting the transmission data al arrival is confirmed.

The communication control program according to the present invention includes, in addition to a process of storing transmission data in a memory serving as a retransmission buffer in a computer serving as a communication device, and a sequence number that is identification information for identifying the transmission data. Processing for inserting storage position information, which is a storage position of the transmission data in the buffer, into the transmission data and transmitting it to the receiving communication device, and the storage position included in the arrival confirmation information received from the receiving communication device And a process of deleting the transmission data whose arrival has been confirmed from the memory based on the information.

  In the present invention, when the transmission side transmits transmission data, the storage location information of the data in the retransmission buffer is mounted on the transmission data and transmitted. When the reception side returns the arrival confirmation information, the storage location information is mounted on the arrival confirmation information and returned to the transmission side. The transmission side that has received the arrival confirmation information loaded with the storage position information refers to the storage position and releases the retransmission buffer. In this case, it is possible to reduce the retransmission buffer capacity and improve the processing speed by releasing the flow from the beginning to the storage position.

  According to the present invention, the processing time for buffer release can be shortened, and restrictions on circuit size and processing speed can be relaxed.

  The reason is that the information necessary for releasing the buffer is provided from the transmitting side, the receiving side returns as it is, and the transmitting side receiving the information can release the buffer without searching.

Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In this embodiment, the cumulative acknowledgment system and the Go Back N system are used as a retransmission buffer management method. The cumulative confirmation response method is a method in which the receiving side confirms whether the sequence numbers of a certain number of received packets are in a normal order and notifies the transmitting side of the sequence number of the next necessary packet. The Go Back N method stores the sent frame in the retransmission buffer, sends a certain amount of frame without waiting for the ACK from the receiving side, and deletes the corresponding frame when the ACK is returned (releases the retransmission buffer) ) In this retransmission, the receiver starts retransmission from the next frame that has been successfully received.
[First Embodiment]
[1] Description of Configuration FIG. 1 is a block diagram showing a configuration of a first embodiment of a data communication system according to the present invention. The data communication system of the present embodiment is composed of transceivers 1-1-1 and 1-2-1, which are communication devices, and are connected to each other. However, for convenience of explanation, the transmitting side is assumed to be a transceiver 1-1-1 (becomes a first communication device), and the receiving side is assumed to be a transceiver 1-2-1 (becomes a second communication device). Originally, the transceivers 1-1-1 and 1-2-1 have no distinction between a transmission side and a reception side, and can be a transmission side and a reception side.

  In the transceiver 1-1-1 of FIG. 1, blocks indicated by solid lines indicate components necessary for transmission according to the present embodiment, and blocks indicated by dotted lines are for reception according to the present embodiment. The necessary components are shown. On the other hand, in the transceiver 1-2-1 in FIG. 1, blocks indicated by solid lines indicate components necessary for reception according to the present embodiment, and blocks indicated by dotted lines are used for transmission according to the present embodiment. The required configuration is shown.

  The transceiver 1-1-1 includes a retransmission buffer 1-1-2, a sequence number insertion unit 1-1-3, a storage location insertion unit 1-1-4, a storage location base buffer control unit 1-1-5, and a sequence. Consists of a number increment counter 1-1-6, a frame analysis unit 1-1-7, a reception buffer 1-1-8, an arrival confirmation unit 1-1-9, and a storage position inclusion ACK generation unit 1-1-10. .

  The transceiver 1-2-1 has the same configuration as the transceiver 1-1-1, and has the same function. That is, the transceiver 1-2-1 includes a retransmission buffer 1-2-2, a sequence number insertion unit 1-2-3, a storage location insertion unit 1-2-4, and a storage location base buffer control unit 1-2-5. , Sequence number increment counter 1-2-6, frame analysis unit 1-2-7, reception buffer 1-2-8, arrival confirmation unit 1-2-9, storage position inclusion ACK generation unit 1-2-10 Is done.

  As described above, since the transmitter / receiver 1-1-1 and the transmitter / receiver 1-2-1 have the same configuration, in the following description, each component of the transmitter / receiver 1-1-1 is described in order to avoid duplication. Only will be described. Of course, the description of each component of the transceiver 1-1-1 can be applied to the description of each component of the transceiver 1-2-1.

