JP2002318790A - System and program for communication applied to decentralized object environment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system which eliminates the need to discard or re-establish a connection even if trouble occurs to a server in decentralized object environment. SOLUTION: An object of a client obtains information on a proxy object from a managing object. Then the object of the client sends information on requested processing to the proxy object. The proxy object sends the information on the requested processing to a plurality of multiplied service objects by broadcast communication. Each service object sends a processing result to the proxy object, which sends the processing result received first to the object of the client.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication system and a communication program applied to a distributed object environment in which objects distributed on a network communicate with each other.
The present invention relates to a communication system and a communication program that perform communication based on a common object request broker architecture (quest Broker Architecture).

[0002]

2. Description of the Related Art In a distributed object environment in which objects distributed on a network communicate with each other, a function of communicating objects is called an ORB (Object R).
equestBroker: Object Request Broker). OMG (Object Management Group), an organization that standardizes object technology
Management Group), as ORB specifications, C
ORBA is defined. OMG also uses IIOP as a protocol for interconnecting ORBs.
(Internet Inter-ORB Protocol). C
In IIOP defined in ORBA, TCP /
Peer-to-Peer communication based on IP
er communication).

In a distributed object environment, a client requests processing from a server and obtains a response. In IIOP, a peer / server based on TCP / IP is used.
Since the two-peer communication is performed, a logical communication line (hereinafter, referred to as a connection) is set between transmission and reception prior to the communication, and the connection is released after the communication is completed. Once the client and server have established a connection, they must continue to use the connection until the communication is terminated after transmitting and receiving a series of requests and responses.

[0004] In CORBA, IOR is used as a format for storing information for specifying an object.
(Interoperable Object Reference). Each object establishes a connection with another object based on information described in the IOR.

FIG. 4 is a block diagram showing an example of a communication system applied to a conventional distributed object environment.
The communication system shown in FIG. 4 multiplexes servers and switches the servers when a failure occurs, thereby improving reliability.

The storage devices 103, 113, and 12 of each device
3 and 133 are the object 104, the management object 114, and the service objects 124 and 134, respectively.
Hold. Each CPU 102, 112, 122, 132
Are the objects 104, 114, 124, 1 respectively
The processing is executed according to. Each object is COR
Communication is performed according to BA and IIOP.

The interface units 105 and 11 of each device
5, 125, 135 transmit and receive information to and from other devices via the communication network 150. Interface unit 10
5, 115 are connected to the communication network 150.
Interface section 125,1 of each server 121,131
35 is connected to the path switching device 140. Route switching machine 1
40 connects one of the servers 121 and 131 to the communication network 150. The route switcher 140 switches a server connected to the communication network 150 by a manual operation of an operator.

Each server 121, 131 has the same IP
Address is assigned. However, the route switcher 140
Communicates only one server with the communication network 15
0, no inconsistency occurs in the communication network 150 due to duplication of IP addresses. In addition, the internal states and the contents of the servers 121 and 131 maintain the same identity, and both servers perform the same processing.

The client 101 (object 10
4) requests the process specified by the user from any service object. Service object 12
4 and 134 perform processing requested by the client 101. The management object 114 defines a service object that executes a process requested by the client 101.

FIG. 5 is a flowchart showing an example of an operation when a client requests a process and a server executes the requested process in a conventional communication system. The client 101 transmits the information of the requested processing to the management object 114 based on the operation of the user (step S
171). This information includes the name of the function to be executed.

Subsequently, the management object 114 determines a service object for executing the function (step S172). The management object 114 holds in advance information indicating the correspondence between each process (each function) and the IP address of a server having a service object that executes the function. The management object 114 extracts a function name from the information received in step S171, and specifies an IP address corresponding to the function name. The management object 114 determines the service object that executes the processing requested by the client 101 by specifying the IP address.

For example, the service objects 124, 1
If the function executes the “function A”, the management object 114 holds information indicating the correspondence between the IP address common to the servers 121 and 131 and the function A in advance. Then, when there is a request for “function A” in step S171, an IP address common to the servers 121 and 131 is specified. By specifying this IP address, it is determined that the service object 124 or the service object 134 executes the processing (function A) requested by the client 101. However, which service object receives the processing request from the client 101 depends on the state of the path switch 140.

Subsequently, the management object 114 transmits the information of the determined service object to the client 101.
(Step S173). The management object stores the information of the service object in step S1.
The information of the IP address specified at 72 is transmitted to the client 101. The management object 114 is an IO
Send the IP address using R.

