JP4636864B2 - Relay equipment - Google Patents

Description

  The present invention relates to a client terminal, a service providing apparatus, a relay device, a service load distribution system, and a service load distribution method.

  Numerous studies have been conducted on a mechanism for a client terminal to discover other services as a service discovery protocol. For example, Jlni, UPnP (Universal Plug & Play), SLP (Service Location Protocol), and the like have been proposed as protocols that define service discovery procedures. In the service discovery protocol, a client using a service designates a service requested in the service request function and broadcasts it to the surroundings. When the service provided by the service matches the service provided by the service and the service described in the client service request, the service response function generates a service response message and responds to the client. Thus, a technique for efficiently discovering a communication partner has been disclosed (for example, see Patent Document 1).

Further, since the service does not know the client to be connected before connection, it is necessary to return a service response to an unspecified number of clients that request connection. It is also important that the service provides a digital signature to the service response in order to prove the identity of the service itself. This digital signature function is not necessarily a function installed in the existing service discovery protocol, but is provided as an option in SLP. By using the digital signature function for the service response, it is possible to prevent an attack that prevents a malicious service from sending a fake service response and prevents the client from connecting to a legitimate service.
JP 2004-88428 A

  However, in the above prior art, the service response function of a service needs to respond to a service request by an unspecified number of arbitrary clients. For this reason, when a malicious client sends a large number of service requests, the service needs to give a digital signature to these service requests and return a service response. Since digital signatures require heavy computational processing for services with poor computing capabilities such as digital cameras, services that compute a huge number of digital signatures run out of CPU resources and cannot process new service requests. There was a problem.

  In view of the above-described problems, the present invention provides a client terminal and a service that allow a legitimate client to find and connect to a service in a short time as usual even when a malicious client sends a huge service request It is an object to provide a providing device, a relay device, a service load distribution system, and a service load distribution method.

  In order to achieve the above object, a first feature of the present invention is a client terminal to which data or a function is provided from a service providing apparatus, and (a) generates a service request message for requesting a service to the service providing apparatus. A request generation unit; (b) an operation mode determination unit that determines an operation mode including information on a transmission destination of the service request message; and (c) a service request message is transmitted according to the operation mode determined by the operation mode determination unit. The gist of the invention is that the client terminal includes a communication unit.

  According to the client terminal according to the first feature, even if a malicious client sends a huge service request, a legitimate client can find and connect to the service in a short time as usual.

  The client terminal according to the first feature further includes a message storage unit that stores a service request message and a state monitoring unit that monitors a state of the message storage unit, and the operation mode determination unit is obtained by the state monitoring unit. The operation mode may be determined based on the amount of service request messages stored in the message storage unit.

  According to this client terminal, the load on the service providing apparatus can be reduced by determining the operation mode based on the amount of the service request message.

  A second feature of the present invention is a service providing apparatus that provides data or a function to a client terminal, wherein (a) a message storage unit that stores a service request message for requesting a service received from the client terminal; The gist of the present invention is a service providing apparatus including an operation mode determination unit that determines an operation mode including a transmission destination of a service request message.

  According to the service providing apparatus according to the second feature, even when a malicious client sends a huge service request, a legitimate client can find and connect to a service in a short time as usual.

  The third feature of the present invention further includes a status monitoring unit that monitors the status of the message storage unit, and the operation mode determination unit is a service request message stored in the message storage unit obtained by the status monitoring unit. The operating mode may be determined based on the quantity.

  According to this service providing apparatus, it is possible to reduce the load on the service providing apparatus by determining the operation mode based on the amount of the service request message.

  A fourth feature of the present invention is a relay device that relays communication between a client terminal and a service providing apparatus that provides data or a function to the client terminal, and (a) a service providing apparatus received from the client terminal A message accumulating unit for accumulating a service request message for requesting a service, (b) a request proxy processing unit for processing the service request message, and (c) an operation mode determination for determining an operation mode including a transmission destination of the service request message The gist of the present invention is that it is a relay device provided with a section.

  According to the relay device according to the third feature, even if a malicious client sends a huge service request, a legitimate client can find and connect to the service in a short time as usual.

  The relay device according to the third feature further includes a state monitoring unit that monitors the state of the message storage unit, and the operation mode determination unit is a service stored in the message storage unit obtained by the state monitoring unit. The operating mode may be determined based on the amount of request messages.