  The retransmission buffer 1-1-2 is connected to the sequence number insertion unit 1-1-3, the storage position base buffer control unit 1-1-5, and the sequence number increment counter 1-1-6. The data is stored until arrival confirmation is performed for receiving and performing retransmission control.

  The retransmission buffer 1-1-2 sends the transmission data to the sequence number insertion unit 1-1-3, increments the sequence number increment counter 1-1-6 at that time, and sets the storage position to the storage position base buffer control unit. Notify 1-1-5. The retransmission buffer 1-1-2 preferably has a configuration that is classified for each flow. For example, the block configuration is divided for each fixed size, and is dynamically allocated for each flow. The allocated block is used exclusively so that other flows cannot be used until the flow is used up. Further, it is desirable that the released area in the block is not used until the entire block is released, and always stored after the previous frame or in a new block when storing the frame. When storing, an identification bit is set at the end of the frame, and the position where the bit is set is used as storage position information.

  The sequence number insertion unit 1-1-3 is connected to the retransmission buffer 1-1-2, the storage position insertion unit 1-1-4, and the sequence number increment counter 1-1-6, and the retransmission buffer 1-1-2. When the data frame is transmitted, the value of the sequence number increment counter 1-1-6 is inserted into the header part and sent to the storage position insertion unit 1-1-4.

  The storage position insertion unit 1-1-4 is connected to the sequence number insertion unit 1-1-3, the storage position base buffer control unit 1-1-5, and the transceiver 1-2-1. The storage location information is received from the unit 1-1-5, inserted into the header portion of the data frame, and sent to the receiving side transceiver 1-2-1. Although the storage position insertion unit has a data transmission function, a data transmission unit may be provided separately.

  The storage location base buffer control unit 1-1-5 is connected to the retransmission buffer 1-1-2, the storage location insertion unit 1-1-4, and the frame analysis unit 1-1-7. The storage location information is received from -1-2 and notified to the storage location insertion unit 1-1-4. When the ACK frame is received, the retransmission buffer 1-1-2 is released (transmission data is deleted) based on the storage position information loaded in the ACK frame from the frame analysis unit 1-1-7.

  The frame analysis unit 1-1-7 is connected to the transceiver 1-2-1 and the reception buffer 1-1-8. The received frame is identified as a data frame or an ACK frame. If the received frame is a data frame, the received frame is sent to the reception buffer 1-1-8. Notify 1-1-5. Although the frame analysis unit has a data reception function, a data reception unit may be provided separately.

  The reception buffer 1-1-8 is connected to the frame analysis unit 1-1-7 and the arrival confirmation unit 1-1-9, temporarily holds the data frame from the frame analysis unit 1-1-7, and arrives. Deliver to confirmation section 1-1-9.

  The arrival confirmation unit 1-1-9 is connected to the reception buffer 1-1-8 and the storage position inclusion ACK generation unit 1-1-10. Based on the sequence number, the arrival order is reversed or an unreachable frame is detected. To do. If it is normally received and it is an ACK frame transmission opportunity, the storage position-containing ACK generation unit 1-1-10 is notified of the storage position of the data frame.

  The storage position inclusion ACK generation unit 1-1-10 is connected to the arrival confirmation unit 1-1-9 and the retransmission buffer 1-1-2, and based on the storage position information from the arrival confirmation unit 1-1-9. An ACK frame (acknowledgment response frame, which is arrival confirmation information) is generated and transmitted (returned) to the opposite transceiver 1-2-1 via the retransmission buffer 1-1-2. At this time, since the ACK frame is a frame that is not subject to retransmission control, the ACK frame is immediately transmitted without being buffered to the retransmission buffer 1-1-2, and the sequence number insertion unit 1-1-3, the storage location insertion unit 1- 1-4 is passed without doing anything and transmitted to the opposite transceiver 1-2-1.

