JPH09219721A - Data retransmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a retransmitting time suitable for the terminal equipment of a transmission destination without imposing burden to an operation system. SOLUTION: A data transmitting part 12 transmits connection request data or transmission data to the transmission destination, which is generated based on the contents of a parameter table 13, reads a re-transmitting time value corresponding to the transmission destination from the parameter table 13 so as to set it in a transmission monitor timer 14 and monitors the time till the reception of a response frame from the transmission destination. When response frame is received, a data receiving part 15 cancels the transmission monitor timer 14. When the transmission monitor timer 14 is becomes time-out before the data reception response frame is received from the transmission destination, a time-out report is outputted to a data transfer control part 11. In inputting the time-out report, a data transfer control part 11 outputs the re-transmission request of the data to the data transmitting part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer system, and more particularly to a data resend method of a network system for controlling transfer data in a transport layer.

[0002]

2. Description of the Related Art Conventionally, in this type of network system, transfer data is controlled in a transport layer, and a connection is first established to a transfer destination terminal device to which data transfer is desired. . This connection is established not for each terminal device but for each process of the terminal device. Therefore, a plurality of connections may be established between the same terminal devices.

The connection is established by transmitting a connection request frame to which a port number assigned to the process is added from the terminal device on the transmitting side to the terminal device on the receiving side. When the terminal device on the receiving side normally receives the connection request frame, it transmits to the transmitting side a response frame in which the port number of its own process is added to the connection request frame.

If the response frame from the terminal device on the receiving side is normal, the terminal device on the transmitting side recognizes that a connection has been established, and transfers the transfer data with the mutual port number added to the terminal device on the receiving side. To send.

However, if a response frame is not returned from the terminal device on the receiving side, the terminal device on the transmitting side waits for a certain period of time in the transport layer and performs a retransmission process of the transfer data. The retransmission time is set in advance in the transport layer, or is set by an algorithm for calculating the retransmission time by calculating the response to the transfer data.

Further, as shown in FIG. 7, the terminal devices 4a,
If the network 5a composed of 4b and the network 5b composed of the terminal devices 4c and 4d are connected via the relay device 6, when the transfer data is transferred from the terminal device 4a to the terminal device 4c, the return is made prior to the communication. There is a method to send a frame.

In this method, the relay device 6 is the terminal device 4
When the return frame is received from a, the specific field of the return frame is updated, and the return frame is relayed to the terminal device 4c.

The terminal device 4a is configured to set the data retransmission time with the destination device according to the content of the specific field of the return frame returned from the destination device.

That is, a plurality of networks 5a, 5
In a system in which b is connected via a relay device, the terminal device 4a transmits to the destination terminal device 4 at the start of communication.
The folded frame 11 as shown in FIG. 8A is sent to c.

In the relay device 6, the folded frame 11
When relaying, the number part (N
UM: Number) 112 is updated to calculate the number of networks to relay. In the destination terminal device 4c, the field portion (CMD: Co
8), the response (RSP: Response) of the response frame 12 as shown in FIG.
se) 121, and the transmission destination address and the transmission source address are exchanged and transmitted.

The relay device 6 relays the response frame 12 to the terminal device 4a without changing the updating unit of the response frame 12 from the terminal device 4c. Therefore, the terminal device 4a knows the number of networks to be relayed up to the destination terminal device 4c based on the data written in the number part (NUM) 122 of the returned response frame 12, and determines the data retransmission time. To set.

The DA in FIGS. 8A and 8B is Dest.
Indication Address (transmission destination address), and SA is Sender Address (transmission source address). The above technique is described in detail in Japanese Patent Laid-Open No. 1-264428.

[0013]

In the above-mentioned conventional network system, when the response frame is not returned from the terminal device on the receiving side, it is set in the transport layer as the retransmission time until the retransmission processing of the transfer data is performed. If the value is fixed, the retransmission time will be the same regardless of whether the communication partner is a terminal device in the same network or a terminal device that relays a plurality of networks.

Further, if the algorithm is set based on the response to the transfer data and the resending time is determined, the resending time is complicated and the response data must be calculated for each data. The burden on the operating system increases.

Further, as described above, when the data retransmission time is set by knowing the number of networks to be relayed, the relay device that relays between groups is provided with a function of updating a specific field of the return frame. Therefore, the destination terminal device also needs a function of exchanging the destination address and the source address for transmission.

In this case, the traffic on the line increases due to the transmission and reception of the return frame and the response frame to the return frame, and the above method is applied between the terminal devices that do not go through the relay device, that is, between the terminal devices in the same network. It cannot be used.