[0014] The client 101 selects the IOR from the IOR.
The P address information is extracted, and a connection with the service object is established (step S174). The client 101 establishes a connection with a server (service object) specified by an IP address by TCP / IP peer-to-peer communication. Since the route switcher 140 connects only one of the plurality of servers to which the same IP address is assigned to the communication network 150, in step S174,
A connection is established with the server connected by the path switching device 140. For example, in the case shown in FIG. 4, a connection is established between the client 101 and the server 121. Subsequently, the client 101
The information of the requested processing is transmitted to the server 121 (step S175).

If a failure occurs in the server 121 while the service object 124 is performing the requested processing, the client 101 detects a communication error and
Output to the operator (step S176). Server 1
The operator who has confirmed the failure of the 21
Is operated to switch the server connected to the communication network 150 to the server 131 (step S177). II
In the OP, when such switching is performed, the client 1
01 and the service object 124 are discarded. Thereafter, the client 101 establishes a connection with the service object 134 (step S178), and requests the service object 134 for processing. In step S178, the communication system performs the same operation as steps S171 to S174.

[0016]

If a failure occurs in the server while the client and the server are communicating with each other, the server for processing is switched. However, in IIOP, a connection that has been secured must be used until a communication is completed after a series of processing, and if the path is switched before releasing the connection, the client may be in the middle of processing. The connection between the server and the server is destroyed. Therefore, if the server is switched, the connection must be established again. For example, if a failure occurs in the server 121,
When switching to the server 131, the communication system must repeat the same processing as in steps S171 to S174.

The operator operates the client 101
Detects the occurrence of the failure by detecting the communication error, and operates the path switching device 140. However, since the occurrence of a communication error depends on the OS (Operating System),
Whether or not a communication error can be detected and the timing of the detection depend on the OS. Therefore, the timing at which the operator recognizes the occurrence of the failure may be delayed depending on the type of the OS.

Recently, CORB has also been developed for a system in which if a device stops due to a failure, the operation is greatly hindered.
A is about to be applied. For example, a bank ATM
CORBA is being applied to (Automatic Teller's Machine), an ordering system within a company, and the like. In such a system, it is preferable to realize a communication system that does not need to re-establish a connection when a communication error occurs.

In the conventional communication system, each server 12 is controlled by a disk mirror device or the like (not shown).
Although the identity of 1,131 contents etc. is secured,
It is preferable that the identity of each server can be ensured without using such special equipment.

The present invention provides a communication system applicable to a distributed object environment in which it is not necessary to discard or re-establish a connection even when a failure occurs in a server, and the performance such as response time does not deteriorate. It is intended to provide a communication program. It is another object of the present invention to provide a communication system and a communication program that can ensure the identity of the internal state and contents of each server without using special equipment.

[0021]

A communication system applied to a distributed object environment according to the present invention comprises a client requesting processing, and a plurality of servers performing processing in response to a request from the client, wherein the client And the server is a communication system applied to a distributed object environment in which objects for communication are arranged, wherein the objects for communication are arranged, and a proxy device for relaying communication between the client and the server is provided.
The client transmits information of the requested process to the proxy device according to the object arranged in the own device, and the proxy device broadcasts information of the process requested by the client to each server in accordance with the object arranged in the own device. And transmits the processing result received first from the server to the client.Each server performs processing based on the information received from the proxy device according to the object arranged in the own device, and processes the processing result of the processing. The information is transmitted to the proxy device.

The objects located on the client, server, and proxy device communicate according to a common object request broker architecture.

An object for communication is arranged, and there is provided a management device for preliminarily holding information indicating the correspondence between various processes requested by the client and the proxy device. The information of the requested process is transmitted to the management device, and the information of the requested process is transmitted to the proxy device determined based on the information received from the management device. Specifies the proxy device corresponding to the process requested by the client, and transmits information on the proxy device to the client.

Objects located on the management device communicate according to a common object request broker architecture.

The management device previously stores information indicating the correspondence between various processes and a proxy device that performs broadcast communication with a plurality of servers executing the processes. In addition, each server transmits the processing result to the proxy device by broadcast communication.

