JPH05158877A - Fault countermeasure system for network system - Google Patents

Abstract

PURPOSE:To obtain a network which is difficult to be affected by a fault. CONSTITUTION:A master device 20 and slave devices 21, 22... and 2n operates an in-line communication through an exclusive communication network 31 (s2). When the abnormality of a communication is present (s3), or when a normality message periodically transmitted from the master device 20 is not confirmed (s5), the in-line communication is switched to an ISDN (integrated services digital network) communication through an ISDN bus 41 (s6). When the normality message through the exclusive communication network 31 is confirmed (s5), the ISDN communication is switched to the in-line communication again (S2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure countermeasure method for a network system composed of a plurality of terminals such as a point-of-sale information management (hereinafter abbreviated as "POS") system.

[0002]

2. Description of the Related Art The structure of a conventional POS system is shown in FIG. In a relatively large-scale POS system that uses a network, a plurality of terminal devices are slave units 1, 2,
, ..., N and the base unit 10 are connected inline, that is, by a dedicated communication network 11, and the base unit 10 is generally connected online with a general-purpose computer 13 via a public communication line or a dedicated communication line 12. Is.

.. n, which are terminal devices, and the parent device 10, sales data of products are input in real time. The master device 10 is a slave device 1, 2, 3, ..., N.
Including the data from the general-purpose computer 1 from the public communication line or the dedicated communication line 12 through the dedicated communication network 11.
3 to transmit data. The general-purpose computer 13 performs various processes based on the transmitted data,
, ..., N and signals for controlling the base unit 10 are transmitted by the base unit 10 via the public communication line or the dedicated communication line 12. When the parent device 10 receives a signal transmitted from the general-purpose computer 13 via the public communication line or the dedicated communication line 12, the parent device 10 itself or the child devices 1, 2, 3, 3.
.., n is discriminated. Cordless handsets 1, 2, 3,
, N are given to the slave units 1, 2, 3, ..., N via the dedicated communication network 11. The master unit 10 or the slave units 1, 2, 3, ..., N to which the signal is applied in this way are controlled according to the contents of the signal. When a failure occurs in the master device 10, the slave devices 1, 2,
, N is used as a substitute for the base unit 10, and the handset units 1, 2, 3, ...

[0004]

In the conventional network system as shown in FIG. 3, the master unit 10 usually has the performance and information of slave units 1, 2, 3, ..., N or more. Therefore, when a failure occurs in the master device 10 and recovery from the failure takes too long, the slave devices 1, 2,
There is a limit to the work that can be done independently. Further, when the failure is caused not by the base unit 10 but by the dedicated communication network 11, that is, in-line, such as an increase in communication amount, communication with the base unit 10 or its substitute device becomes impossible, and the handset units 1, 2, 3, ... n
Hindrance to business. Further, even when online communication with the general-purpose computer 13 is required via the master device 10, if a failure occurs in the master device 10 or the in-line device, the slave device 1,
The work of 2, 3, ..., N is hindered.

It is an object of the present invention to provide a network system failure countermeasure method in which even if a failure occurs in a part of the network system, the entire system is unlikely to be in an unusable state.

[0006]

According to the present invention, a plurality of terminal devices are connected so that they can communicate with each other via a dedicated communication network.
In a network system in which one terminal device performs information communication via an online line as a master device, each terminal device is connected to a bus transmission line, one end of which is connected to the network termination device of the integrated service digital communication network, and a dedicated communication network is connected. When a failure occurs in the communication via the bus, each terminal device communicates via the bus transmission line.

