JPH06187276A - Communication system in multiplexing server system - Google Patents

Abstract

PURPOSE:To perform the efficient operation of a system and to make a prompt backup possible when a failure occurs in a server device by constituting that a business communication service is performed with a prescribed load allotment for a terminal equipment by a polling system by using plural server devices having the same functions and the same constitutions. CONSTITUTION:A communication switching device 6 has a communication right decision part 61 connected with control lines 43, 44, and when a communication request signal is outputted from the communication right request part of each server device 4, 5, the device decides which of the server devices the communication right should be imparted to and outputs a communication permission signal to the server device to which the communication right should be imparted via the control line 43. Namely, the communication permission is alternately imparted to a first server device 4 and a second server device 5, and each server device 4, 5 performs the polling of terminal devices 31 to 3N in its own charge in a prescribed order every time the communication permission signal is imparted and is capable of executing a business terminal communication service.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system in a multiplex server system in which a plurality of server devices can provide communication services to a plurality of terminal devices with high efficiency and reliability.

[0002]

2. Description of the Related Art Conventionally, a duplex system having a plurality of server devices has been adopted so as not to hinder the terminal communication service when the server device fails. As a conventional redundant system of this type, for example, an active system and a standby system are prepared, and by monitoring the operating state of each system, when the own system or the partner system fails, the active system is used. A configuration in which a system system and a standby system are switched is known (see Japanese Patent Publication No. 58-41535 and Japanese Patent Publication No. 61-224757). In addition, when a server device that has control authority makes an inquiry to another server device by a polling method, and if there is a request, it transfers the control authority directly to that server device and automatically switches in a short time. Is known (Japanese Patent Publication No. 3-2510
See Japanese Patent Publication No. 4).

[0003]

As described above, in the conventional duplex system of this type, when a failure occurs in the active system while the terminal communication service is provided by the active system, an appropriate means is provided. The standby system will switch to the standby system and continue the terminal communication service, so the standby system will be in a standby state while the active system is operating normally, and the terminal communication service will not be provided. However, there is a problem that the operating efficiency of the entire system is low.

Furthermore, as another problem, when switching to the standby system, it is necessary to transmit the data state of the active system to the standby system without contradiction, which requires a waiting time for switching. There was a problem that the terminal communication service was temporarily interrupted when the system was switched. In addition, when the active system is restored, the required data must be transferred from the standby system to the active system, which makes the maintenance and replacement of the device complicated. ing. Further, in the method of transferring the control right to the other server device by the polling method, if a failure occurs in the server device that currently has the control right and polling cannot be performed, the control right is transferred to the other server device. However, there is a problem that the entire communication service is stopped due to failure of migration. The purpose of the present invention is to
Therefore, it is an object of the present invention to provide a communication method in a multiplex server system that can solve the above-mentioned problems in the conventional technology.

[0005]

The feature of the present invention for achieving the above object is that polling communication is performed to a plurality of terminal devices using a plurality of server devices via a predetermined communication path. In the communication method in the multiplex server system, a plurality of server devices having the same functions and configurations are connected to the communication path, and the plurality of terminal devices are assigned to the plurality of terminal devices with a predetermined load sharing for the plurality of server devices. In addition to providing the required terminal communication service, the plurality of server devices are constantly notified of the status of each server device and the update data information via the required communication channel, which may interfere with any of the server devices. When it occurs, the remaining normal server devices are operated with new load sharing according to the trouble state.

As a communication path between the server device and the terminal device, a common transmission path such as a local area network can be used, but a communication switching device is provided between the server device and the terminal device. A configuration using a road may be used. Further, the communication channel for communication between the server devices can be provided not only as a physical communication path but also as a logical communication path.

[0007]

[Operation] When each server device is operating normally,
A plurality of server devices perform polling communication with the terminal devices according to a predetermined load sharing. Even during this period, the respective server devices communicate their respective states, that is, the failure monitoring is performed between the server devices, and when a failure occurs in any of the server devices, the remaining A new load sharing is determined in the server device, and the required terminal communication service can be continued without any trouble accordingly.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram schematically showing the configuration of an embodiment of a multiplex server type communication system according to the present invention. The communication system 1 includes a plurality of terminal devices 31 connected to a communication path 2. , 32, ..., 3N, a required terminal communication service is provided by polling communication from a plurality of server devices. In this embodiment, first and second server devices 4 and 5 having exactly the same functions and configurations are provided, and the connection state between the first and second server devices 4 and 5 and the communication path 2 is It is controlled by the communication switching device 6.