FIG. 2 shows a frame format used in this embodiment. An area for mounting a sequence number and a storage position is provided in an extension header portion and a data area following an Ethernet (Ethernet registered trademark) frame header. Alternatively, as shown in FIG. 3, a sequence number may be directly mounted on the TCP / IP header portion, and storage location information may be mounted as an extension header after the TCP / IP header. As described above, the storage location information of the transmission data is mounted between the header area and the data area (payload area).
[2] Description of Operation FIG. 4 shows a flowchart of the operation of the data communication system of this embodiment.

  When a transmission frame arrives at the transmitter / receiver 1-1-1 on the transmission side (step S1), the transmission frame is stored in the corresponding flow of the retransmission buffer 1-1-2 whose storage position is different for each flow (step S2). . Next, when sending a transmission frame from the retransmission buffer 1-1-2, the sequence number increment counter 1-1-6 is incremented, and the sequence number is inserted in the header portion (step S3). Further, when sending a transmission frame from the retransmission buffer 1-1-2, the storage location insertion unit 1-1-4 is notified of the storage location through the storage location base buffer control unit 1-1-5 and stored in the header. A position is inserted (step S4). Then, the data frame is sent to the receiving side transceiver 1-2-1.

  When the receiving transceiver 1-2-1 receives the data frame (step S6), the frame analysis unit 1-2-7 analyzes the destination, transmission source, frame type, and frame check sequence of the frame (step S7). ). In the case of a data frame, the data frame is sent to and stored in the reception buffer 1-2-8 (step S8), and the arrival confirmation unit 1-2-9 confirms whether or not the data frame is normally received (step S8) S9). If the ACK frame is not sent when it is normally received (No in step S10), nothing is performed and the data is sent to the upper layer or another apparatus. If it is normally received and it is an ACK frame transmission opportunity (Yes in step S10), the storage position information read from the header of the frame (or the storage position information read by the frame analysis unit 1-2-7) ) (Step S11), an ACK frame including the storage position is generated by the ACK generation unit 1-2-10 (step S12). The generated ACK frame passes through the retransmission buffer 1-2-2 but is not stored, and is immediately sent to the transmitting side transceiver 1-1-1. At that time, the sequence number insertion unit 1-2-3 and the storage position insertion unit 1-2-4 do nothing.

When the transmitting-side transceiver 1-1-1 receives the ACK frame sent from the receiving-side transceiver 1-2-1, the frame analyzing unit 1-1-7 first receives the frame. The destination, transmission source, frame type, and frame check sequence are analyzed (step S15). Then, the storage position is read (step S16), and the retransmission buffer 1-1-2 is released from the beginning of the retransmission buffer of the corresponding flow of the ACK frame to the storage position mounted on the ACK frame (step S17).
[Second Embodiment]
FIG. 5 is a block diagram showing the configuration of the second embodiment of the data communication system according to the present invention. In this embodiment, the transceivers are connected by a switch 4-1 (which becomes a switching device) used in a general network. The transmitter / receiver is the same as that described in the first embodiment, and the other transmitter / receiver 4-2 may use either the same transmitter / receiver as in the first embodiment or a transmitter / receiver having a different configuration. .

  The operation of this embodiment is different in that communication is performed via the switch 4-1 when a data frame and an ACK frame are transmitted / received. The operation of the switch 4-1 is an operation of a switch used in a general network.

  The effect by this embodiment is a point which can communicate between several transmitter / receivers by using a switch.

  The transmitter / receiver (becomes a communication device) of each embodiment described above can be configured by hardware using a dedicated IC or the like, but can also be realized by software using a computer as a transmitter / receiver. That is, for example, the transmitter / receiver 1-1-1 on the transmission side and the transmitter / receiver 1-2-1 on the transmission side in FIG. 1 or FIG. 5 are each configured by a computer as shown in FIG. 6, and the flow shown in FIG. The function of the transceiver can be realized by the communication control program describing Both the transmitter / receiver 1-1-1 and the transmitter / receiver 1-2-1 may be configured by a computer, or one may be configured by a computer. A communication control program for realizing the function of the transceiver is stored in a disk device 14 such as a hard disk device or a storage device such as a ROM (here, a disk device is shown), and a RAM or the like as a buffer for transmission data and reception data A program that realizes the functions of the transceiver 1-1-1 or 1-2-1 shown in FIG. 1 or FIG.