  According to this relay device, it is possible to reduce the load on the service providing apparatus by determining the operation mode based on the amount of the service request message.

  A fourth feature of the present invention is a service load distribution system including a client terminal, a service providing apparatus that provides data or a function to the client terminal, and a relay device that relays communication between the client terminal and the service providing apparatus. And (a) a message storage unit that stores a service request message for requesting a service to the service providing device, and (b) an operation mode determination unit that determines an operation mode including information on a transmission destination of the service request message. The gist of the service load balancing system.

  According to the service load distribution system according to the fourth feature, even when a malicious client sends an enormous service request, a regular client can find and connect to a service in a short time as usual.

  According to a fifth aspect of the present invention, there is provided a load distribution system including a client terminal, a service providing apparatus that provides data or a function to the client terminal, and a relay device that relays communication between the client terminal and the service providing apparatus. A service load distribution method for distributing a load for processing a service request message for requesting a service to a service providing apparatus, comprising: (a) a step of storing the service request message; and (b) information on a transmission destination of the service request message. And a service load distribution method including a step of determining an operation mode to be included.

  According to the service load distribution method according to the fifth feature, even if a malicious client sends a huge service request, a legitimate client can find and connect to a service in a short time as usual.

  According to the present invention, even when a malicious client sends a huge service request, a client terminal, a service providing device, and a relay device that can be found and connected by a regular client in a short time as usual A service load distribution system and a service load distribution method can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic.

(Service load balancing system)
As shown in FIG. 1, the service load distribution system according to the exemplary embodiment of the present invention relays communication between the client terminal 100, the external service device 200 (service providing apparatus), and the client terminal 100-service providing apparatus 200. It is comprised from the relay apparatus 300 (for example, proxy server).

  The client terminal 100 is connected to the external service device 200 for the purpose of expansion of input / output functions, communication with a remote device / status confirmation / control, and the like. The external service device 200 is a device having an input / output function superior to a client terminal such as a digital camera, a video camera, a TV, a speaker, etc., and a white goods such as a refrigerator, a washing machine, a microwave oven, an air conditioner having a network function. Some functions for client terminals such as various sensors such as thermometers, hygrometers, infrared sensors, thermometers, sphygmomanometers, weight scales, client terminals such as other PCs, mobile phones, PDAs, and all software on the network Alternatively, it is hardware or software that provides data.

  The client terminal 100 realizes various applications that cannot be realized by the client terminal 100 alone by connecting to the external service device 200. For example, it is possible to realize an application in which images taken with a high-functional digital camera are transferred to the client terminal 100 and stored, and transferred to an arbitrary large-screen television for display. In addition, an application is conceivable in which information on daily body temperature and weight is acquired from a sensor and stored in a mobile phone, and a one-month history is displayed on a television for confirmation. In order to realize these applications, a mechanism for the client terminal 100 to discover other services is necessary.

  As shown in FIG. 1, the client terminal 100 includes a central processing unit 101, a communication unit 102, a message storage unit 103, a request generation unit 104, an operation mode determination unit 105, a state monitoring unit 106, an operation mode, And a recording unit 107.

  The central processing unit 101 controls the flow of information between each component of the client terminal 100.

  The communication unit 102 communicates with the communication unit 202 of the external service device 200 and the communication unit 302 of the relay device 300. For example, the message generated by the request generation unit 104 is transmitted to the external service device 200 according to the operation mode determined by the operation mode determination unit 105, and a response message is received from the external service device 200.

  The message storage unit 103 stores the service request message generated by the request generation unit 104. Further, the message storage unit 103 stores service response messages received from the external service device 200 and the relay device 300 and transfers them to the request generation unit 104.

  The request generation unit 104 generates a service request message describing the type and attributes of the requested service and transmits the service request message to the external service device 200 or the relay device 300.

  Based on the load of the client terminal 100, the operation mode determination unit 105 obtains information such as a service request message processing method, a service request message transmission destination (external service device 200 or relay device 300), and a service request message transmission path. Determine the operating mode to include.

  The state monitoring unit 106 monitors the amount of service request messages stored in the message storage unit 103 and notifies the operation mode determination unit 105 of the monitoring result.

  The operation mode recording unit 107 records the operation mode determined by the operation mode determination unit 105.