Further, the communication program according to the present invention provides a computer which relays communication between a client according to a common object request broker architecture and a plurality of multiplexed servers with information on processing requested by the client. , A process of transmitting information of a process requested by the client to each server by broadcast communication, and a process of transmitting a process result first received from a server to the client.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a communication system applied to a distributed object environment according to the present invention. In the communication system of the present example, a plurality of multiplexed servers 21 and 31
Connected to 0. That is, the servers 21 and 31 can perform the same processing. The number of multiplexed servers is not limited to two.

Client 1, management device 11, server 2
1, 31 and the proxy device 41 are mutually connected via a communication network 50. Each of the servers 21 and 31 is assigned a unique IP address, and both are connected to the communication network 50. Storage device 3 for each device
Reference numerals 3, 23, 33, and 43 denote object 4, management object 14, service object 24, and object 3, respectively.
4. Hold the proxy object 44. Each CPU2,1
2, 22, 32, and 42 are programs (objects 4, 14, 24, 34, 4) stored in the storage device, respectively.
Execute the processing according to 4). The interface units 5, 15, 25, 35, and 45 of each device are connected to a communication network 50.
To send and receive information to and from other devices. Each of the objects 4, 14, 24, 34, and 44 performs communication according to CORBA and IIOP. The internal states and contents of the servers 21 and 31 are the same.

The client 1 includes an input device (not shown) for inputting an instruction from a user and an output device (not shown) for outputting information. The input device is, for example, a keyboard or a mouse, and the output device is, for example, a display device.

The client 1 (object 4) transmits the processing information specified by the user to the proxy object 44.
Send to The service objects 24 and 34 execute processing requested by the client 1.

The proxy object 44 is the client 1
It relays communication of processing requests and responses performed between the server and the service objects 24 and 34. Specifically, the proxy object 44 receives the information of the process requested by the client 1 from the client 1, and transmits the information to each of the service objects 24 and 34 by broadcast communication (broadcast communication). Also,
A processing result is received from one of the service objects, and the processing result is transmitted to the client 1.

The management object 14 is the client 1
The proxy object 44 is uniquely determined in response to a request from. Although FIG. 1 shows only one proxy device, the number of proxy devices may be plural. FIG. 2 is an explanatory diagram illustrating an example where the communication system includes a plurality of proxy devices. The servers 56 and 57 are multiplexed servers, and have the same internal state and content. Server 2
1, 31 and the servers 56, 57 perform different processing. A segment in which the proxy devices 41 and 55 perform broadcast communication is predetermined, and each proxy device transmits a processing request to a service object (server) in the segment. For example, the proxy device 41 performs broadcast communication to a segment including the servers 21 and 31, and the proxy device 5
5 performs broadcast communication to a segment including the servers 56 and 57.

Next, the operation will be described. FIG. 3 is a flowchart illustrating an example of an operation when a client requests a process and a server executes the requested process. The client 1 transmits the information of the requested processing to the management object 14 based on the operation of the user (Step S7).
1). In step S71, the client 1 includes the name of the function to be executed in the information of the requested processing.

The management object 14 determines in step S71
When the information including the function name is received in step (2), a proxy object that relays the communication between the service object executing the function and the client is determined (step S72). The management object 14 previously stores information indicating the correspondence between each process (each function) and each proxy device. This information indicates the correspondence between each function and the IP address of each proxy device. The management object 14 extracts a function name from the information received in step S71, and specifies an IP address corresponding to the function name. The management object 14 determines the proxy object by specifying the IP address of the proxy device.

The functions held by the management object 14 and I
Information indicating the correspondence with the P address will be described.
The management object 14 associates each function with an IP address of a proxy device that performs broadcast communication with a plurality of servers executing the function, and holds information indicating the correspondence. For example, service objects 24 and 34
Executes the “function A”, the management object 14 determines the IP address of the proxy device 41 that requests the servers 21 and 31 to perform processing by broadcast communication,
"Function A" is made to correspond, and the correspondence information is held.
Then, when the request of “function A” is received in step S71, the IP address of the proxy device 41 corresponding to the function A is specified.

The management object 14 proceeds to step S72.
Is transmitted to the client 1 (step S73). Management object 1
4 is the information of the proxy object 44 as step S
At 72, the information of the IP address specified is transmitted to the client 1. The management object 11 transmits an IP address using the IOR.

The client 1 extracts information on the IP address of the proxy object 44 (proxy device 41) from the IOR, and establishes a connection with the proxy object specified by the IP address (step S).
74). The client 1 establishes a connection with a proxy object by TCP / IP peer-to-peer communication.

