JPH0548631A - Transmission destination address decision method for data transmission system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency of the entire data transmission by sending a transmission request only once at first to check an address of a destination station address and setting the result onto an address table thereby confirming the address only once at first. CONSTITUTION:Either of destination stations 15a and 15b is in operation and the other is in standby. Thus, when a sender station 10 sends a line establish request text 16 at application of power, a reply signal 17 comes from only the destination station in operation and the address of the destination station in operation is stored as a destination address on an address table 11. After the address is stored in this way, the destination address is added to each data and the resulting data is sent. As a result, every time the data is sent, the transmission reception processing of a line establish request signal 16 and a reply signal 17 between the sender station 10 and the destination station 15 is not required different from a conventional system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system for transmitting information from a source station to one destination station among a plurality of destination stations.
The present invention relates to a transmission destination address determining method for determining a transmission destination address when a transmission source station transmits information.

[0002]

2. Description of the Related Art For example, a plurality of stations having an information processing function are connected in a network by a transmission line,
In a data transmission system in which various information is transmitted and received between stations, a network transmission method is adopted as a data transmission procedure.

That is, in this network transmission, when the source station does not know the address of the destination station, the source station determines the information (data) to be transmitted and the logical station name (information name) determined by the type of this information. ) Is sent to the transmission line by broadcast communication that does not specify the destination address. All stations except the transmission source station connected to the transmission line receive the electronic message, and only when the logical station name (information name) related to itself is included, the information (data) included in this electronic message is written, for example. The information is taken into the memory and predetermined information processing is executed.

In addition, in a connection type transmission method such as TCP / IP transmission, when transmitting information from a transmission source station to a transmission destination station, the transmission source station and the transmission destination station must be previously set. It is necessary to connect one-to-one in terms of software. And 1
When the transmission processing of the information of the times is completed, the one-to-one connection state is released. Therefore, every time information is transmitted, the processing operation of the connection establishment processing and the actual information transmission processing is required twice.

On the other hand, in the case of a data transmission system employing serial transmission or modem transmission (connectionless system), the address of the destination station is often known in advance.

FIG. 5 is a block diagram showing an example of a data transmission system adopting serial modem transmission (connectionless system). In this example, one source station 1 has communication interfaces 2a, 2 respectively.
Two destination stations 4 via b, 3a, 3b
a and 4b are connected. The source station 1 stores the addresses ADa and ADb of the destination stations 4a and 4b. Further, the source station 1 is connected to an input device 5 for the operator to designate the destination stations 4a and 4b.

In such a data transmission system,
One of the two destination stations 4a and 4b is designated as the backup station. Therefore, normally, the transmission source station 1 transmits information (data) to one of the regular transmission destination stations 4a by designating the transmission destination address ADa.
Then, if any abnormality is detected in the authorized destination station 4a, the operator switches the destination address to the destination address ADb of the destination station 4b designated as the backup station via the input device 5. .. Then, thereafter, the transmission source station 1 transmits the information (data) to the other transmission destination station 4b by designating the transmission destination address ADb.

[0008]

However, the above-mentioned network transmission method and the serial modem transmission (connectionless system) shown in FIG. 5 still have the following problems to be improved.

That is, in the case where the same type of information (data) is continuously transmitted from the source station to the destination station designated in advance, the information (data) disappears when an abnormality occurs in the destination station. There is a data transmission system equipped with a destination station for backup to prevent this. In such a case, it is not clear when the information (data) destination will be changed from the regular (operating) destination station to the backup (standby) destination station. The address cannot be fixed.

As a result, as described above, it is necessary to transmit information (data) by broadcast communication each time. Therefore, when a large number of stations are connected to the transmission path, it is necessary for each station to read the content of the received electronic message and determine whether or not the information (data) is relevant to itself. Therefore, there is a problem that the load on each station increases.

Further, in the transmission method in which information (data) is transmitted after establishing a connection with the destination station each time instead of the broadcast communication, the average transmission time of information (data) once However, there is a problem that the data transmission processing efficiency of the entire data transmission system decreases.

Further, in the serial modem transmission system shown in FIG. 5, when an abnormality occurs, it is necessary for the operator to manually switch the transmission destination address. Therefore, there is no guarantee that the destination station 2b on the backup side is immediately switched to when an abnormality occurs.

The present invention has been made in view of the above circumstances, and when transmitting a plurality of pieces of information of the same type, the transmission request is transmitted only the first time and the address of the destination station is checked. After that, by sending each information using the obtained address, even if the destination address is initially unknown, there is no need to perform broadcast communication or connection processing every time, and the destination address can be manually operated. It is possible to shorten the average transmission time required for one-time information transmission without switching, and to automatically set the transmission destination address to improve the data transmission efficiency of the entire data transmission system. The purpose is to provide a scheme.

