JPS63169855A - Packet transmission system with error retransmission function - Google Patents

Abstract

PURPOSE:To transfer data with high speed by providing a device transferring data packet and a device applying data packet transfer control such as retransmission control independently so as to form a single function thereby facilitating the hardware forming of each device. CONSTITUTION:A transmission control section 11 writes transmission designation information to all packets in a buffer 14 at first to a packet selection table 15 and a packet transmission section 13 adds the identification information representing the packet location in a buffer and an error detection code and sends the result to a communication line 25. A packet reception section 18 references the identification information added to the packet and writes the result to the designated location in the reception side packet buffer 19, applies error detection and writes the result to a reception table 20. The transmission control section 11 inquires about the reception state to a reception control section 16, which sends the content of the reception table 14. If missing or transmission error exists, the transmission designation information to the packet is written in the selection table 15.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a packet transmission device.

(Prior Art) Multiple local area networks (Local
AreaNetwork) When performing high-speed data transfer between terminals via an interconnected communication network, link control such as Nonoke Nodo delivery confirmation and retransmission control is performed between nodes relaying each local area network. This is accompanied by a decrease in data transfer efficiency due to an increase in processing overhead within the network, so this is omitted, and protocols that restore the reliability of transferred data between transmitting and receiving terminals are often used. This is an ISO standard (ISO8073
) corresponds to the class 4 transport layer protocol defined in

When using such a protocol with conventional terminal devices, the data to be transferred and communication for transfer control such as packet delivery confirmation and retransmission control are multiplexed into one packet transmission path between the sending and receiving terminals, and transfer control is performed by software. After processing ν).

(Problems to be Solved by the Invention) However, when the transmission path becomes wider and the transfer speed of data communication between terminals increases, the overhead of software processing in such terminals can become a factor that prevents the speeding up of data transfer. Furthermore, even if data transfer equipment is implemented in hardware to reduce overhead, conventional protocols require multiplexing of data to be transferred and communication for transfer control such as packet delivery confirmation and retransmission control between sending and receiving terminals. Because of this, multiplexing and demultiplexing functions are required, and the procedures are complex, so it cannot be implemented with simple hardware.

According to the present invention, a data packet transfer mechanism for performing data communication and a transfer control mechanism for the data packets can be configured with a simple hardware device, and the communication speed can be increased.

(Means for Solving Problems) According to the present invention, there is provided a packet transmission method with an error retransmission function in a communication system consisting of two stations, a transmitting station and a receiving station, in which the transmitting station and the receiving station are A first communication line performs one-way communication from the station to the receiving station, and a second communication line performs bidirectional communication between the two stations, and the transmitting station temporarily transmits packets input from the outside. The packet is stored in the buffer, and the packet is sent out using the first communication line, and the receiving station is asked about the reception status using the second communication line, and the receiving station stores the arrived packet in the buffer. At the same time, a transmission error check is performed, and in response to the receiving status inquiry from the transmitting station, the presence or absence of a transmission error and the presence or absence of packet arrival are transmitted to the transmitting station using the second communication line as a response, and the transmitting station responds to the inquiry. Based on the response, if there is a packet that has not arrived or has a transmission error, only the packet that has not arrived or has a transmission error is sent, and the second communication line is used to notify the receiving station of the reception status. A packet transmission system with an error retransmission function is obtained, which is characterized in that ν1 matching is performed and this packet transmission and reception status inquiry are repeated until there are no packets that have not arrived or have transmission errors. A packet transmission device with an error retransmission function in a communication system consisting of two stations, a transmitting station and a receiving station,
The transmitting station side device includes a transmitting side packet buffer that temporarily stores packets input from the outside, a packet selection table that specifies a packet to be transmitted from among the packets accumulated in the transmitting side packet buffer, and the a packet sending unit capable of selecting and transmitting a packet specified by a packet selection table from the sending side packet buffer memory; a means for making an inquiry to a receiving station to confirm reception status; and updating the packet selection table. The receiving station side device consists of a packet receiving unit that can check for transmission errors in arriving packets, a receiving side packet buffer that temporarily stores packets, and a receiving side packet buffer that temporarily stores packets. A packet receiving device comprising a packet receiving table that records arrival and the presence or absence of transmission errors, and a transmission control unit that can transmit the contents of the packet receiving table to the transmitting station in response to an inquiry from the transmitting station to confirm the reception status. The packet receiving unit is configured to include a packet transmission device with an error retransmission function capable of accumulating arriving packets in the receiving side packet buffer, performing a transmission error check, and writing the result to the packet reception table. can get.