Referring to FIG. 2, the first server device 4 is
Data storage device 11 for storing data necessary for communication service and other necessary data, control C
The PU 12, the terminal communication control unit 13 that controls communication with the terminal device, the inter-server communication control unit 14 that controls communication between the servers, and the terminal device that the server device should be in charge of are shown. A memory 15 for storing a terminal table in charge of data is provided, and these are connected to a data bus 16 as illustrated. Code 17
Shown by is a power supply device for supplying necessary power to each unit of the first server device 4.

The terminal communication control section 13 is a transmission circuit 18 for transmitting a required signal to a transmission line 41 for signal transmission from the server side to the terminal side, and between the transmission circuit 18 and the transmission line 41. And a receiving circuit 20 for receiving a signal from a receiving line 42 for signal transmission from the terminal device side to the server device side. A communication permission signal output from the communication switching device 6 as described below is supplied to each of the circuits 18, 19 and 20.
Are input via the communication switching device 6, and only when a communication permission signal is given from the communication switching device 6, these circuits 18, 19,
20 is brought into an operable state, and communication between the first server device 4 and the terminal device becomes possible.

The terminal communication control unit 13 further includes a communication right requesting unit 21 and a timer monitoring unit 22, and when there is a communication request from the control CPU 12 as described later, the communication right requesting unit 21 will In response to this, it outputs its own communication right request signal, and this communication right request signal is sent out to the control line 44 via the timer monitoring section 22 and sent to the communication switching device 6.

The inter-server communication control unit 14 is for exchanging necessary data with a server device other than itself, that is, the second server device 5 in this embodiment. Transmission circuit 2 connected to a pair of dedicated lines 45 and 46, which form a dedicated channel for
3 and the receiving circuit 24. Under the control of the control CPU 12, the transmission circuit 23 transmits data regarding its own failure status to the second server device 5. The receiving circuit 24 receives the data regarding the failure status of the second server device 5 similarly sent from the second server device 5, and the control CPU
12 has the function of sending. Inter-server communication control unit 14
Is also used for exchanging the update data of the information of the terminal device to be in charge between the server devices.

Although the configuration of the first server device 4 has been described above, the second server device 5 has the same configuration, and a detailed description thereof will be omitted. In FIG. 1, the input / output lines connected to the second server device 5 are
The same reference numerals as those given to the first server device 4 are attached to the corresponding input / output lines.

As can be seen from FIG. 1, the transmission line 41 and the reception line 42 are connected to the communication path 2 in the communication switching device 6, and the pair of dedicated lines 45 and 46 are shown via the communication switching device 6. Thus, the transmission circuit 23 and the reception circuit 24 are connected to each other.

The communication switching device 6 has a communication right determining unit 61 connected to the control lines 43 and 44, and will be described later when a communication request signal is output from the communication right requesting unit 21 of each server device. According to the circuit operation, the server device to which the communication right should be given is determined, and the communication permission signal is output to the server device to which the communication right is given via the control line 43. In this embodiment, communication permission is alternately given to the first server device 4 and the second server device 5, and each server device is in charge of its own every time a communication permission signal is given. The required terminal communication service can be executed by polling the terminal devices to be operated in a predetermined order.

Next, the operation of granting the communication right by the communication switching device 6 will be described with reference to FIG. The communication right request signal A from the first server device 4 shown in FIG. 3A and the communication right request signal B from the second server device 5 shown in FIG. Is input to the communication right determination unit 61, the communication right request signal whose level has risen first is accepted and the communication permission signal C or D is output to the corresponding server device. This communication permission signal is output by generating a high level signal on the corresponding control line 43.

