JP2001027979A - Client server type computer system and method for establishing connection between client server type computers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a connection irrelevantly to the start order of computers and programs without repeatedly issuing a connection request. SOLUTION: Each computer 1 has client connection establishment part 3 (13) which establishes a connection by issuing a connection request, server connection establishment part 4 (14) which establishes a connection in response to connection requests from another computer 1, and connection monitor and control part 5 (15) which controls the execution of each of the connection establishment part 3 and 4 (13 and 14). A computer 1 issues a connection request as a client when started and expects a connection request from the other computer 1 as a server when there is no answer to the connection request. When there is an answer to the issued connection request or when the computer answers to a connection request from the other computer 1, a connection is established.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the establishment of a connection in a client-server type computer system.

[0002]

2. Description of the Related Art TCP / IP (Transmission Control Pr
In a client-server type computer system that communicates according to the otocol / Internet Protocol) protocol, conventional online processing is started (connection established).
In doing so, the server computer must be started first, and the server program must be started first so that it can respond to a connection request from the client computer. On the client computer side, for example, the operator of the client computer confirms that the server program has been started on the server computer, starts the client computer, further starts the client program, and connects to the server computer. The connection was established by issuing a request.

[0003]

As described above, conventionally, in order to establish a connection between a client and a server, it is necessary to be aware of the order in which the server computer and the client computer are started.

In order to establish a connection without being aware of the startup sequence, the client program is repeatedly issued a connection request until the server program responds to the connection request, that is, until the startup of the server program is completed. However, repeatedly issuing a connection request may increase resources and processing load on a client computer and communication load on a network due to the repeated processing.

In order to re-establish the connection when the connection is disconnected due to a failure in the network connecting the client-server computer or due to the stoppage of any program, the server program must be started up first (connection Request reception waiting state). That is, for example, when the server computer program is stopped, the client program must also be forcibly stopped, and after confirming that the server program has been restarted, the client program must also be restarted.

[0006] As described above, there has been a problem that the degree of freedom is low and it takes time and effort to establish a connection in the related art.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to establish a connection irrespective of the starting order of computers and programs without repeatedly issuing connection requests. It is an object of the present invention to provide a client-server type computer system and a method for establishing a connection between client-server type computers.

[0008]

In order to achieve the above object, a client-server type computer system according to the present invention is arranged such that a server computer responds to a connection request sent from a client computer. In a client-server type computer system in which a connection is established between each computer, each computer includes a connection establishment control unit having a function of issuing a connection request as a client computer and a function of responding to a connection request from another as a server computer. The connection establishment control means issues a connection request by itself and attempts to establish a connection. If the connection cannot be established, the connection establishment control unit enters a connection request reception wait state and is sent from another computer. Connection It is intended to establish a connection with the other computers in responding to determined.

Further, in a client-server type computer system in which a connection is established between each computer via a network by a server computer responding to a connection request sent from the client computer, each of the computers comprises a connection A client connection establishing means for issuing a request to establish a connection; a server connection establishing means for establishing a connection in response to a connection request from another computer; and a connection state monitoring section for monitoring the connection state of the connection. Connection monitoring control means for performing execution control, wherein the connection monitoring control means is configured to execute the server connection when a connection cannot be established by the previously activated client connection establishment means. It is to start the Deployment establishing means.

[0010] Further, the connection monitoring control means of any one of the computers for establishing a connection,
When the recovery of the failed network is detected, the client connection establishment means is restarted.

Further, the connection is established by a procedure according to the TCP / IP communication protocol.

According to another aspect of the invention, there is provided a client-server type computer-to-computer connection establishment method in which a server computer responds to a connection request sent from a client computer to establish a connection between the computers. In the system, each computer issues a connection request by itself to establish a connection, and a client connection establishment step, and when the connection cannot be established by the client connection establishment step, is sent from another computer. A server connection establishing step of establishing a connection with the other computer by responding to the connection request.

Further, one of the computers for establishing a connection stops the server connection establishing step before a connection request is sent from another computer, and executes the client connection establishing step again. Including.

[0014]

Preferred embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 shows a first embodiment of a client-server computer system according to the present invention.
Is a configuration diagram showing a configuration in which a plurality of computers 1 are connected to a network 2. Each computer 1 in the present embodiment performs communication according to the TCP / IP communication protocol. To the computer A, a client connection establishing unit 3 that issues a connection request to establish a connection, a server connection establishing unit 4 that establishes a connection in response to a connection request from another computer 1, and each connection establishing unit 3 , 4 are provided. The computer B includes the same components as the computer A. In FIG. 1, for convenience of explanation, the computer B is given a code obtained by adding 10 to the code shown in the computer A.

By the way, in the TCP / IP communication protocol, the side that issues a connection request when establishing a connection is a client computer, the side that responds to the connection request is a server computer, and the client or server is established after the connection is established. Communication is performed between computers without being aware of this. That is, a client computer and a server computer are merely determined for convenience in establishing a connection.