Therefore, an object of the present invention is to solve the above problems and to easily set the retransmission time suitable for the destination terminal device without burdening the operation system. To provide.

[0018]

A data retransmission system according to the present invention is a network system composed of a plurality of terminal devices, and when a transfer data is transmitted from a transmission side, the reception side waits until a time monitoring timer measures a set time. Is a data retransmission system that retransmits the transfer data if it does not receive the response frame of the terminal device, the identification information of each terminal device other than the own terminal device, the address information of each terminal device, and the terminal device A parameter table storing the response waiting time for the response frame in association with each other, and reading the response waiting time corresponding to the transfer destination of the transfer data from the parameter table when transmitting the transfer data, and reading the response waiting time in the time monitoring timer. Each of the plurality of terminal devices is provided with means for setting the set time.

Another data retransmission system according to the present invention is
In addition to the above configuration, when the response frame is received before the time monitoring timer measures the response waiting time, means for canceling the response waiting time set in the time monitoring timer is provided in each of the plurality of terminal devices. Is equipped with.

Another data retransmission system according to the present invention is
In the above configuration, the network system is configured to connect a plurality of systems each including a plurality of terminal devices to each other via a relay device.

In still another data retransmission system according to the present invention, in the above configuration, the network system controls transfer data at a transport layer, and at the start of transfer of the transfer data, a transmission side and a reception side are connected between the transmission side and the reception side. Configured to establish a connection.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the operation of the present invention will be described below.

The device name of each terminal device other than the own terminal device, the address of each terminal device, and the retransmission time value (response waiting time) set in each terminal device are registered in the parameter table in association with each other. When transmitting the transfer data, the retransmission time value corresponding to the transfer data transfer destination is read from the parameter table and set in the time monitoring timer.

As a result, the small-scale network (LA
In N), it is possible to easily set the retransmission time value suitable for the transfer destination terminal device without burdening the operation system with the retransmission time value for each transfer destination terminal device.

That is, since the value set in the transport layer as the retransmission time value until the retransmission processing of transfer data is performed is not fixed, the retransmission time value is used by the terminal devices in the same system group as the transfer destination terminal device. Even if there is, or even a terminal device in another system group, it is possible to set with a corresponding value.

Further, since it is not necessary to set the retransmission time value by the algorithm for determining the retransmission time by calculating based on the response to the transfer data, it is necessary to perform a complicated calculation for the retransmission time value for each response data. Therefore, it is possible to reduce the burden on the operating system.

Further, the function of transmitting the destination address and the source address in the transfer destination terminal device by exchanging the transmission destination address without providing the relay device for relaying between the system groups with the function of updating the specific field of the return frame. No longer needed. Therefore, it is possible to use the above-described retransmission method between terminal devices that do not go through a relay device, that is, between terminal devices that are in the same system group, without causing an increase in traffic on the line.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a terminal device according to an embodiment of the present invention. In the figure, the terminal device 1 includes a data transfer control unit 11, a data transmission unit 12,
It includes a parameter table 13, a transmission monitoring timer 14, and a data receiving unit 15.

When a data transfer request is generated, the data transfer control unit 11 sends a connection request to the data transmission unit 12 to establish a connection with the destination. When the connection request is input, the data transmission unit 12 transmits the connection request data to the transmission destination created based on the contents of the parameter table 13.

At the same time as the connection request data is transmitted, the data transmission unit 12 sets a retransmission time value corresponding to the transmission destination registered in the parameter table 13 in the transmission monitoring timer 14. After that, the terminal device 1 waits for a response frame from the destination.

Here, in the parameter table 13, identification information (device name) of each terminal device (not shown) other than its own terminal device, address information of each terminal device, and each terminal device are set. The retransmission time value (response waiting time) is registered in advance.

When the data receiving section 15 receives the connection request response frame from the transmission destination, the transmission monitoring timer 14
Is canceled and the reception notification of the connection request response frame is sent to the data transfer control unit 11. The data transfer control unit 11 knows the establishment of the connection by the reception notification of the connection request response frame from the data receiving unit 15, and instructs the data transmitting unit 12 to start the data transmission.

When the data transmission unit 12 is instructed to start the data transmission, the data transmission unit 12 starts transmitting the data to the transmission destination and at the same time, the transmission monitoring timer 14 sets the retransmission time value corresponding to the transmission destination.
Set to. After that, the terminal device 1 waits for a data reception response frame from the transmission destination.

The data receiving unit 15 outputs a time-out notification to the data transfer control unit 11 when a time-out is notified from the transmission monitoring timer 14 before receiving the data reception response frame from the transmission destination.