Subsequently, the client 1 transmits information on the requested processing to the proxy object 44 (step S).
75). In the information transmitted and received in step S75, the IP address of the client 1 is set as the information of the transmission source, and the IP address of the proxy device 41 is set as the information of the transmission destination. Specifically, the IP header of the transmitted / received information includes the I
The P address is written, and the IP address of the proxy device 41 is written as destination information. The source address is also entered in IIOP.

The proxy object 44 determines in step S75
The information of the process requested by the client 1 received in the above is transmitted by the broadcast communication of the TCP / IP.
It is transmitted to each service object 24, 34 (step S76). When performing the broadcast communication, the proxy object 44 converts the information of the transmission source and the transmission destination of the information received from the client 1 and transmits the information to the service objects 24 and 34. That is, the source information in the IP header is converted from the IP address of the client 1 to the IP address of the proxy device 41, and the destination information is converted from the IP address of the proxy device 41 to an address used for broadcast communication. Also, the source address in the IIOP is converted from the address of the client 1 to the address of the proxy device 41.

Since the broadcast communication is performed in step S76, the proxy device 41 requests the processing to a plurality of service objects 24 and 34 instead of requesting only one service object. Note that FIG.
Then, the proxy object 44 becomes the service object 2
4 and 34 request processing, but proxy object 4
4 transmits the service objects 24 and 34
As well as to other devices in the same segment.

Each of the service objects 24 and 34 performs a requested process. With this operation, the server 2
The internal state and the contents of 1, 31 change. But,
Each of the service objects 24 and 34 performs the same processing according to the same processing request.
The way of changing the internal state and the content of the content becomes the same.

Each of the service objects 24 and 34 transmits the processing result to the proxy device 41 (step S7).
7, S78). Each service object 24, 34
The processing result is transmitted by TCP / IP broadcast communication. In the IP header of the information transmitted by each service object, the IP address of the server is written as source information, and the address used for broadcast communication is written as destination information. Also, IIO
P also contains the address of the server that is the transmission source. In FIG. 3, the service objects 24 and 34 transmit information to the proxy object 44. However, since the broadcast communication is used, the information is transmitted not only to the proxy object 44 but also to other devices in the same segment.

The proxy object 44 receives the processing result from each service object, and after receiving the processing result for the first time, transmits the processing result to the client 1 (step S79). Proxy object 44 is TCP
The processing result is transmitted to the client 1 by the / IP peer-to-peer communication. In the example shown in FIG. 3, the service object 24 transmits the processing result to the proxy object 44 before the service object 34. Therefore, after step S76, the processing result received first is:
This is the result of the process executed by the service object 24. Therefore, the proxy object 44 transmits the processing result to the client 1 after receiving the processing result from the service object 24.

When transmitting the processing result to the client 1,
The proxy object 44 converts the source and destination information of the information received from the service object 24,
Send to client 1. That is, in the IP header, the information of the transmission source is obtained from the IP address of the server 21.
The IP address of the proxy device 41 is converted, and the destination information is converted from the address used for the broadcast communication to the IP address of the client 1. Also, IIOP
Also, the address of the sender included in the server 21 is converted from the address of the server 21 to the address of the client 1.

When a failure occurs in the server 21, the proxy object 44 cannot receive the processing result from the service object 24. In this case, the processing result from the service object 34 is the processing result received first. Therefore, the proxy object 44 transmits the processing result received from the service object 34 to the client 1
Send to On the other hand, when a failure occurs in the server 31, the processing result from the service object 24 is the processing result received first. In this case, the proxy object 44 transmits the processing result received from the service object 24 to the client 1.

As described above, in the communication system according to the present invention, the proxy object 44 transmits a processing request to the multiplexed service objects 24 and 34, and transmits the processing result returned first to the client 1. . Therefore, even when a failure occurs in some servers, the processing result can be received from another server, and the reliability is improved.

Then, the processing result received from the server having no failure can be transmitted to the client 1 without switching the route in the communication system. Since there is no need to switch the route, there is no need to discard the connection once established and re-establish a new connection. Therefore, the operation of the communication system when a failure occurs can be reduced.

Furthermore, the need for a path switch is eliminated, and the client 1 does not need to recognize a communication error due to the occurrence of a failure and operate the path switch. Therefore, there is no problem that the timing at which the operator recognizes the occurrence of the failure may be delayed depending on the type of the OS.

