JPH0621965A - Data communication device - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the data communication time from increasing due to congestion in the packet network. [Structure] The difference between the time data transmitting means 5 for including the transmission time data of the communication message in the communication message transmitted by the packet communication means 3 and the transmission time data included in the received communication message and the incoming time exceeds a predetermined time. In this case, the switching system switching means 6 for switching the packet switching system to the circuit switching system and continuing the transmission and reception of communication messages is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication device for transmitting and receiving communication telegrams through a switching network, and more particularly, to selectively execute both a packet switching system and a circuit switching system. Data communication device.

[0002]

2. Description of the Related Art In online transaction processing such as CD caching, data is transmitted and received between a host device at a center and a terminal device such as a cash dispenser via a public telephone network. As described above, in the case of performing data communication using the public telephone network, there is a problem in that a general circuit switching method causes an increase in communication cost because the fee is charged according to the communication time. Therefore, there is a tendency that data communication by a packet switching system, which is charged according to the amount of data, is conventionally adopted.

[0003]

However, in data communication by the packet switching system, there is no regulation of the maximum delay time in the packet network, and a large number of communication devices connected to the packet network send and receive data at the same time. In the case of execution, there is a problem that data is input into the network beyond the processing capability of the packet network and congestion occurs, resulting in a long data transmission time.

Such a long data transmission time is
In a system that requires a short processing time such as online transaction processing, it causes a system failure.

An object of the present invention is to extend the data transmission time by switching to the circuit switching system and conducting data communication when congestion occurs in the packet network during data communication by the packet switching system. It is an object of the present invention to provide a data communication device capable of preventing the occurrence of a system failure by preventing the above.

[0006]

As shown in FIG. 1A, a data communication apparatus 1 of the invention described in claim 1 includes a packet communication means 3 for transmitting and receiving a communication message by a packet switching system, and a circuit switching. A line communication means 4 for transmitting and receiving a communication telegram according to the method, a time data transmitting means 5 for including the transmission time data of the communication telegram in the communication telegram transmitted by the packet communication means, and a transmission time included in the received communication telegram. Switching system switching means 6 for switching to the circuit switching method by the circuit communication means when the difference between the data and the arrival time exceeds a predetermined time.

Further, as shown in FIG. 1B, the data communication device 11 of the invention described in claim 2 is a packet communication means 3 for transmitting and receiving communication messages by a packet switching system.
A line communication means 4 for transmitting / receiving a communication message by a circuit switching method, a dummy message communication means 15 for transmitting / receiving a dummy message by the packet communication means prior to the transmission of the communication message, and a transmission / reception by the dummy message communication means. Switching method selecting means for transmitting and receiving communication telegrams by the circuit switching means 4 when the time difference between the arrival and departure of the received dummy telegram exceeds a predetermined time, and when the time difference does not exceed the predetermined time 16 and 16 are provided.

[0008]

In the invention described in claim 1, the communication data of the packet switching system by the packet communication means 3 includes the transmission time data of the communication data by the time data transmission means 5. The data communication device that receives this communication message switches the downlink message to the circuit switching method by the line communication means 4 and transmits it when the difference between the transmission time data included in the communication message and the reception time exceeds a predetermined time. Therefore, congestion occurs in the packet network of the public telephone network 2, and the time from the transmission of the upstream communication message transmitted from one data communication apparatus 1 to the arrival at the other data communication apparatus 1 becomes long, When the data transmission time becomes long, the transmission / reception of the communication message by the packet switching method is switched to the transmission / reception of the communication message by the circuit switching method.

According to the second aspect of the invention, the packet communication means 3 transmits / receives the dummy telegram prior to the transmission / reception of the communication telegram, and if the data communication time of the dummy telegram is within a predetermined time, in the packet network. It is determined that congestion has not occurred, the communication message is transmitted / received by the packet switching means 3, and if the transmission / reception time of the dummy message exceeds a predetermined time, it is determined that congestion is occurring in the packet network of the public telephone network 2. Then, the communication message is sent and received by the circuit switching method. Therefore, by configuring the dummy telegram with relatively short data, the state of the packet network can be recognized in advance before the transmission and reception of the communication telegram, and the packet switching method or the circuit switching method can be used according to the state of the packet network. Communication messages are transmitted and received by using one of them alternatively.