When the time-out notice is input, the data transfer control unit 11 outputs a resend request for the data to the data transmission unit 12. When the data resending request is input, the data sending unit 12 starts resending the data to the destination, and sets the resending time value corresponding to the destination in the transmission monitoring timer 14.

FIG. 2 is a block diagram showing the system configuration of an embodiment of the present invention. The network system according to one embodiment of the present invention is composed of system groups 2a and 2b connected to each other via a relay device 3.

In the system group 2a, the terminal devices 1a and 1b are connected to each other by the bus 100a, and the bus 100a is connected to the relay device 3. In the system group 2b, the terminal devices 1c and 1d are connected to each other by the bus 100b, and the bus 100b is connected to the relay device 3. Each of the terminal devices 1a to 1d includes at least the same configuration as the terminal device 1 shown in FIG.

FIG. 3 is a diagram showing the structure of the parameter table 13 shown in FIG. In the figure, parameter table 1
3 is a device name 13a (“1b”, “1c”, of the terminal devices 1b to 1d to be connected in the above network system).
"1d") and the address 13 of each of the terminal devices 1b to 1d
b (“123”, “456”, “789”) and the retransmission time value 13c (“1” set for each of the terminal devices 1b to 1d).
1 ”,“ 12 ”, and“ 13 ”) are associated with each other and registered.

FIG. 4 is a sequence chart showing a data retransmitting process when a connection is established in one embodiment of the present invention, and FIG. 5 is a sequence chart showing a data retransmitting process after a connection is established in one embodiment of the present invention. FIG. 6 is a flowchart showing a data retransmission process according to an embodiment of the present invention. The data retransmission processing according to the embodiment of the present invention will be described with reference to FIGS.

Data transfer from the terminal device 1a in the system group 2a to the terminal device 1c in the system group 2b will be described below. First, the terminal device 1a registers the device names, addresses, and retransmission time values of the terminal devices 1b to 1d that perform data transfer in the parameter table 13 (step S1 in FIG. 6).

When the connection request is input from the data transfer controller 11 to the data transmitter 12 of the terminal device 1a,
Address 13b of the parameter table 13 ("45
6 ”), the connection request data created based on
00a (step S2 in FIG. 6). Bus 100a
The above connection request data is the relay device 3 and the bus 10.
It is transmitted to the terminal device 1c via 0b.

At this time, the data transmission unit 1 of the terminal device 1a
2 sets the retransmission time value 13c (“12”) corresponding to the terminal device 1c in the parameter table 13 in the transmission monitoring timer 14 and starts the transmission monitoring by the transmission monitoring timer 14 (step S3 in FIG. 6).

When the data receiving unit 15 of the terminal device 1a receives a timeout from the transmission monitoring timer 14 before receiving the connection request response frame from the terminal device 1c (step S4 in FIG. 6), the data transfer control unit 11 is notified. Output timeout notification. When the data transfer control unit 11 receives the time-out notification from the data receiving unit 15, the process returns to step S2 and outputs the connection request to the data transmitting unit 12 again (see FIG. 4).

On the other hand, when the data receiving unit 15 of the terminal device 1a receives the connection request response frame from the terminal device 1c, it cancels the transmission monitoring timer 14 and sends a reception notification of the connection request response frame to the data transfer control unit 1.
Send to 1. The data transfer control unit 11 is the data receiving unit 1.
The establishment of the connection is known by the reception notification of the connection request response frame from 5, and the data transmission unit 12 is instructed to start the data transmission.

When the data transmission unit 12 is instructed to start the data transmission, the data transmission unit 12 starts the data transmission to the terminal device 1c (step S5 in FIG. 6) and sets the retransmission time value "12" corresponding to the terminal device 1c. The transmission monitoring timer 14 is set. After that, the terminal device 1a waits for a data reception response frame from the terminal device 1c (step S6 in FIG. 6).

The data receiving unit 15 of the terminal device 1a outputs a time-out notification to the data transfer control unit 11 when the transmission monitor timer 14 reports a time-out before receiving the data reception response frame from the terminal device 1c ( 6 step S7).

When the time-out notice is input, the data transfer control unit 11 outputs a resend request for the data to the data transmission unit 12. When the data resending request is input, the data sending unit 12 returns to step S5 and tries again.
The terminal device 1c
The retransmission time value “12” corresponding to is set in the transmission monitoring timer 14 (see FIG. 5).

On the other hand, when the data receiving unit 15 of the terminal device 1a receives the data reception response frame from the terminal device 1c, it cancels the transmission monitoring timer 14 and sends the reception notification of the data reception response frame to the data transfer control unit 11. . The data transfer control unit 11 knows the normal transmission of data by the reception notification of the data reception response frame from the data reception unit 15, and when the data transmission unit 12 starts the transmission of the next data.
To instruct.

