JPH10294776A - Circuit-switching controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent data from being lost and to prevent the transmission efficiency of data communication from being lowered by sending data which is stored in memory at the point of time, when data communication due to a line interchangeable ISDN line becomes available. SOLUTION: As soon as an abnormality is detected in a fast digital line and a fast digital line interface part, a receiving memory 9 stores data that is received from a data terminal. Next, a controlling part 7 sends an instruction that connects to an ISDN line to an ISDN line interfacing part 6, in order to perform data communication by using the ISDN line and the part 6 is connected to the ISDN line. After the connection is completed, a switch 8 switches a data transmission route from a fast digital line to the ISDN line, and data stored in the memory 9 is sent to the part 6, via the switch 8 and sent to the ISDN line. This enables prevention of data in the process of line-switching processing from the digital line to the ISDN line from being lost and to perform communication, without lowering the data communication efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data assurance control of a line switching control device for switching between a high-speed digital line and a line-switched ISDN line.

[0002]

2. Description of the Related Art A line switching control device uses a high-speed digital line as a normally used line, uses an ISDN line as a backup line, and automatically and manually switches lines to be used when a high-speed digital line fails. Although switching control devices have been used in the related art, these line switching control devices have a problem in that data generated during a connection processing time required for exchanging connection control data with an ISDN line cannot be communicated. For example, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-14321, there is a method for preventing data loss when a line is switched from a backup line ISDN line to a dedicated line, but when switching from a dedicated line to a backup line ISDN line. There was no way to prevent data loss.

[0003]

A spare line is provided as means for continuing data communication when data communication cannot be continued due to a failure of the high-speed digital line during data communication using the high-speed digital line, There is a method of continuing data communication by using a protection line.
At this time, there is a method in which a circuit-switched ISDN line is used as a protection line. In a general line switching method, a circuit-switched ISD line is used when a failure such as a high-speed digital line is detected.
Until the N-line becomes available, data communication cannot be performed on either the high-speed digital line or the line-switched ISDN line. The data terminal device is discarded on the digital line or the line switching ISDN line, and the data terminal device performs retransmission processing of the lost data, so that the data transmission efficiency is deteriorated.

An object of the present invention is to store data received from a data terminal device in a memory from the time when a failure of a high-speed digital line is detected until the time when a line-switched ISDN line becomes usable, and to store the data in the memory using the line-switched ISDN line. By transmitting data stored in the memory from the point at which data communication becomes possible, data loss is prevented by reducing data retransmission processing for lost data in the data terminal device and reducing the transmission efficiency of data communication. For the purpose of prevention.

[0005]

According to the present invention, there is provided a line switching control apparatus capable of preventing data loss and minimizing retransmission processing of lost data, thereby preventing a reduction in data communication transmission efficiency. it can.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail.

FIG. 1 is a system configuration diagram to which the present invention is applied.

The line switching control device 3 is a high-speed digital line 1
Is connected to the ISDN line 2 and the data terminal device 4, and transmits and receives data transmitted and received by the data terminal device 4 using the high-speed digital line 1 or the ISDN line 2.

FIG. 2 is an internal configuration diagram of the line switching control device 3.

The high-speed digital line interface unit 5 is connected to the high-speed digital line 1 and controls transmission and reception of data between the switch 8 and the high-speed digital line 1. The ISDN line interface unit 6 is connected to the ISDN line 2,
Connection and disconnection control with SDN line, switch 8 and ISD
Data transmission / reception control between the N lines 2 is performed. The data terminal interface unit 10 is connected to the data terminal device 4,
Data transmission / reception control is performed between the switch 8 and the data terminal device 4. The reception memory 9 has a function of storing data transmitted from the data terminal interface unit 10 and simultaneously transmitting the stored data to the switch 8 in order from the oldest stored data. When the data in the memory is full, the receiving memory 9
New data is stored by overwriting data in order from the oldest data. The control unit 7 monitors and controls the status of each line and interface unit. Specifically, it issues a high-speed digital line state monitoring instruction and a report instruction to the high-speed digital line interface unit 5. It issues to the ISDN line interface unit 6 an instruction to connect to and disconnect from the ISDN line, and an instruction to monitor and report the status of the ISDN line. It instructs the data terminal interface unit 10 to monitor and report the status of the line interface signal of the data terminal device. For the switch 8, a transmission route switching instruction indicating whether data is transmitted / received to / from a high-speed digital line or an ISDN line depending on a line to be used, and data to be received from a data terminal are directly received from a data terminal interface unit or a reception memory. An instruction is given as to whether or not to receive the message via the Internet. As for the reception memory, instructions for starting and stopping data storage, instructions for starting and stopping transmission of recorded data, and instructions for discarding stored data are issued.

FIG. 3 is a diagram showing a control sequence for line switching.

