KR101160382B1 - Session management system and method of controlling the same - Google Patents

Abstract

A session management system is provided that enables efficient use of network resources when a communication address is assigned to a network interface. The system manages sessions between a server and a client having a plurality of addresses. When an application provided to a client requires communication with a server, it is determined whether an address different from the address specified by the application has already been established between the client and the server. If it is determined that the session is already established, then the application uses the already established session to communicate with the server. If it is determined that the session is not established, then the application uses the newly established session to communicate with the server.

Server, Client, Session, Application, and Identification Information

Description

Session management system and control method {SESSION MANAGEMENT SYSTEM AND METHOD OF CONTROLLING THE SAME}

The present invention relates to a session management technique that represents a logical connection relationship in communication between applications.

Background Art Conventionally, various information processing apparatuses including PCs (personal computers), printers, and MFPs (Multi-Function Peripherals) are known as communication apparatuses used in a network (intranet such as a LAN or the Internet).

Currently, IP protocols are widely used in information processing apparatuses connected to a network. In this IP protocol, connection apparatuses are identified from each other by assigning an IP address (communication address) unique to each information processing apparatus.

Under the conventional IP protocol (IPv4 (IP version 4)), generally, one IP address has been assigned to one network interface as an IP address for identifying one information processing device from another information processing device.

On the other hand, under IPv6 (IP version 6), which has been widespread in recent years, when connected to a router, the terminal device communicates with the router and automatically acquires an IP address. In addition, in order to enable communication even when no router exists, an IPv6 address is assigned to each network interface in addition to the IP address.

In addition, there may be a Dynamic Host Configuration Protocol (DHCP) server. As described above, in an environment using IPv6, a plurality of IPv6 addresses are assigned to one network interface. As a result, in the information processing apparatus supporting IPv6, an IPv4 address and a plurality of IPv6 addresses can be assigned to one network interface.

In addition, when the information processing apparatuses communicate with each other, a set of network sockets, that is, an IP address and a port number, of a sender and a sender is created. This network socket creation process consumes memory space and CPU processing time which are network resources of each information processing apparatus.

Therefore, the server which connects and communicates with many information processing apparatuses consumes the network resource corresponding to the quantity of connections. On the other hand, since the amount of network resources available to an information processing apparatus such as a printer and an MFP is smaller than the amount of network resources available to a server, the number of communication devices that can be connected to the information processing apparatus at the same time is small.

In addition, in the case of TCP communication in which the time until the network socket is opened regardless of the data size is set longer than in the case of UDP communication, the number of concurrent connections that can be established per unit time is smaller than in the case of UDP communication. Because of this limitation, the server generates a connection error when a request from a client floods.

In order to solve this problem, in a client / server system, there is a proposal to save network resources when a plurality of applications provided to a client establishes and communicates with multiple servers assigned to the same address. (See Japanese Patent Application Laid-Open No. 10-177548).

However, in Japanese Patent Laid-Open No. 10-177548, when a plurality of IPv6 addresses are allocated to one network interface, even in communication with the same server, network resources for establishing a connection to the plurality of server addresses are saved. Can not.

The present invention provides a session management system and a control method thereof.

In a first aspect of the present invention, there is provided a session management system for managing sessions between a server having a plurality of addresses and a client, wherein the application provided to the client requests communication with the server. A determination unit configured to determine whether a session using a different address is already established between the client and the server, and the server using the session in which the application has already been established if it is determined that the session is already established. And a control unit configured to cause the application to communicate with the server using the newly established session when it is determined that the session is not established.

In a second aspect of the present invention, there is provided a method for controlling a session management system for managing sessions between a server and a client having a plurality of addresses, wherein the application provided to the client requests communication with the server. Determining whether a session using an address different from the address specified by the client is already established between the client and the server, and if it is determined that the session is already established, the application uses the already established session. Communicating with a server, and if it is determined that the session is not established, causing the application to communicate with the server using a newly established session.

According to the present invention, when a plurality of communication addresses are assigned to one network interface, network resources can be efficiently used or saved.

Other features of the present invention will become more apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

The accompanying drawings, which are incorporated in and constitute a part of the specification, together with the description serve to explain embodiments of the invention and to explain the principles of the invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, which illustrate embodiments of the present invention. Note that the present invention is not limited to the first to seventh embodiments described below. In addition, not all combinations of the feature items according to the first to seventh embodiments are essential to the present invention.

1 is a diagram showing the software configuration of a client / server system to which the session management system according to the first to third and seventh embodiments of the present invention is applied.

As shown in FIG. 1, the client PC (client terminal) 100 and the server PC 105 are interconnected via a network 106. In the first to third and seventh embodiments, the network 106 is assumed to be implemented by LAN or WAN, but it is also possible to use a different type of network than the LAN and WAN. In addition, the client PC 100 and the server PC 105 can be connected not by the network 106 but by an interface (cable) according to the standard such as IEEE 1394 or 1284.

In addition, in the first to seventh embodiments, the client PC 100 is assumed to be implemented by a normal PC (Personal Computer), but a printer or a multifunction peripheral (MFP) may be used instead of the PC. That is, the feature items according to the first to seventh embodiments can be applied to various devices such as portable information terminals, scanners, and facsimile devices having a network communication function.

The client PC 100 includes client applications 101 and 101a. However, even when the client PC 100 includes only one or three or more client applications, the first embodiment can be applied (this also applies to the second to seventh embodiments).

The client applications 101 and 101a communicate using the stub objects 102 and 102a, respectively. In this case, the actual communication process is performed by the communication process 103 between client processes.

The client interprocess communication unit 103 communicates with the server PC 105 using the communication library 104a of the operating system. The communication performed using the communication library 104a includes not only socket (IP address + port number) communication but also communication by RPC (Remote Procedure call), LPC (Local Procedure Call), Web service, and the like.

In the server PC 105, the server application 108 is operating. The server application 108 communicates using the server process communication unit 107. The server inter-process communication unit 107 communicates with the client PC 100 via the network 106 using the communication library 104b. In addition, one or more server applications 108 may be provided.

As described above, the actual communication processing between the client application 101 or 101a and the server application 108 is performed by the inter-client communication unit 103 and the inter-server communication unit 107. This actual communication process also includes session management processing according to a series of requests and responses. In other words, the session management process peculiar to the present invention is performed by the client interprocess communication unit 103 and the server interprocess communication unit 107.

In addition, in the client / server system of FIG. 1, although the client and the server are each implemented by a personal computer (PC), the client / server system includes a first network device configured of another network device, an information processing apparatus having a communication function, a peripheral device, and the like. The third embodiment can also be applied. In this case, a CPU provided to an operation of a program performed by the client PC 100 or the server PC 105 of the client / server system of FIG. 1 may be provided to a network device other than the client PC 100 and the server PC 105, or the like. You just need to configure your system to run using ROM or RAM.

The client PC 100 and the server PC 105 are realized by a computer 2000 having hardware configured as shown in FIG. 2.

The computer 2000 includes a main body control unit 200, a keyboard 209 as a peripheral device, a display device 210, and an external memory 211. The main body control unit 200 includes a CPU 201, a RAM 202, a ROM 203, a keyboard control unit 205, a display control unit 206, a disk control unit 207, and a network control unit 208.

The CPU 201 performs overall control of the devices connected to the system bus 204. The CPU 201 provides document processing and service provision based on an application (document processing program, service providing program, etc.) stored in the program ROM 203b of the ROM 203 or the external memory (HD) 2101. Various processing including processing is performed.

In addition, the document processing program performs document processing for processing a document including a mixture of figures, images, characters, and tables (including a spreadsheet). In addition, the external memory 211 stores not only an application for document processing but also an application for acquiring and processing various information such as image information, music information, sound information, and the like in still and moving images. You may also

The CPU 201 performs rasterization processing of an outline font in the display RAM set in the RAM 202, for example, and displays the character string on the display device 210 through the display control unit 206. In addition, the CPU 201 opens the related one among various windows and executes the related one among various data processing or service providing processing based on a command designated by a mouse cursor (not shown) or the like on the display device 210. When the user uses the client application 101 or 101a or the server application 108, the user can open a setting window for the application and make various settings on this window. The display device 210 can be realized by any of a CRT display, a liquid crystal display, a plasma display, and the like.

The RAM 202 is used as a main memory of the CPU 201, a work area, and the like. The ROM 203 is comprised by the font ROM 203a, the program ROM 203b, and the data ROM 203c.

The font ROM 203a and the external memory 211 store font data and the like used in document processing and service providing processing. The program ROM 203b and the external memory 211 store an operating system, which is a control program of the CPU 201, and similar other programs. The data ROM 203c and the external memory 211 store various data (including a program) used for document processing or service providing processing. Programs stored in the external memory 211 are loaded into the RAM 202 at the time of execution.

The keyboard control unit 205 controls input data and commands from the keyboard 209 and the pointing device (not shown). The display control unit 206 controls the display operation of the display device 210. The disk control unit 207 controls access to the external memory 211.

The network control unit 208 is connected to the network 106 via the bidirectional interface 212. This network control unit 208 performs connection or disconnection processing of a network and a session based on the client inter-process communication unit 103 or 107 and the communication library 104a or 104b shown in FIG. 1, respectively.

The keyboard 209 is provided with keys for inputting various data and commands. The display device 210 displays various types of information according to document processing, service providing processing, and the like. The external memory 211 is implemented by a hard disk HD, a flexible disk FD, or the like. This external memory 211 stores a boot program, various applications, font data, user files, edit files, and the like. In addition, the external memory 211 is an application, as a application, a control program that executes each of the processes described later with reference to the flowcharts and sequence diagrams shown in FIGS. I also remember.

3 is a block diagram showing the detailed software configuration of the server interprocess communication unit 107 of the server PC 105.

The interprocess communication unit 107 has a server interprocess communication control unit 301 and a server identifier return unit 302, and responds to a communication request from the client PC 100. That is, the server inter-process communication control unit 301 returns the server identifier 504 (see FIG. 5) by the server identifier reply unit 302 in response to a request from the client PC 100, or the server application ( The data created by 108 may be returned to the client PC 100. Details of the reply processing of this server identifier 504 will be described later.

4 is a block diagram showing the detailed software configuration of the client interprocess communication unit 103 of the client PC 100. In FIG. 4, description of the stub objects 102 and 102a demonstrated with reference to FIG. 1 is abbreviate | omitted (applies also to FIG. 15 and FIG. 24). As illustrated in FIG. 4, the inter-process communication unit 103 includes an inter-process communication control unit 401, a server identifier acquisition unit 402, a session management unit 403, a DB (database) management unit 405, and session disconnection. A management unit 407 and a session reconnection manager 409. The inter-process communication unit 103 further includes a session determination unit 404, a session management information DB 406, and a connection reference count storage unit 408.

The client interprocess communication unit 103 controls the communication operation performed between the client applications 101 and 101a and the server application 108 by managing the session under the control of the interprocess communication control unit 401. The server identifier acquisition unit 402 acquires the server identifier 504 returned by the server identifier reply unit 302 of the server PC 105. The server identifier 504 is used to select the session used.

The session management unit 403 performs a process of creating session information or determines whether to delete a part of the management information stored in the session management information DB 406. The session determination unit 404 determines whether an existing session for a destination address different from the destination address specified at the connection request includes the same server identified by the server identifier 504 (server identification information). In other words, the session determination unit 404 determines whether to communicate by establishing a new session or by using an existing session.

The DB manager 405 controls access to the session management information DB 406 (see FIG. 5). The session truncation management unit 407 performs session management on the basis of the connection reference count. The connection reference count storage unit 408 stores the connection reference count. This connection reference count is used to determine the timing to close the session. The session reconnection management unit 409 controls to continue the communication currently being performed in the session in which the communication error has occurred, by reconnecting at another address (socket).

5 is a diagram illustrating session management information registered in the session management information DB 406. The application identifier 501 is an identifier (instance handle) that identifies the client application 101 or 101a that generated the connection request.

The request address information 502 indicates a destination address designated by the client application 101 or 101a when the client application 101 or 101a requests a connection. This destination address includes an IP address 502a and a port number 502b. The communication address information 503 indicates the address of the connection destination (server PC 105) of the session selected for actual communication after determining the availability of an existing session based on the designated destination address. This communication address includes an IP address 503a and a port number 503b.

The communication address information 503 is, in addition to the IP address 503a and the port number 503b, an endpoint as replacement information of the port number 503b, or replacement information of the IP address 503a and the port number 503b. It may also include channel information as.

The server identifier 504 (instance handle) is obtained by requesting the server PC 105 based on the destination address (IP address, port number, etc.) of the client application 101 or 101a of the connection request source. The session number 505 is different for each session established based on a series of requests and responses (data transmission) exchanged between the client application 101 or 101a of the connection request source and the server application 108 as the connection destination. An identification number assigned to identify from one section.

Next, session management processing performed by the server inter-process communication unit 107 of the server PC 105 will be described based on the flowchart of FIG. 6.

When the server interprocess communication control unit 301 of the server process intercommunication unit 107 receives a connection request from the client PC 100, the server identifier reply unit 302 creates a server identifier 504 (step S601). ). As this server identifier 504, a universally unique identifier (UUID) or the like that enables unique identification is used. From now on, the server interprocess communication unit 107 of the server PC 105 returns the same server identifier 504 regardless of the IP address and the port number of the socket that received the packet.

Next, the inter-server communication control unit 301 receives the packet from the client PC 100 via the communication library 104b (step S602). Then, the inter-process communication control unit 301 determines whether the packet received from the client PC 100 is in accordance with the acquisition request of the server identifier 504 (step S603).

If the packet is in accordance with the acquisition request of the server identifier 504, the inter-process communication control unit 301 determines the server identifier 504 generated by the server identifier reply unit 302 in step S601. Reply to the client PC requesting This process is performed in step S604. In this case, the server identifier 504 is returned as a reply packet to the client PC 100 via the network 106 using the communication library 104b.

Next, the inter-server communication control unit 301 determines whether or not a service end instruction has been received (step S608). If no service end instruction has been received, the process returns to step S602 to continue service provision.

On the other hand, when the received packet does not comply with the acquisition request of the server identifier 504, the inter-process communication control unit 301 determines whether the received packet is a request for transmission of new data (step S605).

If the received packet requests the transmission of new data, the server inter-process communication control unit 301 creates a socket for transmitting data to the client PC 100 (step S606). This socket creation process is performed through the approval process based on the TCP protocol as a communication protocol using the communication library 104b.

After the processing of step S606, the processing proceeds to step S607. On the other hand, if the received packet does not require transmission of new data, the process skips the socket creation process in step S606 and proceeds to step S607.

In step S607, the inter-server communication control unit 301 causes the server application 108 to execute service processing for the packet received in step S602. That is, the inter-server communication control unit 301 transmits the received data from the client PC 100 to the server application 108, and the server application 108 returns the reply data in response to a request from the client PC 100. Write. In addition, the server application 108 transmits the created reply data to the inter-server communication control unit 301. The inter-process communication control unit 301 uses the communication library 104b to return the reply data to the client PC 100 via the network 106. Then, the server process communication control unit 301 performs step S608.

Next, the session management processing performed by the client interprocess communication unit 103 of the client PC 100 will be described based on the flowchart of FIG. 7. In addition, the process of this flowchart is actually or directly performed by the inter-process communication control part 401 (FIGS. 10A, 10B, 12A, 12B, 18, 20, 21, 26A, and 26B). Equally).

The interprocess communication control unit 401 of the client interprocess communication unit 103 receives a connection request for the server application 108 of the server PC 105 (step S701). This connection request is made from the client application 101 or 101a.

Next, the inter-process communication control unit 401 acquires, via the server identifier acquisition unit 402, the server identifier 504 returned from the server PC 105 in response to the connection request sent to the destination address ( Step S702). That is, the server identifier acquisition unit 402 acquires the server identifier 504 from the server PC 105 via the network 106 using the communication library 104a under the control of the inter-process communication control unit 401. Send request information. The server identifier acquisition unit 402 also acquires the server identifier 504 transmitted from the server PC 105 under the control of the interprocess communication control unit 401.

Next, the session managing unit 403 determines, under the control of the inter-process communication control unit 401, whether there is an existing session associated with the same server identifier 504 as the server identifier 504 acquired in step S702 (step S703). ).

In this case, the session management unit 403 causes the DB management unit 405 to acquire session management information from the session management information DB 406. Based on the session management information, the session manager 403 uses the same server identifier 504 as the server identifier 504 acquired as a response to this connection request during the existing session currently in communication using another address. Determine if there is an existing session involved. This determination processing is actually performed by the session determination unit 404.

Referring to the example of session management information in Fig. 5, in the communication indicated by management numbers 1 and 2, a connection request for connection with different addresses from the client application 101 or 101a is made. The addresses are different, but these communications are executed with the same server PC 105. Therefore, since it is not efficient to create a plurality of sessions in order to communicate with the same server PC 105, the communication indicated by the management numbers 1 and 2 is executed here using one session.

That is, for example, when attempting to start the communication indicated by the management number 2 while the communication indicated by the management number 1 has been started, the inter-process communication control unit 401 does not create a new session. Instead, the inter-process communication control unit 401 selects the existing session indicated by the management number 1 as the session for data transmission of the communication indicated by the management number 2 (step S707). The process then proceeds to step S708, which will be described later.

If you select an existing session, you do not need to disconnect the session if the session is based on UDP protocol (non-connection protocol) communication, but if the session is based on TCP protocol (connection protocol) communication, It is necessary to cut. This also applies to step S707 of Figs. 10A to 12B.

If there is no existing session associated with the server identifier 504 that is the same as the server identifier 504 obtained this time, the session manager 403 creates a new socket to establish a new session (step S704). In this case, the session managing unit 403 uses the communication library 104a to create a new socket based on the destination address specified by the client application 101 or 101a.

Next, the session manager 403 registers the information of the new session including the new socket in the session management information DB 406 by the DB manager 405 (step S705). Then, the interprocess communication control unit 401 selects a new session as the session for data transmission this time based on the destination address specified by the client application 101 or 101a (step S706).

Next, the inter-process communication control unit 401 transmits the data from the client application 101 or 101a to the server application 108 by the session selected in step S706 or step S707 (step S708).

In addition, when a new session is selected as the session for data transmission, it should be noted that in steps S704 to S708, the destination address specified by the client application 101 or 101a and the communication address to actually communicate with each other are the same. The communication processing by the new session as described above is the same as that performed by the RPC (Remote Procedure Call) which is a conventional interprocess communication technology.

On the other hand, when an existing session is selected, the destination address specified by the client application 101 or 101a is different from the communication address that actually communicates. However, in response to the current connection request, the server identifier 504 acquired in step S702 and the server identifier 504 of the existing session are identical. Therefore, the inter-process communication unit 103 of the client PC 100 can communicate with the inter-process communication unit 107 of the same server PC 105.

For this reason, in the present embodiment, in the processing of step S707, an existing session associated with the same server identifier 504 as the server identifier 504 obtained as a response to the current connection request is selected as the session for data communication. . In this case, a socket (session) for data communication is not newly created based on the destination address specified by the client application 101 or 101a.

In this way, by communicating with an existing session without creating a new socket, the client PC 100 and the server PC 105 can reduce the number of communication sockets, thereby saving network resources. ．

Next, the inter-process communication control unit 401 determines whether a close request from the client application 101 or 101a or a disconnect request from the communication library 104a has been received (step S709). If the close request or the disconnect request has not been received, the process returns to step S701 to continue the processing of steps S701 to S709.

On the other hand, when either a close request or a disconnect request is received, the session manager 403 performs a close process by the communication library 104a to close the session or socket of an address associated with the close request. (Step S710). Then, the session manager 403 causes the DB manager 405 to update the session manager information in the session manager information DB 406 based on the processing result in step S710 (step S711).

Next, the processing example shown in FIG. 6 and FIG. 7 is demonstrated based on the sequence diagram shown in FIG. 8A-9B. 8A and 8B show a processing sequence when the existing session does not exist.

In the process P801 of FIG. 8A, the server inter-process communication unit 107 starts a Listen process for receiving packets from the client PC 100 when the server application 108 starts a service. In addition, in step S601, the server inter-process communication unit 107 performs the process of generating the UUID to be used as the server identifier 504.

In addition, in the process P801, the server inter-process communication unit 107 creates a reception socket for reception at the IPv4 address [10.0.0.10] and port number [1025] in the Listen process. Similarly, the server interprocess communication unit 107 also creates a reception socket for the IPv6 address [2001 :: 10] and the port number [1025].

In the process P802, the client application 101 or 101a requests the client inter-process communication unit 103 to connect to the IPv4 address [10.0.0.10] and port number [1025]. In process P803, the client inter-process communication unit 103 receives this connection request and performs the acquisition processing of the server identifier 504 in step S702. In process P804, the server inter-process communication unit 107 performs the reply processing of the server identifier 504 in step S604.

Further, although the negotiations of the processes P803 and P804 are somewhat inferior to the TCP communication, the communication is preferably performed using UDP communication that enables high-speed communication. However, you may negotiate using TCP communication. This also applies to the negotiation in FIGS. 9A, 9B, 11A, 11B, 13A, and 13B described later.

In process P805, the client inter-process communication unit 103 performs the processing of step S703, that is, determining whether there is an existing session associated with the same server identifier 504 based on the session management information. In the sequence example of Figs. 8A and 8B, it is determined that there is no existing session in this process. For this reason, in process P806, the process of creating a new session in steps S704 to S706 is performed.

In process P807, the server interprocess communication unit 107 performs a TCP-based accept process to create a socket for a new session. In process P808, the client inter-process communication unit 103 returns the result of the connection process performed in response to the connection request in process P802 to the client application 101 or 101a.

In process P809, the process of step S708 is performed. That is, the inter-process communication unit 103 performs data transmission processing for transmitting data to the IPv4 address [10.0.0.10] and port number [1025] designated by the client application 101 or 101a.

Following this transmission process, the inter-client communication unit 103 transfers the data toward the server PC 105 in the processes P810-1 to P810-n in accordance with the amount of data from the client application 101 or 101a. do.

In process P811, the server inter-process communication unit 107 receives data from the client application 101 or 101a and transmits data to the server application 108. In process P812, the client inter-process communication unit 103 notifies the client application 101 or 101a of the data transfer result when the data transfer is completed.

In addition, the actual data communication in the processes P809 to P810-n is preferably performed using highly reliable TCP communication, although the communication speed is lower than that of the UPD communication. However, UPD communication may be used for actual data communication. This also applies to the negotiation in FIGS. 9A, 9B, 11A, 11B, 13A, and 13B.

In process P813, the client application 101 or 101a issues a disconnect (close) request of the IPv4 address [10.0.0.10] and port number [1025] to the client interprocess communication unit 103. In response to this disconnect request, the client interprocess communication unit 103 performs the disconnection process of step S710.

In process P814, the server inter-process communication unit 107 receives the connection close instruction of the IPv4 address [10.0.0.10] and the port number [1025] from the client inter-process communication unit 103, and performs a session disconnection process. In process P815, the client inter-process communication unit 103 performs the process of step S711, and notifies the client application 101 or 101a of the disconnection of the session.

9A and 9B show a processing sequence when there is an existing session executed by the session management system according to the first embodiment. In process P901 of FIG. 9, when the server application 108 starts a service, the server interprocess communication unit 107 starts a Listen process in order to receive a packet from the client, and in step S601 a server identifier (UUID). Generate 504.

In the process P901, the server inter-process communication unit 107 creates a reception socket in order to perform reception processing at the IPv4 address [10.0.0.10] and port number [1025] by Listen processing. Similarly, the server interprocess communication unit 107 also creates a reception socket for the IPv6 address [2001 :: 10] and the port number [1025].

In process P902, the client application 101 or 101a issues a connection request to the IPv4 address [10.0.0.10] and port number [1025] to the client inter-process communication unit 103. In process P903, the client inter-process communication unit 103 receives this connection request, and performs acquisition processing of the server identifier 504 in step S702. In process P904, the server inter-process communication unit 107 performs reply processing of the server identifier 504 as a response in step S604.

In process P905, the client inter-process communication unit 103 determines whether or not there is an existing session associated with the same server identifier 504 obtained in response to the connection request, based on the process of step S703, that is, session management information. The process is performed. In the sequence example of FIG. 9A and FIG. 9B, it is determined that there is no existing session in the determination process of process P905. For this reason, in process P906, the creation process of the new session of step S706 is performed from step S704.

In process P907, the server inter-process communication unit 107 creates a socket for the new session by TCP-based accept processing. In process P908, the client inter-process communication unit 103 returns the result of the connection process performed in response to the connection request in process P802 to the client application 101 or 101a.

In process P909, the process of step S708 is performed. That is, the inter-process communication unit 103 performs data transmission processing for transmitting data to the IPv4 address [10.0.0.10] and port number [1025] designated by the client application 101 or 101a. Following this transmission process, the client inter-process communication unit 103 sends data to the server PC 105 in the processes P910-1 to P910-n in accordance with the amount of data from the client application 101 or 101a. send.

In process P911, the server inter-process communication unit 107 transmits the data received from the client application 101 or 101a to the server application 108. In the process P912, when the data transfer is completed, the client inter-process communication unit 103 notifies the client application 101 or 101a of the completion of the data transfer.

In step P913, the client application 101 or 101a issues a connection request to the client inter-process communication unit 103 for connection to the IPv6 address [2001 :: 10] and port number [1025]. In process P914, the server inter-process communication unit 107 receives this connection request from the client inter-process communication unit 103, and performs a reply process of the server identifier 504 as a response in step S604. In this case, the client application 101 or 101a acquires the server identifier 504 associated with the IPv6 address [2001 :: 10] and the port number [1025].

In process P915, the client inter-process communication unit 103 determines whether there is an existing session associated with the same server identifier 504 obtained in response to the connection request, based on the process of step S703, that is, session management information. A process is performed.

In the sequence example of Figs. 9A and 9B, the same identifier as the server identifier "10" obtained by the IPv6 address [2001 :: 10] and the port number [1025] is the IPv4 address [10.0.0.10], which has already established a session, Reply from port number [1025]. Accordingly, the client interprocess communication unit 103 determines that there is an existing session associated with the same server identifier 504 obtained as a response to the connection request, and that the IPv6 address [2001 :: 10], port number [1025] Does not establish a session.

Thereafter, the client inter-process communication unit 103 transmits data related to the initial IPv6 address [2001 :: 10], the port number [1025], to the IPv4 address [10.0.0.10] and the port number [1025].

That is, in process P916, the client application 101 or 101a requests the client inter-process communication unit 103 to transmit data to the IPv6 address [2001 :: 10] and the port number [1025].

In response to this data transfer request, the client inter-process communication unit 103, in process P917, specifies the IPv6 address [2001 :: 10], port number [1025] specified by the client application 101 or 101a for data transfer. Data associated with a request for an IPv4 address [10.0.0.10], a port number [1025], which is a different address from [].

In the process P918, the client inter-process communication unit 103 repeats the necessary transfer process using the existing session until the data transfer is completed, in accordance with the amount of data from the client application 101 or 101a.

In process P919, the server inter-process communication unit 107 transmits the data received from the client application 101 or 101a to the server application 108. In process P920, the client application 101 or 101a instructs the client interprocess communication unit 103 to disconnect (close) the IPv4 address [10.0.0.10] and the port number [1025]. In response to this disconnect instruction, the client inter-process communication unit 103 performs the disconnect process of step S710.

In process P921, the server inter-process communication unit 107 receives a disconnect instruction from the client inter-process communication unit 103, and performs a session disconnection process for the IPv4 address [10.0.0.10] and the port number [1025].

As described above, according to the first embodiment, an existing session established for an address different from the destination address specified by the client application 101 or 10 1a but associated with the same server identifier 504 is used as the session for data communication. I use it.

As a result, network resources such as sockets can be efficiently used or reduced. The second and third embodiments described below can also provide the same effects.

In the first embodiment, for example, when the client application 101 disconnects the first session, the client application 101a using the first session as an existing session can no longer perform data communication.

However, for example, in response to a connection request or a close request from the client application 101 or 101a, the client inter-process communication unit 103 increments only the reference counter of the session and actually the session when the reference counter becomes zero. If the client application 101 and 101a share the session, it is possible to prevent the problem from occurring due to the disconnection of the session.

Therefore, in the second embodiment, even when data transmission is performed in an existing session established at an address different from the destination address designated by one of the client applications 101 and 101a, communication by the existing session is performed by the applications 101 and 101a. ) Is not inadvertently cut by the cutting instruction from the other.

10A and 10B are flowcharts showing session management processing performed by the client process interprocess communication unit 103 of the session management system according to the second embodiment of the present invention. In addition, since the configuration of the session management system according to the second embodiment is the same as that of the session management system according to the first embodiment, the description thereof is omitted (the same applies to the third embodiment). In addition, in FIG. 10B, since the process of step S701-S711 is the same as the process of step S701-S711 in the flowchart of FIG. 7, the description will be given only as needed.

Referring to FIG. 10B, in step S1001, the inter-process communication control unit 401 increments the count of the close reference counter of the session selected in step S706 or step S707 by one. This close reference counter corresponds to the reference counter or the connection reference counter shown in Fig. 4, and counts the number of cut requests. The session disconnection management unit 407 of the client PC 100 stores the count of the closed reference counter of each session in the connection reference count storage unit 408, and determines whether to disconnect the associated session based on each count.

Next, the inter-process communication control unit 401 transmits the data from the client applications 101 and 101a to the server application 108 by the session selected in step S706 or step S707 (step 708). In addition, in step S707, when an existing session established at an address different from the destination address is selected, only the count of the close reference counter of the existing session for data transmission is incremented by one, and a new session is not created.

Next, the inter-process communication control unit 401 determines whether a close request from the client application 101 or 101a or a disconnect request from the communication library 104a has been received (step S709). If no close request or cut request has been received, the process returns to step S701 to continue the processing of steps S701 to S709.

On the other hand, when a close request or a disconnect request is received, the inter-process communication control unit 401 causes the session management unit 403 to inform the session disconnect management unit 407 of the session for the address associated with the close request or disconnect request. It is made to request to perform the closing process to close (step S1002). In this case, the session truncation management unit 407 decreases the close reference count of the corresponding session in the connection reference count storage unit 408 by one (step S1002).

Next, the inter-process communication control unit 401 determines whether or not it becomes 0 after the count of the close reference counter is decreased by one (step S1003). If the count does not become zero, the process returns to step S701.

On the other hand, when the count of the close reference counter is 0, the inter-process communication control unit 401 closes the session or socket to which the session management unit 403 and the communication library 104a close the session or socket associated with the close request. (Step S710). Then, the session manager 403 causes the DB manager 405 to update the session manager information in the session manager information DB 406 based on the processing result in step S710 (step S711).

Next, an example of the session management processing of FIGS. 10A and 10B will be described with reference to the sequence diagrams of FIGS. 11A and 11B. 11A and 11B show a case where data transmission is performed by an existing session established at an address different from the destination address. In the following sequence, a case where the existing session is appropriately disconnected is shown so that communication by the existing session is not inadvertently disabled.

That is, in the process P1101, the client inter-process communication unit 103 establishes a new session in step S706, and therefore performs a process of incrementing the count of the close reference counter of step S1001 by one. This close reference counter functions as a counter that counts the number of connection requests and the number of disconnect requests for each destination address at which a connection request is made.

In process P1102, an existing session established at an address different from the destination address is used in step S707. Accordingly, the client inter-process communication unit 103 does not create a new session, but performs a process of incrementing the count of the closed reference counter by step S1001 by one.

At this time, the count of the close reference counter stored in the connection reference count storage unit 408 becomes "2" for the server PC 105 to which the server identifier 504 is assigned "10". The actual communication address is set to [10.0.0.10] and port number [1025] of the IPv4 address.

As the destination address, in addition to the IPv4 address [10.0.0.10] and the port number [1025], an IPv6 address [2001 :: 10] and a port number [1025] exist, and these addresses exist in the connected state, respectively.

In process P1103, the client inter-process communication unit 103 performs the closing process for the IPv4 address [10.0.0.10] and port number [1025]. At this time, the process of step S1002 is performed so that the count of the closed reference counter stored in the connection reference count storage unit 408 in association with the session is reduced by one.

When this closing process is performed, the count of the close reference counter stored in the connection reference count storage unit 408 becomes 1 for the server PC 105 to which the server identifier is assigned "10". In addition, the actual communication address remains as an IPv4 address [10.0.0.10] and a port number [1025]. As the destination address, an IPv6 address [2001 :: 10] and a port number [1025] exist, and this address is in a connected state.

In process P1104, the client inter-process communication unit 103 performs the closing process for the IPv6 address [2001 :: 10] and the port number [1025]. At this time, the process of step S1002 is performed, and the count of the closed reference counter stored in the connection reference count storage unit 408 is decremented by one.

When this closing process is performed, the counter of the close reference counter stored in the connection reference count storage unit 408 becomes zero with respect to the server PC 105 to which the server identifier "10" has been assigned. Since the count of the close reference counter has become 0, the client inter-process communication unit 103 performs the session closing process of step S710 in process P1105. In this example, the client application 101 or 101a instructs the client inter-process communication unit 103 to cut off the IPv6 address [2001 :: 10] and the port number [1025].

However, the inter-client communication unit 103 receives a disconnect instruction from the client application 101 or 101a, and performs a truncation process for the IPv4 address [10.0.0.10] and the port number [1025] which are actual communication addresses. This cutting process is performed in step S710 and step S711.

Next, in process P1106, the server inter-process communication unit 107 performs the following processing: The server inter-process communication unit 107 is an IPv4 address [10.0.0.10], port number from the client inter-process communication unit 103. In response to the disconnect instruction for [1025], a truncation process is performed to disconnect the associated session using the communication library 104b.

This means the following: That is, when communicating in an existing session established at an address different from the destination address designated by one application, suppose that a disconnect instruction for disconnecting the existing session has been issued from another application. In this case, the existing session is not disconnected.

In other words, according to the second embodiment, even when data transmission is performed in an existing session established at an address different from the destination address, communication by the existing session is not inadvertently disconnected by a disconnect instruction from another application.

For example, when the client application 101 disconnects the session that the client application 101a uses for data communication as an existing session, the client application 101a can no longer perform data communication.

However, for example, the client interprocess communication unit 103 responds to each connection request and each close request from the client application 101 or 101a to the same server, and then to an existing session with the server. By increasing or decreasing the count of the provided reference counter and configuring the session to actually disconnect only when the reference counter becomes zero, even if the session is shared by the client application 101 or 101a, the above problem occurs when the session is disconnected. Can be prevented.

According to the first embodiment, even when the client applications 101 and 101a respectively designate different destination addresses, the same session can be used. At this time, the communication address actually used for communication is set to the first destination address used to create the session.

However, if a communication failure occurs in the communication using the first destination address used to create the session, even when communication at the second destination address is possible, the client application that originally specified the second destination address may select the first destination address. You can no longer communicate through the session you created.

According to the third embodiment, even when such a communication failure occurs in the session, when there is a destination address that can be communicated with, the communication in the session is enabled.

12A and 12B are flowcharts of session management processing performed by the inter-process communication unit 401 of the client PC 100 of the session management system according to the third embodiment of the present invention. 12A and 12B, the steps S701 to S711 are the same as the steps S701 to S711 in the flowchart of Fig. 7, and therefore only the steps specific to the third embodiment will be described instead of all the steps.

12B, the inter-process communication control unit 401 transmits data from the client application 101 or 101a to the server application 108 by the session selected in step S706 or step S707 (step S708).

Next, the inter-process communication control unit 401 determines whether or not the data transfer is successful (step S1201). If the data transfer is successful, the inter-process communication control unit 401 determines whether a close request from the client application 101 or 101a or a disconnect request from the communication library 104a has been received (step S709).

On the other hand, when the data transfer fails, the inter-process communication control unit 401 causes the session management unit 403 to determine the presence or absence of another destination address associated with the same server identifier 504 (step S1202).

As a result, when there is no other destination address associated with the same server identifier 504, the inter-process communication control unit 401 performs an error process of data transfer (step S1206), and the process proceeds to step S709.

On the other hand, when there is another destination address associated with the same server identifier 504, the inter-process communication control unit 401 causes the session reconnection management unit 409 to reconnect to another destination address associated with the same server identifier 504. To establish a session (S1203). In this case, a new socket is created using a destination address different from the communication address that failed to communicate.

Next, the inter-process communication control unit 401 registers the reconnection session with the session management information DB 406 by the DB management unit 405 (step S1204). The interprocess communication control unit 401 then selects the reconnection session as the session for data transmission (step S1205). The process then returns to step S708 to perform data transfer using the reconnection session.

13A and 13B are sequence diagrams showing session management processing performed between the server PC 105 and the client PC in the third embodiment of the present invention. This sequence enables session reconnection processing when data transmission is performed using an existing session established at an address different from the destination address. In addition, in FIG. 13A and 13B, the description about the process similar to the process sequence of FIG. 9A and FIG. 9B is abbreviate | omitted.

In process P1301, the inter-process communication control unit 401 performs a confirmation process of data transmission success in step S1201. At this point in time, the count of the close reference counter stored in the connection reference count storage unit 408 becomes two for the server PC 105 to which the server identifier 504 is assigned "10". The actual communication address is set to an IPv4 address [10.0.0.10] and a port number [1025].

At this point, two destination addresses, an IPv4 address [10.0.0.10], a port number [1025], and an IPv6 address [2001 :: 10] and a port number [1025], respectively exist in the connected state.

In this sequence example, in process P1301, the inter-process communication control unit 401 determines that data transfer using the IPv4 address [10.0.0.10] and the port number [1025], which are actual communication addresses, has failed.

In process P1302, the inter-process communication control unit 401 causes the session reconnection management unit 409 to perform a process of determining whether there is another destination address associated with the same server identifier 504 in step S1202.

In this sequence example, the session reconnection manager 409 determines that there is another destination address associated with the same server identifier 504, and establishes a reconnection session. (Process P1303). The session reconnection manager 409 causes the DB manager 405 to register the reconnection session with the session management information DB 406.

At this point in time, the count of the close reference counter stored in the connection reference count storage unit 408 is kept at 2 for the server PC 105 to which the server identifier is assigned "10".

The actual communication address is set to an IPv6 address [2001 :: 10] and a port number [1025]. As the destination address, an IPv4 address [10.0.0.10], a port number [1025], [2001 :: 10] and a port number [1025] of the IPv6 address are present in the connected state, respectively.

In process P1304, the interprocess communication control unit 401 transmits the data specified by the client application 101 or 101a using the IPv6 address [2001 :: 10] and the port number [1025].

Therefore, when a session associated with the same server identifier includes one or more connectable destination addresses, the client applications 101 and 101a can continue the communication without being aware of the communication failure.

In the first to third embodiments, the client PC 100 determines the presence or absence of an existing session based on the server identifier acquired from the server PC 105, that is, the server identification information.

However, in order to do this, a function of returning a server identifier (server identification information) to the server PC 105, that is, a server identifier reply unit 302 which returns a server identifier under the control of the inter-process communication control unit 301. It is necessary to provide. This not only increases the processing burden of the server PC 105 communicating with a large number of client PCs, but also effectively uses network resources.

In order to solve this problem, according to the fourth embodiment, the client PC 100 is configured to determine the presence or absence of an existing session based on the server identifier obtained from the server PC 105. That is, the client PC 100 is configured to determine the presence or absence of an existing session without cooperating with the server PC 105.

Fig. 14 is a diagram showing the software configuration of a client / server system to which each session management system according to the fourth to sixth embodiments of the present invention is applied.

The client / server system of FIG. 14 differs from the client / server system of FIG. 1 in which each session management system according to the first to third embodiments is applied to a network 106 by a DNS server 1401. Is connected to.

In the fourth embodiment, by using the DNS server 1401 or the like, the client PC 100 does not cooperate with the server PC 105 to determine the presence or absence of an existing session. In addition, the specification of the DNS service operating in the DNS server 1401 is based on the IETF (Internet Engineering Task Force) technical specification. Specifically, the DNS server 1401 provides an address problem solving service according to a specification specified in RFC (Request for comments) 1034, RFC 1035, or the like.

RFC 1034, RFC 1035, and the like describe the implementation of an A record specification and response corresponding to IPv4. Also, RFC 1886 and the like describe the implementation of the AAAA record specification and response corresponding to IPv6. These RFCs can be referenced at http://www.ietf.org/rfc.htm1.

FIG. 15 is a block diagram showing the detailed software configuration of the inter-process communication unit 103 of the client PC 100 of the client / server system to which the session management system according to the fourth embodiment is applied.

In response to a request from the client application 101 or 101a, the client PC 100 uses the server inter-process communication unit 103 and the communication library 104a through a stub object (not shown) to communicate with the server PC 105. ) To communicate with.

The client inter-process communication unit 103 includes the inter-process communication control unit 401, the session management unit 403, the session management information DB 406, and the session determination unit 404, similarly to the first to third embodiments.

In addition, the inter-client communication unit 103 includes a session disconnection management unit 407 and a session reconnection management unit 409 as in the first to third embodiments. In addition, the inter-process communication unit 103 is software specific to the fourth embodiment and includes an address list acquisition unit 1501 and an address list storage unit 1502.

The inter-process communication control unit 401 collectively controls the communication performed between the client applications 101 and 101a and the server application 108 while managing the session. The address list obtaining unit 1501 obtains, from the DNS server 1401, one or a plurality of addresses associated with the destination addresses specified by the client applications 101 and 101a, and stores the obtained addresses in the address list storing unit 1502. To remember sequentially. The address list information stored in the address list storage unit 1502 will be described in detail later with reference to FIGS. 16 and 23.

The session management unit 403 manages session management information registered in the session management information DB 406. The session management information in the fourth embodiment will be described in detail later with reference to FIG. 17. The session determination unit 404 determines the creation process of the new session or the availability of the existing session based on the address list and the session management information.

Each of the session disconnection management unit 407, the connection reference count storage unit 408, and the session reconnection management unit 409 performs the same processing as in the first to third embodiments.

Next, the address list information stored in the address list storage unit 1502 will be described in detail with reference to FIG. In the address list storage unit 1502, address list information about a destination (server) obtained from the DNS server 1401 is sequentially stored and formed into a database.

The server identifier 1601 is a server identifier (server identification information) of a server (server PC 105) associated with a destination (connection destination) designated by the client application 101 or 101a of the connection request source. Examples of the server identifier 1601 include a host name, a NetBIOS name, a computer name, a fully qualified domain name (FQDN), and the like.

However, as will be described later, in the fourth embodiment, the address list obtaining unit 1501 uses a server of a different format when the client applications 101 and 101a make a connection request using server identification information of different formats. Converts identification information to a host name. The address list obtaining unit 1501 obtains an address list of host names from the DNS server 1401.

Therefore, each server identifier 1601 in the address list information in FIG. 16 is actually represented by a host name. For the same reason, the server identifier 504 in the session management information of FIG. 17 is also actually represented by a host name. However, although each server identifier 1601 in the address list information in FIG. 23 is actually in the form of a host name, for convenience of description, it shows the server identifier (server identification information) actually designated by the client application 101 or 101a. .

The address acquiring method 1602 is information indicating a protocol used when acquiring an address of an associated destination (server) from the DNS server 1401, and the acquiring method. The address type 1603 is information indicating the type of the address actually obtained from the DNS server 1401. The IP address 1604 is information indicating the address (IP address) itself actually obtained from the DNS server 1401.

In the example of FIG. 16, for the server indicated by the server identifier 1601 as "AppServer: host name", an IPv4 address [10.0.0.10] is obtained for the communication indicated by list numbers 1 and 4. FIG. Further, for the server indicated by the server identifier 1601 as "AppServer: host name", an IPv6 address [2001 :: 10] is obtained for the communication indicated by the list number 2, and IPv6 for the communication indicated by the list number 3. The address [fe80 :: 10] is acquired.

Further, for the server whose server identifier 1601 is represented by "AppServer 2: Host Name", the IPv4 address [10.0.0.20] is obtained for the communication shown in list number 5, and the IPv6 address is shown for communication shown in list number 6. The address [2001 :: 20] is obtained.

17 is a diagram illustrating session management information. The application identifier 501 is an identifier (instance handle) for identifying the client application 101 or 101a at the connection request side. The request address information 502 indicates a destination address designated as a connection destination when the client application 101 or 101a requests a connection. This destination address (request address information 502) includes server identification information (host name, FQDN, etc.), an IP address 502a such as an IPv4 address, an IPv6 address, and a port number 502b.

The communication address information 503 indicates the address of the connection destination of the session actually selected for communication after determining the availability of an existing session based on the destination address. This communication address information 503 includes an IP address 503a and a port number 503b.

The server identifier 504 indicates the server identifier (in this example, the host name) of the server that the client application 101 or 101a requests to supply the address list of the connection destination to the DNS server 1401. The session number 505 indicates a management number (session identification instance handle) of the session that actually communicates.

Next, the session management processing according to the fourth embodiment performed by the inter-process communication control unit 401 of the client inter-process communication unit 103 will be described based on the flowchart of FIG. 18. In addition, in FIG. 18, it should be noted that the same process number is attached | subjected about the same process as FIG. 7 (it applies also to FIG. 20, FIG. 21, FIG. 22A, FIG. 22B, FIG. 26A, FIG. 26B and FIG. 27). .

The interprocess communication control unit 401 of the client interprocess communication unit 103 receives a connection request for the server application 108 of the server PC 105 (step S701). This connection request is issued from the client application 101 or 101a.

Next, the inter-process communication control unit 401 causes the address list acquisition unit 1501 to acquire an address list relating to the destination address (step S1801).

In this case, the address list acquisition unit 1501 issues an acquisition request such as an A record or an AAAA record on the address list to the DNS server 1401 via the network 106 using the communication library 104a. do. The DNS server 1401 returns an associated address list in response to an address list acquisition request from the address list acquisition unit 1501.

In addition, in step S1801, the address list acquisition unit 1501 performs address list acquisition processing using various address problem solving services in addition to the DNS server 1401. Examples of address problem solving services include LLMNR (Link Local Multocast Name Resolution) and broadcast search by NetBIOS.

When "Numeric host address" is specified as the server identification information in the destination address, the address list acquisition unit 1501 converts the "Numeric host address" into a host name and performs address list acquisition processing.

Details of the address list acquisition process performed in step S1801 will be described based on the flowchart of FIG. 19.

The address list obtaining unit 1501 determines, from among the destination information from the client application 101 or 101a, whether to specify a server using either server identification information in a host name format or server identification information in an address format (step). S1901). Here, "address" refers to "Numeric host address".

When the server is designated using the server identification information in the address format, the address list acquisition unit 1501 searches the DNS server 1401 for the host name associated with the address (step S1902). In this case, the address list acquisition unit 1501 searches for a host name associated with the designated address by, for example, the getnameinfo () function in C / C ++ socket programming.

Next, the address list obtaining unit 1501 obtains the address list of the server associated with the host name from the DNS server 1401 by designating the host name retrieved based on the address obtaining function (step S1903). In this case, for example, in C / C ++ socket programming, a value AF_UNSPEC is set in the ai_family of the getaddrinfo () function and a function call is made to obtain an address list associated with a host name.

On the other hand, when a server is specified using server identification information in the form of host name, the process skips step S1902 and proceeds to step S1903. When the process of step S1903 ends, the address list acquisition unit 1501 registers the host name and the address list associated with the host name in the address list storage unit 1502 (step S1904), and the process is the main process of FIG. Return to.

Then, under the control of the inter-process communication control unit 401, the session determination unit 404 determines the availability of the existing session based on the address list acquired in step S1801 and the information of the session management information DB 406. (Step S1802).

In this case, the session determination unit 404 determines whether an existing session registered in the session management information DB 406 is available as an existing session associated with a host (server) of the same host name in association with the address described in the obtained address list. Determine.

In other words, the session determination unit 404 acquires the address list from existing sessions currently communicating using an address different from the address used when acquiring the acquired address list (which may include only one address). It is determined whether there is a session related to the same server as the established server. As a result, when there is an existing session associated with the same server, the session determination unit 404 determines that the existing session is available.

In this case, as described above, the address list is obtained in the state of uniformly converting the server identification information into the host name. Therefore, the session determination unit 404 identifies the server based on the host name.

This substantially means that if the server identification information associated with the destination address specified by the client applications 101 and 101a at the time of the connection request are different from each other, the server identification information relating to the same server is treated as the same identification information.

As a result, even if a server is designated by different server identification information, the availability of an existing session can be appropriately determined, which makes it possible to use network resources more efficiently. This advantage will be described later in detail with reference to FIG.

Thereafter, when the existing session is available, the inter-process communication control unit 401 selects the existing session as the session for data transmission performed this time (step S1803).

For example, in the example of session management information in Fig. 17, sessions indicated by management numbers 1 and 2 are sessions for respective different destination addresses designated by the client application 1. However, for management number 2, as an existing session already established, there is an existing session (associated with management number 1 and assigned session number 1) associated with the same server identifier "AppServer". In such a case, the inter-process communication control unit 401 selects the existing session as the data transfer session without creating a new session.

In the example of the address list of Fig. 16, since the IP addresses [10.0.0.10] and [2001 :: 10] are associated with the same server identifier "AppServer", as described above, there is an existing session associated with the same server identifier. Can be determined.

In the examples of Figs. 16 and 17, for the communication regarding the connection request to the address [2001 :: 10] associated with the list / management number 2, the same server identifier "AppServer" and management as those associated with the address [2001 :: 10] are managed. Data transfer is performed using an existing session at address [10.0.0.10] associated with number 1.

Therefore, by using the existing session, the client PC 100 and the server PC 105 do not need to newly create a communication socket for the destination address, and it is possible to save network resources such as the communication socket. ．

Steps S704, S705 and S708 to S711 in FIG. 18 are the same as the steps indicated by the same step numbers in FIG. 7, and therefore description thereof will be omitted.

Next, a description is provided when the first and second client applications respectively designate the server by different server identification information (host name, FQDN, etc.).

As described above, in the fourth embodiment, even if the server identification information used to designate a destination is different, if the server identification information is for identifying the same server, use of the existing session is handled as the same server identification information. The possibility can be determined appropriately.

Fig. 23 illustrates the address list information obtained in such a case. Since the information items in FIG. 23 are exactly the same as the information items in the address list information in FIG. 16, the same information items are assigned the same reference signs, and description thereof is omitted. However, the server identifier 1601 in the address list information in FIG. 23 is not for the host name obtained by uniformly converting the server identification information specified in the different format into the host name. It is indicated by the server identification information used initially.

In the example of FIG. 23, the server identified by the server identifier "AppServer.foo.test" and the server identified by the server identifier "AppServer" are associated with the same IP address "fe80 :: 10" (see list numbers 2 and 3). ).

In such a case, as described above, the server identifiers "AppServer.foo.test" and "AppServer" are uniformly converted into host names, and these servers are treated as the same server. And the session determination part 404 judges the availability of an existing session based on the address list information containing these server identifiers which are substantially single.

For example, suppose that the server identifier "AppServer.foo.test" is specified in the destination information at the time of the connection request, but there is no existing session for the IP address associated with the server identifier. In this case, it is also assumed that there is a session for the IP address [2001 :: 10] as an existing session associated with the server identifier "AppServer" that identifies the same server as the server identifier "AppServer.foo.test".

In such a case, the session determination unit 404 responds to the connection request using the server identifier "AppServer.foo.test" and uses the existing session for the IP address [2001 :: 10] associated with the server identifier "AppServer". It is determined that it is possible.

As described above, the server identifiers are different from each other. However, by treating the server identifiers associated with the same server as the same server identifier, even if a server is designated by a different server identifier, an existing session can be used for the server. Network resources such as sockets can be used more efficiently.

In the first to fourth embodiments, even when the client application 101 and the client application 101a respectively designate different destination addresses, both client applications may use the same session. In this case, the client inter-process communication unit 103 performs actual communication using the destination address for the session (same session) initially established.

However, in the communication performed with the initially designated destination address, when a communication failure occurs, even if communication using a different address is possible, other client applications that communicate in the same session also become incapable of communication.

In order to solve such a problem, in the fifth embodiment, even if a communication failure occurs, when there is another address that can be connected, a session is established to communicate with another address that can be connected.

Next, session management processing performed by the inter-process communication control unit 401 of the client PC 100 of the session management system according to the fifth embodiment will be described based on the flowcharts of FIGS. 20 and 21. The flowcharts of FIG. 20 and FIG. 21 partially coincide with the flowchart of FIG. Therefore, in FIG. 20 and FIG. 21, about the same step as FIG. 18, the same step number is attached | subjected and the description is abbreviate | omitted. In the following, only differences from the fourth embodiment will be described.

In step S2001 of FIG. 21, the inter-process communication control unit 401 determines whether or not the data transfer performed using the session selected in step S708 is successful. As a result, when data transfer is successful, the processing of steps S709 to S711 is performed.

On the other hand, if data transmission fails, the session determination unit 404, under the control of the inter-process communication control unit 401, has another address associated with the same server identification information (host name, etc.) in the session management information DB 406. It is determined whether it exists (step S2002). As a result, when there is no other address associated with the same server identification information, the inter-process communication control unit 401 performs error processing of data transfer (step S2006) and proceeds to step S709.

On the other hand, if there is another address associated with the same server identification information, the inter-process communication control unit 401 establishes a session for reconnecting to another address associated with the same server identification information (host name) (step S2003). . In this case, the interprocess communication control unit 401 creates a new socket for another address associated with the same server identification information (host name).

When there are a plurality of different addresses associated with the same server identification information (host name), the inter-process communication control unit 401 preferentially establishes a session for the address specified by the client application 101 or 101a.

Next, the inter-process communication control unit 401 causes the session management unit 403 to register the session information for reconnection with the session management information DB 406 (step S2004). Then, the inter-process communication control unit 401 selects the session for reconnection as the session for data transmission (step S2005), and the process returns to step S708.

As described above, according to the fifth embodiment, even when a failure occurs while communicating using one application when a plurality of applications are performing data transmission in the same session, the other application (s) can continue the communication. . Therefore, in the fifth embodiment, it is possible to construct a communication system which is resistant to communication disturbance and has high reliability of data transmission.

In the fourth and fifth embodiments, for example, when the application 101 disconnects the first session, the client application 101a using the first session cannot communicate.

In the sixth embodiment, this problem is solved as follows. In other words, the inter-process communication control unit 401 does not close each session each time the session close request is received, and closes each session based on the close reference counter provided to each session. In the sixth embodiment, the connection reference count storage unit 408 stores the close reference counter.

The session management processing in the sixth embodiment will be described based on the flowcharts in FIGS. 22A and 22B. 22A and 22B partially coincide with the flowchart of FIG. 18. Therefore, in FIG. 22A and FIG. 22B, about the same step as FIG. 7 and FIG. 18, the same step number is attached | subjected and the description is abbreviate | omitted. Hereinafter, only differences from the fourth embodiment will be described.

Under the control of the inter-process communication control unit 401, the session truncation management unit 407 increments the count of the close reference counter for the session selected in step S706 or S707 by one in step S2201 of FIG. 22B. At this time, the session truncation management unit 407 stores the count of the closed reference counter incremented by one in the connection reference count storage unit 408.

Next, the inter-process communication control unit 401 performs data transfer by the session selected in step S706 or S707 (step S708). Next, the inter-process communication control unit 401 determines whether a close request from the client application 101 or 101a or a disconnect request from the communication library 104a has been received (step S709). If the close request or the cut request is not received, the process returns to step S701.

On the other hand, when either of the close request or the disconnect request is received, the session cut management unit 407 decrements the count of the close reference counter of the session established for the address associated with the request by one (step S2202). . As described above, the session truncation management unit 407 increments the count of the close reference counter by one in response to the connection request for connecting to the destination address for each destination address associated with the session, and by one in response to the truncation request. Decrease.

Thereafter, the inter-process communication control unit 401 determines whether the count of the closed reference counter has become zero by decreasing the count of the closed reference counter by one (step S2203). If the count of the close reference counter is not 0, processing returns to processing step S701.

On the other hand, if the count of the close reference counter is zero, the process proceeds to step S710, and the inter-process communication control unit 401 performs the closing process of the session and the socket of the address associated with the close request or the disconnect request.

As described above, according to the sixth embodiment, the session is closed based on the close reference counter provided to the session, instead of closing each session each time a session close request is received.

Therefore, when different client applications transmit data using the same session, the disconnection instruction from one client application can prevent the other client application from being unable to transmit data. This makes it possible to use network resources such as sockets more efficiently.

In the first to sixth embodiments, when an existing session can be used, communication is always performed using the existing session. However, compared to the existing session established for the first communication that was first started, the communication efficiency in terms of the communication speed, the number of routers through which the new session, which should be originally established for the second communication that is started later, and the like are communicated. This is a good case.

For this reason, in the seventh embodiment of the present invention, even when there is a session available, if a new session to be established in this communication has a better communication efficiency than the existing session, a new session is established to continue communication. have.

In order to determine the communication efficiency, in the seventh embodiment, as shown in FIG. 24, the line information acquisition unit that acquires line information is controlled by the inter-process communication control unit 401 under the control of the inter-process communication control unit 401. (2401) is installed.

Since the other software configuration of the client PC 100 is almost the same as that of the corresponding part of the first embodiment shown in Fig. 4, only the differences will be described below. It should be noted that in FIG. 24, the session disconnection manager 407, the connection reference count storage unit 408, and the session reconnection manager 409 of FIG. 4 are not shown.

The line information acquisition unit 2401 acquires the line information of the communication route with respect to the destination address on the network 106 from the communication library 104a. Then, the line information acquisition unit 2401 registers the line information as the session management information in the session management information DB 406 through the DB manager 405.

The line information acquired by the line information acquisition unit 2401 includes a Traffic Class, a Flow Label and a Hop Limit of an IPv6 header, a Service Type and a Time To Live of an IPv4 header, and an additional communication band.

The line information acquisition unit 2401 can detect the Path MTU using Path MTU (Maximum Transmission Unit) Discovery of the IP protocol, and Path MTU Discovery automatically determines the maximum value of datagrams that can be transmitted by one data transmission. Path MTU Discovery is specified in RFC (Request for Comments).

The line information acquisition unit 2401 acquires the Path MTU Discovery for IP version 6 specified in RFC 1981, the Path MTU Discovery specified in RFC 1191, and the like from the communication library 104a.

The line information acquisition unit 2401 can acquire the band information of the network card attached to the client PC 100 with respect to the communication band. In addition, the line information acquisition unit 2401 can acquire the band information of the band controlled by the client application by using the network control protocol specified in RFC 2205.

25 is a diagram showing session management information used in the session management system according to the seventh embodiment. This session management information is registered in the session management information DB 406 as a database.

The session management information used in the session management system according to the seventh embodiment shown in FIG. 25 is distinguished from the session management information used in the session management system according to the first embodiment shown in FIG. 5. The line information 2501 is added to the same data item as the management information. This line information 2501 indicates the line state of the communication route to the destination address specified as the destination when the client application 101 or 101a makes a connection request, and the associated port number.

The line information 2501 includes band information 2501a, the number of routers 2501b, and the Path MTU 2501c, for example. However, it is also possible to determine communication efficiency using line information other than these information.

Next, session management information by the session management system according to the seventh embodiment will be described based on the flowcharts of FIGS. 26A, 26B, and 27. This flowchart includes the same number of processing steps as the flowchart of FIG. 7 according to the first embodiment. These steps are denoted by the same corresponding step symbols and their description is omitted.

The inter-process communication control unit 401 obtains a server identifier from the server PC 105 in accordance with the destination address specified by the client application 101 or 101a in step S702. In addition, the interprocess communication control unit 401 causes the line information acquisition unit 2401 to acquire line information corresponding to the communication route to the destination address specified by the client application 101 or 101a (step S2601).

In this case, the line information acquisition unit 2401 can acquire the information on the communication route from the socket library on the OS of the client PC 100 based on the getsockopt function. The line information acquisition unit 2401 may also acquire Path MTU Discovery from the communication library 104a on the OS, and obtain Path MTU 2501c regarding the communication route using this Path MTU Discovery. The line information acquisition unit 2401 can also acquire TTL (Time To Live) information of the IPv4 header and Hop Limit information of the IPv6 header.

Next, the inter-process communication control unit 401 determines, by the session management unit 403, whether there is an existing session established with respect to the same server identifier 504 as the server identifier 504 acquired in step S702 (step) S703).

In this case, the session manager 403 obtains session management information from the session management information DB 406 through the DB manager 405. Based on the session management information obtained, the session management unit 403 is associated with the same server identifier 504 as the server identifier 504 acquired at the time of the connection request during the existing session currently in communication using another address. Determine if an existing session exists. This determination processing is actually performed by the session determination unit 404.

If there is an existing session associated with the same server identifier 504 as the server identifier 504 acquired in step S702, the processing proceeds to step S2602.

In step S2602, the interprocess communication control unit 401 compares, by the session determination unit 404, the line state of the existing session that is already connected with the line state of the destination address specified at the time of the connection request, and the latter. Determine if it is good.

In the example of session management information in FIG. 25, the communication assigned to management numbers 1 and 2, respectively, is based on a connection request issued from a client application for an address having a different address but the server having the same server identifier. Comparing these communications from the viewpoint of Path MTU 2501c, Path MTU 2501c of management number 1 is 1500 and Path MTU 2501c of management number 2 is 9000. From this, it is determined that the line state of management number 2 with a large Path MTU (that is, a small communication overhead) is good.

In addition, when the quantum communication is compared in terms of the number of routers 2501b, the number of routers of management number 1 is three and the number of routers of management number 2 is one. From this, it is determined that the line state of the management number 2 with a small number of routers passing through for communication (that is, a small communication overhead) is good. In addition, the acquisition method of the band information 2501a is demonstrated in detail later.

It may be assumed that the determination result of the goodness of the line state by each method based on the band information 2501a, the number of routers 2501b, and the Path MTU 2501c is inconsistent with each other. In total, discrimination can be made based on the total communication overhead.

Further, it is also possible to determine the goodness of the line state based on communication conditions other than the band information 2501a, the number of routers 2501b, and the Path MTU 2501c. For example, it is possible to use a communication condition that changes at any time, such as traffic of a communication route. Further, by designation of the user, goodness of the line state is determined based on the total communication overhead obtained by weighting each of the parameters including the band information 2501a, the number of routers 2501b, and the Path MTU 2501c. It is also possible.

If the line state for the destination address specified at the time of this connection request is better than the line state for the existing session already connected, the inter-process communication control unit 401 causes the session management unit 403 to establish a new session. (Step S2603). In this case, the session manager 403 creates a new socket using the communication library 104a based on the destination address specified by the client application 101 or 101a.

Next, the session manager 403 registers the information of the new session including the new socket in the session management information DB 406 by the DB manager 405 (step S2604). Then, the inter-process communication control unit 401 selects a new session established for the destination address specified by the client application 101 or 101a as the session for data transmission this time (step S2605).

Next, the inter-process communication control unit 401 changes the existing session according to the same server of the communication performing data transfer into a new session (step S2606). The interprocess communication control unit 401 deletes the existing session from the session management information DB 406 (step S2607).

In the example of the session management information of FIG. 25, for the communication indicated by the management number 3 and the management number 2, the communication of the management number 2 is in a better line state. In this line state, it is assumed that the client application 101 issues a connection request in the order of the management number 3 and the management number 2. FIG.

In this case, first, a session indicated by the management number 3 is newly created. In this session, the communication address at which the client application 101 actually transmits data is [2001 :: 20] and port number 1025.

After that, when the connection request of the management number 2 is issued from the client application 101a, the line number of the management number 2 is better than the line state of the management number 3, so that a session with the management number 2 is newly created.

Subsequently, by the processing of steps S2605 to S2607, subsequent data transfer in accordance with the client applications 101 and 101a is performed at the communication address [2001 :: 10] and the port number 1025 using a new session of the management number 2. .

If the line state of the existing session already connected is better than the line state for the newly designated destination address, the process proceeds to step S707. In this step S707, the inter-process communication control unit 401 sends the current data connected to the previously-connected existing session associated with the same server identifier 504 as the server identifier 504 obtained as a response to the connection request of the current loop. Select as session for communication.

Next, the acquisition method of the band information 2501a contained in the line information 2501 is demonstrated. This band information 2501a is acquired by the line information acquisition unit 2401 in accordance with the destination address specified by the client application 101 or 101a in step S2601 of FIG. 26A.

In this case, the line information acquisition unit 2401 uses the LinkSpeed acquisition function to set LinkSpeed, which indicates the speed when linking from the source address to the destination address of the network adapter of the client PC 100, to the OS on the client PC 100. From the socket library on the top.

In addition, the line information acquisition unit 2401 can acquire a network control protocol for realizing a Quality of Service (QoS) of the network device from the socket library on the OS, and recognize the band information 2501a. In this case, the line information acquisition unit 2401 acquires the setting value of RSVP (Resource Reservation Protocol) (RFC 2205) from the network control protocol.

The line information acquisition unit 2401 checks these setting values and determines the goodness of the line state by acquiring LinkSpeed of the network adapter of the client PC 100 and utilization band information of the network device on the communication path.

Thereafter, the client inter-process communication unit 103 performs data transmission by a session established at another address by comprehensively determining the band information 2501a, the number of routers 2501b, and the Path MTU 2501c. Select the address to use. The inter-process communication unit 103 then selects a session different from the selected address as the session to be used for the actual data transfer.

In addition, when determining the goodness of the line state, it is not necessary to use all of the band information 2501a, the number of routers 2501b, and the Path MTU 2501c. Any one or two of these may be arbitrarily combined to determine the goodness of the line state.

The present invention can be applied to a system including a plurality of devices or a device consisting of one device. In each of the above embodiments, it is assumed that IPv6 is mainly used as a communication protocol. However, even when using any other communication protocol capable of assigning a plurality of addresses to one node or the like, a technical idea according to each embodiment is given. Is applicable.

In addition, the present invention provides a recording medium storing a program code of software for realizing the function of any of the above embodiments to a system or an apparatus, and the computer (CPU or MPU) of the system or apparatus is a recording medium. It should be understood that this can also be accomplished by having the program code stored in the program read and executed.

In this case, since the program code itself read out from the recording medium realizes the functions of any of the above-described embodiments, the program code and the recording medium storing the program code constitute the present invention.

As a recording medium for supplying the program code, for example, a floppy disk, a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, Optical discs such as DVD-RW and DVE + RW, magnetic tapes, nonvolatile memory cards, ROMs, and the like. Alternatively, the program code may be downloaded via a network.

In addition, by executing the program code read out by the computer, the functions of any of the above-described embodiments are realized, and the OS (operating system) or the like running on the computer is actually processed based on the instruction of the program code. It is to be understood that by performing some or all of the above, the functions of any of the above-described embodiments can be realized by the processing.

Furthermore, after the program code read out from the recording medium is written in the memory provided on the expansion board inserted into the computer or in the memory provided in the expansion unit connected to the computer, the expansion board or It is to be understood that the functions of any of the above-described embodiments can be realized by causing the CPU or the like provided in the expansion unit to perform part or all of the actual processing.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions.

This application claims the priority of Japanese Patent Application Publication No. 2008-098363, filed April 4, 2008 and Japanese Patent Application Publication No. 2009-002433, filed January 8, 2009, which are incorporated herein in their entirety. Included for reference.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing the software configuration of a client / server system to which the session management system according to the first to third and seventh embodiments of the present invention is applied.

Fig. 2 is a block diagram showing the hardware configuration of the client PC or server PC shown in Fig. 1 (first to third embodiments).

Fig. 3 is a block diagram showing the detailed software configuration of the server inter-process communication unit of the server PC (first to third embodiments).

Fig. 4 is a block diagram showing the detailed software configuration of the communication process between the client processes of the client PC (first to third embodiments).

5 is a diagram showing an example of session management information (Examples 1 to 7 (6)).

Fig. 6 is a flowchart showing session management processing performed by a server-to-server communication unit of the server PC according to the first embodiment.

Fig. 7 is a flowchart showing session management processing performed by a communication process between client processes of the client PC in the first embodiment.

8A and 8B are sequence diagrams showing examples of the processing of Figs. 6 and 7 (if no existing session exists).

9A and 9B are sequence diagrams illustrating examples of the processing of FIGS. 6 and 7 (if an existing session exists).

10A and 10B are flowcharts showing session management processing performed by a communication process between client processes of a client PC in the second embodiment of the present invention.

11A and 11B are sequence diagrams showing session management processing performed between a server PC and a client PC in the second embodiment of the present invention.

12A and 12B are flowcharts illustrating session management processing performed by a communication process between client processes of a client PC in the third embodiment of the present invention.

13A and 13B are sequence diagrams showing session management processing performed between a server PC and a client PC in the third embodiment of the present invention.

Fig. 14 is a diagram showing the software configuration of a client / server system to which the session management system according to the fourth to sixth embodiments of the present invention is applied.

Fig. 15 is a block diagram showing the detailed software configuration of the inter-process communication unit of the client PC according to the fourth embodiment.

Fig. 16 is a diagram showing address list information according to the fourth embodiment.

Fig. 17 is a diagram showing an example of session management information according to the fourth embodiment.

Fig. 18 is a flowchart showing session management processing performed in the fourth embodiment.

FIG. 19 is a flowchart showing details of an address list acquisition process performed in step S1801 of FIG. 18;

Fig. 20 is a flowchart showing session management processing performed in the address list acquisition processing according to the fifth embodiment.

FIG. 21 is a continuation of the flowchart of FIG. 20;

22A and 22B are flowcharts illustrating session management processing performed in the sixth embodiment.

Fig. 23 is a diagram illustrating address list information when the same server is designated with different server identification information.

Fig. 24 is a block diagram showing the detailed software configuration of the inter-process communication unit of the client PC according to the seventh embodiment.

Fig. 25 is a diagram illustrating session management information according to the seventh embodiment.

26A and 26B are flowcharts illustrating session management processing performed in the seventh embodiment.

FIG. 27 is a continuation of the flowchart of FIG. 26A;

<Explanation of symbols for the main parts of the drawings>

100: Client PC

101, 101a: Client application

102, 102a: stub object

103: communication unit between client processes

104a, 104b: communication library

106: network

107: communication process between server processes

108: server application

105: server PC

Claims (8)

A session management system for managing sessions between a server and a client having a plurality of addresses, If an application provided to the client requires communication with the server through the address of the server specified by the application, a session has already been established between the client and the server through a different address of the server that is different from the specified address. A judging unit, configured to judge whether a check is made; And Cause the application to communicate with the server using the already established session if it is determined that the session is already established, and if the application is determined that the session is not established, the application uses the newly established session. A control unit configured to communicate with the server Session management system comprising a. The method of claim 1, And the determination unit makes the determination based on the identification information for identifying the server. 3. The method of claim 2, And a first acquiring unit, configured to acquire the identification information from the server. 3. The method of claim 2, And a second obtaining unit, configured to acquire the identification information from an external device which is a DNS server. delete The method of claim 1, A management unit configured to manage a value that is updated based on a connection request and a disconnect request from the application, And said control unit to disconnect a session established between said client and said server based on said managed value. The method of claim 1, The control unit uses the session with which the application is newly established when the session using the address specified by the application is more efficient than the already established session, even when it is determined that the session is already established. Session management system for communicating with a user. A method of controlling a session management system for managing sessions between a server and a client having a plurality of addresses, the method comprising: If an application provided to the client requires communication with the server through the address of the server specified by the application, a session has already been established between the client and the server through a different address of the server that is different from the specified address. Determining whether the operation is completed; Causing the application to communicate with the server using the already established session if it is determined that the session is already established; And Causing the application to communicate with the server using the newly established session if it is determined that the session is not established. Control method of the session management system comprising a.

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