JPS6234187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite exchange in which the same exchange performs line switching, typically for telephone communication, and store-and-forward for digital data communications, and particularly relates to a redundancy system for the composite exchange.

The redundancy system in conventional composite switching is to duplicate devices with the same function or create an n+1 configuration, so that if a failure occurs in the active system, the mate or standby device continues service in place of the failed system. It was taking shape. Although such a system configuration is effective in very large scale systems, it becomes expensive in small scale systems.

An object of the present invention is to perform a mutual health check between the part in charge of analog communication and the part in charge of digital data communication in a composite switching device, even if the device configuration is equivalent to a single device, if one of the communication parts fails. The present invention provides a method that enables redundant operation under certain conditions without causing system downtime.

In the composite exchange redundancy system of the present invention, the composite exchange has a data exchange section that handles digital data and a line exchange section that handles analog data, and each exchange section has a processing system, and the latter processing system is the processing system of the former. Although it operates in dependence on it, it can also operate independently.
In other words, a health check is performed from the data exchange section to the line exchange section at regular intervals, and if an abnormality is detected in the line exchange section, the line exchange section is disconnected and service to the terminals subordinated to the line exchange section is interrupted, allowing only the data exchange section to provide service. The state transitions to . On the other hand, the line switching unit also performs a health check on the data exchange unit at regular intervals, and if a failure occurs in the data exchange unit, that is, a failure that makes the data exchange unit inoperable (for example, a health check from the line switching unit If the data exchange section is in a state where it cannot respond normally to a health check and an abnormality is detected in the data exchange section (such as "non-response", "abnormal sequence number", "abnormal format", etc.), the data exchange section is disconnected and the line exchange section is disconnected. The state transitions to the only service. Furthermore, even if the other system is down, each system continues to perform health checks, and when the system is restored to normal, the system can be automatically restored to normal.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, reference numeral 1 denotes a central control section and a data channel section connected to a storage device 2, which controls the processing system of the data exchange section and also controls the line exchange section 3. 4 is a control unit of the line switching unit 3, which is under the control of the data channel unit 1, and when an abnormality occurs,
In other words, there is a problem in which the health check sequence is interrupted for a certain period of time due to a hardware failure, software runaway, etc., or a violation of regulations in the contents of the health check sequence command and response (e.g. abnormal order, abnormal format, etc.). ) is detected, the channel part 1
The switching network 5 is logically separated from the switching network 5 and includes switching circuits, line circuits, and trunk circuits. 6 is a communication control device;
Performs character processing, block processing, and transmission control of digital data. 7 is an input/output control device that controls various peripheral devices under the control of the central control unit 1, and includes various input/output devices such as a magnetic disk device 8 for data storage and a teletypewriter 9 for inputting various information. Device is connected. 10 is a modulation/demodulation device, and 11 is a branch amplifier for bidirectional branching of digital information and analog information. 12 is a composite terminal accommodated in the composite switching system of the present invention, and the terminal control device 13 is a telephone (TEL) 14
and a digital fax (FAX) 15.

Under normal conditions, calls made from the terminal are TEL/
In either case, the terminal control device 13 sends the modulated digital data signal or analog signal from the line to the data exchange section and the line as digital data information based on the high-level data link control procedure. The information is transmitted to the communication control device 6 via the bidirectional branch amplifier (11) which has the function of amplifying and converging the modulated digital data signal and analog signal sent from each switching section into one line and transmitting the converged signal. The information is interpreted and passed to the central processing section and the data channel section 1, and in the case of information to be subjected to line switching processing, the central processing section 1 closes the switch network 5 via the communication path control section 4 and exchanges the information.

On the other hand, if the information being handled is digital data, the information is exchanged via the communication control device 6.
In the above system, health check data is exchanged between the central processing unit 1 and the communication path control unit 4 at regular intervals as shown in Fig. 2, and n "ACT" signals are sent from the central processing unit 1 side. If a normal “SNS” signal is not returned from the communication path control unit 4 despite sending the message (T>Tn) and abnormal “SUS” information from the line switching unit 3, an abnormality in the line switching unit 3 is recognized. do. In addition, the line switching section 3 monitors the health check signal from the central control unit 1 at regular intervals, and recognizes an abnormality in the central processing unit 1 based on the stoppage of the signal (T>T ₂ ) and the content of the "ACT" information. When an abnormality is detected in the line switching section, for example, when a call is received from a telephone, the data switching section sends a connection failure message to the terminal control device 13. The terminal can only send fax information.

On the other hand, if a failure occurs in the central processing unit 1,
Upon detecting an abnormality, the communication path control unit 4 immediately controls a specific transmitting terminal, depending on the system configuration, as shown in FIG.
For example, since terminal n is forced to switch all at once to other terminals 1 to (n-1), the switching circuit 17
The RL relays operate simultaneously, and the rln relay of the switching circuit 17 selected for transmission operates, and the transmission signal line Sn from terminal n is connected to all other terminals 1 to 1.
It is connected to the reception signal line R1 (n-1) to (n-1) via the amplifier 16, and is used to control the transmission of terminal n and the reception control of other terminals 1 to (n-1).
Operates as a forced simultaneous broadcast using the End control method.

FIG. 4 shows a control frame for connection/switching, in which the A field specifies a global address during forced simultaneous broadcasting, and no response is received from each receiving terminal.

Under normal operating conditions, the A field is assigned the terminal address, and if the data exchange section is abnormal, the 3rd field is assigned the terminal address.
Connected in the form of dashed lines shown in the figure End to End
control. In this case, the A field sets the global address.

As described above, in the case of a fault in the line switching section, only digital data communication is possible as usual, and in the case of a fault in the data switching section, operation is possible with the restriction that communication from a specific terminal station is possible.

The embodiments of the present invention have been described above, but according to the present invention, there are two systems with different processing functions.
Even if a failure occurs in one of the devices, switching operation can be performed to match the operating mode to one of the devices without causing a system down, resulting in an economical redundant configuration.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a connection system in the composite exchange of the present invention, Fig. 2 is a diagram explaining health check data in the present invention, Fig. 3 is a diagram of a switching control scheme in the present invention, and Fig. 4 is a diagram of switching control in the present invention. FIG. 1... Central processing unit (CC), 2... Main memory unit (MM), 3... Line switching unit, 4... Communication path control unit (SPC), 5... Switching network (SW), 6... Communication control device (CCE), 7... Input/output control device (IDC), 8... Magnetic disk device, 9... Typewriter, 10... Modulation/demodulation device,
11... Branch amplification device, 12... Terminal device, 13
... terminal control device, 14 ... telephone, 15 ... digital fax, 16 ... amplifier, 17 ...
switching circuit.

Claims (1)

[Claims] 1. In a composite switching device that performs digital data communication and analog communication, a data exchange section that handles digital data and a line exchange section that performs analog communication are installed in parallel on the line, and each section performs health checks on the other sections. If a failure occurs in the data exchange section, the health check detection mechanism of the line exchange section will detect this and all the receiving signal lines from the terminals connected 1:1 to the line circuit of the line exchange section will be By operating a switching circuit that disconnects, branches and amplifies the transmission/reception line from a specific transmitting terminal and switches the connection to the connected terminal, a simultaneous broadcast system is created from a pre-registered specific outgoing line to a specific incoming line. In the event of a failure in the line switching section, the health check mechanism of the data exchange section sends connection failure information to the line that requested circuit switching service, and the exchange is limited to digital data exchange only. Composite exchange redundancy scheme.