[0010]

FIG. 2 is a schematic diagram showing the configuration of a data communication system to which a data communication apparatus according to an embodiment of the invention described in claim 1 is applied. In this embodiment, a configuration of a system for online transaction processing in which a plurality of cash dispensers are connected to a host device via an ISDN network is shown. The plurality of cash dispensers 22a to 22n are connected to the ISDN network 26 via DSUs 24a to 24n. The host device 23 of the center is connected to the ISDN network 26 via the DSU 25. Each of the cash dispensers 22a to 22n transmits / receives data to / from the host device 23 of the center via the ISDN network 26. The ISDN network 26 can use both the packet switching system and the circuit switching system on a single line, and can select either the packet switching system or the circuit switching system prior to transmitting / receiving a communication message. In the system 21 for executing online transaction processing, the cash dispensers 22a-2a-2
A payment request message is transmitted from 2n to the host device 23. The host device 23 of the center performs a payment approval / disapproval determination process based on the transmitted payment request message, and transmits the result to the cash dispensers 22a to 22n as a downlink communication message. The cash dispensers 22a to 22n execute cash payment processing when receiving the payment permission data transmitted from the host device 23.

FIG. 3 is a flow chart showing a time-series structure of a communication message and a processing procedure of the communication device in the data communication system to which the data communication device is applied. When the cash dispensers 22a to 22n are activated, the opening message is transmitted from the host device 23 to each of the cash dispensers 22a to 22n (n1). The opening message includes the opening instruction code for instructing opening and the current time data indicating the current time of the clock of the host device 23. Each of the cash dispensers 22a to 22n that has received this opening message executes the opening process, and at the same time, each of the cash dispensers 22a to 22n.
The time of the clock built in is set to the time obtained by adding the delay time in the circuit switching network to the current time data included in the opening message. As a result, each cash dispenser 22a
The measured time of 22n and the measured time of the host device 23 match.

Each cash dispenser 22a-22n
Waits for the customer to start transaction processing in this state.
When the customer starts transaction processing, the cash dispensers 22a to 22n create payment request data based on the customer code and the payment amount, and use this payment request data as a payment request message together with the current time data of the clock built in itself. It is transmitted to the host device 23. This payment request message is sent by ISD by the packet switching method.
It is performed via the packet network in the N network 26.

When the host device 23 receives the payment request message transmitted from any of the cash dispensers 22a to 22n, the current time data contained in the payment request message and the clock contained in the host device 23 itself are clocked. The difference from the current time is calculated as the delay time in the packet network. When the delay time in the packet network obtained by this calculation is within 2 seconds, the host device 23 determines that congestion has not occurred in the packet network, and the payment permission message is sent to the corresponding cache by the packet switching method. It transmits to dispenser 22a-22n. On the other hand, when the delay time in the packet network exceeds 2 seconds, the host device 23 determines that congestion has occurred in the packet network, disconnects the connection in the packet network, and then uses the circuit switching method to make a payment permission message. To send.

With the above processing, in this embodiment,
When the station is opened, the clocked time of the clock contained in the cache dispensers 22a to 22n and the clocked time of the clock contained in the host device 23 are matched so that each of the cache dispensers 22a to 22n outputs the host device 2
Whether or not congestion has occurred in the packet network is determined based on the delay time in the packet network, which is represented by the difference between the transmission time data included in the payment request message and the current time. In accordance with the result of this judgment, the host device 23 sends the downstream communication message by either the packet switching method or the circuit switching method to the cash dispenser 22a.
~ 22n. Therefore, when the payment request message transmitted from any of the cash dispensers 22a to 22n is delayed for a predetermined time or longer in the packet network, the host device 23 determines that congestion has occurred in the packet network, Payment approval / disapproval data can be transmitted by the exchange method, and delay in transmission time due to data transmission using a congested packet network can be avoided in advance.

FIG. 4 is a diagram showing a configuration of a data communication system to which the data communication apparatus according to the embodiment of the invention described in claim 2 is applied. This figure shows a plurality of card terminal devices 3
2a-32n through ISSU 34a-34n to ISDN
The host device 33 of the center is connected to the network 35.
Is connected to the ISDN network 35 via the DSU 36. This store system 3
In No. 1, the center host device 33 transmits a communication message requesting sales inspection to each of the card terminal devices 32a to 32n, and the card terminal devices 32a to 32n make sales within a predetermined time in response to the sales inspection request. The data is transmitted to the host device 33 as sales inspection response data.