[0014]

In order to solve the above problems, a transmission destination address determining method in a data transmission system according to the present invention designates one transmission destination station among a plurality of transmission destination stations from a transmission source station. In a data transmission system that transmits information by

The transmission source station sends a transmission request message to each transmission destination station, which specifies a transmission source address and a logical station name determined by the type of information to be transmitted, and each transmission destination station has a logic related to itself. When a transmission request message with a station name specified is received, a response message incorporating its own address and logical station name is sent back by specifying the sender address, and when the source station receives the response message, this response message is sent. Is stored in the address table as a destination address, and thereafter, each piece of information to be transmitted is transmitted by designating the destination address stored in the address table.

[0016]

According to the transmission destination address determining method having such a configuration, the address stable is provided in the transmission source station. Then, the transmission source station transmits the information to be transmitted by designating the transmission destination address set in this address table. If the destination address is not set in the address table, the source station sends a transmission request message to the plurality of destination stations connected to this source station to obtain the destination address. .. The destination station which should receive the information among the plurality of destination stations incorporates its own address in the response message and returns it. When the source station receives the response message for this transmission request message, the address included in this response message is set in the address table.

Therefore, when a plurality of pieces of information (data) are continuously transmitted to the same transmission destination station, the transmission request message is transmitted only in the first information transmission to obtain the transmission destination station address. By executing the processing of transmitting the message and receiving the response message, each information (data) can be transmitted using the obtained transmission destination address from the second time onward unless there is any command from the outside.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a data transmission system adopting the destination address determining method of the embodiment.

An address table 11 for storing an address of a destination station to which data (information) is to be transmitted is provided in a storage unit in the destination station 10 which is constituted by an information processing device such as a computer. And
This destination station 10 has a communication interface 12
a, the transmission path 13a and the communication interface 14a, and is connected to one destination station 15a. At the same time, the destination station 10 includes the communication interface 12b, the transmission line 13b, and the communication interface 1
It is connected to the other destination station 15b via 4b.

In such a data transmission system,
One destination station 15a is designated as a regular (operating) destination station, and the other destination station 15b is designated as a backup (standby) destination station. Then, the transmission source station 10 transmits the same type of data to the legitimate (operating) transmission destination station 15a, for example, in a constant cycle, and the transmission destination station 15a performs a predetermined arithmetic processing on the data received in the constant cycle. To execute.

Each destination station 15a, 15
b does not perform information processing in parallel, and when one is operating, the other is waiting. Then, when an abnormality occurs in the operating transmission destination station, the standby transmission destination station becomes active and the active transmission destination station becomes standby.

Then, the regular destination station 15a
If any abnormality is detected in the source station 1
0 transmits each data to the destination station 15b changed to the working side, and the destination station 15b changed to the working side executes a predetermined arithmetic process in place of the destination station 15a.

When the power source station 10 is turned on, the transmission source station 10 executes a transmission process for each data according to the flow chart shown in FIG. That is, when the flow chart is started, first, both destination stations 15a and 15b are
A line establishment request message 16 as a transmission request message including the logical station name determined by the type of data to be transmitted and its own address ADs is transmitted. When receiving the response message 17 including the address and the logical station name addressed to itself from one of the destination stations 15a and 15b, the address included in the response message 17 is set in the own address table 11 as the destination address. Yes (P2).

When an address change request is not input from the outside at P3 and a data transmission request is generated at P4, the destination address stored in the address table 11 is read out at P5 and transmitted. The data is sent with this destination address. When the data is transmitted, the process returns to P3, and if the address change request is not input, the process proceeds to P4 and waits for the next data transmission request.

Then, when an abnormality occurs in the operating destination station and a transmission error occurs, an address change request is issued. Note that an address change request may occur in response to an operation instruction from the operator. When an address change request is generated at P3, the process returns to P1 and the line establishment request message 16 is sent again to both transmitting stations 15a and 15b.

Further, each of the destination stations 15a, 15
b performs a data transmission process according to the flowchart of FIG. That is, when the line establishment request message 16 is received in Q1, if the logical station name included in the line establishment request message 16 is related to the own station, the self address and the received logical station name are returned. It is incorporated in the message 17, and the transmission source address also included in the line establishment request message 16 is designated as the transmission destination address and transmitted (Q3). Further, when the data to which the address addressed to itself is attached is received in Q4, this data is fetched and the predetermined data processing is executed.