[0007]

According to the present invention, a plurality of terminal devices are connected to the network system via a dedicated communication network so that they can communicate with each other. One terminal device performs information communication as an master device via an online line. Each terminal device is connected to a bus transmission line, one end of which is connected to a network terminating device of an integrated service digital communication network (hereinafter abbreviated as "ISDN"). When a failure occurs in the communication via the dedicated communication network, each terminal device communicates via the bus transmission line. Therefore, when a failure occurs in the parent device or the dedicated communication network, the terminal devices can communicate with each other via the bus transmission line. Further, each terminal device is connected to a comprehensive service digital communication network through a network terminating device, and online communication is possible with a general-purpose computer or the like through the comprehensive service digital communication network. Therefore, all of the plurality of terminal devices can communicate with each other via the integrated service digital communication network, and can also communicate with each other via the bus transmission line. Therefore, the tolerance of the entire network system to failures is improved.

[0008]

1 shows an embodiment of the present invention. Figure 1
FIG. 1A shows the configuration of the network system, and FIG.
(B) shows a part of the operation.

In FIG. 1A, a plurality of POS terminal devices, that is, a master unit 20 and slave units 21, 22, ..., 2n are connected inline via a dedicated communication network 31. The in-line connection form (topology) includes bus type, star type, ring type and the like. Master device 20, slave devices 21, 22,
, 2n are performed according to a protocol which is a predetermined agreement.

The base unit 20 is connected to a general-purpose computer 33 via an online line 32. Online line 3
As 2, a public line or a private line is used. The general-purpose computer 33 collects sales data and the like transmitted via the online line 32 and manages sales, inventory, purchasing, and the like. From the general-purpose computer 33, the main unit 2
Control data for 0, slave units 21, 22, ..., 2n are given to the master unit 20 via the online line 32. The master device 20 uses the control data for itself or the slave devices 21, 22 and 22.
.., 2n is determined as control data, and the slave units 21, 2
For data for 2, ..., 2n, the dedicated communication network 3
, 2n to the target slaves 21, 22, ..., 2n.

As described above, the work as the terminal device in the POS system of the slaves 21, 22, ...
Also, on the assumption that the operation of the dedicated communication network 31 is normal, inline communication is performed. In the normal state, the parent device 20 periodically transmits a "normal message", which is data indicating that the parent device is in the normal state, to all the child devices 21, 22, ..., 2n.

A master unit 20 and a slave unit 2 which are a plurality of terminal devices.
, 2n are also connected to each other via a service integrated digital communication network (hereinafter abbreviated as "ISDN") bus 41. One end of the ISDN bus 41 has an ISDN
Is connected to a digital service unit (hereinafter abbreviated as “DSU”) 42 which is a network terminating device. DSU42
Is connected to the ISDN 44 via the interface line 43. The ISDN 44 is connected to the general-purpose computer 33 via a communication line 45.

Master unit 20 and slave units 21, 22, ..., 2n
And the DSU 42 via the ISDN bus 41 are connected based on the I series recommendation of the International Telegraph and Telephone Consultative Committee (abbreviated as "CCITT"). Master device 20 or slave devices 21 and 21
2, ..., 2n can individually communicate online with the general-purpose computer 33 via the ISDN 44. Furthermore, since they are connected to each other via the ISDN bus 41, they can communicate with each other if a protocol is defined in advance.

FIG. 1 (B) shows an operation when a fault countermeasure is taken in the network system shown in FIG. 1 (A). Starting from step s1, inline communication is performed via the dedicated communication network 31 in step s2. In the in-line communication via the dedicated communication network 31, according to a predetermined protocol, if the transmission is successful, the other party sends a signal for confirmation thereof. If the confirmation signal is not received, the sender can determine that there is a communication error. As long as there is no communication abnormality in step s3 and there is the next data in step s4, in-line communication from step s2 is performed.

If there is a communication error in step s3, or if there is no next data in step s4, step s
Go to 5. Since the base device 20 periodically sends out a normal message via the dedicated communication network 31, in step s5,
The confirmation of the normal message is performed. When the normal message is confirmed, in step s6, the slaves 21, 22, ...
2n switches communication from in-line communication to ISDN communication via the ISDN bus 41. Cordless handsets 21, 22, ..., 2
n is in the ISDN communication state, but when data is not transmitted / received, the in-line reception state via the dedicated communication network 31 is checked. As a result, step s5
When the normal message is confirmed in step s4, the process returns to step s4, and if there is next data, the process proceeds to step s2 and the communication is performed.
Switch from DN communication to in-line communication. Step s5
If the normal message is not confirmed in step s
Continue ISDN communication of 6.

FIG. 2 shows an electrical configuration of the parent device 20 and the child devices 21, 22, ..., 2n shown in FIG. 1 (A). Figure 2
2A shows the configuration of the master device 20, and FIG. 2B shows the slave device 2.
The configuration of 1, 2, ..., 2n is shown. In the master device 20, an inline interface 51, an online interface 52, and an ISDN interface 53 are connected to the processing device 50. In the slave units 21, 22, ..., 2n, an inline interface 61 and an ISDN interface 62 are connected to the processing circuit 60. Base unit 20
In-line interface 51 and slaves 21, 22,
The 2n inline interface 61 is shown in FIG.
(A) In-line connection is made via the illustrated dedicated communication line 31. The online interface 52 of the parent device 20 is connected to the general-purpose computer 33 via the online line 32 shown in FIG. The ISDN interface 53 of the parent device 20 is connected to the ISDN interfaces 62 of the child devices 21, 22, ..., 2n via the ISDN bus 41.

According to this embodiment, the master unit 20 and the slave unit 21,
.., 2n are redundantly connected via the dedicated communication network 31 and the ISDN bus 41, so that even if a failure occurs in the inline communication, the communication state can be maintained by switching to the ISDN communication. Moreover, since the ISDN interfaces 53 and 62 can use standardized mass-produced products, the inline interfaces 51 and 61 can be used.
It is possible to reduce the required cost as compared with the case of duplicating hardware such as. In addition, when a dedicated line is used as the online line 32, it requires a large amount of money to add it, but I
By using SDN's public services, costs can be greatly reduced. In addition, the master unit 20 and the slave unit 2
1, 2, 2, ..., 2n are ISDN44 via DSU42
The online function is added to each terminal device because it is connected to the general-purpose computer 3.
It is possible to receive various data directly from the No. 3 or to communicate with a plurality of other parties via the ISDN 44, so that various uses can be achieved.

In the above embodiments, the case where a plurality of POS terminal devices constitute a network system is shown, but it goes without saying that the network system may be a network system for factory production control.

[0019]

As described above, according to the present invention, a plurality of terminal devices are connected to a dedicated communication network and a bus transmission line, one end of which is connected to a network terminating device of an integrated service digital communication network, and are connected to each other. It is also possible to communicate via the integrated service digital communication network. One of the plurality of terminal devices performs information communication as a master unit via an online line such as a public communication line or a dedicated communication line. When a part of the network system fails, it becomes difficult to communicate via the online line. Since each terminal device can communicate with each other via the bus transmission line and also via the integrated service digital communication network, it is difficult for the entire network system to be in an unusable state, and a network that is resistant to failures. The system can be realized. Further, since each terminal device can perform online communication directly via the integrated service digital communication network without going through the master device, the network system as a whole can be used in various ways.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention and a flow chart showing an operation.

FIG. 2 is a parent device 20 and child devices 21, 22 shown in FIG.
, 2n is a block diagram showing an electrical configuration.

FIG. 3 is a block diagram showing an electrical configuration of a conventional network system.

[Explanation of symbols]

 20 parent device 21, 22, ..., 2n slave device 31 dedicated communication network 32 online line 41 ISDN bus 42 DSU 44 ISDN

Claims (1)

[Claims] 1. A network system in which a plurality of terminal devices are communicably connected to each other via a dedicated communication network, and one terminal device serves as a master device to perform information communication via an online line. Connected to a bus transmission line, one end of which is connected to the network terminating device of the integrated digital communication network, and when a failure occurs in communication through the dedicated communication network, each terminal device is supposed to perform communication through the bus transmission line. A characteristic network system failure countermeasure method.