  As shown in FIG. 1, the external service device 200 includes a central processing unit 201, a communication unit 202, a message storage unit 203, a request response unit 204, an operation mode determination unit 205, a state monitoring unit 206, an operation A mode recording unit 207.

  The central processing unit 201 controls the information flow between the components of the external service device 200.

  The communication unit 202 performs communication between the communication unit 102 of the client terminal 100 and the communication unit 302 of the relay device 300. For example, a service request message is received from the client terminal 100 and the service response message generated by the request response unit 204 is transmitted to the client terminal 100. Alternatively, a processed message is received from the request proxy processing unit 304 of the relay device 300 and a service response message is transmitted to the client terminal 100.

  The message storage unit 203 stores service request messages received from the client terminal 100 and the relay device 300.

  The request response unit 204 processes the message stored in the message storage unit 203, generates a service response message, and transmits it to the client terminal 100.

  The operation mode determination unit 205 monitors the amount of the service request message stored in the message storage unit 203, and determines the service request message processing method and the service request message transmission destination (external service device 200 or relay device) according to the monitoring result. 300), an operation mode including information such as a transmission path of the service request message is determined.

  The state monitoring unit 206 monitors the amount of service request messages stored in the message storage unit 203 and notifies the operation mode determination unit 305 of the monitoring result.

  The operation mode recording unit 207 records the operation mode determined by the operation mode determination unit 205.

  As shown in FIG. 1, the relay device 300 includes a central processing unit 301, a communication unit 302, a message storage unit 303, a request proxy processing unit 304, an operation mode determination unit 305, a state monitoring unit 306, an operation A mode recording unit 307.

  The central processing unit 301 controls the flow of information between the components of the relay device 300.

  The communication unit 302 performs communication between the communication unit 102 of the client terminal 100 and the communication unit 202 of the external service device 200.

  The message storage unit 303 stores messages received from the client terminal 100 and the external service device 200.

  When receiving a service request message from the client terminal 100, the request proxy processing unit 304 processes the message as a proxy for the external service device 200. For example, processing for calculating the priority of a message and processing for assigning a service signature are performed.

  The operation mode determination unit 305 includes an operation mode including information such as a method for processing a service request message transmitted from the client terminal 100, a transmission destination of the service request message (external service device 200 or relay device 300), and a transmission path of the service request message. To decide.

  The state monitoring unit 306 monitors the amount of service request messages stored in the message storage unit 303 and notifies the operation mode determination unit 305 of the monitoring result.

  The operation mode recording unit 307 records the operation mode determined by the operation mode determination unit 305.

  The message storage unit 103, the operation mode recording unit 107 of the client terminal 100, the message storage unit 203 of the external service device 200, the operation mode recording unit 207, the message storage unit 303 of the relay device 300, and the operation mode recording unit 307 are stored in the RAM. An internal storage device such as a hard disk or a flexible disk may be used.

  The client terminal 100 according to the present embodiment includes a processing control device (CPU), and includes the above-described central processing unit 101, communication unit 102, request generation unit 104, operation mode determination unit 105, state monitoring unit 106, and the like. The module can be built in the CPU. These modules can be realized by executing a dedicated program for using a predetermined program language in a general-purpose computer such as a personal computer.

  Although not shown, the client terminal 100 may include a program holding unit that stores a program for causing the CPU to execute request generation processing, operation mode determination processing, state monitoring processing, and the like. The program holding unit is a recording medium such as a RAM, a ROM, a hard disk, a flexible disk, a compact disk, an IC chip, and a cassette tape. According to such a recording medium, it is possible to easily store, transport, and sell programs.

  Similarly, the external service device 200 includes a processing control device (CPU), and the above-described central processing unit 201, communication unit 202, request response unit 204, operation mode determination unit 205, state monitoring unit 206, and the like are modules. It can be configured to be built in the CPU. These modules can be realized by executing a dedicated program for using a predetermined program language in a general-purpose computer such as a personal computer.

  Although not shown, the external service device 200 may include a program holding unit that stores a program for causing the CPU to execute request response processing, operation mode determination processing, state monitoring processing, and the like. The program holding unit is a recording medium such as a RAM, a ROM, a hard disk, a flexible disk, a compact disk, an IC chip, and a cassette tape. According to such a recording medium, it is possible to easily store, transport, and sell programs.

