JPH11112541A - Message repeating method, message processing method, router device, network system and storage medium storing program controlling router device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a network load and to shorten the booting time of a net work computer by providing a cache function at a router device and transmit ting data on a cache to a terminal-side instead of a server. SOLUTION: When a reception packet is judged to be a cache object based on a transfer request management table 204, it is judged whether the packet is cached or not based on the cache management table 216. When it is cached, a substitute transfer control part 205 generates a data transmission packet following a transfer protocol, rewrites header information into the value of source IP address of the transfer request packet and transmits it to the data terminal-side. When it is not cached, the update processing of the transfer request management table 204 is executed and the packet is transmitted to a high-order network 231. When the reception packet is not the cache object, it is transmitted to the high-order network 231 as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing method, and more particularly, to a method for efficiently communicating a server and a data terminal in a network including a plurality of sub-networks each connecting a plurality of data terminals. .

[0002]

2. Description of the Related Art Conventionally, all software other than a boot loader without a static storage device (OS, application programs, resources used by the OS, etc.)
There is a network computer (NC) that downloads and executes from a server via a network.

When such NCs are introduced and used in units of a company (generally, hundreds to thousands), the OS itself, OS resources, and users of the company before and after the start time of the company However, the download of software such as standard applications frequently used is concentrated, and the overload of the network has become a serious problem. In particular, when such an overload phenomenon occurs in a network having a hierarchical structure based on Ethernet (registered trademark), there has been a problem that the time required for booting the NC becomes long.

[0004] The above problem becomes more serious when considering the use of NC in a language environment such as Japanese that requires larger resources (such as a kanji font and a kana-kanji conversion mechanism) than English. . At present, the total amount of Japanese-specific resources (outline fonts, kana-kanji conversion dictionaries, etc.) used on existing OSs has reached several megabytes to over a dozen megabytes, and is equivalent to or equivalent to the NC OS itself. It is larger than that. Therefore N
Even if the above-mentioned problems were mitigated in English-speaking countries by slimming down the OS of C, the above-mentioned problems could be a major alienation factor for the spread of NCs in Japan and Asia.

[0005] Conventional techniques for alleviating such problems include:
There are the following three methods, each of which has disadvantages when considering use in NC.

(1) By installing a static storage device (hard disk, flash memory, etc.) in the NC and storing frequently downloaded software on the storage device, the download from the network becomes unnecessary. Method.

(2) A line having a capacity to withstand a temporary load and a high-performance server to withstand a concentration of transfer requests are used.

(3) The network is clustered for each unit, and a server is provided for each unit.

In the method (1), having a static storage means that the user is required to manage the storage contents (OS and the like). Therefore, NC for the user
Can no longer be a turnkey system that requires no management.

In addition, mounting static storage of a compact hard disk and a flash memory in each NC requires N
The price of C is increased, and the price difference with the PC is reduced. In addition, the amount of investment when introducing an NC on a company scale is the price increase of the NC alone × the number of introduced NCs, which is expensive.

On the other hand, in the method (2), introduction of a large-capacity line and a high-performance server is expensive, and it is more efficient to measure the load distribution than to provide a temporary load. (In normal traffic, the line and the server are idle).

[0012] Further, if the installation of the NC requires the user to re-route the network equipment (line), and if the existing facilities cannot be used, the burden on the user will increase.
In particular, existing dumb terminals connected to the host system,
Simply replacing the PC with an inexpensive NC simply prevents the rebuilding of the in-house network system.

In the method (3), one server is required for every several to several tens of NCs, and a burden is imposed on the user. Usually, the server system is expensive, and the server system requires a display, a keyboard and the like for its management, and requires a considerable installation area on the customer side. In addition, the end user needs to manage the server system.

In connection with such problems of the prior art, there are JP-A-6-261078, JP-A-8-202543, and JP-B-61-57747.

Japanese Patent Laid-Open Publication No. Hei 6-261078 discloses a technique for performing high-speed routing by registering a destination address having a large number of searches in a cache memory.

Also, Japanese Patent Application Laid-Open No. Hei 8-202463 discloses that
An inter-network relay device that stores a history of frame information is disclosed.

Furthermore, Japanese Patent Publication No. 61-57747 discloses a data relay device for inhibiting reception of data from a data terminal at a set time and securing communication with a main device.

However, according to these techniques, a file that a data terminal requests to be transferred to a server is cached in a router device, and a file to be cached is cached for a subsequent transfer request to a server. It does not disclose any technology for sending back.

[0019]

SUMMARY OF THE INVENTION One object of the present invention is to provide a router device with a cache function to reduce the network load and the boot time of a network computer.

Another object of the present invention is to provide a network system in a hierarchical network in which the network load of a lower-level subnet group does not affect the higher-level network.

Another object of the present invention is to provide a hierarchical network system that can be added and expanded without considering the influence on a higher-level network.

Another object of the present invention is to provide a network system using an NC having a large total amount of software downloadable on a terminal side.

Another object of the present invention is to provide a network system that requires less resources on the terminal side.

Another object of the present invention is to provide a network system which requires less resources for a server.

Another object of the present invention is to provide an efficient network system capable of flexibly responding to the contents of the business of the subnet group by changing the file to be cached for each router device. Is to do.

Another object of the present invention is to provide a network system which can be constructed at low cost.

Another object of the present invention is to provide a network system that requires a small total installation area of necessary devices.

Another object of the present invention is to provide a network system with reduced management work.

Another object of the present invention is to provide a network system independent of the terminal platform.

Another object of the present invention is to provide a network system in which the amount of communication data between an upper network and a lower network is reduced.

Another object of the present invention is to provide a highly reliable computer system which is less likely to be affected by a failure such as a server going down or a router in an upper network going down.

Another object of the present invention is to fill a cache of a router device with data immediately before a time at which a concentration of transfer requests is expected, so that a very short time period can be achieved.
At the same time, the cache of the router device can be used even when each data terminal accesses a specific resource of the server.

[0033]

A network router device (a network relay device having a route control function such as a router and a brouter including a bridging function, hereinafter referred to as a router device) is provided for each subnet constituting the network. And have a cache function.

Data on the cache (OS, resources, applications, etc. to be downloaded)
About the transfer protocol (BO
OTP: BOOT Protocol, FTP: Fil
e Transmission Program, HT
TP: HyperText Transmission
Protocol (eg, Protocol) packet (transfer request packet) is not transmitted, and the data in the cache of the router device is transmitted to the data terminal side to reduce the network load.

In one embodiment of the present invention, a built-in program periodic start function is provided. By using this function, the router device stores a copy of the target resource in the cache of each router before the time period when access to a specific resource is concentrated on the network, or when the cache contents are unnecessary, Clear

One embodiment of the present invention is implemented on a router device that includes a cache storage unit and a cache target management table in which files to be cached are registered, and relays transfer requests transmitted from a plurality of data terminals to a server. (A) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; and (b) receiving the transfer request Determining whether the file corresponding to the included requested file identification information is to be cached by inspecting the cache target management table; and (c) if it is determined that the file is to be cached, One of the files held in the cache storage unit and corresponding to the requested file identification information included in the transfer request And transmitting to the data terminal,
(D) transmitting the transfer request to the server when it is determined that the transfer request is not to be cached. It should be noted that, in the claims of the present specification, “cache target management table”
Is a concept including a transfer request management table and a setting condition storage unit in the preferred embodiment of the present invention. The “server” is not only a boot server that transmits a file held by itself to the NC side in response to a transfer request of the NC, but also a “server”.
In response to data transmission requests from data terminals widely, data managed by itself (not only data held by itself,
(Including data obtained from other servers) to the data terminal side. further,
"Server identification information" refers to information used to identify a server, such as server address information and alias information. Similarly, “requested file identification information” also refers to information used to specify a requested file.

According to another aspect of the present invention, there is provided a cache storage unit, and a cache management table for managing data stored in the cache storage unit, and relays a transfer request transmitted from a plurality of data terminals to a server. A message relay method implemented on a router device,
(A) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; and (b) responding to the requested file identification information included in the transfer request. (C) determining whether a file to be stored is held by inspecting the cache management table;
And (d) transmitting the transfer request to the server when the corresponding file is not stored.

According to another aspect of the present invention, there is provided a cache storage unit, which holds transfer request frequency information in association with requested file identification information, and transmits the information from a server in response to transfer requests from a plurality of data terminals. (A) transmitting a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals. Receiving; (b) updating transfer request frequency information corresponding to file identification information included in the transfer request; (c) transmitting the transfer request to the server; and (d) transferring the transfer request. Receiving, from the server in response to the request, data terminal destination information, file identification information, and a packet including file information;
(E) determining whether the updated transfer request frequency information satisfies a predetermined trigger condition; and (f) determining that the updated transfer request frequency information satisfies the trigger condition, the file information included in the packet. In the cache storage unit. In the claims of the present specification, “transfer request frequency information” does not mean only the number of requests per unit time described in the preferred embodiment of the present invention, but only the number of requests or the total number of requests. This concept includes all information related to the frequency of transfer requests, such as the time required for download. Also,
“Data terminal destination information” refers to information used to identify the data terminal, such as address information of the data terminal and alias information.