FIG. 5 is a flow chart showing the time-series structure of the communication message and the processing procedure of the communication device in the store system. The host device 33 of the center performs sales inspection by reading sales data of each of the card terminal devices 32a to 32n at a predetermined timing.

The host device 33 transmits a dummy downlink message to a specific card terminal device 32a prior to the sales inspection process. The host device 33 stores the transmission time of this dummy downlink message. When receiving the dummy downlink message, the card terminal device 32a transmits a predetermined dummy uplink message to the host device 33. The host device 33 calculates the difference between the transmission time of the dummy downlink message and the reception time of the dummy uplink message as the delay time in the packet network. If the transmission / reception time difference of this dummy message is 10 seconds or less,
The host device 33 determines that congestion has not occurred in the packet network, and executes the sales inspection process by the packet switching method. That is, the communication message of the sales inspection request is transmitted from the host device 33 to each of the card terminal devices 32a to 32n by the packet switching method. On the other hand, the card terminal devices 32a to 32n transmit a message including sales data to the host device 33 by the packet switching method.

On the other hand, when the transmission / reception time difference of the dummy message exceeds 10 seconds, the host device 33 carries out subsequent sales inspection processing by the circuit switching system. That is, the host device 33 sends the communication message of the sales inspection request to each card terminal device 3
It transmits to 2a-32n via a circuit switching network. On the other hand, the card terminal devices 32a to 32n transmit a response message including sales data to the host device 33 via the circuit switching network.

By the above processing, in this embodiment,
Prior to the formal transmission / reception of a communication message between the host device 33 and the card terminal devices 32a to 32n, a dummy message is transmitted / received, and congestion occurs in the packet network from the time required for the transmission / reception of the dummy message. The presence or absence of is detected. Then, based on this detection result, the host device 33 executes data communication by either the packet switching system or the circuit switching system. Therefore, when the data length transmitted / received between the communication devices is long, the state of the packet network can be recognized in advance by the communication device prior to the transmission / reception of the communication telegram, and the optimal switching method is based on this state. Can be selected.

[0020]

According to the invention described in claim 1, packet switching is performed based on the difference between the transmission time of the communication message transmitted from one data communication device and the arrival time of the communication message at the other data communication device. The presence or absence of congestion in the network is detected, and according to this result, it is possible to select whether to continue transmission and reception of communication messages by the packet switching method or switch to transmission and reception of communication messages by the circuit switching method. There is an advantage that it is possible to prevent the data transmission time from being lengthened by automatically selecting the exchange method according to the state.

According to the invention described in claim 2,
Dummy message transmission / reception is executed prior to transmission / reception of a communication message between data communication devices, and presence / absence of congestion in the packet network is detected in advance based on the time required for transmission / reception of this dummy message, and based on this result. It is possible to select whether to perform transmission / reception of a communication message by the packet switching method or the circuit switching method. Therefore, it is possible to select the exchange method that can minimize the data transmission time according to the state of the packet network detected in advance, and there is an advantage that the extension of the transmission time can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a communication system using the data communication device of the embodiment according to the invention described in claim 1.

FIG. 3 is a flowchart showing a time-series configuration of communication messages and a processing procedure of the communication device in the communication system.

FIG. 4 is a schematic diagram showing a configuration of a communication system to which the data communication device of the embodiment according to the invention described in claim 2 is applied.

FIG. 5 is a flowchart showing a time-series configuration of communication messages in the communication system and a processing procedure in the data communication device.

[Explanation of symbols]

 21, 31-Data communication system 22a-22n-Cash dispenser 23-Host device 24-ISDN network

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8529-5K H04L 11/20 102 Z

Claims (2)

[Claims] 1. A packet communication means for transmitting / receiving a communication message by a packet switching system, a line communication means for transmitting / receiving a communication message by a circuit switching system, and a communication message transmitted by the packet communication device Time data transmission means including transmission time data, and switching method switching means for switching to the circuit switching method by the line communication means when the difference between the transmission time data included in the received communication message and the reception time exceeds a predetermined time. A data communication device comprising: 2. A packet communication means for transmitting / receiving a communication message by a packet switching method, a line communication means for transmitting / receiving a communication message by a circuit switching method, and a dummy message by the packet communication means prior to the transmission of the communication message. When the time difference between the dummy message communication means for executing transmission and reception and the dummy message transmitted / received by the dummy message communication means exceeds a predetermined time, the circuit switching means causes the circuit to change the time. A data communication device, comprising: a switching system selecting means for transmitting and receiving a communication message by means of a packet switching means.