To explain according to the example of FIG. 3, time t = t
In No. 1, the communication permission signal C is output to the control line 43 of the first server device 4 in response to the high level of only the communication right request signal A. The communication permission signal C is output to the control line 43 of the first server device 4, and the first server device 4 provides the terminal communication service E to any terminal device. t =
At t2, the communication of the first server device 4 is completed, and
When the level of the communication right request signal A becomes a low level state, in response to the communication right request signal B continuously output from the second server device 5 during this time, the communication permission signal D from the communication right determination section 61 is t = t2. Control line 43 of the second server device 5
Is output to. Therefore, the communication right is given to the second server device 5 from t = t2, and the second server device 5 can provide the terminal communication service E to the required terminal device. t
= T3, the communication of the second server device 5 is completed and the level of the communication right request signal B is once lowered to a low level.
At t3, the communication right is returned to the first server device 4 again.

When a failure occurs in the first server device 4 at t = t4, the first server device 4 does not issue a request for communication right. Therefore, the communication right is always second after t4.
It is given to the server device 5. The timer monitoring units 22 of the first and second server devices 4 and 5 forcibly reduce the communication right request signals A and B to a low level after a lapse of a certain period of time after the communication right request signals A and B are in the high level state. The action to return to the level. As a result, it is prevented that some trouble occurs in the control CPU 12 or the like and one of the first and second server devices 4 and 5 continues to occupy the communication path 2.

As described above, when both server devices 4 and 5 are operating normally, the first and second server devices 4 and 5 are
, The communication right is alternately given according to a predetermined rule, and the server device to which the communication right is given performs polling communication with the terminal device as described later. on the other hand,
When any one of the server devices is in a failure state, only the normal server device is given the communication right, and all the terminal devices are polled by the normal server device to provide the required terminal communication service.

When a communication permission signal is given,
The polling communication with the terminal device to be executed by each server device is executed based on the data stored in the data storage device 11 and the memory 15 according to the communication control program stored in the control CPU 12.

FIG. 4 is a flow chart showing a communication control program stored in the control CPU 12 and executed here. This communication control program is composed of a first task for server-to-server communication and a second task for communication between terminal devices, and both tasks are executed in parallel by a multitask processing method.

The operation of the first server device 4 will be described below with reference to FIG. First, the execution of the first task will be described. First, in step 71, the data relating to the state of the own server, that is, the state of the first server device 4, is transmitted to the transmission circuit 2.
3, the data relating to the state of the partner server, that is, the state of the second server device 5 is received by the receiving circuit 24 in step 72, and this received data is stored in the data storage device 11.

Thereafter, step 73 is entered, and based on the data transmitted in step 71 and the data received in step 72, it is determined whether or not there is a failure in the own server and the partner server. When it is determined that both the own server and the partner server are operating normally, in step 74, the memory 15 is set so that half of the plurality of terminal devices 31 to 3N are assigned to the first server device 4.
The terminal table in charge that has been stored in is updated, and step 75 is entered.

In step 75, the update data of the own server is transmitted to the partner server, and in the next step 76, the update data similarly performed in the partner server is received from the partner server. Then, in step 77, these updated data are processed so that the data of both server devices 4 and 5 are always equivalent. Then, step 71
Return to.

On the other hand, if it is determined in step 73 that the own server is in a failure state, step 78
Then, the responsible terminal table stored in the memory 15 is updated, the share of the responsible terminal device of the own server is set to zero, and the process returns to step 71.

On the other hand, if it is determined in step 73 that the partner server is in a failure state, or if there is no response from the partner server, step 79 is entered, in which the own server has all The contents of the in-charge terminal table stored in the memory 15 are updated so as to be in charge of the terminal device, and the process returns to step 71. Next, the second task will be described. The second task is executed in parallel with the first task. In step 81, the in-charge terminal table is read from the memory 15 and, based on the read table, the own server is read in step 82. The terminal communication service is provided in accordance with a predetermined order that is predetermined for the terminal devices in charge.