  The communication unit 10 corresponds to the data transmission unit of the storage position insertion unit and the data reception unit of the frame analysis unit. The display unit 11 includes an LCD (Liquid Crystal Display), a CRT, or the like, and displays a communication status. Reference numeral 15 denotes a data bus or the like.

  The present invention is applied to a data communication system, a communication device, a data communication method, and a communication control program capable of buffer management with excellent processing speed when performing retransmission control.

It is a block diagram which shows the structure of 1st Embodiment of the data communication system by this invention. It is a figure which shows the frame format used for 1st Embodiment of this invention. It is a figure which shows the frame format which uses this invention for 1st Embodiment. It is a flowchart which shows the operation | movement of the data communication system and transmitter / receiver of 1st Embodiment of this invention. It is a block diagram which shows the structure of 2nd Embodiment of the data communication system by this invention. It is a block diagram which shows the structural example of a computer.

Explanation of symbols

1-1-1 Transceiver 1-2-1 Transceiver 1-1-2, 1-2-2 Retransmission Buffer 1-1-3, 1-2-3 Sequence Number Insertion Unit 1-1-4, 1- 2-4 Storage Position Insertion Unit 1-1-5, 1-2-5 Storage Position Base Buffer Control Unit 1-1-6, 1-2-6 Sequence Number Increment Counter 1-1-7, 1-2-7 Frame analysis unit 1-1-8, 1-2-8 Reception buffer 1-1-9, 1-2-9 Arrival confirmation unit 1-1-10, 1-2-10 Storage position inclusion ACK generation unit

Claims (6)

In addition to a retransmission buffer for storing transmission data and a sequence number that is identification information for identifying the transmission data, storage for inserting storage position information that is a storage position of the transmission data in the retransmission buffer into the transmission data A first communicator having a position insertion means and transmitting transmission data into which the storage position information is inserted to a destination;
An arrival confirmation unit for confirming arrival of transmission data in which the storage position information is inserted; and arrival confirmation information generating means for generating arrival confirmation information including the storage position information when arrival is confirmed by the arrival confirmation unit And a second communication device that returns arrival confirmation information including the storage position information to the transmission-side communication device,
The first communication device further includes control means for deleting the transmission data confirmed to arrive from the retransmission buffer based on the storage position information transmitted from the second communication device. A data communication system.   The data communication system according to claim 1, wherein the first and second communication devices are connected to each other via a network using a switching device.   The data communication system according to claim 1 or 2, wherein the transmission data storage position information is mounted between a header area and a payload area to perform transmission / reception. A retransmission buffer for storing transmission data;
In addition to a sequence number that is identification information for identifying the transmission data, storage location information that is a storage location of the transmission data in the retransmission buffer is inserted into the transmission data and transmitted to a communication device on the receiving side Position insertion means;
Control means for deleting the transmission data whose arrival has been confirmed from the retransmission buffer based on the storage location information included in the arrival confirmation information received from the receiving-side communication device;
A communication device characterized by comprising: In the first communication device on the transmission side, the transmission data is stored in the retransmission buffer, and separately from the sequence number that is identification information for identifying the transmission data , the transmission data is stored in the retransmission buffer. Inserting storage location information into the transmission data and transmitting the transmission data with the storage location information inserted;
In the second communication device on the receiving side, when the arrival of the transmission data in which the storage position information is inserted is confirmed, and the arrival confirmation unit confirms the arrival of the transmission data, the arrival confirmation including the storage position information Generating information and returning the arrival confirmation information including the storage position information to the first communication device;
And a step of deleting, on the first communication device side, the transmission data whose arrival has been confirmed from the retransmission buffer based on the storage location information transmitted from the second communication device. To a computer as a communication device,
A process of storing transmission data in a memory as a retransmission buffer;
A process of inserting storage position information, which is the storage position of the transmission data in the retransmission buffer, into the transmission data separately from the sequence number, which is identification information for identifying the transmission data, and transmitting the transmission data to the receiving communication device When,
A communication control program for executing a process of deleting the transmission data whose arrival has been confirmed from the memory based on the storage location information included in the arrival confirmation information received from the communication device on the receiving side.

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