  Similarly, the relay device 300 includes a processing control device (CPU), and the above-described central processing unit 301, communication unit 302, request proxy processing unit 304, operation mode determination unit 305, state monitoring unit 306, and the like as modules. It can be configured to be built in the CPU. These modules can be realized by executing a dedicated program for using a predetermined program language in a general-purpose computer such as a personal computer.

  Although not shown, the relay device 300 may include a program holding unit that stores a program for causing the CPU to execute a request proxy process, an operation mode determination process, a state monitoring process, and the like. The program holding unit is a recording medium such as a RAM, a ROM, a hard disk, a flexible disk, a compact disk, an IC chip, and a cassette tape. According to such a recording medium, it is possible to easily store, transport, and sell programs.

(Service load balancing method)
Next, the service load distribution method according to the present embodiment will be described with reference to FIGS. Here, the entity that determines the operation mode including the transmission destination of the service request message may be the client terminal 100, the external service device 200, or the relay device 300.

  FIG. 2 is a flowchart illustrating a method for determining an operation mode in the client terminal 100.

  First, in step S11, the request generation unit 104 of the client terminal 100 generates a service request message.

  Next, in step S12, the message storage unit 103 of the client terminal 100 stores a service request message.

  Next, in step S <b> 13, the state monitoring unit 106 monitors the amount of service request messages stored in the message storage unit 103 and notifies the operation mode determination unit 105 of the monitoring result.

  Next, in step S <b> 14, the operation mode determination unit 105 determines a service request message processing method, a service request message transmission destination (external service device 200 or relay device 300), a service request message based on the load on the client terminal 100. The operation mode including information such as the transmission route of the mobile phone is determined. For example, when an enormous amount of service request messages are transmitted to the same external service device 200, an operation mode in which a part thereof is transmitted to the relay device 300 is set.

  In step S <b> 15, the communication unit 102 transmits a service request message according to the operation mode determined by the operation mode determination unit 105.

  FIG. 3 is a flowchart illustrating a method for determining an operation mode in the external service device 200.

  First, in step S21, the message storage unit 203 of the external service device 200 stores the service request message received from the client terminal 100.

  Next, in step S <b> 22, the state monitoring unit 206 of the external service device 200 monitors the amount of service request message stored in the message storage unit 203 and notifies the operation mode determination unit 205 of the monitoring result.

  Next, in step S23, the operation mode determination unit 205 determines a service request message processing method, a service request message transmission destination (external service device 200 or relay device 300), service request based on the load of the external service device 200. An operation mode including information such as a message transmission path is determined. For example, when an enormous amount of service request messages are accumulated, the subsequent service request messages are set to an operation mode to be transmitted to the relay device 300.

  In step S <b> 24, the communication unit 102 of the external service device 200 notifies the client terminal 100 and the relay device 300 of the operation mode determined by the operation mode determination unit 205.

  The client terminal 100 transmits a service request message according to the notified operation mode.

  FIG. 4 is a flowchart illustrating a method for determining the operation mode in the relay device 300. Here, it is assumed that the client terminal 100 is transmitting a service request message to the relay device 300.

  First, in step S31, the message storage unit 303 of the relay device 300 stores the service request message received from the client terminal 100.

  Next, in step S <b> 32, the state monitoring unit 306 of the relay device 300 monitors the amount of service request message stored in the message storage unit 303 and notifies the operation mode determination unit 305 of the monitoring result.

  Next, in step S33, the operation mode determination unit 305 determines the service request message processing method, the service request message transmission destination (the external service device 200 or the relay device 300) based on the loads on the external service device 200 and the relay device 300. ) And an operation mode including information such as a transmission path of the service request message is determined. For example, if the accumulated service request message is smaller than a prescribed amount, it is assumed that the relay device 300 still has processing capability, and the subsequent service request message is set to an operation mode to be transmitted to the relay device 300.

  In step S <b> 34, the communication unit 302 of the relay device 300 notifies the client terminal 100 and the external service device 200 of the operation mode determined by the operation mode determination unit 305.

  The client terminal 100 transmits a service request message according to the notified operation mode.

  Next, details of the service load distribution method will be described using the sequence diagram of the client terminal 100, the external service device 200, and the relay device 300 shown in FIG.