According to the transmission destination address determination method having such a configuration, only one of the transmission destination stations 15a and 15b is in operation and the other is in standby. Therefore, when the transmission source station 10 sends out the line establishment request message 16 when the power is turned on, the response signal 17 is returned only from the transmission destination station that is operating. Therefore, the address of the operating destination station is stored in the address table 11 as the destination address. The destination address once stored in the address table 11 cannot be rewritten unless an abnormal situation such as a transmission error occurs with respect to the operating destination station.

Therefore, after the destination address is stored in the address table 11, each data is sent with this destination address. As a result, unlike the conventional method, it is not necessary to transmit and receive the line establishment request signal and the response signal between the transmission source station and the transmission destination station every time one data is transmitted. Therefore, the average transmission time for transmitting one piece of data is significantly reduced.

When some abnormality occurs in the operating destination station and the standby destination station is changed to the operating destination station, the data sent from the source station 10 is Since the transmission destination station of the transmission destination address is in a standby state, a transmission error occurs, the line establishment request message 16 is transmitted again, and the address of the transmission destination station that has been newly activated is stored in the address table 11 as a new transmission destination address. Is set. That is, when an abnormality occurs, the destination address stored in the address table 11 is automatically changed. FIG. 4 is a block diagram showing a data transmission system to which a destination address determining method according to another embodiment of the present invention is applied.

The system of this embodiment has five stations 19a, 19b, 19c, 19d on one transmission line 18.
A network transmission system in which 19e and 19f are connected. In such a data transmission system, for example, when the station 19a transmits a large amount of data to the station 19b at a constant cycle, the station 1
9a is connected to all other stations 19 via the transmission line 18.
It sends out a line establishment request message incorporating its own address and logical station name to b to 19f.

When the station 19b receives the line establishment request message, since the logical station name incorporated in this line establishment request message is a logical station name related to itself, the station 19b transmits a response signal incorporating its own address. The original station 19a replies. The station 19a, which is the transmission source and receives the response signal, sets the address of the station 19b included in the response signal in its own address table as the destination address. Therefore, thereafter, data is transmitted by designating the destination address stored in the address table, that is, the address of the station 19b.

In order to prevent the destination address set in the address table from being erased, even after one data transmission process is completed, the soft connection with the destination station is maintained without interruption. To do. When any abnormality occurs, the soft connection is cut off. When the soft connection is cut off, the source station clears the address table again, and again sends the line establishment request message incorporating the logical station name of the destination and its own address to send. The acquisition process for the address of the destination station is started.

Even with the transmission address determining method of this kind of method, when transmitting a large number of data, it is only necessary to execute the address acquisition processing of the transmission destination station only once at the beginning, and therefore FIG. It is possible to obtain almost the same effect as the transmission destination address determination method described in.

[0034]

As described above, according to the transmission destination address determining method of the present invention, when a large amount of information is transmitted, only the first transmission request is transmitted and the address of the transmission destination station is checked, The information is set in the address table, and thereafter, each information is transmitted using the address set in the address table. Therefore, even if the destination address is initially unknown, there is no need to perform broadcast communication or connection processing every time, and it is not necessary to switch the destination address by manual operation. As a result, 1
The average transmission time required for transmitting information once can be shortened, and the destination address can be automatically switched, and the data transmission efficiency of the entire data transmission system can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a data transmission system adopting a destination address determining method according to an embodiment of the present invention;

FIG. 2 is a flowchart showing the operation of the transmission source station of the method of the embodiment.

FIG. 3 is a flowchart showing the operation of the destination station of the method of the embodiment.

FIG. 4 is a block diagram showing a data transmission system adopting a destination address determining method according to another embodiment of the present invention;

FIG. 5 is a block diagram showing a data transmission system using a conventional destination address determination method.

[Explanation of symbols]

10 ... Source station, 11 ... Address table,
12a, 12b, 14a, 14b ... Communication interface, 15a, 15b ... Destination station, 16 ... Line establishment request message, 17 ... Response message, 18 ... Transmission line, 19a
~ 19f ... Station.

Claims (1)

[Claims] 1. A data transmission system for transmitting information by designating one destination station from a plurality of destination stations from a source station, wherein the source station is a source station for each destination station. When sending a transmission request message specifying a logical station name determined by the address and the type of information to be transmitted, and each of the destination stations receiving the transmission request message specifying the logical station name related to itself, When the response station receives the response message, the source station stores the response message incorporating the address and the logical station name in the address table as the destination address when receiving the response message. After that, each piece of information to be transmitted is recorded in this address table. Destination address determining method in a data transmission system for transmitting by specifying a destination address that is.