(Operation) According to the present invention, when performing packet transmission with error retransmission between a transmitting station and a receiving station, the means for transferring data packets and the means for controlling transfer of data packets such as retransmission control are provided. By making each unit independent and having a single function, it is possible to easily implement each unit in hardware and achieve high-speed data transfer.

(Embodiment) FIG. 2 is a diagram showing an example of a logical configuration of a packet transmission system with an error control function according to the present invention, and FIG. 3 is a time chart showing an example of a packet transmission form according to the present invention. In FIG. 2, 41 is a transmitting station, 42 is a receiving station,
43 is a transmitting station side buffer, 44 is a receiving station side buffer, 5
1 to 54 are terminals connected to the outside, 61 is a first communication line for transferring packets in one direction from the transmitting station to the receiving station, and 62
indicates the second communication line for bidirectional communication between the transmitting station and the receiving station, and the arrow mark located outside the two vertical lines in Fig. The arrow between the two vertical lines shows the flow of data going back and forth between the two-way communication stations, the solid line shows the flow of the main data, and the broken line shows the flow of control data. Here, it is not essential that the first communication line and the second communication line be connected by separate physical transmission media, and they may be multiplexed on the same transmission medium by time division multiplexing or the like.

In FIG. 2, the transmitting station temporarily stores packets input from the terminal 52 in the transmitting station side buffer 43, and
When a packet transfer request signal is given via 1, all packets in the buffer 43 are first sent to the receiving station via the communication line 61, and then the reception status is sent to the receiving station via the second communication line 62. Make inquiries.

The reception station becomes ready for reception by a reception preparation signal given from the outside via the terminal 53, and the first communication line 6
At the same time, the packets arriving via the second communication line 62 are stored in the receiving station side buffer 44 and checked for transmission errors, and the results are held together with the arrival information regarding each packet in the buffer. When receiving an inquiry about the reception status from the station, the reply is transmitted to the transmitting station via the second communication line. At this time, if this response information indicates normal reception of all packets, the completion of reception is notified to the outside via the terminal 53, and the received data is read out to the outside via the terminal 54.

At the transmitting station, based on the response to the reception status inquiry,
If there is a packet that has not arrived or has a transmission error, it transmits only the packet that has not arrived or has a transmission error, and uses the second communication line to inquire of the receiving station about the reception status. Packet transmission and reception status inquiries are repeated until there are no packets that have not arrived or have transmission errors.

FIG. 2 shows the above data transmission procedure in a time chart.

At this time, the information regarding the reception status inquiry or the response thereto may be erroneously transmitted through the second communication line, or
Even if packets are lost, if the transmitting station retransmits the reception status inquiry using an interrupt such as a timer, no discrepancy will occur in packet transmission.

The above packet transmission with error control function uses a one-way communication line from the transmitting station to the receiving station and a two-way communication line connecting the transmitting station and the receiving station.
At the transmitting station, a function that temporarily stores packets input from the outside in a buffer, a function that selects packets to be transmitted from among the packets stored in the buffer and sends them to a communication line, and a bidirectional communication line. The function of giving commands to the receiving station via and receiving data sent by the receiving station,
At the receiving station, there is a function to temporarily store the arrived packets, and a function to inspect the arrived packets for transmission errors.
This is realized by a function of holding the result together with the arrival information of each packet, a function of receiving a command from a transmitting station via a communication line, and a function of sending the held data to the communication line based on the command.

Next, as a device configuration embodying the above packet transmission system, an example of the configuration of a packet transmission device according to the present invention is shown in FIG. In FIG. 1, 11 is a transmission control section, 12 is a transmitting station side control data transmitting/receiving section, 13 is a packet sending section, 1
4 is a transmitting side packet buffer, 15 is a packet selection table, 16 is a receiving control section, 17 is a receiving station side control data transmitting/receiving section, 18 is a packet receiving section, 19 is a receiving side packet buffer, 20 is a packet receiving table, 21- 24 is a terminal connected to the outside, 25 is a one-way communication line from the transmitting station to the receiving station, and 26 is a two-way communication line.

In FIG. 1, packets input from the outside via a terminal 22 are temporarily stored in a transmitting side packet buffer 14, and a packet transfer request signal is given to the transmission control unit 11 via a terminal 21. The transmission control section 11 first writes transmission designation information for all packets in the buffer 14 into the packet selection table 15, and gives a packet transmission start command to the packet transmission section 13. When the packet sending unit 13 receives the packet sending start command, it immediately takes out the packet corresponding to the specified information from the buffer 14 and adds identification information indicating the position of the packet in the buffer and an error detection code. It is sent to the communication line 25.

When a packet arrives from the communication line 25, the packet receiving unit 18 refers to the identification information added to the packet, writes it to a specified position in the receiving side packet buffer 19, and performs error detection. is written to the reception table 2o.