The line switching control device normally performs data communication using a high-speed digital line (1). During communication on the high-speed digital line, a failure of the high-speed digital line or the high-speed digital line interface is monitored (2). If the high-speed digital line or the high-speed digital line interface section is normal, communication using the high-speed digital line is performed as it is, but if an abnormality is detected, the storage of the data received from the data terminal device is immediately stored in the reception memory. Start (3). Next, in order to perform data communication using the ISDN line, the control unit issues an instruction for connection to the ISDN line to the ISDN line interface unit, and the ISDN line interface unit performs a connection operation to the ISDN line (4).
Wait for the connection between the ISDN line and the ISDN line interface unit to end (5). After the connection between the ISDN line and the ISDN line interface is completed, the data transmission route is switched from the high-speed digital line to the ISDN line by the switch, and the data recorded in the reception memory is sent to the ISDN line interface via the switch and transmitted to the ISDN line. (6). During the use of the ISDN line, the state of the high-speed digital line and the high-speed digital line interface unit is constantly monitored (7). If the high-speed digital line and the high-speed digital line interface unit become normal during the state monitoring, The transmission route is changed according to the determined conditions (8). If the transmission route change condition is determined in advance, the data transmission route is set to ISDN.
In order to change from a line to a high-speed digital line, the ISDN line interface performs an ISDN line disconnection process (11). After the disconnection of the ISDN line, the transmission of data from the reception memory is stopped, the transmission route is switched, and the data stored in the reception memory is cleared (11). If the transmission route change condition is not met, the data communication using the ISDN line is continued without changing the data transmission route. If the data communication disabled state on the high-speed digital line continues, the state of the ISDN line and the ISDN line interface is checked next (9), and the reception of the disconnection signal from the ISDN line and the abnormality of the ISDN line interface. (9), and if the disconnection signal is received or a failure occurs, the ISDN line interface unit performs line disconnection processing ISDN times to change the data transmission route from the ISDN line to the high-speed digital line (11). . IS
After the disconnection of the DN line, the transmission of data from the reception memory is stopped, the transmission route is switched, and the data stored in the reception memory is cleared (11).

[0013] Receiving a disconnection signal from the ISDN line or IS
If there is no abnormality in the DN line interface unit, the signal of the line interface of the data terminal device is monitored next, and it is checked whether the data terminal device has completed the data communication termination process (10). If the data terminal device has not performed the data communication termination processing, the data transmission using the ISDN line is continued, and the process returns to the high-speed digital state monitoring sequence (7). If the data terminal device is performing data communication termination processing, the data transmission route is changed from the ISDN line to the high-speed digital line after the data communication with the data terminal device is completed. (11). I
After the SDN line disconnection processing, the data transmission from the reception memory is stopped, the transmission route is switched, and the data stored in the reception memory is cleared (11).

[0014]

As described above, according to the present invention, it is possible to prevent data loss during line switching processing from a high-speed digital line to an ISDN line, and to perform communication without lowering data communication efficiency. Become.

[Brief description of the drawings]

FIG. 1 shows a system configuration example to which the present invention is applied.

FIG. 2 shows an internal structure of the line switching control device 3.

FIG. 3 shows a control sequence of line switching.

[Explanation of symbols]

1: High-speed digital line, 2: ISDN line, 3
... Line switching control device, 4 ... Data terminal device, 5 ...
High-speed digital line interface unit, 6 ISDN line interface unit, 7 control unit, 8 switch, 9 reception memory, 10 data terminal unit interface unit, 11 communication data flow, 12 control data flow.

Claims (1)

[Claims] 1. An I / O which is connected to a high-speed digital line and a circuit-switched ISDN line and cannot be directly connected to the high-speed digital line and the ISDN line due to a difference in interface.
TU-T Recommendation X. 21 and V.I. 24 and V.I. 35, and a high-speed digital circuit and the circuit-switched ISDN.
The conversion of the interface between the line and the data terminal device and the transmission of the data transmitted and received by the data terminal device,
Normally, the communication is performed using the high-speed digital line, and when communication cannot be performed via the high-speed digital line due to a failure in the high-speed digital line and a failure in the high-speed digital line connection function part of the line switching control device, Exchangeable IS
In the line switching control device having a function of continuously performing communication using a DN line, the line switching control device includes a memory for storing data received from the data terminal device in the line switching control device. From the point in time when communication via the high-speed digital line becomes impossible due to a failure and a failure in the high-speed digital line connection function part of the line switching control device, until data communication can be performed using the circuit-switched ISDN line. The data received from the data terminal device at the time is stored, and the circuit-switched IS
When the DN line becomes available, the data stored in the memory is used to prevent the data transmitted by the data terminal from being lost in the line switching device or the high-speed digital line and the line-switched ISDN line, A line switching control device characterized by preventing reduction in data communication efficiency by reducing data retransmission processing.