  Here, in response to the service request transmitted by the client terminal 100, the first step until the external service device 200 transmits a service response and the client terminal 100 receives the service response, and the load on the external service device 200 increases. The second step until the relay terminal 300 is notified of the change, the operation mode is changed, and the client terminal 100 and the external service device 200 are notified of the new operation mode, and the client terminal 100 transmits to the relay device 300 according to the new operation mode. It consists of a third step until a service request is transmitted, message priority control and response message signature processing are performed on behalf of the relay device, and a response message is returned to the client terminal 100 via the external service device 200 Is done.

= First step =
First, in step S <b> 101, the request generation unit 104 of the client terminal 100 generates a service request message and transmits it to the communication unit 102.

  Next, in step S102, the communication unit 102 of the client terminal 100 transmits a service request message to the external service device 200, and the communication unit 202 of the external service device 200 receives the service request message.

  Next, in step S <b> 103, the communication unit 202 of the external service device 200 transmits the received service request message to the message storage unit 203.

  Next, in step S104, the message storage unit 203 of the external service device 200 transmits the received message to the request response unit 204, confirms the content of the requested service, and matches the service provided by the external service device 200. Confirm whether or not to do. If it does not match the requested service, the service request message is discarded.

  Next, if they match, in step S105, the request response unit 204 of the external service device 200 creates a service response message, adds the electronic signature of the service, and transmits it to the communication unit 202.

  Next, in step S106, the communication unit 202 of the external service device 200 transmits a service response message to the client terminal 100, and the communication unit 102 of the client terminal 100 receives the service response message.

  Next, in step S107, the communication unit 102 of the client terminal 100 transmits a service response message to the request generation unit 104, and the request generation unit 104 acquires information for connecting to the discovered service.

= Second step =
Next, in step S201, the state monitoring unit 206 of the external service device 200 monitors the message storage unit 203, confirms and records the amount of messages stored in the message storage unit 203.

  Next, in step S <b> 202, the operation mode determination unit 205 of the external service device 200 confirms the accumulation state of the message recorded in the state monitoring unit 206.

  Next, in step S203, the operation mode determination unit 205 transmits an operation state change notification to the operation mode determination unit 305 of the relay device 300 when the load of the external service device 200 exceeds the specified threshold, and the relay device The operation mode determination unit 305 of 300 receives the operation state change notification.

  Next, in step S204, the operation mode determination unit 305 of the relay device 300 changes the service request message transmitted from the client terminal 100 to the operation mode for transmitting to the external service device 200 via the relay device 300, The change is notified to the operation mode determination unit 105 of the client terminal 100 and the operation mode determination unit 205 of the external service device 200.

= Third step =
Next, in step S <b> 301, the request generation unit 104 of the client terminal 100 generates a service request message and transmits it to the communication unit 102.

  Next, in step S302, the client terminal 100 confirms the operation mode recorded in the operation mode recording unit 107, transmits a service request message to the communication unit 302 of the relay device 300, and the communication unit 302 of the relay device 300 Receive a service request message.

  Next, in step S <b> 303, the communication unit 302 of the relay device 300 stores the service request message in the message storage unit 303.

  Next, in step S304, the message storage unit 303 transmits a service request message to the request proxy processing unit 304.

  Next, in step S <b> 305, the request proxy processing unit 304 executes the service request message processing as a proxy for the external service device 200. For example, a service response message is generated and an electronic signature of the external service device 200 is given. Alternatively, when a large number of service request messages from the same source are received, a message having a possibility of DoS attack is eliminated by lowering the processing priority. After finishing these processes, a newly generated service response message is transmitted to the communication unit 302.

  Next, in step S306, the communication unit 302 of the relay device 300 transmits a service response message to the communication unit 202 of the external service device 200.

  Next, in step S307, the communication unit 202 of the external service device 200 stores the service response message in the message storage unit 203.

  Next, in step S308, the message storage unit 203 of the external service device 200 transmits a service response message to the request response unit 204, and processes the service response message.

  Next, in step S309, the request response unit 204 of the external service device 200 transmits a service response message to the communication unit 202.

  Next, in step S310, the communication unit 202 of the external service device 200 transmits a service response message to the communication unit 102 of the client terminal 100, and the communication unit 102 of the client terminal 100 receives the service response message.

  Next, in step S311, the communication unit 102 of the client terminal 100 transmits a service response message to the request generation unit 104, and the request generation unit 104 acquires information for connecting to the service.