In the communication system according to the present invention, the proxy object 44 transmits the same processing request to each of the service objects 24 and 34, and each of the service objects 24 and 34 performs the same processing. Therefore, the manner of changing the internal state and the content of each of the servers 21 and 31 in accordance with the requested operation is the same. Therefore, the identity of the internal state of each server can be maintained without using a special device such as a disk mirror device.

In some servers, a process different from the process requested by the proxy object 44 occurs, and a response time to the proxy object 44 may take a long time. However, even in such a case, the proxy object 44 transmits the processing result received first to the client 1. Therefore, even if the response of some service objects is delayed, it is possible to prevent the performance from deteriorating.

[0051]

According to the present invention, an object for communication is arranged, and a proxy device for relaying communication between a client and a server is provided. The client requests processing according to the object arranged on its own device. The proxy device transmits the information of the process requested by the client to each server by broadcast communication according to the object arranged in the own device, and transmits the process result first received from the server to the client. Each server performs a process based on the information received from the proxy device according to the object arranged in the own device, and transmits the processing result of the process to the proxy device, so that a failure occurs in some servers. Even in this case, the processing result can be received from another server. Since there is no need to discard the connection once established and establish a new connection, it is possible to reduce the number of operations at the time of occurrence of a failure, and to prevent a decrease in performance at the time of occurrence of a failure. Further, the identity of the contents of the server can be ensured without using a disk mirror device or the like. Further, it is possible to solve the problem that the timing at which the operator recognizes the occurrence of the failure may be delayed depending on the type of OS.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a communication system applied to a distributed object environment according to the present invention.

FIG. 2 is an explanatory diagram illustrating an example in which a communication system includes a plurality of proxy devices.

FIG. 3 is a flowchart illustrating an example of an operation when a client requests a process and a server executes the requested process.

FIG. 4 is a block diagram illustrating an example of a communication system applied to a conventional distributed object environment.

FIG. 5 is a flowchart showing an example of an operation when a client requests a process and a server executes the requested process in a conventional communication system.

[Explanation of symbols]

 Reference Signs List 1 client 2 CPU 3 storage device 4 object 11 management device 12 CPU 13 storage device 14 management object 21, 31 server 22, 32 CPU 23, 33 storage device 24, 34 service object 41 proxy device 42 CPU 43 storage device 44 proxy project 50 Communication network

Claims (7)

[Claims] 1. A distributed object environment, comprising: a client requesting a process; and a plurality of servers performing a process in response to a request from the client, wherein the client and the server are provided with objects for communication. A communication system in which objects for communication are arranged, and a proxy device for relaying communication between the client and the server is provided. The client transmits information of a requested process in accordance with the objects arranged in its own device. The proxy device transmits the information of the process requested by the client to each server by broadcast communication according to the object arranged in the device, transmits the process result first received from the server to the client, Each server acts as a proxy according to the objects located on its own device. Performs processing based on the information received located et al,
A communication system applied to a distributed object environment, wherein a processing result of the processing is transmitted to a proxy device. 2. The communication system applied to a distributed object environment according to claim 1, wherein objects located in the client, the server, and the proxy device communicate according to a common object request broker architecture. 3. A management device in which objects for communication are arranged, and information indicating the correspondence between various processes requested by the client and the proxy device is provided in advance. The information of the requested processing is transmitted to the management device, and the proxy device determined based on the information received from the management device,
2. The information processing apparatus according to claim 1, wherein the management apparatus specifies a proxy apparatus corresponding to the processing requested by the client in accordance with an object placed in the management apparatus, and transmits the information of the proxy apparatus to the client. A communication system applied to the distributed object environment according to claim 2. 4. The object arranged in the management device,
The communication system applied to a distributed object environment according to claim 3, wherein communication is performed according to a common object request broker architecture. 5. The distributed object environment according to claim 3, wherein the management device previously stores information indicating a correspondence relationship between various processes and a proxy device that performs broadcast communication to a plurality of servers executing the processes. Communication system applied to. 6. The communication system applied to the distributed object environment according to claim 1, wherein each server transmits a processing result to a proxy device by broadcast communication. 7. A process for receiving, from a client, information of a process requested by a client to a computer that relays communication between the client and a plurality of multiplexed servers according to a common object request broker architecture; A communication program for executing a process of transmitting information of a process requested by the server to each server by broadcast communication, and a process of transmitting a process result first received from a server to the client.