The present embodiment focuses on this point, and is characterized in that any of the computers 1 can function as a client computer or a server computer in some cases. That is, as will be apparent from the following description, in the present embodiment, when a certain computer A issues a connection request as a client computer and another computer B responds to this connection request and a connection is established, the computer A A is the client computer, while
When the connection request is issued, but the other computer does not respond to this connection request, and as a result, the computer A becomes the server computer when the connection is established by itself in response to the connection request from the other computer B. As a result, a connection can be established between the computers 1 without being aware of the activation order.

It is unknown whether each computer 1 in the present embodiment becomes a client or a server when a connection is established. However, in the present embodiment, for convenience of explanation and for comparison with the prior art, only a client and a server are referred to, and it is not necessary to be conscious of being a client computer or a server computer as described above. It doesn't make sense.

Next, connection establishment processing in the present embodiment will be described with reference to the flowchart shown in FIG. Here, computer A and computer B
The case where a connection is established between the server and the server will be described as an example.

For example, when the computer A is started,
The connection monitoring control unit 5 is called to establish a connection with the computer B. The connection monitoring control unit 5 activates the client connection establishment unit 3 to issue a connection request (step 101). And
The connection monitoring controller 5 determines whether a connection has been established (step 102). This determination may be made based on the return code of the data (connection request) communication process, or may be detected by timeout. If the computer B responds to the connection request issued by the client connection establishment unit 3, it means that the connection has been established, and the connection monitoring control unit 5 ends this connection establishment processing (step 10).
2). When the computer B is not operating or has not been started up because the system is stopped or started, and the computer B cannot respond to the connection request from the computer A, that is, when the connection request ends with an error, the connection monitoring control unit 5
Activate the server connection establishment unit 4 and execute the computer B
Waits for a connection request from the server (step 10).
3).

On the other hand, when the computer B is started, the same connection establishment processing as that of the computer A is executed. That is, the computer B sends the connection monitoring control unit 15 to establish a connection with the computer A.
Is called. The connection monitoring control unit 15 activates the client connection establishment unit 13 to issue a connection request (Step 201). At this time, the computer A in the connection request reception waiting state is
Will respond to the connection request from. Computer A
In, after the connection monitoring control unit 5 confirms that the connection has been established, the connection establishment processing ends (step 102).

Since the computer B has responded to the connection request issued by the computer A, the connection has been established, and the connection monitoring controller 15 ends the connection establishment processing (step 202). In FIG. 2, the flowcharts of the computer A and the flowchart of the computer B are given different step numbers for convenience of explanation, but the connection establishment processing in the computers A and B is the same.

As described above, when a connection is established between the computers A and B, online processing is executed.

According to the present embodiment, each computer 1
Connection request as a client computer (connect)
And a function of responding (listen, accept) to another connection request as a server computer, so that a connection can be established even if any of the computers 1 is activated first. That is, the execution of the connection establishment process can be started without confirming the activation state of the computer 1 as the connection establishment destination.

In the above embodiment, the connection monitoring control unit 5 is provided, and the execution of the separately provided client connection establishing unit 3 and server connection establishing unit 4 is controlled. The connection establishment units 3 and 4 may be incorporated into the unit 5 to form an integrated connection establishment control unit.

Embodiment 2 FIG. The present embodiment relates to a connection establishment process when a failure occurs in the network 2 and the network 2 recovers from the failure. The connection establishment process executed on each computer according to the present embodiment will be described with reference to the flowchart shown in FIG. Note that, in the present embodiment, the connection establishment process itself is the same as in the first embodiment shown in FIG.
The activation control of the connection establishment processing is added to the first embodiment.

After the connection is established between the computers A and B (steps 111 and 211), the network 2
If any trouble occurs in each computer, each computer A, B
When the connection monitoring control units 5 and 15 detect the disconnection of the connection, the computers A and B activate the connection establishment process described in the first embodiment to re-establish the connection (Step 112,
212). When the failure has not been recovered, both devices enter a connection request reception waiting state (steps 102, 103, 103).
202, 203).

When the failure is recovered, one of them, for example, the connection monitoring control unit 5 of the computer A temporarily stops the connection establishment process in a connection request waiting state and restarts the connection establishment process (step 11).
3). Thereby, the client connection establishment unit 3
Can issue a connection request (step 10).
1) The computer B in the connection request reception waiting state responds to the connection request.

According to the present embodiment, the connection establishment process is stopped and restarted in one of the computers 1 after the network restoration as described above, so that the connection is established after the disconnected network 2 is restored. It can be easily and quickly re-established. It should be noted that the connection establishment process of any computer 1 may be stopped or restarted, as in this embodiment, when all the computers 1 are equivalent, any computer 1 may be selected. It is considered to be determined by the operation of the computer system.