Although the communication control of the first server device 4 has been described in the above description, the communication control of the second server device 5 is performed in exactly the same manner. That is, when both server devices 4 and 5 are operating without failure, polling communication is performed for the respective terminal devices in charge in a predetermined order according to the terminal table in charge stored in each memory 15 to obtain the required information. The terminal communication service is provided. Here, as for the terminal device in charge of each server device in a normal state, for example, the first server device 4 is an odd-numbered terminal device 31, 3,
, 35, ..., and the second server device 5 is responsible for even numbered terminals 32, 34, 36, .. it can. In this state, when a failure occurs in one of the server devices, the server device in which the communication of the server device has not failed has all the terminal devices 31 to 3
The terminal table in charge in the memory 15 is updated to handle N, and the required terminal communication service is executed by one of the server devices for all the terminal devices.

As can be seen from the above description, the two server devices 4 and 5 bear half of the load during normal operation, and therefore execute the required service at high speed, but one server device fails. In the event of occurrence, a single server device can bear the full load, thereby ensuring a highly reliable communication service. In this way, unlike the conventional backup system, all server devices are normally operating, so high-speed processing is possible, and in the event of a failure, the required service can be continued and operational efficiency is improved. It is possible to realize a communication system that is highly reliable.

In the above embodiment, since the first and second server devices 4 and 5 each have a power supply device, when replacing a unit of a defective server device when a failure occurs,
The other server device will not be disabled.

As can be seen from FIG. 1, the dedicated line 45,
Since 46 is configured to connect both server devices 4 and 5 via the communication switching device 6, when exchanging a unit of either server device, communication between the server device and the terminal device and communication between the server devices are performed. Communication will be cut off at the same time, mistakes in disconnecting each communication path and connection forgetting will be surely prevented, and if any server device is removed, the remaining server devices will immediately perform communication services to all terminal devices. Therefore, there is an advantage that it is possible to prevent an accident that the communication service for a specific terminal device is interrupted when the unit is replaced.

In the above embodiment, the first and second server devices 4, 5 are connected to the terminal devices 31, 3 via the communication switching device 6.
Although it is configured to connect to the communication path 2 to which 2 ... 3N are connected, it is not always necessary to use this communication switching device 6.

For example, as shown in FIG. 5, the first server device 4, the second server device 5, and the terminal devices 31 to 3N are connected to a common transmission line 9 such as a local area network, and each server device serves as a terminal. It can be configured to poll the device. In the local area network, a common transmission path 9 is used, data transmission between each device can be transmitted and received in frame units, and a logical communication path between the first and second server devices 4 and 5 and each terminal device 3N. 91, 9
2 and the logical communication path 93 between the first and second server devices 4 and 5, the same terminal communication service and server device communication as in the above embodiment can be performed, and the same effect can be obtained. it can.

Furthermore, the number of server devices is not limited to two, and two or more server devices can be used in the same manner to obtain the same effect.

[0035]

According to the present invention, a plurality of server devices having the same function and the same configuration are used to provide a required communication service to a terminal device by a predetermined load sharing by a polling method. Can be effectively used to efficiently operate the system, and in the case where any of the server devices has a problem, it is possible to effectively and quickly pack up the system.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram schematically showing a configuration of an embodiment of a multiplex server type communication system according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a first server device shown in FIG.

3 is a signal waveform diagram of each part for explaining a switching operation by the communication switching device 6 of FIG.

4 is a flowchart showing a communication control program executed by the control CPU of FIG.

FIG. 5 is a schematic configuration diagram schematically showing another configuration example of the multiplex server type communication system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 communication system 2 communication path 4 1st server apparatus 5 2nd server apparatus 12 control CPU 13 terminal communication control section 14 inter-server communication control section 15 memory 31, 32, ..., 3N terminal apparatus 45, 46 dedicated line

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[Procedure amendment]

[Submission date] February 8, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (1)

[Claims] 1. A communication method in a multiplex server system in which a plurality of server devices are used to perform polling communication to a plurality of terminal devices via a predetermined communication path, and a plurality of functions and configurations are equivalent to each other. A server device is connected to the communication path, and a required terminal communication service is provided to the plurality of terminal devices with a predetermined load sharing predetermined for the plurality of server devices. In this case, the status of each server device and the update data information are constantly notified via a required communication channel, and when any of the server devices fails, the remaining normal status is returned according to the failure status. A communication method in a multiplexed server system, characterized in that a server device is operated by a new load sharing.