The transmission control unit 11 sends data to the communication line 26 via the transmission side control data transmission/reception unit 12 to the reception control unit 16 to inquire about the reception status. Reception control section 15
When receiving this inquiry via the receiving side control data transmitting/receiving section 17, it sends the contents of the receiving table 14 to the communication line 26 via the receiving side control data transmitting/receiving section 17 as response data, and transmits the transmitting side control data. The transmitter/receiver 12 receives this and transmits it to the transmission controller 11.

The transmission control unit 11 receives this response data and reports it to the outside via the terminal 21 if all packets are shown to have been received normally, but some packets are not received normally due to loss or transmission error. If so, the transmission designation information for those packets is written into the selection table 15. Here, packet selection table 15 and reception table 2
o can be made homomorphic, and each packet consists of one bit, so that each bit indicates the successful arrival of the corresponding packet (
= for example 0) and packet transmission error or non-arrival (=1)
, the packet selection table 15 can be updated simply by writing the response to the inquiry as is.

When transmitting multiple packets from a transmitting station to a receiving station using the packet transmission device configured as described above, first, the packets to be transmitted are accumulated in the transmitting side buffer, and the packet transmission is started via the terminal to the transmission control unit. All you have to do is give the command.

When the transmission control unit receives a packet transfer start command, it repeats data transfer and retransmission with the receiving device until all data is transferred to the receiving packet buffer without error.

(Effects of the Invention) According to the present invention, when performing packet transmission with error retransmission between a transmitting station and a receiving station, a device that transfers data packets and a device that performs data packet transfer control such as retransmission control. By making each device independent and having a single function, it is possible to easily implement hardware for each device and achieve high-speed data transfer.

[Brief explanation of the drawing]

FIG. 1 shows a configuration example of a packet transmission device according to the present invention, FIG. 2 shows a logical configuration example of a packet transmission system with an error control function according to the present invention, and FIG. Shown in Figure 3. In the figure, 11 is a transmission control unit, 12 is a transmitting station side control data transmission/reception unit, 13 is a packet sending unit, 14 is a transmitting side packet buffer, 15 is a packet selection table, 16 is a reception control unit, and 17 is a receiving station side control Data transmitting/receiving section, 18
is a packet receiving unit, 19 is a receiving side packet buffer, 2
0 is the packet reception table, 41 is the transmitting station, 42 is the receiving station, 43 is the buffer on the transmitting station side, 44 is the first diagram 2 (Fig. 3 transmitting station receiving station □ data body (first communication path)

Claims (2)

[Claims] (1) A packet transmission method with an error retransmission function in a communication system consisting of two stations, a transmitting station and a receiving station,
The transmitting station and the receiving station are connected by a first communication line for unidirectional communication from the transmitting station to the receiving station, and a second communication line for bidirectional communication between the two stations. , temporarily accumulates externally input packets in a buffer,
The packet is sent out using the first communication line, and an inquiry is made to the receiving station about the reception status using the second communication line, and the receiving station stores the arrived packet in a buffer and performs a transmission error check. In response to the receiving status inquiry from the transmitting station, the presence or absence of a transmission error and the presence or absence of packet arrival are transmitted to the transmitting station using the second communication line, and the transmitting station determines whether or not the received status has been received based on the response to the inquiry. If there is a packet that arrived or had a transmission error, only the packet that did not arrive or had a transmission error is sent, and the receiving station is asked about the reception status using the second communication line, and this packet is sent. A packet transmission method with an error retransmission function that repeats sending and receiving status inquiries until no packets arrive or have transmission errors. (2) A packet transmission device with an error retransmission function in a communication system consisting of two stations, a transmitting station and a receiving station,
The transmitting station side device includes a transmitting side packet buffer that temporarily stores packets input from the outside, and a packet selection table that specifies packets to be transmitted from among the packets accumulated in the transmitting side packet buffer. a packet sending unit capable of selecting and transmitting a packet specified by the packet selection table from the sending packet buffer; a means for making an inquiry to a receiving station to confirm reception status; and updating the packet selection table. The receiving station side device consists of a packet receiving unit that can check for transmission errors in arriving packets, a receiving side packet buffer that temporarily stores packets, and a packet reception table that records the arrival of the packet and the presence or absence of transmission errors;
and a reception control unit capable of transmitting the contents of the packet reception table to the transmission station in response to an inquiry from the transmission station to confirm the reception status, and the packet reception unit transfers the arrived packet to the reception side packet buffer. A packet transmission device with an error retransmission function, comprising: a packet reception device capable of accumulating data, checking transmission errors, and writing the results to the packet reception table.