In the above description, the data transfer from the terminal device 1a to the terminal device 1c has been described.
data transfer from a to the terminal devices 1b and 1d and the terminal device 1
Data transfer from b to 1d to the terminal device 1a and data transfer between the terminal devices 1b to 1d can be performed in the same manner as the above-described processing.

In this way, the device name of each terminal device other than the own terminal device, the address of each terminal device, and the retransmission time value (response waiting time) set in each terminal device are associated with each other and the parameter table is associated with each other. 13 and the retransmission time value corresponding to the transfer destination of the transfer data is read from the parameter table 13 at the time of transmitting the transfer data and is set in the time monitoring timer 14, each transfer destination terminal device in the small-scale network (LAN). Moreover, it is possible to easily set the retransmission time value suitable for the transfer destination terminal device without burdening the operation system with the retransmission time value.

That is, since the value set in the transport layer as the retransmission time until the retransmission processing of the transfer data is performed is not fixed, the retransmission time value is the terminal device in the same system group. However, it is possible to set the corresponding value for each terminal device in another system group.

Further, since it is not necessary to set the retransmission time value by the algorithm for determining the retransmission time by calculating based on the response to the transfer data, it is necessary to perform a complicated calculation for the retransmission time value for each response data. The load on the operating system can be reduced.

Further, the transfer destination address and the source address are exchanged in the transfer destination terminal device without providing the relay device 3 for relaying between the system groups 2a and 2b with the function of updating the specific field of the return frame. The function to send by sending is unnecessary. In that case, the above-mentioned retransmission method can be used between terminal devices that do not pass through the relay device 3, that is, between terminal devices that are in the same system group, without increasing traffic on the line.

[0054]

As described above, according to the present invention, in a network system including a plurality of terminal devices,
When sending the transfer data from the sending side, if the response frame from the receiving side is not received before the time monitoring timer measures the set time, when the transfer data is retransmitted, the identification information of each terminal device other than the own terminal device And the address information of each of the terminal devices and the response waiting time for the response frame set in each of the terminal devices are stored in the parameter table in association with each other, and when the transfer data is transmitted, the transfer destination of the transfer data is transferred from the parameter table. By reading the response waiting time corresponding to the above and setting it in the time monitoring timer as the set time, it is possible to easily set the retransmission time suitable for the destination terminal device without burdening the operating system. There is an effect.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a terminal device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a system configuration according to an embodiment of the present invention.

3 is a diagram showing a configuration of a parameter table of FIG.

FIG. 4 is a sequence chart showing a data retransmission process at the time of establishing a connection in the embodiment of the present invention.

FIG. 5 is a sequence chart showing a data retransmission process after establishing a connection in the embodiment of the present invention.

FIG. 6 is a flowchart showing a data retransmission process according to an embodiment of the present invention.

FIG. 7 is a block diagram showing a system configuration of a conventional example.

FIG. 8A is a diagram showing a configuration of a return frame according to a conventional example, and FIG. 8B is a diagram showing a configuration of a response frame according to the conventional example.

[Explanation of symbols]

 1, 1a to 1d Terminal device 2a, 2b System group 3 Relay device 11 Data transfer control unit 12 Data transmitting unit 13 Parameter table 14 Transmission monitoring timer 15 Data receiving unit

Claims (4)

[Claims] 1. In a network system composed of a plurality of terminal devices, if a response frame from the receiving side is not received before the time monitoring timer measures the set time when the transmitting side transmits the transfer data, A data retransmission system for performing retransmission, in which identification information of each terminal device other than the own terminal device, address information of the terminal device, and response waiting time for the response frame set in each of the terminal devices are associated with each other. A plurality of parameter tables to be stored in a plurality of units, and a means for reading the response waiting time corresponding to the transfer destination of the transfer data from the parameter table when transmitting the transfer data and setting the response waiting time as the set time in the time monitoring timer. A data retransmission system, characterized in that each terminal device has it. 2. Each of the plurality of terminal devices includes means for canceling the response waiting time set in the time monitoring timer when the response frame is received before the time monitoring timer measures the response waiting time. The data retransmission system according to claim 1, wherein 3. The network system is configured such that a plurality of systems each including a plurality of terminal devices are connected to each other via a relay device.
Alternatively, the data retransmission system according to claim 2. 4. The network system is configured to control transfer data at a transport layer and establish a connection between a transmission side and a reception side at the start of transfer of the transfer data. The data retransmission system according to any one of claims 1 to 3.