According to another aspect of the present invention, there is provided a router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. The message relay method implemented above, comprising: (a) receiving data terminal destination information, file identification information, and a packet including file information from the server side; and (b) file identification included in the packet. Determining whether the packet is to be cached based on the information; (c) transmitting the packet to the data terminal based on the data terminal destination information; and (d) determining that the packet is to be cached. If determined, generating a packet including the file information included in the packet and the destination information of the self, (e)
Storing the file information included in the generated packet in the cache storage unit. In the claims of the present specification, “own destination information” refers to information used for transmitting the packet to the router device.

In another aspect of the present invention, a message relay method implemented on a router device having a cache storage unit and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. And
(A) receiving data terminal destination information, file identification information, and a packet including file information from the server side; and (b) determining whether the packet is to be cached based on the file identification information included in the packet. And (c) storing the file information included in the packet in the cache storage unit when it is determined that the packet is to be cached.

According to another aspect of the present invention, there is provided a cache storage unit and a cache management table for managing data stored in the cache storage unit, and relays transfer requests transmitted from a plurality of data terminals to a server. Message processing method implemented on a router device that performs
(A) receiving a message including request type information and file identification information from one data terminal included in the plurality of data terminals; and (b) determining whether the request type information included in the message is a predetermined value. (C) If it is determined that the value is the expected value,
Judging whether or not the file corresponding to the file identification information included in the message is held by inspecting the cache management table; and (d) when the corresponding file is held, Erasing retained files. In the claims of the present specification, the “request type” refers to information used for determining the type of a request for the message, such as a port number and an operation.

According to another aspect of the present invention, a cache storage unit and a timer are provided, program start time specifying information is held in association with a start program including transfer file specifying information, and transmitted from a plurality of data terminals to a server. (A) comparing the program start time specifying information with a current time obtained from the timer to determine the program start time. Determining whether to execute the startup program associated with the information; and (b) executing the associated program when it is determined that the startup program associated with the information is to be executed. Generating a packet requesting transfer of a file corresponding to the transfer file specifying information; A message processing method is provided, comprising: transmitting a requested packet to the server; and (d) storing file information transmitted from the server in response to the requested packet in the cache storage unit. You. It should be noted that, in the claims of the present specification, the “program start time specifying information” is a concept including not only information such as date and time but also information indicating an execution cycle such as “every Tuesday”.

In another aspect of the present invention, a cache storage unit and a timer are provided, and program start time specifying information is held in association with a start program including erased file specifying information, and transmitted from a plurality of data terminals to a server. (A) comparing the program start time specifying information with a current time obtained from the timer to determine the program start time. Determining whether to execute the startup program associated with the information; and (b) executing the associated program when it is determined that the startup program associated with the information is to be executed. Erasing the transfer of the file corresponding to the erased file specifying information from the cache storage unit. No message processing method is provided.

According to another aspect of the present invention, there is provided a router device having a cache storage unit and a cache target management table in which files to be cached are registered, and relaying a transfer request transmitted from a plurality of data terminals to a server. (A) a connection port for receiving a transfer request including server identification information and request file identification information from one data terminal included in the plurality of data terminals; and (b) request file identification included in the transfer request. A transfer protocol / cache control unit for determining whether a file corresponding to the information is to be cached by examining the cache target management table; and (c) when it is determined that the file is to be cached, The file corresponding to the requested file identification information included in the transfer request and held in the cache A proxy transfer control unit that transmits to the one data terminal, if it is determined not to be (d) cache object, a routing control unit that transmits the transfer request to the server, a router device including a is provided.

According to another aspect of the present invention, there is provided a cache storage unit and a cache management table for managing data stored in the cache storage unit, and relays transfer requests transmitted from a plurality of data terminals to a server. A connection port for receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals;
(B) a cache control unit for judging whether or not a file corresponding to the requested file identification information included in the transfer request is held by checking the cache management table; and (c) holding a corresponding file. If the corresponding file is not held, the proxy transfer control unit sends the held file to the one data terminal. (D) If the corresponding file is not held, the transfer request is sent to the server. And a routing control unit.

According to another aspect of the present invention, there is provided a cache storage unit, which holds transfer request frequency information in association with requested file identification information, and transmits the information from a server in response to transfer requests from a plurality of data terminals. (A) a first connection port for receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; (B) a transfer protocol analysis / cache control unit for updating transfer request frequency information corresponding to file identification information included in the transfer request, (c) a routing control unit for transmitting the transfer request to the server, d) receiving a packet including data terminal destination information, file identification information, and file information transmitted from the server in response to the transfer request. It includes a second connecting port, and
(E) the transfer protocol analysis / cache control unit includes:
It is determined whether or not the updated transfer request frequency information satisfies a predetermined trigger condition. (F) If it is determined that the trigger condition is satisfied, the file information included in the packet is stored in the cache memory. There is provided a router device including a cache control unit stored in a unit.

According to another aspect of the present invention, there is provided a router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. (A) data terminal destination information and file identification information from the server side;
A connection port for receiving a packet containing file information,
(B) a transfer protocol analysis / cache control unit that determines whether or not the packet is to be cached based on file identification information included in the packet; and (c) converts the packet based on the data terminal destination information. (D) the transfer protocol analysis / cache control unit, when it is determined that the packet is to be cached, the file information included in the packet and the own destination (E) A router device including a cache control unit that generates a packet including information and further stores file information included in the generated packet in the cache storage unit.

According to another aspect of the present invention, there is provided a router device having a cache storage unit for relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. Based on the data terminal destination information, the file identification information, the connection port for receiving the packet including the file information from the server, and (b) determining whether the packet is to be cached based on the file identification information included in the packet. A router device that includes a transfer protocol analysis / cache control unit that performs the transfer, and (c) a cache control unit that stores, in the cache storage unit, file information included in the packet when it is determined that the packet is to be cached. Provided.

According to another aspect of the present invention, there is provided a cache storage unit, and a cache management table for managing data stored in the cache storage unit, and relays transfer requests transmitted from a plurality of data terminals to a server. (A) a connection port for receiving a message including request type information and file identification information from one data terminal included in the plurality of data terminals;
(B) a transfer protocol analysis / cache control unit that determines whether or not the request type information included in the message is a scheduled value; and (c1) if the request type information is determined to be a scheduled value, the request type information is included in the message. It is determined by checking the cache management table whether a file corresponding to the file identification information to be held is held. (C2) If the corresponding file is held, the held file is A router device including a cache control unit to be erased is provided.

According to another aspect of the present invention, a cache storage unit and a timer are provided, program start time specifying information is held in association with a start program including transfer file specifying information, and transmitted from a plurality of data terminals to a server. And (a) comparing the program start time specifying information with the current time obtained from the timer, so that the start program associated with the program start time specifying information is obtained. And (b) when it is determined that the associated startup program is to be executed, the associated program is executed to determine whether or not to execute the associated file. A transfer program for generating a packet requesting transfer of a corresponding file; and (c) the requested packet. A router device is provided that includes: a routing control unit that transmits to the server; and (d) a cache control unit that stores file information transmitted from the server in response to the requested packet in the cache storage unit. .

In another aspect of the present invention, a cache storage unit and a timer are provided, and program start time specifying information is held in association with a start program including erased file specifying information, and transmitted from a plurality of data terminals to a server. And (a) comparing the program start time specifying information with the current time obtained from the timer, so that the start program associated with the program start time specifying information is obtained. And (b) when it is determined that the associated startup program is to be executed, by executing the associated program, the A cache control unit for erasing a corresponding file transfer from the cache storage unit. It is subjected.

According to another aspect of the present invention, the data terminal includes a plurality of data terminals, a server, a cache storage unit, and a cache management table for managing data stored in the cache storage unit. And a router device for relaying a transfer request transmitted from the server to the server, and (a) transmitting a file held by the terminal device in response to a transfer request from the plurality of data terminals. A server, (b) a data terminal for transmitting a transfer request including server identification information and request file identification information, and (c1) a connection port for receiving the transfer request from one data terminal included in the plurality of data terminals And (c2) determining whether or not a file corresponding to the requested file identification information included in the transfer request is held by the cache management data. (C3) when a corresponding file is stored, a proxy transfer control unit that transmits the stored file to the one data terminal; c4) If no corresponding file is held, a router system including a routing control unit for transmitting the transfer request to the server is provided.

According to another aspect of the present invention, a plurality of data terminals, a server, and a cache storage unit are provided, and transfer request frequency information is held in association with requested file identification information. And a router device for relaying a packet transmitted from the server in response to the transfer request of (a). (B) a data terminal that transmits a transfer request including server identification information and requested file identification information; and (c1) the transfer request from one data terminal included in the plurality of data terminals. (C2) Transfer protocol analysis for updating transfer request frequency information corresponding to file identification information included in the transfer request A cache control unit, and a routing control unit for transmitting (c3) the transfer request to the server,
(C4) including a data terminal destination information, a file identification information, and a second connection port for receiving a packet including file information transmitted from the server in response to the transfer request; The transfer protocol analysis / cache control unit determines whether or not the updated transfer request frequency information satisfies a predetermined trigger condition. (C6)
When it is determined that the trigger condition is satisfied, a network system is provided that includes: a router device that includes a cache control unit that stores file information included in the packet in the cache storage unit.

According to another aspect of the present invention, a plurality of data terminals, a server, and a cache storage unit are provided, and a packet transmitted from the server in response to a transfer request from the plurality of data terminals is relayed. A data terminal transmitting a transfer request including server identification information and requested file identification information; and (b) responding to a transfer request from the plurality of data terminals. Server for transmitting a packet including the data terminal destination information, the file identification information, and the file information,
(C1) a connection port that receives the packet from the server side, and (c2) a transfer protocol analysis / cache control unit that determines whether the packet is to be cached based on file identification information included in the packet. ,
(C3) If it is determined that the content is to be cached,
A router device including a cache control unit that stores file information included in the packet in the cache storage unit.

According to another aspect of the present invention, a plurality of data terminals, a server, a cache storage unit, and a timer are provided, and program start time specifying information is held in association with a start program including transfer file specifying information. A router for relaying a transfer request transmitted from the plurality of data terminals to the server, and (a) holding a router in response to the transfer request from the plurality of data terminals. (B) a data terminal for transmitting a transfer request including server identification information and requested file identification information, and (c1) a current time at which the program start time specifying information is obtained from the timer. It is determined whether or not to execute the start program associated with the program start time specifying information by comparing And (c2) when it is determined that the associated startup program is to be executed, by executing the associated program, a request is made to transfer a file corresponding to the transfer file specifying information. A transfer program for generating a packet; (c3) a routing control unit for transmitting the requested packet to the server; and (c4) a cache storage unit for storing file information transmitted from the server in response to the requested packet. And a router device that includes a cache control unit that stores the information in the network system.

According to another aspect of the present invention, there is provided a cache storage unit, a cache management table in which files to be cached are registered, and a router which relays transfer requests transmitted from a plurality of data terminals to a server. A recording medium storing a message relay program to be executed, the program comprising: (a) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; Program code for instructing the router device to perform
(B) a program code for instructing the router to determine whether a file corresponding to the requested file identification information included in the transfer request is to be cached by inspecting the cache target management table. And (c) transmitting, to the one data terminal, a file stored in the cache storage unit and corresponding to the requested file identification information included in the transfer request when it is determined that the file is to be cached. A program code for instructing the router device, and (d) a program code for instructing the router device to transmit the transfer request to the server when it is determined that the transfer request is not to be cached. A recording medium is provided.

According to another aspect of the present invention, there is provided a cache storage unit, and a cache management table for managing data stored in the cache storage unit, and relays transfer requests transmitted from a plurality of data terminals to a server. A storage medium storing a message relay program to be executed on a router device, comprising: (a) transmitting, from one data terminal included in the plurality of data terminals, server identification information and requested file identification information; A program code for instructing the router device to receive the transfer request including the transfer request, and (b) determining whether or not a file corresponding to the requested file identification information included in the transfer request is stored in the cache management table. A program code for instructing the router device to make a judgment by inspection; When a file to be stored is stored, a program code for instructing the router device to transmit the stored file to the one data terminal and (d) a corresponding file are stored. If not, a recording medium is provided that includes a program code for instructing the router device to transmit the transfer request to the server.

According to another aspect of the present invention, a cache storage unit is provided to hold transfer request frequency information in association with requested file identification information, and to be transmitted from a server in response to transfer requests from a plurality of data terminals. A storage medium storing a message relay program executed on a router device for relaying a packet to be transmitted, the program comprising: (a)
A program code for instructing the router device to receive a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; A program code for instructing the router to update transfer request frequency information corresponding to included file identification information; and (c) instructing the router to transmit the transfer request to the server. And the program code of
(D) a program code for instructing the router device to receive a data terminal destination information, file identification information, and a packet including file information transmitted from the server in response to the transfer request; (E) a program code for instructing the router device to determine whether or not the updated transfer request frequency information satisfies a predetermined trigger condition; and (f) it is determined that the trigger condition is satisfied. In this case, a recording medium is provided that includes a program code for instructing the router device to store the file information included in the packet in the cache storage unit.

According to another aspect of the present invention, there is provided a router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. A storage medium storing a message relay program implemented in the above, wherein the program comprises: (a) receiving, from the server, data terminal destination information, file identification information, and a packet including file information by the router; A program code for instructing the router, and (b) a program code for instructing the router to determine whether the packet is to be cached based on file identification information included in the packet, (C) instructing the router to transmit the packet to the data terminal based on the data terminal destination information; And program code for, (d)
If it is determined that the packet is to be cached, file information included in the packet, a program code for instructing the router device to generate a packet including the own destination information, and (e) And a program code for instructing the router device to store file information included in the generated packet in the cache storage unit.

According to another aspect of the present invention, there is provided a message relay program embodied on a router device having a cache storage unit and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. A program code for instructing the router device to receive data terminal destination information, file identification information, and a packet including file information from the server side. (B) a program code for instructing the router device to determine whether or not the packet is to be cached based on the file identification information included in the packet; and (c) that the packet is to be cached. If it is determined, the rule indicates that the file information included in the packet is to be stored in the cache storage unit. Recording medium containing a program code instructing data device is provided.

According to another aspect of the present invention, there is provided a cache storage unit and a cache management table for managing data stored in the cache storage unit, and relays transfer requests transmitted from a plurality of data terminals to a server. A message processing program to be executed on a router device, the program including: (a) request type information and file identification information from one data terminal included in the plurality of data terminals; A program code for instructing the router device to receive the message, and (b) a program code for instructing the router device to determine whether or not the request type information included in the message is a predetermined value. Code, and (c) if it is determined to be the expected value, the file identification included in the message A program code for instructing the router device to determine whether or not a file corresponding to the information is held by inspecting the cache management table; and (d) holding a corresponding file. And a program code for instructing the router device to delete the held file.

In another aspect of the present invention, a cache storage unit and a timer are provided, and program start time specifying information is held in association with a start program including transfer file specifying information, and transmitted from a plurality of data terminals to a server. A storage medium storing a message processing program executed on a router device for relaying a transfer request to be transmitted, the program comprising: (a) comparing the program start time specifying information with a current time obtained from the timer; By doing, a program code for instructing the router device to determine whether to execute a startup program associated with the program startup time identification information,
(B) If it is determined that the associated startup program is to be executed, the associated program is executed to generate a packet requesting transfer of a file corresponding to the transfer file specifying information. Program code for instructing the router device that
(C) a program code for instructing the router device to transmit the requested packet to the server; and (d) file information transmitted from the server in response to the requested packet in the cache storage. And a program code for instructing the router device to store the information in a unit.

According to another aspect of the present invention, a cache storage unit and a timer are provided, program start time specifying information is held in association with a start program including erased file specifying information, and transmitted from a plurality of data terminals to a server. A storage medium storing a message processing program executed on a router device for relaying a transfer request to be transmitted, the program comprising: (a) comparing the program start time specifying information with a current time obtained from the timer; By doing, a program code for instructing the router device to determine whether to execute a startup program associated with the program startup time identification information,
(B) If it is determined that the associated boot program is to be executed, the transfer of the file corresponding to the erased file specifying information is erased from the cache storage unit by executing the associated program. And a program code for instructing the router device to perform the operation.

[0064]

【Example】

A. Outline An outline of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a computer system according to a preferred embodiment of the present invention. Corporate backbone 101
Are the boot server 103, NC 201, 202, 20
3 and routers 151, 152 and 153 are connected.
Each router 151 connected to this corporate backbone,
The subnets 152, 153 have subnets 111, 112, 1 respectively.
13 are connected. Subnets 111, 112, 1
Further, a router for connecting NCs and subnets is connected to 13.

Each NC has downloaded from the boot server 103 all software (OS, resources used by the OS, application programs, etc.) other than the boot loader.

At this time, all the NCs are
If the data is to be received directly from the network 3, the backbone 101 is burdened by the entire company, and the lower subnets 111, 112, and 113 are burdened by all the NCs connected to the lower subnets.

For example, a transfer request issued from the NC 281 reaches the boot server 103 via the backbone 101 via the subnets 121 and 111. NC28
1 and the boot server 103 are connected, and the transfer protocol is performed directly between the server and the NC. But,
Since all the packets exchanged between the NC 281 and the server 103 pass through the routers 161 and 151, if the router 161 or the router 151 has a caching and protocol analysis function, the router 161 or the router 151
By monitoring the transfer between the NC and the server, the original data on the server can be restored and cached.

When another NC (for example, NC 283) of the same subnet issues a transfer request to the server 103 with respect to the data in the cache, the router 161 or 151 does not transmit the request, and the router 161 does not transmit the request.
Alternatively, the router 151 acts as a server and
83 and a session with NC2
Transfer to 83. By such caching on a per-subnet basis, only one load on the subnet is applied to the upper net, and thereafter, traffic can be processed within the subnet.

In one embodiment of the present invention, a router device with a data cache obtains a passive trigger from a data terminal connected to a lower subnet by monitoring a data transfer protocol across the subnet. If the data is cached, but the validity of the data in the cache cannot be guaranteed before one transfer ends normally, if a transfer instruction to the same data is received from another data terminal during caching, Since the router wraps the incomplete data in the cache and cannot transfer the data to the data terminal, the transfer command is transmitted to the original destination.

Therefore, in this mode, the operation is good when the same data is downloaded from the data terminal with a slight time difference, but the transfer is performed in a very short time (within the time until the router finishes caching). When requests are concentrated, the router cannot effectively use the cache, and as a result, it does not lead to reduction of the network load.

For this reason, in another aspect of the present invention, a mechanism for attaching a storage medium storing a program such as a memory card to a router device is provided, and the medium realizes a client function of a data transfer protocol on the medium. Is stored, and the program can be started at a regular time using a clock mechanism.

By providing this mechanism, the network router with the cache function makes a call to the server with a dummy data transfer request so that data expected to be accessed frequently is sent from the server to the router. This allows the router cache to be filled with the data before the access is concentrated. According to this method, even when access from each data terminal to a specific resource of the server is concentrated in a very short time, the caching function of the router can be sufficiently used.

B. Hardware Configuration Next, the hardware configuration of the router device of the present invention will be described. The router device 100 according to the preferred embodiment of the present invention can be realized by a router having the following mechanism.

(1) A storage mechanism for a cache (implemented by a RAM in the preferred embodiment of the present invention).

(2) A storage mechanism for storing a program for performing a transfer protocol analysis and proxy execution (in a preferred embodiment of the present invention, implemented by a ROM. In a preferred embodiment of the present invention, a transfer A program for performing protocol analysis and proxy execution is executed by being loaded into RAM.)

(3) A storage mechanism for storing the setting of the cache condition (implemented by a rewritable ROM in the preferred embodiment of the present invention).

(4) Clock mechanism (in a preferred embodiment of the present invention, implemented by a timer and a periodic start program unit).

Many of the popularized routers at the time of filing of the present application are ordinary P-type printers except that they do not have display and key input devices.
It has the same hardware configuration as C (general-purpose CPU, memory, static storage device, network adapter, etc.).
(In some cases, the display and keyboard are removed from an inexpensive PC, and the computer is sold as a router with the minimum necessary OS installed.)
For other devices such as those described above, those used as standard in the router can be used for the cache function.

FIG. 2 shows a router 100 (151-153, 161-166, 17) used in the present invention.
1, 172) is an overview diagram showing an embodiment of a hardware configuration.

The router 100 has a central processing unit (CP)
U) 1 and a memory 4. CPU 1 and memory 4
Is connected via a bus 2 to a hard disk device 13 as an auxiliary storage device. Floppy disk drive (or recording medium drive such as MO, CD-ROM, etc.)
20 is a floppy disk controller 19 (or I
It is connected to the bus 2 via a DE controller, a SCSI controller, etc.).

Floppy disk drive (or MO, C
A recording medium driving device such as a D-ROM 20 includes a floppy disk (or a recording medium such as an MO or a CD-ROM).
The floppy disk or the like, the hard disk device 13, or the ROM 14 can cooperate with the operating system to give instructions to the CPU or the like, and record computer program codes for implementing the present invention. This is executed by being loaded into the memory 4. The code of the computer program can be compressed or divided into a plurality of pieces and recorded on a plurality of media.

The router device 100 can further include user interface hardware.
Pointing device (mouse,
A joystick 7) or keyboard 6 and a display 12 for presenting visual data to the user. Further, a modem can be connected via the serial port 15. This router 100
Can be connected to a network via the serial port 15 and a modem or a communication adapter 18 (Ethernet or token ring card) or the like, and can communicate with another computer or the like.

As described above, the router 100 of the present invention can easily be implemented by a computer having a communication function including a normal personal computer (PC), a workstation, a notebook PC, or the like, or a combination thereof. You can understand. However, these components are merely examples, and not all of them are essential components of the present invention.

In particular, since the hardware configuration described here is only required to perform the relay between networks, the keyboard 6, the mouse 7, and the keyboard / mouse that enable direct input from the operator Controller 5, CRT 1 for presenting visual data to user
2. Display device 11, VRAM 9, VGA 8, various recording medium processing devices 19, 25, 27, etc. are not essential components.

Various changes such as combining a plurality of machines, distributing functions to them, and implementing each of the components of the router device 100 are easily envisioned by those skilled in the art. This is a concept included in the concept of the present invention.

The data terminal 110 used in the present invention can also be implemented by the hardware configuration shown in FIG. That is, the data terminal 11
0 may have a function of inputting an information acquisition request and transmitting the information request.
C) and various home appliances such as a workstation, a notebook PC, a palmtop PC, a television with a built-in computer, etc., and a communication function including a game machine having a communication function, a telephone, a FAX, a mobile phone, a PHS, an electronic organizer, and the like. It can be easily understood that the present invention can be implemented by a data terminal or a combination thereof.

However, these components are merely examples,
Not all of the components are essential components of the present invention. In particular, in a preferred embodiment of the present invention, all the software (OS, resources used by the OS, application programs, etc.) other than the boot loader is provided from the server via the network without the static storage device. The hard disk device 13 and the like are not indispensable components, as a network computer (NC) to be downloaded and executed is used as a data terminal.

The audio controller 21, the amplifier 22, the speaker 23, the microphone 24, and the keyboard 6, the mouse 7, the keyboard / mouse controller 5, and various kinds of recordings which enable direct input from an operator and necessary for voice processing. The media processing devices 19, 25, 27, etc. are not necessarily required components.

In the preferred embodiment of the present invention, the route control software and the like of the router device 100 may be stored in a ROM as dedicated firmware.
NT (a trademark of Microsoft), Windows 95
(Trademark of Microsoft), Windows3. x (Microsoft trademark), OS / 2 (IBM trademark), M
Operating systems and applications such as acOS (trademark of Apple Inc.) and X-WINDOW system (trademark of MIT) on AIX (trademark of IBM)
It can also be realized by a combination of software.

Operating system on the data terminal 110 side
The system is WindowsNT (Microsoft trademark), Windows95 (Microsoft trademark),
Windows3. x (Microsoft trademark), OS
, Which supports the GUI multi-window environment as standard, such as X / 2 (IBM trademark), MacOS (Apple trademark), and X-WINDOW system (MIT trademark) on AIX (IBM trademark). DOS (I
BM trademark), MS-DOS (Microsoft trademark)
Such as character-based environment, OS /
Open (trademark of IBM), VxWorks (Wind
River Systems, Inc. Not only a real-time OS such as a trademark), an OS embedded in a network computer such as Java OS, but also a Zaurus OS used for "Saurus" (trademark of Sharp Corporation), "Data Scope" (trademark of Kyocera Corporation) ) Can be realized by a chip card OS or the like used in, for example, and is not limited to a specific operating system environment.

C. System Configuration FIG. 3 shows a router device 10 according to a preferred embodiment of the present invention.
0 is a functional block diagram showing a system configuration of No. 0. FIG.

The network connection ports 221 and 223 are connected to the upper network 231 and the lower network 233, respectively.
Connected to

Transfer Protocol Analysis / Cache Control Unit 2
03 analyzes the IP address and transfer protocol (port number) of the IP packet. In addition, for a request packet from a lower network, the cache control unit 215 is inquired about whether or not there is data requested in the cache. FIGS. 13 to 16 show packets relayed by the router device 100 in the preferred embodiment of the present invention.

If a response indicating that the data exists is received from the cache control unit 215, the proxy transfer control unit 2
When a proxy transfer request is made at 05 and a response indicating that it does not exist is received, the request packet is passed to the routing control unit 201.

In the preferred embodiment of the present invention, when a transfer request for data is made to the information source of data stored in the cache, the transfer protocol analysis / cache control unit 203 The information is rewritten, and the request is sent to the protocol handler (proxy transfer control unit 205) incorporated therein. Also,
This protocol handler (bootp, ftp, h
(tp server function) generates a packet from the data in the cache in response to a request from the client, and sends the packet to the client via the routing control unit 201.

On the other hand, with respect to the packet from the upper network, the header information of the packet is analyzed, and it is determined whether or not the packet satisfies the cache target condition based on the data in the setting condition storage unit 207. If the condition matches the cache target, the data to be transferred is extracted and the cache control unit 215 stores the cache dynamic storage unit 209.
Ask me to remember.

In the preferred embodiment of the present invention, the transfer protocol analysis / cache control unit 203 holds a transfer request management table 204 as shown in FIG. It manages the frequency information of transfer requests. In a preferred embodiment of the present invention, the transfer request management table 204 stores
Address 341, port number 343, protocol ID 3
44, file name 345, cache flag 346,
Data terminal address 35 corresponding to file name 345
1, and has an entry of access time 353.

In the preferred embodiment of the present invention, this transfer request management table is generated based on the contents of a setting condition storage unit 207 described later when the router is started, and is added / deleted when the setting conditions are changed. Specifically, a table is generated for each file registered as a cache target in the setting condition storage unit 207 in FIG. 6, and the corresponding host address 341, port number 343, protocol ID
344, the file name 345 is set, and the cache
Flag 346 is set to zero. Transfer request entry 3
Numeral 50 sets the source IP address of the TCP / IP packet and the time obtained from the clock mechanism 211 (timer) when the transfer request packet is received from the data terminal 110. If the transfer request entry meets the predetermined trigger condition, the cache flag 34
Turn 6 on.

The routing control unit 201 analyzes a destination address and a port number, determines a port to which a packet is to be transmitted, and transmits the packet.

When a data transfer request is made to the information source of the data stored in the cache, the proxy transfer control unit 205 generates a packet from the data in the cache, and controls the routing control unit 201. To the client via

The remote control command processing unit 213 receives a control command (condition setting, cache clear command, time adjustment, etc.) sent from the network 231 or 233 or the setting terminal 235, and executes the command. .

The cache control unit 215 controls reading and writing of a cached file. In the preferred embodiment of the present invention, the cache control unit 215 includes a cache management table 216 as shown in FIG. 5, which holds management information of cached files.

In the preferred embodiment of the present invention, this cache management table stores
When it is stored in the file 09, it is generated for each file, and the corresponding host address 361, port number 363, protocol ID 365, and file name 367 are set. Also, when storing the data in the cache storage unit 209, the clock mechanism 21 is used.
1 (timer), the generation time 371 is set, and the last access time 373 and the current access time are set.
Set count 375 to zero. Last access time 3
73 and the current access count 375 are updated when the file stored in the cache storage unit 209 is downloaded to the data terminal 110.

The setting condition storage unit 20 shown in FIG.
7 and the time calculated on the basis of the generation time 371 and the scheduled time 377
Set to. The pointer 369 is pointer information for accessing a corresponding file stored in the cache storage unit 209.

As shown in FIG. 6, the setting condition storage unit 207 manages a table for specifying a packet to be cached and for holding various management information. Specifically, the setting condition storage unit 207 stores a host address (host name) 301, a port number 311, a protocol ID 31
3, the information of the file name 321 is retained, and the cache retention period 323, the cache trigger 3
25 (request frequency 327, unit time 329).

In the preferred embodiment of the present invention, the cache trigger 325 can be set to hold the cache when three or more transfer requests are received in one day (24 hours). In the preferred embodiment of the present invention, this cache trigger condition can be variously set, for example, when the data terminal address 351 (FIG. 4) is a specific address, the cache flag 346 is set.
Can be turned on, or the access count can be increased only for a specific address, whereby a file accessed from a specific data terminal can be preferentially cached.

If a certain condition is satisfied, a cache clear trigger for clearing the cache can be set separately. The information in the setting condition storage unit 207 can be directly registered / changed from the setting terminal 235 connected via the setting connection port 225. In the preferred embodiment of the present invention, information in the setting condition storage unit 207 can be registered / changed not only from a setting terminal but also by receiving a packet instructing a setting change from an upper or lower network. .

The clock mechanism 211 includes a timer mechanism and a regular start-up program section 212 included in an ordinary computer or router. Scheduled startup program section 212
Starts the external transfer program 243 stored in the external storage medium 241 when the set time comes with reference to the scheduled activation program table 214.

The external transfer program 243 performs various processes such as a cache command and a cache clear command according to the set contents. The external storage medium driving unit 217 is a driver for driving the external storage medium 241.

Although the functional blocks shown in FIGS. 3 to 5 have been described above, these functional blocks are logical functional blocks, which means that they are realized by hardware or software having one unit. Rather, they can be implemented with complex or common hardware and software. Further, not all the functional blocks shown in FIGS. 3 to 5 are essential components of the present invention.

For example, if the condition setting packet is received from the lower or upper network, the setting terminal 235 and the setting terminal port 225 are unnecessary, and the external transfer control unit 243 is incorporated in the router device. , The external storage medium 241 becomes unnecessary.

D. Packet Processing Procedure Next, a packet processing procedure by the router device in a preferred embodiment of one aspect of the present invention will be described.

FIG. 5 is a main flow of packet processing in the preferred embodiment of the present invention. When the router apparatus 100 receives the packet, the transfer protocol analysis / cache control unit 203 analyzes the IP address of the IP packet and determines whether the packet is addressed to itself or a packet addressed to another party (block 503).

Specifically, in the case of the preferred embodiment of the present invention, TCP / IP (Transmission Con
control Protocol / Internet Pr
The destination IP address (destination IP address in FIG. 13) of the packet of the protocol of the protocol of FIG. 13 is compared with its own IP, and if they match, the packet is addressed to itself; Is determined.

If the packet is addressed to another party, a routing process described later is performed (block 511). If the packet is addressed to itself, the port protocol is further checked to determine whether it is a remote control protocol or an external transfer protocol (block 505).

More specifically, in the case of the preferred embodiment of the present invention, UDP (User Datagram Proto) is used.
col) protocol (FIG. 14)
Is determined according to whether or not the UDP destination port) is a designated value that matches the expected value.

If the packet is determined to be the external transfer protocol, the packet is transferred to the external transfer unit 243 of the external storage medium 241 (block 507). External transfer unit 243
Performs a regular startup process described later.

If it is determined that the protocol is the remote control protocol, the transfer protocol analysis / cache control unit 203
Transfers control to the remote control command processing unit 213 to perform remote control processing (self-control processing) (block 50).
9).

D-1. Proxy Transfer Processing FIG. 9 is a flowchart showing the procedure of the routing processing in the preferred embodiment of the present invention. If it is determined in block 503 of FIG. 7 that the packet is addressed to another party, it is determined whether the packet is from a lower network or a higher network, as shown in FIG. 9 (block 551). Specifically, the router device 100
The IP address of the data terminal managed by itself is registered, and by analyzing the source IP address of the TCP / IP packet, it is determined that the packet is from a lower network (others are packets from an upper network). Can be recognized.

It should be noted that, as in the preferred embodiment of the present invention shown in FIG.
31 and the packet from the lower network 233 are sent from the dedicated network connection ports 221 and 223, respectively, depending on which port the packet came in from, a packet from the lower network or a packet from the upper network. Can also be determined.

FIG. 10 is a flowchart showing a procedure for processing a packet from a lower network in the preferred embodiment of the present invention. In the packet processing from the lower network, first, the transfer protocol analysis / cache control unit 203 determines whether the port is a cache target port (block 563), a cache target file (block 565), or a transfer request (block 567). to decide.

Specifically, the transfer protocol analysis / cache control unit 203 determines whether or not the port number and file name of the packet are registered in the transfer request table 204 of FIG. In the preferred embodiment of the present invention, the determination is made based on whether or not it is registered in the transfer request table 204.
Alternatively, it can be replaced by checking whether or not the information is registered in 7.

In the preferred embodiment of the present invention, whether or not a transfer request is made is determined based on whether or not the value of the operation (OP in FIG. 15) in the BOOTP message format is a predetermined value. I have.

If it is determined that the packet is not a port to be cached, the packet is passed to the routing control unit 201 as it is, and a route according to the destination IP address is determined as in a conventional router, and the packet is transmitted to the upper network. 231 (block 565).

If it is a transfer request, it is determined whether or not it has been cached by referring to the cache management table 216 (block 569).

If the cache has already been cached, the transfer protocol analysis / cache control unit 203 passes control to the proxy transfer control unit 205. The proxy transfer control unit 205 creates a data transmission packet according to the transfer protocol (block 571), rewrites the header information with the value of the source IP address of the transfer request packet, and converts the data transmission packet via the routing control unit 201. To the data terminal 110 (block 575).

When it is determined that the data has not been cached, the transfer request management table 204 is updated (block 578). Specifically, the host address 341 and the port number 34 in the transfer request management table 204 in FIG.
3. The source IP address of the TCP / IP packet and the time obtained from the clock mechanism 211 (timer) are set in the entry (transfer request entry 350) of the data terminal address 351 corresponding to the protocol ID 344, the file name 345, and the access time 353. .

The cache trigger condition 32 of FIG. 6 of the transfer request entry 350 of the transfer request management table 204
5 is determined, and the cache trigger condition is satisfied (for example, the number of requests 327 per unit time 329).
Is exceeded, the cache flag 346 is set to 1 and the transfer request entry 350 is cleared. In the preferred embodiment of the present invention, the transfer request management table 204 is generated based on the contents of the setting condition storage unit 207 when the router device 100 is started, and is added / deleted when the setting conditions are changed. For each transfer request, a method may be employed in which it is checked whether or not the corresponding file is registered in the transfer request table 204, and if not registered, a table corresponding to the file is generated.

Thereafter, the packet is transferred to the routing control unit 201, a route is determined according to the destination IP address as in a conventional router, and the packet is transmitted to an upper network (block 579).

D-2. Caching Processing Referring again to FIG. 9, if it is determined in block 551 that the packet is a packet from the upper network, as shown in FIG. 11, the transfer protocol analysis / cache control unit 203 is used for transfer. Packet TC
Analyze the P / IP header information to determine if the cached condition is met (blocks 583,58)
7).

More specifically, the host address 341 and the port number 34 in the transfer request management table 204 shown in FIG.
3. Check the protocol ID 344 and the file name 345 to determine whether the file is registered in the transfer request management table 204 and whether the cache flag 346 is set to 1. In a preferred embodiment of the present invention,
The determination is made based on whether or not it is registered in the transfer request table 204, but it is checked whether or not it is registered in the setting condition storage unit 207 in FIG. It can be replaced by checking whether 350 is satisfied or not.

If it is determined that the packet does not satisfy the cache target condition, the packet is passed to the routing control unit 201 as it is, a route according to the destination IP address is determined, and the packet is transmitted to the lower network. (Block 585).

If it is determined that the condition of the cache target is satisfied, the transfer protocol analysis / cache control unit 20
3 makes a copy of the packet (block 58)
9), copy the source packet to the routing control unit 201
Pass to. The routing control unit 201 determines a route according to the destination IP address, and sends the packet to the lower network (block 591).

On the other hand, the destination address of the packet created by the copy is rewritten to its own address, and the port is rewritten to that of the cache control unit corresponding to the transfer protocol (block 593).

Transfer Protocol Analysis / Cache Control Unit 2
03 transfers the copied and rewritten packet to the routing control unit 201. Routing control unit 201
Sends the copy packet to the cache control unit 215 according to the rewritten destination IP address (block 595). The cache control unit 215 sets the contents of the cache management table 216, and stores the data of the packet in the cache storage unit 209. Further, the transfer protocol analysis / cache control unit 203 clears the contents of the cache flag 346 and the transfer request entry 350.

The main function of currently used routers is to analyze the header information of a packet and determine the packet transmission route. Adding functions can be done easily. In fact, many routers on the market today have additional functions such as header rewriting and filtering of packet transmission / non-transmission using a protocol, in addition to the above-mentioned transmission path determination function. The above functions can be easily added by modifying / adding the program.

D-3. Remote Control Process FIG. 6 is a flowchart showing the procedure of the remote control process in the preferred embodiment of the present invention. In the remote control processing, first, the remote control instruction processing unit 213
Checks the port protocol and determines whether it is a cache clear command or a time setting command (block 523).

Specifically, in the case of the preferred embodiment of the present invention, when the destination port of the UDP packet has a predetermined port address as the cache clear command, it is determined to be the cache clear command. If the port address is a predetermined port address as the time setting command, it is determined to be the time setting command, and otherwise, it is determined to be an error.

If it is determined that the command is a time setting command, the remote control command processing unit 213 interprets the command and extracts a set time (block 525). In particular,
In the case of the preferred embodiment of the present invention, time data is incorporated in the data portion of the UDP packet. The extracted set time is set in the clock mechanism 211 (block 527).

If it is determined that the instruction is a cache clear instruction, the remote control instruction processing unit 213 interprets the instruction, extracts a file name to be cleared, and passes control to the cache control unit 215 (block 531). Specifically, in the case of the preferred embodiment of the present invention, a server host name and a boot file name are incorporated in the data portion of the UDP packet.

The cache control unit 215 receiving this file name checks whether or not the file to be cleared is cached, using the server host name and the file name in the cache management table as keys (block 53).
3).

If the cache control unit 215 determines that the file to be cleared is not cached,
The response to the erasure failure is sent to the remote control instruction processing unit 213.
(Block 535). Receiving this, the remote control command processing unit 213 generates a packet including a message indicating erasure failure, and returns it to the transmission source of the cache clear packet via the routing control unit 201.

When it is determined in block 533 that the target file is cached,
Check whether the target file is currently in use (block 5)
39).

If the target file is in use, after waiting for a certain period of time, it is checked whether the target file has been released (block 541). In the cache management table 216 in the preferred embodiment of the present invention, information of the current access count 375 is managed, so that it is possible to know how many data terminals 110 the file is currently downloaded. it can.

When the target file is not in use, the cache control unit 215 deletes the target file from the cache dynamic storage unit 209 (block 543), and returns a normal end response to the remote control instruction processing unit 213 (block 543). Block 545). Upon receiving this, the remote control command processing unit 213 generates a packet including a message indicating normal termination, and returns the packet to the transmission source of the cache clear packet via the routing control unit 201.

D-4. Scheduled Start-up Processing In one aspect of the preferred embodiment of the present invention, by referring to a clock mechanism, a predetermined condition (when a transfer request to cached data for a fixed period of time does not come, another data If the frequency of transfer requests to the source is more frequent than the currently cached data, if a cache forced clear command is received over the network, the cache becomes full, etc.)
Clear the contents of the cache and perform caching.

FIG. 12 is a flowchart showing the procedure of the regular startup process in the preferred embodiment of the present invention. In the preferred embodiment of the present invention, the router device 100 periodically performs a timer interrupt (block 601), and FIG.
Referring to the scheduled start-up program table 214 shown in FIG.
It is determined whether there is a program to be started (block 603).

When there is a program to be started, an operand registered in the regular start-up program table 214 is added (if registered). The program is started (block 605). In the regular start-up program table 214, the start date and time can be registered for each program. Also, for example, by setting the year and month to blank, the weekday to “EMO (Every week: E, Monday: MO)”, the day to blank, and the time to “0600000”, the program is started at 6:00 am on every Monday. It can also be done. In addition, in response to the detection of a cache full, a cache that meets certain conditions is erased.
There are also programs that are executed even if they are not registered in the regular startup program table 214.

In the preferred embodiment of the present invention, the object code of the program to be started is stored in the external storage medium 241 as the external transfer program 243, and the regular start-up program section 212 loads this object code into the memory. And running. The following is an example of a typical startup program.

(1) Specific file cache instruction When the user designates the program of “execute cache” as the start program name of the regular start program table 214 and registers the file to be cached in the operand, this program Is executed at the specified time.

In the preferred embodiment of the present invention, when this program is executed, the transfer request management table 2 shown in FIG.
04, the cache flag 346 of the corresponding file is set to ON, and a transfer request packet of this file is sent to the server where this file exists.
1 via When the server sends out the requested file in response to this, the contents of the file are cached according to the packet processing procedure from the upper network described in FIG.

With this program, a copy of the target resource can be stored in the cache of each router before the time period when access to the specific resource is concentrated on the network.

(2) Clearing the Cache of a Specific File When the user specifies the program “Clear Cache” as the startup program name in the regular startup program table 214 and registers the cache clear target file in the operand. , This program is executed at the specified time. The file to be cleared
When “11” is registered, all the files stored in the cache storage unit 209 can be deleted.

In the preferred embodiment of the present invention, when this program is executed, it instructs the cache control unit 215 to delete the target file. In response to this, the cache control unit 215 checks whether the file is currently being used, deletes the file if it is not being used, and deletes the contents of the cache management table 216 and the transfer request entry 350 of the transfer request management table. clear. If the file is in use, wait for the file to be released, and then delete the file after release. In the preferred embodiment of the present invention, if the file is not released for a certain period, the processing is aborted.

With this program, it is possible to erase a specific resource that is rarely used in a specific time zone, and store a more used resource in a cache.

(3) Clearing Unused File Cache When the user designates the program “Clear Cache” as the startup program name in the regular startup program table 214 and registers the unused period in the operand,
This program runs at the specified time.

In the preferred embodiment of the present invention, when this program is executed, the cache control unit 215 is instructed to erase files before the last access time 373 (FIG. 5) is specified. In response, the cache control unit 215 searches the cache management table 216 and deletes the target file.

(4) Clearing the cache of the file whose retention period has expired When the user designates the program "clear cache" as the startup program name in the regular startup program table 214 and sets the operand to blank,
This program runs at the specified time.

In the preferred embodiment of the present invention, when this program is executed, the cache control unit 215 instructs the cache control unit 215 to delete files whose scheduled clear time 377 (FIG. 5) is before the current time. In response, the cache control unit 215 searches the cache management table 216 and deletes the target file.

D-5. Condition setting processing In the preferred embodiment of the present invention, the setting condition storage unit 207
Can be registered / changed directly from the setting terminal 235 connected via the setting connection port 225. As a result, the source address and port of the data to be cached, the protocol used for the data transfer to be cached, the cache retention period and clear condition, and the condition to trigger the start of caching (the number of transfer requests / Unit time). Further, the regular start program table 214 managed by the regular start program unit 212 can be registered, changed, and deleted.

These changes can also be implemented by transmitting a packet for instructing registration / change of the setting from the upper or lower network or a packet for instructing registration, change, or deletion of the regular startup program table 214. In the case of the preferred embodiment of the present invention, data such as the type of registration, change, and deletion and the content of data to be registered / changed or the setting content to be deleted are incorporated in the data portion of the UDP packet and transmitted. I have.

[0162]

As described above, according to the present invention,
By providing the router device with a cache function and transmitting the contents to the data terminal instead of the server, the network load can be reduced and the boot time of the network computer can be reduced.

According to another aspect of the present invention, in a hierarchical network, it is possible to provide a network system in which the degree of influence of the network load of a lower subnet group on an upper network is small.

According to another aspect of the present invention, it is possible to provide a hierarchical network system that can be added and expanded without considering the influence on the upper network.

In another aspect of the present invention, an efficient network system which can flexibly cope with the contents of the business of the subnet group by changing the file to be cached for each router device is provided. can do.

According to another aspect of the present invention, a highly reliable computer system which is less affected by a failure such as a server down or a router down in an upper network can be provided.

In another aspect of the present invention, the data terminal is filled with data in the cache of the router immediately before the time when the transfer requests are expected to be concentrated, so that each data terminal can be stored in a very short time slot (simultaneously). The cache of the router device can be used even when an access to a specific resource of the server is issued from the server.

[0168]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a computer network system in a preferred embodiment of the present invention.

FIG. 2 is a block diagram showing one embodiment of a hardware configuration of a router of the present invention.

FIG. 3 is a block diagram showing a structure of a router device according to a preferred embodiment of the present invention.

FIG. 4 is a block diagram showing a structure of a transfer request management table in a preferred embodiment of the present invention.

FIG. 5 is a conceptual diagram showing the structure of a cache management table in a preferred embodiment of the present invention.

FIG. 6 is a conceptual diagram showing a structure of a setting condition storage unit in a preferred embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure of packet processing in a preferred embodiment of the present invention.

FIG. 8 is a flowchart showing a procedure of a self-control process in a preferred embodiment of the present invention.

FIG. 9 is a flowchart illustrating a procedure of a routing process in a preferred embodiment of the present invention.

FIG. 10 is a flowchart showing a procedure of processing a packet from a lower network in a preferred embodiment of the present invention.

FIG. 11 is a flowchart showing a procedure of processing a packet from a higher-level network in a preferred embodiment of the present invention.

FIG. 12 is a flowchart showing a procedure of a scheduled startup process in a preferred embodiment of the present invention.

FIG. 13 is a format of an Internet datagram used in a preferred embodiment of the present invention.

FIG. 14 shows a UDP used in a preferred embodiment of the present invention.
Datagram format.

FIG. 15 shows a BOO used in a preferred embodiment of the present invention.
This is the format of the TP message.

FIG. 16 shows a TFT used in a preferred embodiment of the present invention.
This is the format of the P message.

FIG. 17 is a conceptual diagram showing the structure of a scheduled startup program table in a preferred embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 100 router 110 data terminal 120 Ethernet 130 subnet structure 201 routing control unit 203 transfer protocol analysis / cache control unit 204 transfer request management table 205 proxy transfer control unit 206 condition setting control unit 207 setting condition storage unit 209 cache storage unit 211 clock mechanism 212 Scheduled startup program 213 Remote control instruction processing unit 214 Scheduled startup program table 215 Cache control unit 216 Cache management table 217 External storage medium drive unit 221 Upper network connection port 223 Lower network connection port 225 Setting connection port 231 Upper network 233 Lower network 235 Setting terminal 241 External storage medium 243 External transfer program

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04L 12/54 H04L 11/20 101A 12/58 13/08 (72) Inventor Natsuki Miyamoto 1623 Shimotsuruma, Yamato City, Kanagawa Prefecture 14 Inside the Yamato Office of IBM Japan, Ltd. (72) Inventor Yoshito Kawada 1623, Shimotsuruma, Yamato City, Kanagawa Prefecture 14 Inside the Yamato Office of IBM Japan, Ltd. (72) Inside the inventor Masayuki 1623-14 Shimotsuruma, Yamato-shi, Kanagawa Japan IBM Japan, Ltd.Yamato Works (72) Inventor Saki Shimizu 1623 Shimotsuruma, Yamato-shi, Kanagawa Japan 14 IBM Japan, Ltd. Yamato Office

Claims (28)

[Claims] 1. A message relay method comprising a cache storage unit, a cache target management table in which files to be cached are registered, and a router relaying a transfer request transmitted from a plurality of data terminals to a server. (A) receiving a transfer request including server identification information and request file identification information from one data terminal included in the plurality of data terminals; and (b) request file identification information included in the transfer request. (C) determining whether the file corresponding to (c) is a cache target by inspecting the cache target management table; and (c) if it is determined that the file is a cache target, the file is stored in the cache storage unit. Transmitting a file corresponding to the requested file identification information included in the transfer request to the one data terminal If, (d) if it is determined not to be cached, the message relay method including the steps of transmitting the transfer request to the server. And a cache management unit for managing data stored in the cache storage unit. The cache management table is implemented on a router device that relays transfer requests transmitted from a plurality of data terminals to a server. A message relay method, comprising: (a) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; and (b) including a transfer request included in the transfer request. Checking the cache management table to determine whether a file corresponding to the requested file identification information is held; and (c) if the corresponding file is held, Transmitting the file to the one data terminal; and (d) if the corresponding file is not held, the transfer request is Transmitting the message to the server. 3. A router device having a cache storage unit, holding transfer request frequency information in association with request file identification information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. The message relay method implemented above, comprising: (a) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; (b) Updating transfer request frequency information corresponding to the file identification information included in the transfer request; (c) transmitting the transfer request to the server; and (d) responding to the transfer request to the server. Receiving the packet containing the data terminal destination information, the file identification information, and the file information transmitted from the server; and (e) the updated transfer request frequency information is scheduled. Determining whether the trigger condition is satisfied; and (f) storing the file information included in the packet in the cache storage unit when determined to be satisfied with the trigger condition. Relay method. 4. A message relay method provided on a router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. (A) receiving data terminal destination information, file identification information, and a packet containing file information from the server side; and (b) receiving the packet based on the file identification information contained in the packet. Determining whether the packet is to be cached; (c) transmitting the packet to the data terminal based on the data terminal destination information; and (d) determining that the packet is to be cached. Generating a packet including the file information included in the packet and the destination information of the self, and (e) file information included in the generated packet. Message relay method including the steps of storing in said cache memory unit. 5. A message relay method implemented on a router device having a cache storage unit and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals, wherein: Receiving a packet containing data terminal destination information, file identification information, and file information from the server side; and (b) determining whether the packet is to be cached based on the file identification information contained in the packet. And (c) storing the file information included in the packet in the cache storage unit if it is determined that the packet is to be cached. 6. A cache device comprising: a cache storage unit; and a cache management table for managing data stored in the cache storage unit, and is implemented on a router device for relaying a transfer request transmitted from a plurality of data terminals to a server. A message processing method, comprising: (a) receiving a message including request type information and file identification information from one data terminal included in the plurality of data terminals; and (b) request type included in the message. Judging whether or not the information is a scheduled value; and (c) if it is determined that the information is a scheduled value, determine whether a file corresponding to the file identification information included in the message is held. Judging by inspecting the cache management table; and (d) if the corresponding file is held, Erasing a file, and a message processing method comprising: 7. A router that includes a cache storage unit and a timer, holds program start time specifying information in association with a start program including transfer file specifying information, and relays transfer requests transmitted from a plurality of data terminals to a server. A message processing method carried out on an apparatus, comprising: (a) comparing a program start time specifying information with a current time obtained from the timer, so that a start program associated with the program start time specifying information; And (b) if it is determined that the associated boot program is to be executed, the associated program is executed to execute the associated boot file. Generating a packet requesting transfer of a file to be transferred; and (c) transmitting the request packet to the server. Phase and, (d) message processing method comprising the steps, a to store file information transmitted from the server in response to the packet the request to the cache memory unit to be transmitted to. 8. A router that includes a cache storage unit and a timer, holds program start time specifying information in association with a start program including erased file specifying information, and relays a transfer request transmitted from a plurality of data terminals to a server. A message processing method carried out on an apparatus, comprising: (a) comparing a program start time specifying information with a current time obtained from the timer, so that a start program associated with the program start time specifying information; And (b) when it is determined that the associated boot program is to be executed, by executing the associated program to correspond to the erased file identification information. Erasing the file transfer to be performed from the cache storage unit. 9. A router device comprising a cache storage unit and a cache target management table in which files to be cached are registered, and relaying a transfer request transmitted from a plurality of data terminals to a server. A connection port for receiving a transfer request including server identification information and requested file identification information from one data terminal included in the data terminal; and (b) a file corresponding to the requested file identification information included in the transfer request is to be cached. A transfer protocol / cache control unit that determines whether or not the data is cached by inspecting the cache target management table; and (c) when it is determined that the cache target is used, the data is held in the cache storage unit. Transmitting a file corresponding to the requested file identification information included in the transfer request to the one data terminal; And physical transfer control unit, (d) if it is determined not to be cached, the router device comprising: a routing control unit that transmits the transfer request to the server. 10. A router device, comprising: a cache storage unit; and a cache management table for managing data stored in the cache storage unit, and relaying a transfer request transmitted from a plurality of data terminals to a server. a) a connection port for receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; and (b) corresponding to the requested file identification information included in the transfer request. A cache control unit for determining whether or not a file to be stored is held by checking the cache management table; and (c) when a corresponding file is held, A proxy transfer control unit for transmitting to one data terminal; and (d) when the corresponding file is not held, the transfer request is sent to the data terminal. A routing control unit for transmitting to the server; 11. A router device having a cache storage unit, holding transfer request frequency information in association with requested file identification information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. (A) a first connection port for receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals; A transfer protocol analysis / cache control unit for updating transfer request frequency information corresponding to the included file identification information; (c) a routing control unit for transmitting the transfer request to the server; and (d) responding to the transfer request. And a second connection port for receiving data terminal destination information, file identification information, and a packet containing file information transmitted from the server side. See, (e) the transfer protocol analysis / cache control unit,
Determining whether the updated transfer request frequency information satisfies a predetermined trigger condition; and (f) further, if it is determined that the trigger condition is satisfied, the file information included in the packet is stored in the cache storage. A router device that includes a cache control unit that stores data in a unit. 12. A router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals, wherein: A connection port for receiving data terminal destination information, file identification information, and a packet containing the file information from the server; and (b) determining whether the packet is to be cached based on the file identification information contained in the packet. (C) a routing control unit for transmitting the packet to a data terminal based on the data terminal destination information; and (d) the transfer protocol analysis / cache control unit. ,
If it is determined that the packet is to be cached, a file containing the file information included in the packet and the own destination information is generated. (E) Further, the file information included in the generated packet is cached. A router device including a cache control unit that stores data in a storage unit. 13. A router device having a cache storage unit and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals, comprising: (a) data terminal destination information from the server side; (B) a transfer protocol analyzer / cache controller that determines whether or not the packet is to be cached based on the file identification information included in the packet. And (c) a cache control unit that stores, in the cache storage unit, file information included in the packet when it is determined that the packet is to be cached. 14. A router device comprising: a cache storage unit; and a cache management table for managing data stored in the cache storage unit, and relaying a transfer request transmitted from a plurality of data terminals to a server. a) a connection port for receiving a message including request type information and file identification information from one data terminal included in the plurality of data terminals; and (b) whether the request type information included in the message is a predetermined value. (C1) when it is determined that the value is a predetermined value, it is determined whether or not a file corresponding to the file identification information included in the message is held. (C2) When the corresponding file is held, the judgment is made by checking the cache management table. And a cache control unit for erasing a file being read. 15. A router having a cache storage unit and a timer, holding program start time specifying information in association with a start program including transfer file specifying information, and relaying a transfer request transmitted from a plurality of data terminals to a server. (A) comparing the program start time specifying information with the current time obtained from the timer to determine whether to execute a start program associated with the program start time specifying information (B) when it is determined that the associated boot program is to be executed, the associated program is executed to request the transfer of the file corresponding to the transfer file specifying information. (C) a route for transmitting the requested packet to the server; And Ingu controller, (d) a router device including a cache control unit for storing the file information transmitted from the server in response to the packet the request to the cache memory unit. 16. A router having a cache storage unit and a timer, holding program start time specifying information in association with a start program including erased file specifying information, and relaying a transfer request transmitted from a plurality of data terminals to a server. (A) comparing the program start time specifying information with the current time obtained from the timer to determine whether to execute a start program associated with the program start time specifying information (B) when it is determined that the associated startup program is to be executed, by executing the associated program, the transfer of the file corresponding to the erased file specifying information is performed by the cache. And a cache control unit for erasing from the storage unit. 17. A transfer system comprising: a plurality of data terminals; a server; a cache storage unit; and a cache management table for managing data stored in the cache storage unit, wherein the transfer is transmitted from the plurality of data terminals to the server. A network system comprising: a router device for relaying a request; (a) a server for transmitting a file held by itself in response to a transfer request from the plurality of data terminals; and (b) server identification. A data terminal transmitting a transfer request including information and requested file identification information; (c1) a connection port for receiving the transfer request from one data terminal included in the plurality of data terminals; and (c2) the transfer request. By checking the cache management table, it is determined whether a file corresponding to the requested file identification information included in the (C3) when a corresponding file is stored, a proxy transfer control unit that transmits the stored file to the one data terminal; and (c4) a corresponding file. If not,
A routing device that transmits the transfer request to the server. 18. A system comprising a plurality of data terminals, a server, and a cache storage unit, wherein transfer request frequency information is held in association with requested file identification information, and said request frequency information is stored in response to a transfer request from said plurality of data terminals. A network system comprising: a router device that relays a packet transmitted from a server; and (a) a server that transmits a file held by itself in response to a transfer request from the plurality of data terminals; (B) a data terminal that transmits a transfer request including server identification information and request file identification information; and (c1) a first connection port that receives the transfer request from one data terminal included in the plurality of data terminals. (C2) transfer protocol analysis for updating transfer request frequency information corresponding to file identification information included in the transfer request /
A cache controller, (c3) a routing controller for transmitting the transfer request to the server, and (c4) data terminal destination information and file identification information transmitted from the server in response to the transfer request. A second connection port for receiving a packet including file information; and (c5) the transfer protocol analysis / cache control unit determines whether the updated transfer request frequency information meets a predetermined trigger condition. (C6) a router device including a cache control unit that stores file information included in the packet in the cache storage unit when it is determined that the packet satisfies the trigger condition. 19. A network comprising a plurality of data terminals, a server, and a router device having a cache storage unit and relaying a packet transmitted from the server in response to a transfer request from the plurality of data terminals. (A) a data terminal for transmitting a transfer request including server identification information and requested file identification information; and (b) data terminal destination information and a file in response to the transfer requests from the plurality of data terminals. (C1) a connection port for receiving the packet from the server side; and (c2) a cache for storing the packet based on the file identification information included in the packet. A transfer protocol analysis / cache control unit for determining whether or not the data is to be cached; The,
And a cache control unit for storing file information included in the packet in the cache storage unit. 20. A system comprising: a plurality of data terminals; a server; a cache storage unit; and a timer, wherein program start time specifying information is held in association with a start program including transfer file specifying information. A network system comprising: a router device for relaying a transfer request transmitted to a server; and (a) a server for transmitting a file held by itself in response to a transfer request from the plurality of data terminals. (B) a data terminal for transmitting a transfer request including server identification information and requested file identification information; and (c1) comparing the program start time identification information with the current time obtained from the timer, thereby obtaining the program A clock mechanism for determining whether or not to execute a boot program associated with the boot time specifying information; A transfer program for generating a packet requesting transfer of a file corresponding to the transfer file specifying information by executing the associated program when it is determined that the attached start program is to be executed; c3) a routing control unit that transmits the requested packet to the server; and (c4) a cache control unit that stores file information transmitted from the server in response to the requested packet in the cache storage unit. A router system; and a network system including: 21. A cache storage unit, comprising: a cache target management table in which files to be cached are registered;
A recording medium storing a message relay program executed on a router device for relaying a transfer request transmitted from a plurality of data terminals to a server, the program comprising: (a) one of the data terminals included in the plurality of data terminals; A program code for instructing the router device to receive a transfer request including server identification information and requested file identification information from two data terminals; and (b) corresponding to the requested file identification information included in the transfer request. A program code for instructing the router device to determine whether the file is to be cached by inspecting the cache target management table; and (c) when it is determined that the file is to be cached, , The file stored in the cache storage unit and corresponding to the requested file identification information included in the transfer request. A program code for instructing the router device to transmit the file to the one data terminal; and (d) transmitting the transfer request to the server when it is determined that the transfer request is not to be cached. And a program code for instructing the router device. 22. A cache storage unit, comprising a cache management table for managing data stored in the cache storage unit, and implemented on a router device for relaying transfer requests transmitted from a plurality of data terminals to a server. A recording medium storing a message relay program, the program comprising: (a) receiving a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals. (B) determining whether or not a file corresponding to the requested file identification information included in the transfer request is held by inspecting the cache management table; Holding a program code for instructing the router device, and (c) a corresponding file. (D) when the corresponding file is not held, the program code for instructing the router device to transmit the held file to the one data terminal; And a program code for instructing the router device to transmit a transfer request to the server. 23. A router device having a cache storage unit, holding transfer request frequency information in association with requested file identification information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. A storage medium storing a message relay program executed above, comprising: (a) a transfer request including server identification information and requested file identification information from one data terminal included in the plurality of data terminals. And (b) a program code for instructing the router device to update transfer request frequency information corresponding to file identification information included in the transfer request. And (c) a program code for instructing the router device to transmit the transfer request to the server. (D) a program code for instructing the router device to receive a packet containing data terminal destination information, file identification information, and file information transmitted from the server in response to the transfer request. (E) a program code for instructing the router device to determine whether or not the updated transfer request frequency information satisfies a predetermined trigger condition; and (f) a determination that the update condition satisfies the trigger condition. And a program code for instructing the router device to store the file information included in the packet in the cache storage unit. 24. A message relay program provided on a router device having a cache storage unit, holding its own destination information, and relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. A program code for instructing the router device to receive data terminal destination information, file identification information, and a packet including file information from the server side. (B) a program code for instructing the router device to determine whether the packet is to be cached based on file identification information included in the packet, and (c) the data terminal destination information. And a program code for instructing the router device to transmit the packet to the data terminal based on (D) when it is determined that the packet is to be cached, file information included in the packet, and program code for instructing the router device to generate a packet including the own destination information, (E) a program code for instructing the router device to store file information included in the generated packet in the cache storage unit. 25. A recording medium comprising a cache storage unit and storing a message relay program executed on a router device for relaying a packet transmitted from a server in response to a transfer request from a plurality of data terminals. The program includes: (a) a program code for instructing the router device to receive data terminal destination information, file identification information, and a packet including file information from the server side; A program code for instructing the router device to determine whether or not the packet is to be cached based on the included file identification information; and (c) when it is determined that the packet is to be cached, A program for instructing the router device to store file information included in a packet in the cache storage unit. A recording medium comprising: a program code; 26. A cache storage unit, comprising: a cache management table for managing data stored in the cache storage unit; and implemented on a router device for relaying a transfer request transmitted from a plurality of data terminals to a server. A recording medium storing a message processing program, the program comprising: (a) receiving, from a data terminal included in the plurality of data terminals, a message including request type information and file identification information by the router; (B) a program code for instructing the router device to determine whether or not the request type information included in the message is a predetermined value; If it is determined to be a value, the file corresponding to the file identification information contained in the message is A program code for instructing the router device to determine whether or not the file is held by inspecting the cache management table; and (d) when the corresponding file is held, And a program code for instructing the router device to delete a file in the storage device. 27. A router having a cache storage unit and a timer, holding program start time specifying information in association with a start program including transfer file specifying information, and relaying a transfer request transmitted from a plurality of data terminals to a server. A recording medium storing a message processing program to be executed on an apparatus, the program comprising: (a) comparing the program start time specifying information with a current time obtained from the timer to obtain the program start time A program code for instructing the router device to determine whether to execute a boot program associated with the specific information; and (b) when it is determined that the boot program associated with the specific program is to be executed, Executing the associated program corresponds to the transfer file specifying information. A program code for instructing the router device to generate a packet requesting transfer of a file to be transferred, and (c) a program code for instructing the router device to transmit the requested packet to the server. And (d) a program code for instructing the router device to store the file information transmitted from the server in response to the requested packet in the cache storage unit. 28. A router having a cache storage unit and a timer, holding program start time specifying information in association with a start program including erased file specifying information, and relaying a transfer request transmitted from a plurality of data terminals to a server. A recording medium storing a message processing program to be executed on an apparatus, the program comprising: (a) comparing the program start time specifying information with a current time obtained from the timer to obtain the program start time A program code for instructing the router device to determine whether to execute a boot program associated with the specific information; and (b) when it is determined that the boot program associated with the specific program is to be executed, Executing the associated program corresponds to the erased file specifying information. Recording medium containing a program code, the for instructing the transfer of the file to the router device to erase from the cache storage unit that.