(Action and effect)
According to the client terminal 100, the external service device 200, the relay device 300, the service load distribution system, and the service load distribution method according to the present embodiment, when the external service device 200 receives an enormous service request message, the relay device 300 The route is changed to a route for transmitting the service request message via the relay device, and the processing performed by the external service device 200 is performed on the relay device 300, thereby reducing the load on the external service device 200 and the service from the regular client terminal 100. The request can be processed.

  Further, according to the client terminal 100 according to the present embodiment, the operation mode can be determined based on the amount of service request messages stored in the message storage unit 103 obtained by the state monitoring unit 106.

  Similarly, according to the external service device 200 according to the present embodiment, the operation mode can be determined based on the amount of service request messages accumulated in the message accumulation unit 203 obtained by the state monitoring unit 206. .

  Similarly, according to the relay device 300 according to the present embodiment, the operation mode can be determined based on the amount of service request messages stored in the message storage unit 303 obtained by the state monitoring unit 306.

  In this way, the load on the external service device 200 can be reduced by determining the operation mode based on the amount of service request messages.

(Other embodiments)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the embodiment of the present invention, the relay device 300 may be arranged in a remote place on the assumption that communication is performed via the Internet, or by wireless LAN, Bluetooth, Ethernet (registered trademark), or the like. You may arrange | position in the place near a user on the assumption that it communicates via a local area network. A plurality of relay devices 300 may be arranged. In addition, as processing performed by the relay device 300 as a proxy for the external service device 200, matching of the request content described in the service request message with the service content provided by the external service device, generation of a service response message, and electronic to the service response message Arbitrary processing among various processing such as assignment of a signature and determination of priority of processing of a service request message may be performed.

  In the embodiment of the present invention, the client terminal 100 includes a central processing unit 101, a communication unit 102, a request generation unit 104, an operation mode determination unit 105, a state monitoring unit 106, and the like in one processing control device (CPU). However, they may be divided into two or more processing control devices. In this case, it is assumed that the devices are connected by a bus or the like so that data can be exchanged between the processing control devices. The same applies to the external service device 200 and the relay device 300.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a block diagram of the configuration of a client terminal, an external service device, and a relay device according to the present embodiment. It is a flowchart which shows operation | movement of the client terminal which concerns on this embodiment. It is a flowchart which shows operation | movement of the external service apparatus which concerns on this embodiment. It is a flowchart which shows operation | movement of the relay apparatus which concerns on this embodiment. It is a sequence diagram of the service load distribution method according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Client terminal 101 ... Central processing part 102 ... Communication part 103 ... Message storage part 104 ... Request generation part 105 ... Operation mode determination part 106 ... State monitoring part 107 ... Operation mode recording part 200 ... Service provision apparatus 200 ... External service apparatus DESCRIPTION OF SYMBOLS 201 ... Central processing part 202 ... Communication part 203 ... Message storage part 204 ... Request response part 205 ... Operation mode determination part 206 ... State monitoring part 207 ... Operation mode recording part 300 ... Relay apparatus 301 ... Central processing part 302 ... Communication part 303 ... Message storage unit 304 ... Request proxy processing unit 305 ... Operation mode determination unit 306 ... Status monitoring unit 307 ... Operation mode recording unit

Claims (2)

A relay device that relays communication between a client terminal and a service providing apparatus that provides data or a function to the client terminal,
A message storage unit for storing a service request message for requesting a service to the service providing apparatus received from the client terminal;
A request agent processing unit that transmits the service request message to the service providing apparatus after reducing the load on the service providing apparatus;
A state monitoring unit for monitoring the state of the message storage unit;
An operation mode determination unit for determining an operation mode including a transmission destination in the client terminal of the service request message,
The operation mode determination unit determines the operation mode by determining the load of the service providing device based on the amount of the service request message stored in the message storage unit obtained by the state monitoring unit. And
The load reduction means that when the amount of the service request message received from the same client terminal exceeds a predetermined threshold, the processing priority for the service request message received from the same client terminal is Relay equipment characterized by lowering . The operation mode determination unit, when the amount of the service request message stored in the message storage unit is smaller than a predetermined threshold, sets the transmission destination included in the operation mode as the relay device. The relay device according to claim 1 .

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