Embodiment 3 In the above-described second embodiment, the case where the network 2 is disconnected has been described. However, in the present embodiment, after one of the programs that establishes the connection executed on each computer 1 is stopped, the connection is disconnected after the disconnection. And connection establishment processing when the program is restarted. The connection establishment process executed on each computer according to the present embodiment will be described with reference to the flowchart shown in FIG. In this embodiment, the connection establishment process itself is the same as that of the first embodiment shown in FIG. 2, and activation control of the connection establishment process is added to the first embodiment. Here, the reason for stopping the program does not matter. The program may be stopped abnormally, or may be forcibly stopped manually.

After the connection is established in each of the computers A and B (steps 121 and 221), it is assumed that one of the programs, for example, the program being executed in the computer A is stopped. In this case, when the connection monitoring control unit 15 of the computer B detects the disconnection of the connection, the connection monitoring control unit 15 starts a connection establishment process for reestablishing the connection (step 222). Here, since the program has not been started yet in the computer A, the computer A enters a connection request reception waiting state (step 20).
2,203).

Here, when the program is started in the computer A, the connection monitoring controller 5 of the computer A starts a connection establishment process (step 122). This allows the client connection establishment unit 3 to issue a connection request (step 101), and the computer B in the connection request reception waiting state
Will respond to the connection request.

According to the present embodiment, as long as the stopped program is restarted, the connection can be easily and quickly re-established without being aware of the order in which the programs are started.

In each of the above embodiments, TC
Although the inter-computer communication is performed according to the P / IP communication protocol, the present invention can be applied to any communication protocol in which a connection is established by issuing and responding to a connection request as described above.

[0035]

According to the present invention, each computer 1 is provided with a function of issuing a connection request as a client computer and a function of responding to a connection request from another as a server computer. The connection can be established even if it is started. In other words, the connection can be reliably established without having to be aware of the order in which the computers are started, so that the convenience is improved.

As described above, since one of the computers is not fixed as a client computer, there is no need to repeatedly issue a connection request as in the case where the computer is fixed. Therefore, it is possible to reduce the resources on the computer and the load on the network due to the repetitive processing. Can be planned.

After the network is restored, the connection establishment processing is stopped in one of the computers.
By restarting, the connection can be easily and quickly re-established after restoration of the disconnected network.

Further, if the stopped program is only restarted, the connection can be easily and quickly re-established without being aware of the order in which the programs are started.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a client-server computer system according to the present invention.

FIG. 2 is a flowchart showing a connection establishment process according to the first embodiment.

FIG. 3 is a flowchart illustrating a connection establishment process according to the second embodiment.

FIG. 4 is a flowchart showing a connection establishment process according to the third embodiment.

[Description of Signs] 1 computer, 2 networks, 3, 13 client connection establishment unit, 4, 14 server connection establishment unit, 5, 15 connection monitoring control unit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tatsuo Fujitani 1-2-1, Yurakucho, Chiyoda-ku, Tokyo Mitsubishi Electric Systemware Co., Ltd. F-term (reference) 5B045 BB11 BB43 GG01 5B089 GA11 GA21 HB02 JB10 KA01 KA06 KA07 KC28 KC59 KG03 MB01 MC01

Claims (6)

[Claims] 1. A client-server type computer system in which a server computer responds to a connection request sent from a client computer to establish a connection between the computers. Connection establishment control means having a function of issuing a connection request and a function of responding to a connection request from another as a server computer, wherein the connection establishment control means issues a connection request by itself and establishes a connection. If the connection is not established, the client server waits for a connection request, and establishes a connection with the other computer by responding to the connection request sent from the other computer. Computer system. 2. In a client-server type computer system in which a server computer responds to a connection request sent from a client computer to establish a connection between the computers via a network, each of the computers comprises a connection A client connection establishing means for issuing a request to establish a connection; a server connection establishing means for establishing a connection in response to a connection request from another computer; and And a connection monitoring control means for performing execution control. The connection monitoring control means, when the connection cannot be established by the previously activated client connection establishment means, the server connection control means. A client-server type computer system for activating an application establishing means. 3. The connection monitoring control means of one of the computers which establishes a connection restarts the client connection establishment means upon detecting recovery of a failed network. 3. The client-server computer system according to 2. 4. The client-server computer system according to claim 1, wherein the connection is established in a procedure according to a TCP / IP communication protocol. 5. A client-server type computer system in which a connection is established between computers by a server computer responding to a connection request sent from the client computer, wherein each computer issues a connection request by itself. And a client connection establishing step for establishing a connection with the other computer by responding to a connection request sent from the other computer when the connection cannot be established in the client connection establishing step. A server connection establishing step of establishing a connection; and a client-server type computer-to-computer connection establishing method. 6. The one of the computers that establishes a connection stops the server connection establishment step before a connection request is sent from another computer, and executes the client connection establishment step again. 6. The method according to claim 5, further comprising the steps of: