WO2015001671A1

WO2015001671A1 - Communication control device, method for controlling communication control device, and information processing device

Info

Publication number: WO2015001671A1
Application number: PCT/JP2013/068539
Authority: WO
Inventors: 与一中本; 義則望月; 江端　智一
Original assignee: 株式会社日立製作所
Priority date: 2013-07-05
Filing date: 2013-07-05
Publication date: 2015-01-08

Abstract

[Problem] To make it possible to ensure real-time responses to accesses from a large number of communication terminals, each of which communicates periodically with a communication network such as a data center, while keeping down the amount of memory capacity and/or other resources used. [Solution] A gateway device (102) that is connected to a plurality of communication terminals and a center server so as to be able to communicate therewith and that mediates data communication holds communication-period data from communication-terminal senders in a communication-period management table (310) and stores session information needed for sessions with said senders in a session-information table (309) in correspondence with the communication-period data. A session-information monitoring unit (305) determines, for each session, whether the date and time of the next access associated therewith is closer than a prescribed time threshold, and session information for which it is determined that the date and time of the next access is closer than said time threshold is copied, by a session-information management unit (304), from the session-information table (309) to a faster session-information cache (308).

Description

COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL DEVICE CONTROL METHOD, AND INFORMATION PROCESSING SYSTEM

The present invention relates to a communication control device, a control method for the communication control device, and an information processing system.

Recent advances in information and communication technology have led to an increase in large-scale and wide-area control systems composed of a large number of communication terminals distributed in the field. For example, in an automatic power meter reading system (AMI: Advanced Metering Infrastructure), tens of millions of smart meters installed in a wide area such as houses and buildings are connected to a center server installed in a data center, and data is regularly transmitted. It is assumed to send and receive.

On the other hand, unlike conventional control systems that were built with only closed dedicated networks, large-scale and wide-area control systems utilize the open network such as the Internet as the network infrastructure that connects the field and the center from the viewpoint of infrastructure installation costs. Is being considered. In this case, mainly from the viewpoint of security, a gateway apparatus is often installed between the field communication terminal and the center server of the data center, and the system configuration is often such that the center server cannot be accessed directly from the field. In this system configuration, the gateway device establishes an authentication session with each communication terminal in the field. However, since the number of communication terminals is enormous, the number of session information to be retained is enormous. The amount of session information per case is also increasing as the system becomes more sophisticated. Therefore, it is required to shorten the processing time for searching for a specific session from a large amount of session information during communication while suppressing the cost of memory for storing session information.

In response to such a request, for example, Patent Document 1 proposes a cache device that further shortens the access time for request data from a client computer and reduces network traffic. The cache device is provided in a gateway computer that is interposed between a client computer that requests data and a server computer that distributes stored data, and according to a data request from the client computer, a previous data request time and a current data request time. And a period management table for registering a period for comparison data and determining a data request prediction period. In accordance with the cycle determined by the cycle management table, pre-fetch processing is performed in which the stored data is pre-fetched from the server computer in advance, and the acquired accumulated data is requested to be written to the memory cache.

JP 2001-318902 A

The data processing system includes an information system in which humans are involved in data processing in the system, and data requests from each client to the server often occur irregularly, and a large number of humans such as the AMI described above. And a control system in which a server is periodically accessed from a communication terminal equipped with a measurement control device or the like that does not intervene. The cache device of Patent Document 1 is mainly configured to be applied to an information system in which a data request from a client computer is made irregularly, in other words, the data request is poor in periodicity. Therefore, when the apparatus of Patent Document 1 is applied to a control system, a large amount of resources tend to be consumed for data request generation cycle prediction for a large number of communication terminals. The problem is that the response is difficult to secure.

According to one embodiment of the present invention for solving the above-described problem, the first information processing device is connected to a plurality of first information processing devices and at least one second information processing device so as to be able to communicate with the first information processing device. A communication control device that mediates data communication with the second information processing device, wherein data communication is executed from a transmission source in each of the first information processing devices to the second information processing device. A communication cycle data storage unit storing communication cycle data as time interval information for each first information processing device, and a last time point when data communication from the first information processing device was executed. Calculated from the last access time point information, which is information to be shown, the last access time point information relating to a certain first information processing device, and the communication cycle data obtained from the communication cycle data storage unit regarding the first information processing device. Further, the next access time point information, which is information indicating the next time point at which the first information processing device executes data communication, is set as specific information relating to data communication between a specific transmission source and the second information processing device. A session information storage unit stored as an associated session, a session information cache configured with a storage device faster than a storage device constituting the session information storage unit, and stored in the session information storage unit Based on the next access time point information regarding each of the first information processing devices, it is continuously determined whether the data communication execution time point from the first information processing device has become a predetermined time threshold value or less from the present time point. When it is determined that the predetermined time threshold is not exceeded, session information related to the first information processing apparatus is stored as the session information. When receiving data from the session information management unit to be copied from the storage unit to the session information cache and the first information processing device, the session information corresponding to the transmission source is obtained by referring to the session information storage unit And a transfer processing unit that transfers data received based on the session information to a transmission destination. Another aspect of the present invention is a control method for the communication control device. Still another aspect of the present invention is an information processing system including a plurality of the first information processing apparatuses, the second information processing apparatus, and the communication control apparatus.

According to the present invention, when a large number of communication terminals perform periodic communication with a communication network such as a data center, a real-time response to access from each communication terminal is secured while suppressing the amount of resources used such as memory capacity. Provided are a communication control device, a control method therefor, and an information processing system that enable this to be performed.

FIG. 1 is a diagram showing an example of the overall system configuration of an information processing system 1 including a gateway apparatus 102 that is a communication control apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the overall system configuration of the information processing system 1 including the gateway apparatus 102 which is a communication control apparatus according to an embodiment of the present invention and a relay apparatus. FIG. 3 is a diagram illustrating a functional configuration example of the gateway device 102. FIG. 4 is a diagram illustrating a hardware configuration example of the gateway device 102. FIG. 5 is a diagram showing a table configuration example of the session information cache 308. FIG. 6 is a diagram illustrating a table configuration example of the session information table 309. FIG. 7 is a diagram showing a table configuration example of the communication cycle management table 310. FIG. 8 is a diagram illustrating an example of a processing sequence when a new session is established in the information processing system 1. FIG. 9 is a diagram showing an example of a processing sequence at the time of existing session communication that is executed when the corresponding session information is registered in the cache in the information processing system 1. FIG. 10 is a diagram showing an example of a processing sequence at the time of existing session communication executed when the corresponding session information is not registered in the cache in the information processing system 1. FIG. 11 is a diagram showing an example of a processing sequence at the end of an existing session in the information processing system 1. FIG. 12 is a functional configuration example of the gateway device 102 according to another embodiment of the present invention. FIG. 13 is a diagram showing an example of a processing sequence at the time of existing session communication in the information processing system 1 including the gateway device 102 according to another embodiment of the present invention.

Next, a first embodiment for carrying out the present invention (hereinafter referred to as “first embodiment”) will be described in detail with reference to the drawings as appropriate.

(Overall system configuration in the first embodiment)
First, a configuration example of the information processing system 1 to which the gateway device according to the first embodiment is applied will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a center server 101 (second information processing apparatus) in which each of a plurality of communication terminals 103-1 to 103-n (first information processing apparatus) in the field is an information processing apparatus in a data center. It is a structural example of the information processing system 1 comprised so that data may be transmitted / received mutually. The center server 101 is a server computer on which an application for communication operates, and is a general computer having a communication function. The communication terminals 103-1 to 103-n are computers on which applications that perform communication operate, such as a server computer having a communication function, a personal computer (PC), and a control controller. As shown in FIG. 1, each of the communication terminals 103-1 to 103-n is connected to the gateway apparatus 102 via the wide area network 105. The gateway device 102 (communication control device) is connected to the center server 101 via the center network 104. In the following description, when the communication terminals 103-1 to 103-n are referred to as a single configuration, function, etc., they are simply expressed as “communication terminal 103”. In addition, a configuration in which a plurality of center servers 101 are connected to the center network 104 is also possible.

The gateway device 102 has a function of managing a communication state (session) with each of the communication terminals 103-1 to 103-n. Details of the function of the gateway device 102 will be described later. In this specification, the term “session” refers to a series of data packet communications transmitted / received between the gateway apparatus 102 and a transmission source such as application software operating on each of the communication terminals 103-1 to 103-n. Means.

The center network 104 is a communication network for exchanging data in the data center, and is usually configured as a high-speed and high-security network. The wide area network 105 is a communication network for exchanging data between the data center and the field, more specifically, between the gateway device 102 of the data center and each of the communication terminals 103-1 to 103-n in the field. It consists of a low security network. The center network 104 and the wide area network 105 may be logically separated by a VLAN (Virtual Local Area Network), a network segment, or the like, or may be physically separated by a communication medium level such as light or radio wave. . In this specification, each communication network and the management network in the data center will be described as an IP (Internet Protocol) network, but the present invention is not limited to this. The signal used for communication in the communication network may be, for example, any one of electricity, light, radio waves, sound, or a combination thereof.

FIG. 2 illustrates a modification of the information processing system 1 of FIG. FIG. 2 shows a system configuration example in which relay devices 201-1 to 201-n are provided between the field communication terminal 103 and the data center gateway device 102 in the configuration of FIG. The relay devices 201-1 to 201-n have a function of transferring communication between the communication terminals 103 connected to the field networks 202-1 and 202-2 and the gateway device 102. In some cases, a packet is transferred like a switch or a router, or in the relay devices 201-1 to 201-n, communication with each communication terminal 103 is once terminated. In the latter case, when viewed from the gateway device 102, the relay devices 201-1 to 201-n are one of the communication terminals 103-1 to 103-n in FIG. The field networks 202-1 and 202-2 are intranets configured by, for example, regional units or organizational units.

Hereinafter, the description will be given on the premise of the system configuration of FIG. 1, but this also applies to the system configuration of FIG. 2 or a combination of FIG. 1 and FIG.

(Functional configuration of gateway device in the first embodiment)
Next, the functional configuration of the gateway apparatus 102 that is the communication control apparatus of this embodiment will be described with reference to FIG. The functions of the gateway device 102 illustrated in FIG. 3 are realized based on hardware described later with reference to FIG. The gateway device 102 includes communication interfaces 301-1 and 301-2 configured as a network interface card (NIC), a packet transmission / reception processing unit 302, a transfer processing unit 303, a session information management unit 304, a session information monitoring unit 305, A first storage area 306, a second storage area 307, a session information cache 308, a session information table 309, and a communication cycle management table 310 are provided.

Communication interfaces 301-1 and 301-2 are interfaces between the wide area network 105 and the gateway device 102, the center network 104 and the gateway device 102, respectively, and packet transmission / reception processing units that receive communication packets received from the center network 104 and the wide area network 105. The communication packet delivered to 302 or from the packet transmission / reception processing unit 302 is transmitted to the center network 104 or the wide area network 105.

The packet transmission / reception processing unit 302 reconstructs transfer data from the received packets received from the communication interfaces 301-1 and 301-2 or creates a transmission packet from the transfer data and passes it to the communication interfaces 301-1 and 301-2. . In addition, when reconstructing transfer data from a received packet from the communication terminal 103, the packet transmission / reception processing unit 302 acquires session identification information necessary for establishing a session and a session ID necessary for the transfer process from the received packet. Passed to part 303. Further, when creating a transmission packet, the packet transmission / reception processing unit 302 acquires a session ID necessary for creating the transmission packet from the transfer processing unit 303. A detailed sequence of these transfer processes will be described later.

The transfer processing unit 303 acquires session information from the session information management unit 304 based on the session ID passed from the packet transmission / reception processing unit 302, and performs transfer processing using the acquired session information. A detailed sequence of these transfer processes will be described later.

The session information management unit 304 performs new registration, deletion, reading, and updating of session information managed by the gateway device 102. Details of these processes will be described later.

The session information monitoring unit 305 constantly monitors the session information table 309, and the session information whose difference between the next access date and time and the current time for a specific session is equal to or less than a threshold set in advance by the administrator is stored in the session information monitoring unit 305. A process of copying to the information cache 308 is executed. At this time, if there is no free space in the session information cache 308, the session information monitoring unit 305 displays the session information with the longest scheduled access date and time among the session information stored in the session information cache 308 in the session information table. Copy to 309 and delete from the session information cache 308. Details of these processes will be described later. Note that the above functional blocks that realize the functions of the gateway apparatus 102 that is the communication control apparatus are one configuration example, and functional blocks having different functions can be implemented together as appropriate. For example, the session information monitoring unit 305 can be integrated with the session information management unit 304, and the packet transmission / reception processing unit 302 can be integrated with the transfer processing unit 303.

The first storage area 306 is a storage area that can be read and written at high speed while the amount of information that can be stored therein is small, and is provided by, for example, a DRAM (Dynamic Random Access Memory). The first storage area 306 is generally used as a cache for temporarily storing input / output data because the price per unit information amount (bit unit price) is generally higher than the second storage area 307 described later. .

The second storage area 307 is a storage area that can store a large amount of information and has a relatively slow read / write speed, and is provided by, for example, an HDD (Hard Disk Drive).

The session information cache 308 is a table that temporarily caches session information, and is stored in the first storage area 306. The session information management unit 304 refers to this table and acquires session information necessary for transfer processing. Details of the table structure will be described later.

The session information table 309 (session information storage unit) is a table for managing session information, and is stored in the second storage area 307. This table is the master information of the session information, and a part of the information (entries) stored in this table is stored in the session information cache 308. The session information monitoring unit 305 monitors this table and copies the session information whose next access date / time approaches the current date / time to the session information cache 308. Details of the table structure will be described later.

The communication cycle management table 310 (communication cycle data storage unit) is a table for managing the cycle information of each communication session, and is stored in the second storage area 307. When the session information management unit 304 creates new session information, by referring to this table, the session information management unit 304 acquires the period information of the session and calculates the next access date and time. Details of the table structure will be described later.

(Hardware configuration of gateway apparatus 102 in the first embodiment)
Next, the hardware configuration of the gateway apparatus 102 will be described with reference to FIG. FIG. 4 shows a hardware configuration example of the gateway apparatus 102 of this embodiment. In the following description, FIG. 3 is also referred to as appropriate.

The gateway device 102 includes a processor 401 including a CPU (Central Processing Unit) that performs various data processing, a memory 402, a peripheral I / F 403, an auxiliary storage device 404, communication I / Fs 405-1 and 405-2, and a bus. 406 is provided. The processor 401, the memory 402, the peripheral I / F 403, the auxiliary storage device 404, and the communication I / Fs 405-1 and 405-2 are connected via the bus 406 and can communicate with each other.

The processor 401 executes a program for realizing the function of the gateway apparatus 102 described with reference to FIG.

The memory 402 is a storage device that is used as a working memory and a temporary buffer for input / output data or as the first storage area 307 when the processor 401 executes a program, and is configured by a DRAM, for example.

The peripheral I / F 403 is an interface for connecting to various peripheral devices such as an input / output device such as a mouse, a keyboard, and a monitor, and an external storage such as a USB (Universal Serial Bus) memory.

The auxiliary storage device 404 includes a magnetic disk device, a flash ROM (Read Only Memory), and the like, and includes an operating system (OS), various drivers, various application programs, and various information used in the programs (for example, the system 1 of this journal system 1). Information set by the administrator or maintenance person) is stored. The second storage area 307 of this embodiment is provided by the auxiliary storage device 404.

The communication I / Fs 405-1 and 405-2 are configured such that the gateway device 102 communicates with the communication terminals 103-1 to 103-n, the relay devices 201-1 to 201-n, and the center server 101 via the center network 104 and the wide area network 105. Provides an interface for communication. The communication I / Fs 405-1 and 405-2 can be configured by, for example, a NIC (Network Interface Card). In FIG. 4, two sets of communication I / Fs 405-1 to 405-2 are illustrated, but one set or three or more sets may be provided.

(Session information cache in the first embodiment)
Next, information stored in the session information cache 308 will be described with reference to FIG. As described above, the session information cache 308 temporarily stores information for the gateway device 102 to manage a communication session between the communication terminal 103 and the center server 101 so that the information can be used in real time. . The session information cache 308 includes a session ID 501, last access date / time 502 (last access time point information), next access date / time 503 (next access time point information), communication cycle 504, management information 1 (505), and management information 2 (506). Each item is stored.

The column of the session ID 501 is an area that stores a session ID that is an ID for uniquely identifying a plurality of sessions held in the gateway device 102. The session ID 501 is assigned by the gateway device 102 when a new session is created by the gateway device 102. Note that the session ID 501 may continue to be assigned to the transfer data while the session continues, or the gateway device 102 assumes that the session corresponds one-to-one with the TCP / IP connection. Socket descriptor information for performing transmission / reception may be allocated and used. In the former case, there is not necessarily a one-to-one correspondence between a TCP / IP connection and a session, but a session ID must always be assigned to data. In the latter case, the TCP / IP connection and the session need to correspond one-to-one, but it is not necessary to assign a session ID to the transfer data. In the following description, the former is assumed, but the latter does not affect the essence of the present invention.

The column of the last access date and time 502 is an area that stores the date and time when the session information was last accessed in order to transfer the packet of the session. This area is an area that is updated only when accessed for transfer. For example, the area is not updated when accessed for moving session information from the session information table 309 to the session information cache. As shown in FIG. 5, the item of last access date and time 502 can be expanded so as to record a plurality of past access dates and times as an access history related to a specific session ID 501. FIG. 5 shows an example in which the item of last access date and time 502 is expanded as past access time information so as to include the past 11 access dates and times. The item of the extended last access date and time 502 is used when executing a communication cycle automatic update process to be described later.

The next access date and time 503 column is an area for storing the date and time when the gateway device 102 is scheduled to transfer the packet of the session next. The session information management unit 304 calculates from the last access date and time 502 and the communication cycle 504, and updates this area.

The column of the communication cycle 504 is an area for storing the communication cycle of the session. The session information management unit 304 acquires and registers from the communication cycle management table 310 when a new session is established.

The columns of management information 1 (505) and management information 2 (506) are areas for storing information to be held as session information, and the contents of items can be freely set according to the type of session created by the gateway apparatus 102. Can be designed to In the example of FIG. 5, it is assumed that an authentication session for controlling access from the communication terminal 103 to the center server 101 is created, and the management information 1 (505) stores a user ID for identifying the authentication source. In the management information 2 (506), the session expiration date is stored. Note that although two types of management information are shown in FIG. 5, they may be expanded as necessary.

In the session information cache 308 of FIG. 5, for example, a line 507 includes a session having a session ID 501 of “10000001” with the last access date / time 2013/1/1 and 8: 00: 00: 00 and the next access scheduled date / time 2013 / This indicates that 1/1, 8:30, communication cycle is 30 minutes, authentication source is user1, and session expiration date is 2013/1/2, 8: 00: 00: 00.

The session information recorded in the session information cache 308 is generated only after communication between the communication terminal 103 and the center server 101 is actually performed. Accordingly, no information is stored in the session information cache 308 before operating as the gateway device 102, and when a communication occurs between the communication terminal 103 and the center server 101 and a new session is started. The session information management unit 304 adds an entry. At this time, if the number of entries in the table has reached the upper limit, the session information management unit 304 moves the most recent entry with the next access date and time 503 from the current time to the session information table 309 among the table entries. In addition, the session information monitoring unit 305 monitors the session information table 309, and adds session information that is approaching the next access date and is not registered in the table entry to the table entry. At this time, if the number of entries in this table has reached the upper limit, the session information monitoring unit 305 moves the entry with the next access date and time 503 of this table entry from the current time to the session information table 309, and the free entry area The session information is registered. When the session ends, the session information management unit 304 deletes the entry of the target session from this table. When there is an access from the communication terminal 103 using the session information cache 308 having the above configuration, the gateway apparatus 102 can acquire necessary session information from the session information cache 308 in real time.

(Session information table in the first embodiment)
Next, information stored in the session information table 309 will be described with reference to FIG. The session information table 309 stores session information used by the gateway device 102 to manage a session between each communication terminal 103 and the center server 101. The session information table 309 stores items of session ID 601, last access date and time 602, next access date and time 603, communication cycle 604, management information 1 (605), and management information 2 (606). Since the information in each column is exactly the same as that in the session information cache 308, description thereof is omitted. Similar to the session information cache 308, this table 309 stores no information before the gateway apparatus 102 starts operation. When the entry in the session information cache 308 reaches the upper limit, Among them, the session information management unit 304 registers the entry whose future access date and time is the most future from the current time in this table. When the session ends, the session information management unit 304 deletes the entry of the target session from this table. Note that the item of the last access date and time 602 of the session information table 309 is similarly expanded when the item of the last access date and time 502 of the session information cache 308 is expanded.

(Communication cycle management table in the first embodiment)
Next, information stored in the communication cycle management table 310 will be described with reference to FIG. FIG. 7 shows an example of the communication cycle management table 310 stored in the second storage area 307 in the gateway device 102 of this embodiment. The communication cycle management table 310 stores items of session type identification information 701 and communication cycle 702, and this table is used by the session information management unit 304 to register the communication cycle 604 in the session information when a new session is established. Refer to

The column of the session type identification information 701 is an area for storing information for identifying the type of session managed by the gateway apparatus 102. The identification information 701 may be assigned in units that can specify the communication cycle 702 during system design. For example, the identification information 701 can be assigned in units of TCP / IP connections, in units of communication applications, in units of communication terminals, or in units of groups of devices having the same communication cycle. In the example of FIG. 7, a user ID assigned to a communication application is stored assuming identification in communication application units. However, a combination of an IP address and a TCP port, an apparatus ID, and a group ID may be used.

The column of the communication cycle 702 is an area for storing a cycle in which communication of the session specified by the session type identification information 701 is performed. In the example of FIG. 7, for example, a row 703 indicates that the communication cycle of the session whose identification information 701 is specified by user1 is 30 minutes.

(Processing sequence when establishing a new session in the first embodiment)
Next, an example of a series of processing sequences when the communication terminal 103 establishes a new session and transmits data to the center server 101 via the gateway device 102 will be described with reference to FIG. FIG. 8 schematically illustrates the flow of information among the communication terminal 103, the packet transmission / reception processing unit 302, the transfer processing unit 303, the session information management unit 304, the session information monitoring unit 305, and the center server 101 of the gateway device 102. It shows. Note that the symbol S in FIG. 8 means “step”.

First, the communication terminal 103 transmits a packet to the gateway device 102 (S801).

The packet transmission / reception processing unit 302 of the gateway apparatus 102 performs reception processing of the packet received via the communication interface 301-1, and reconstructs the packetized transfer data (S802). Next, the packet transmission / reception processing unit 302 checks the session ID or the session type identification information from the transfer data (S803). Here, since the packet transmission / reception processor 302 is a new session, it acquires the session type identification information. The session type identification information is recorded in the transmission packet in the communication terminal 103 that is the transmission source. Then, the packet transmission / reception processing unit 302 passes the acquired session type identification information and transfer data to the transfer processing unit 303 (S804).

The transfer processing unit 303 passes the session type identification information received from the packet transmission / reception processing unit 302 to the session information management unit 304 (S805).

The session information management unit 304 refers to the communication cycle management table 310 and acquires the communication cycle 702 corresponding to the session type identification information 701 (S806). Next, the session information management unit 304 creates new session information and registers it in the session information cache 308 (S807). Then, the session information management unit 304 passes the session ID to the transfer processing unit 303 (S808).

The transfer processing unit 303 performs transfer processing such as address resolution of the transfer destination (S809), and passes the session ID and transfer data to the packet transmission / reception processing unit 302 (S810).

The packet transmission / reception processing unit 302 generates a transmission packet from the transfer data including the session ID (S811), and transmits the generated packet to the center server 101 as the transfer destination via the communication interface 301-2 (S812).

According to the above processing sequence, information related to a new session of a certain communication terminal 103 is stored in the session information cache 308 and the session information table 309, and the gateway device 102 responds in real time when communication from the next communication terminal 103 occurs. be able to.

(Processing sequence at the time of existing session communication in the first embodiment)
Next, an example of a series of processing sequences when data is transmitted to the center server 101 via the gateway apparatus 102 using a session that has already been established by the communication terminal 103 will be described with reference to FIGS. 9 and 10.

First, an example of a processing sequence when a packet arrives at the gateway apparatus 102 from the communication terminal 103 as scheduled and the session information can be read from the session information cache 308 will be described with reference to FIG.

First, as a premise of the processing sequence of FIG. 9, the session information monitoring unit 305 checks the next access date and time 603 of the session information table 309 and identifies an entry whose difference from the current date and time is equal to or less than a preset threshold value. (S901). Next, the session information monitoring unit 305 checks whether or not the session information specified in S901 is registered in the session information cache 308, and registers it if not registered (S902). At this time, if the entry in the session information cache 308 has reached the upper limit value, the entry with the most recent access date and time 503 among the entries in the session information cache 308 is moved to the session information table 309 and is free in the session information cache 308. Create a region. The above-described processing of S901 and S902 by the session information monitoring unit 305 is repeatedly executed at an appropriate timing in the background.

In this state, the communication terminal 103 transmits a packet to the gateway device 102 (S903).

The packet transmission / reception processing unit 302 of the gateway apparatus 102 performs reception processing of the packet received via the communication interface 301-1, and reconstructs the packetized transfer data (S904). Next, the packet transmission / reception processing unit 302 checks the session ID or the session type identification information from the transfer data (S905). Here, since it is an existing session, a session ID is acquired. Then, the acquired session ID and transfer data are transferred to the transfer processing unit 303 (S906).

The transfer processing unit 303 passes the received session ID to the session information management unit 304 (S907).

The session information management unit 304 refers to the session information cache 308 and searches for an entry that matches the session ID received by the session ID 501 (S908). Here, when the packet of the session arrives as scheduled, the session information monitoring unit 305 acquires the session information from the session information cache 308 because the session information is registered in the session information cache 308 by the session information monitoring unit 305. be able to. Then, the session information management unit 304 updates the last access date and time 502 and the next access date and time 503 in the session information cache 308 (S909), and passes the session information to the transfer processing unit 303 (S910).

The transfer processing unit 303 performs transfer processing based on the session information (S911). In the case of managing the authentication session of this example, for example, an expiration date check included in the session information and an authentication source ID check are performed. Then, the transfer processing unit 303 passes the session ID and transfer data to the packet transmission / reception processing unit 302 (S912). The subsequent processing is the same as S811 and S812 in the processing example of FIG.

With the processing sequence described above, when a session start packet is received from the communication terminal 103, the session information related to the session is recorded in the session information cache 308 stored in the first storage area 306 accessible at high speed. The gateway device 102 can quickly perform the packet transfer processing from the communication terminal 103 using the session information.

Next, an example of a processing sequence when a packet does not arrive from the communication terminal 103 to the gateway apparatus 102 as scheduled and the corresponding session information is not registered in the session information cache 308 will be described with reference to FIG.

Referring to FIG. 10, the processing from S1001 to S1006 is the same as the processing from S903 to S908 in FIG. Here, when the packet arrives at the gateway apparatus 102 at an unscheduled date and time from the communication cycle set in advance for each session, the session information management unit if the session information of the session is not registered in the session information cache 308 304 refers to the session information table 309, acquires the session information of the session, and registers it in the session information cache 308 (S1007). At this time, if the entry in the session information cache 308 has reached the upper limit value, the entry with the most recent access date / time among the entries in the session information cache 308 is moved to the session information table 309, and free space is stored in the session information cache 308. Create Then, the session information management unit 304 updates the last access date and time 502 and the next access date and time 503 (S1008), and passes the session information to the transfer processing unit 303 (S1009). The subsequent processing is the same as S911 to S914 in FIG.

According to the above processing sequence, even when a packet is received from the communication terminal 103 at a time outside a predetermined communication cycle, the gateway device 102 can execute a normal data transfer process, and at the next scheduled time When a packet is received in the communication cycle, a quick process can be performed using the session information stored in the session information cache 308.

(Processing sequence at the end of the existing session in the first embodiment)
Next, an example of a series of processing sequences when the communication terminal 103 ends an already established session will be described with reference to FIG.

First, the communication terminal 103 transmits a session end packet to the gateway device 102 (S1101).

The packet transmission / reception processing unit 302 of the gateway device 102 performs reception processing of the session end packet received via the communication interface 301-1, and reconstructs the packetized session end request (S1102). Next, the packet transmission / reception processing unit 302 acquires the session ID to be terminated from the termination request (S905). Then, the acquired session ID and transfer data are transferred to the transfer processing unit 303 (S906).

The transfer processing unit 303 passes the session ID to the session information management unit 304 (S907). The session information management unit 304 refers to the session information cache 308 and searches for an entry that matches the session ID received by the session ID 501 (S1106). When it is determined that there is a matching entry, the session information management unit 304 deletes the entry of the session information cache 308 and the entry of the session of the session information table 309 (S1107). When it is determined that there is no matching entry in the session information cache 308, the session information management unit 304 deletes only the entry for the session in the session information table 309 (S1107). Then, the session information management unit 304 returns the session information deletion processing result to the transfer processing unit 303 (S1108).

The transfer processing unit 303 performs transfer processing (S1109), and passes the session ID and the session end request to the packet transmission / reception processing unit 302 (S1110).

The packet transmission / reception processing unit 302 generates a transmission packet from the session ID 501 and the session end request (S1111), and transmits the session end packet to the center server 101 (S1112). According to the above processing sequence, when a session end packet is received from the communication terminal 103, the session information related to the session stored in the session information cache 308 and the session information table 309 of the gateway device 102 is deleted. The memory capacity of the gateway device 102 and the storage capacity of the auxiliary storage device 404 can be used efficiently.

Next, a second embodiment (hereinafter referred to as “second embodiment”) for carrying out the present invention will be described in detail with reference to the drawings as appropriate. In the first embodiment, the communication cycle between the communication terminal 103 and the center server 101 is set in advance and is fixed once set, but the communication cycle is set in advance. However, it may be impossible to cope with a case where a setting value and an error occur during actual operation due to a network environment at the site. Therefore, in the second embodiment, a function of the gateway device 102 that dynamically changes the communication cycle while actually operating the gateway device 102 will be described.

(Functional configuration of gateway apparatus 102 in the second embodiment)
A functional configuration of the gateway apparatus 102 in the second embodiment will be described with reference to FIG. Since the communication terminal 103-1, the wide area network 105, the center network 104, and the center server 101 are the same as those in the first embodiment, description thereof is omitted. Also, each functional block in the gateway apparatus 102 denoted by reference numerals 301-1 to 310 is the same as the element identified by the same reference numeral in the first embodiment, and thus the description thereof is omitted. In the second embodiment, a period update unit 311 is provided to cope with a change in the communication period. The period update unit 311 has a function of recalculating the communication period of the session based on the actual packet arrival date and time passed from the session information management unit 304. As a method for calculating the communication cycle, for example, a moving average of access logs for the past 10 times is conceivable, but is not limited thereto. As described with reference to FIGS. 5 and 6, the access log necessary for the calculation is retained in the gateway apparatus 102 by expanding the items of the last access date and

time

502 and 602 in the session information cache 308 and the session information table 309. can do.

(Processing sequence at the time of existing session communication in the second embodiment)
Next, a series of processing sequence examples in the case where data is transmitted to the center server 101 via the gateway apparatus 102 using a session already established by the communication terminal 103 in the second embodiment will be described with reference to FIG. . This processing sequence example corresponds to the processing sequence example of FIG. 9 in the first embodiment.

As in the case of the processing sequence example of FIG. 9, the session information monitoring unit 305 checks the next access date and time 603 in the session information table 309 and determines an entry whose difference from the current date and time is equal to or less than a preset threshold value. Specify (S1301). Next, the session information monitoring unit 305 checks whether the specified session information is registered in the session information cache 308, and if not registered, registers it (S1302). At this time, if the entry in the session information cache 308 has reached the upper limit value, the entry with the most recent access date / time among the entries in the session information cache 308 is moved to the session information table 309, and free space is stored in the session information cache 308. Create The processing of S1301 and S1302 by the session information monitoring unit 305 is repeatedly executed at an appropriate timing in the background.

In this state, the communication terminal 103 transmits a packet to the gateway device 102 (S1303).

The packet transmission / reception processing unit 302 of the gateway apparatus 102 performs reception processing of the packet received via the communication interface 301-1, and reconstructs the packetized transfer data (S1304). Next, the packet transmission / reception processing unit 302 acquires a session ID from the transfer data (S1305). Then, the acquired session ID and transfer data are transferred to the transfer processing unit 303 (S1306).

The transfer processing unit 303 passes the session ID to the session information management unit 304 (S1307).

The session information management unit 304 refers to the session information cache 308 and searches for an entry in which the session ID 501 matches the received session ID (S1308). Then, the session information management unit 304 passes the acquired session information to the period update unit 311 (S1309). As described above, this session information stores a certain number of past access dates and times necessary for periodic recalculation.

The period update unit 311 recalculates the communication period from the past access date and current communication period included in the session information (S1310). Then, the communication cycle after the recalculation is returned to the session information management unit 304 (S1311).

The session information management unit 304 updates the past access date and time 502, the communication cycle 504, and the next access date and time 503 in the session information cache 308 (S1312), and passes the session information to the transfer processing unit 303 (S1313). The subsequent processing is the same as S911 to S914 in FIG. 9 relating to the first embodiment.

According to the processing sequence example described above, even when it is difficult to set a communication cycle in advance, or even when a setting value and an error occur during actual operation, the gateway device 102 is implemented. It is possible to dynamically change the communication cycle while operating.

In addition, as an application of the second embodiment, by performing a test operation locally for a certain period of time before system operation, it is possible to automatically determine a communication cycle suitable for the local site without setting a communication cycle in advance. Is possible.

As described above, according to the gateway device 102 according to the present embodiment, when a large number of communication terminals perform periodic communication with a communication network such as a data center, respectively, while suppressing the amount of resources used such as memory capacity, It becomes possible to ensure a real-time response to access from each communication terminal.

DESCRIPTION OF SYMBOLS 1 Information processing system 101 Center server 102 Gateway apparatus 103 Communication terminal 104 Center network 105 Wide area network 201 Relay apparatus 202 Field network 301 Communication interface 302 Packet transmission / reception processing part 303 Transfer processing part 304 Session information management part 305 Session information monitoring part 306 1st Storage area 307 Second storage area 308 Session information cache 309 Session information table 310 Communication cycle management table 311 Period update unit 401 Processor 402 Memory 403 Peripheral interface 404 Auxiliary storage device 405 Communication interface 406 Bus

Claims

A plurality of first information processing devices and at least one second information processing device are communicably connected, and data communication is performed between the first information processing device and the second information processing device. A communication control device that mediates,
Communication period data, which is time interval information for performing data communication from the transmission source in each of the first information processing apparatuses to the second information processing apparatus, is stored for each of the first information processing apparatuses. A communication cycle data storage unit;
Last access time information that is information indicating the last time when data communication from the first information processing apparatus was executed, the last access time information regarding a certain first information processing apparatus, and the first information processing Next access time point information, which is information indicating a time point at which the first information processing device next executes data communication, calculated from the communication cycle data acquired from the communication cycle data storage unit with respect to the device, A session information storage unit storing a session associated with specific information related to data communication between the transmission source and the second information processing apparatus;
A session information cache configured with a storage device faster than a storage device constituting the session information storage unit;
Based on the next access time point information relating to each of the first information processing devices stored in the session information storage unit, the data communication execution time point from the first information processing device is a predetermined time threshold from the present time point. Session information for continuously determining whether or not the value has become below or below a predetermined time threshold value, and copying session information on the first information processing apparatus from the session information storage unit to the session information cache The management department,
When data is received from the first information processing apparatus, the session information storage unit is referred to obtain the session information corresponding to the transmission source, and the received data is transferred to the transmission destination based on the session information A transfer processing unit,
A communication control device.
The communication control device according to claim 1,
When the session information management unit determines that the session information corresponding to the first information processing apparatus that has received the data is not stored in the session information cache, the session information management unit acquires the session information from the session information storage unit. Stored in the session information cache and handing over the session information to the transfer processing unit,
Communication control device.
The communication control device according to claim 1,
In the session information storage unit and the session information cache, a plurality of past access time point information indicating a time point when data communication has been received in the past from the first information processing device corresponding to each of the first information processing devices. And the session information management unit calculates the communication cycle data from the past access time point information and stores the communication cycle data in the communication cycle data storage unit at a predetermined time interval.
Communication control device.
The communication control device according to claim 1,
When the session information management unit refers to the session information storage unit when receiving data from the first information processing apparatus and determines that session information corresponding to the transmission source is not stored, the communication information Obtaining communication cycle data corresponding to the transmission source from the cycle data storage unit, calculating the next access time point information corresponding to the transmission source, and storing the session information storage unit in association with the transmission source;
Communication control device.
A plurality of first information processing devices and at least one second information processing device are communicably connected, and data communication is performed between the first information processing device and the second information processing device. An intermediary communication control device control method comprising:
A communication cycle in which communication cycle data, which is time interval information for performing data communication from the transmission source in each of the first information processing devices to the second information processing device, is stored for each first information processing device. A data storage unit;
Last access time information that is information indicating the last time when data communication from the first information processing apparatus was executed, the last access time information regarding a certain first information processing apparatus, and the first information processing Next access time point information, which is information indicating a time point at which the first information processing device next executes data communication, calculated from the communication cycle data acquired from the communication cycle data storage unit with respect to the device, A session information storage unit that stores a session associated with specific information related to data communication between the transmission source and the second information processing apparatus;
A session information cache configured with a storage device that is faster than a storage device that stores the session information,
Based on the next access time point information relating to each of the first information processing devices stored in the session information storage unit, the data communication execution time point from the first information processing device is a predetermined time threshold from the present time point. If it is determined whether it has become the following or not, and it is determined that it has become the predetermined time threshold value or less, the session information related to the first information processing apparatus is copied from the session information storage unit to the session information cache,
When data is received from the first information processing apparatus, the session information storage unit is referred to obtain the session information corresponding to the transmission source, and the received data is transferred to the transmission destination based on the session information To
Control method of communication control device.
A communication control device control method according to claim 5,
If the communication control device determines that session information corresponding to the first information processing device that has received the data is not stored in the session information cache, the communication control device acquires the session information from the session information storage unit. Store in the session information cache, and deliver the session information to the transfer processing unit,
Control method of communication control device.
A communication control device control method according to claim 5,
In the session information storage unit and the session information cache, a plurality of past access time point information indicating a time point when data communication has been received in the past from the first information processing device corresponding to each of the first information processing devices. The communication control device calculates the communication cycle data from the past access time point information and stores the communication cycle data in the communication cycle data storage unit at a predetermined time interval.
Communication control device.
A communication control device control method according to claim 5,
When the communication control device refers to the session information storage unit when receiving data from the first information processing device and determines that session information corresponding to the transmission source is not stored, the communication cycle Obtaining communication cycle data corresponding to the transmission source from a data storage unit, calculating the next access time point information corresponding to the transmission source, and storing the session information storage unit in association with the transmission source;
Control method of communication control device.
A plurality of first information processing devices;
At least one second information processing device performing data communication with the first information processing device;
Data communication between the first information processing apparatus and the second information processing apparatus is connected to the plurality of first information processing apparatuses and the second information processing apparatus in a communicable manner. A communication control device that mediates,
Communication period data, which is time interval information for performing data communication from the transmission source in each of the first information processing apparatuses to the second information processing apparatus, is stored for each of the first information processing apparatuses. A communication cycle data storage unit;
Last access time information that is information indicating the last time when data communication from the first information processing apparatus was executed, the last access time information regarding a certain first information processing apparatus, and the first information processing Next access time point information, which is information indicating a time point at which the first information processing device next executes data communication, calculated from the communication cycle data acquired from the communication cycle data storage unit with respect to the device, A session information storage unit storing a session associated with specific information related to data communication between the transmission source and the second information processing apparatus;
A session information cache configured with a storage device faster than a storage device constituting the session information storage unit;
Based on the next access time point information relating to each of the first information processing devices stored in the session information storage unit, the data communication execution time point from the first information processing device is a predetermined time threshold from the present time point. Session information for continuously determining whether or not the value has become below or below a predetermined time threshold value, and copying session information on the first information processing apparatus from the session information storage unit to the session information cache The management department,
When data is received from the first information processing apparatus, the session information storage unit is referred to obtain the session information corresponding to the transmission source, and the received data is transferred to the transmission destination based on the session information A transfer processing unit,
A communication control device comprising:
An information processing system.