JP2000250803A - Information distribution system, mobile computer, information server device, cache server device and look- ahead cache processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information distribution system capable of effective look-ahead cache even when connecting a mobile terminal through a radio network to an internet. SOLUTION: Concerning this information distribution system, history information containing count information showing how many times the page of every link destination to be linked from a requested page is accessed in the past with the requested page as a link source in the case of providing the world wide web(WWW) page from a WWW server 2 is provided while being added to the requested page and when the access to a certain page occurs in a mobile terminal 1, on the basis of jump probability, which is provided by the history information added to the certain page, from a certain page to each linked destination, it is determined to which link destination page the look-ahead cache is to be performed to the mobile terminal itself and a cache server 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information distribution system in which a mobile computer acquires WWW information from a World Wide Web information server via wireless access, a mobile computer, an information server, a cache server, and a look-ahead cache process. About the method.

[0002]

2. Description of the Related Art The use of computer systems has expanded rapidly and in various fields as computer systems have become smaller, less expensive, and network environments have been enhanced. In recent years, in particular, in recent years, the world's largest computer network, the "Internet ( I
The use of published information and services is often performed by connecting to the Internet.

On the other hand, with the spread of such networks, mobile computers have been developed.
Technology development is also underway. In a mobile computer, a portable terminal or a user having a computer moves and communicates on a network. At times, the position on the network is changed while performing communication, and a wireless network such as a mobile phone or a PHS is used for communication access from a destination in addition to a conventional wired network.

[0004] On the Internet, World W
In many cases, an information distribution system of a hypertext format called ide Web (WWW) is used. This is HTML (Hyp
Using a language called erText Markup Language, it is possible to link a link between mutually related information and easily jump from one information (Web page) to another information. In addition, by using this WWW, not only the WWW server provides information, but also the client device (that is, terminal or computer)
(Eg, questionnaire, ticket reservation, product order) from the WWW server,
Various types of information can be exchanged, such as transmitting image data and audio data together. Therefore, it is also possible to construct a framework such as e-commerce.

[0005] Such WWW access is basically based on TCP / TCP between a client device and a WWW server.
This is performed by communication using the HTTP protocol. However, in general, when using the Internet, if each client device accesses the corresponding WWW server every time an acquisition request for an arbitrary WWW page is issued, the traffic volume on the network becomes enormous, and the network bandwidth becomes large. Access response time is slowed. In addition, when accesses are concentrated on a specific WWW server, the performance of the WWW server is also deteriorated.

[0006] As a method of avoiding these problems, W required for a cache server or the like installed near a client device is used.
There is a method of caching (temporarily storing) the contents (contents) of a WW page. This allows, for example, a page having a high popularity and a high hit count (accessed number) to be resident in the cache, so that the WWW is accessed for each access.
There is no need to communicate with the server, so that traffic can be reduced and response time can be reduced.

As a method of further shortening the response time of the WWW access, when a certain page is displayed, some other pages linked from the page are read ahead and the disk of the cache server or the client device is read. Alternatively, a method of caching in a memory has been proposed.

[0008]

When mobile access is made to the Web via the Internet using a wireless portable terminal device, the wireless network bandwidth on the terminal device side is limited. Cannot receive information service comfortably for a long time. In order to avoid this, it is necessary to reduce the response time and reduce the amount of traffic on the network by prefetching and caching the Web page in the cache server or the terminal device itself along the route.

However, particularly in the case of a portable terminal device using wireless access, the amount of data transfer in a wireless section is limited, and the amount of content that can be read ahead while the user is reading the previous page is limited. I will. In addition, when caching read-ahead content in the memory or disk of the mobile terminal device, there is generally an upper limit to the memory and disk capacity of the mobile terminal, and a W
Only a certain amount of eb page data can be cached. (In consideration of this, a protocol for thinning out and delivering image data for mobile terminals has been proposed. However, even if these are used, contents that can be cached on the mobile terminal side can be used. It is the same that there is a cap on the amount).

Therefore, when applying the prefetch cache method to an information distribution system in which a portable terminal device connects to the Internet via a wireless access network, prefetch cache is performed for contents that are not actually accessed. Should be avoided as much as possible, so that content that is likely to be actually accessed can be preferentially read ahead and cached. However, the conventional look-ahead cache method uses a WWW method that is formal and uniform without considering accessibility.
There was only one that cached the information in advance.

The present invention has been made in consideration of the above circumstances, and has an information distribution system, a mobile computer, and an information delivery system that enable effective prefetching cache even when a mobile computer connected to the Internet via a wireless network is considered. It is an object to provide an information server device, a cache server device, and a prefetch cache processing method.

[0012]

Means for Solving the Problems The present invention (claim 1) provides:
A mobile computer (for example, a mobile terminal device) connects to the Internet via a wireless network, and WWW information (for example, a web page is converted to an HTM from an information server on the Internet).
An information distribution system that receives distribution of data described in L language), wherein when the information server provides the requested WWW information, the WWW information of each link destination linked from the requested WWW information is History information including at least information indicating how much access has been made in the past using the requested WWW information as a link source (for example, count information) is provided in addition to the requested WWW information, and provided in the mobile computer. When an access to a certain WWW information is made, at least an index (for example, a value of a jump probability) relating to a jump possibility to each link destination linked from the certain WWW information, which is obtained from the history information added to the certain WWW information , Based on jump probability), the WWW information to be prefetched and cached in the mobile computer itself. Characterized in that it constant.

Further, the present invention (claim 2) provides a mobile computer (for example, a mobile terminal device) connected to the Internet via a wireless network, an information server for providing WWW information to the mobile computer, and distribution of the information server. A cache server for prefetching and caching information for a mobile computer, the information server providing the requested WWW information when the information server provides the requested WWW information.
The history information including at least information (for example, count information) indicating how much the WWW information of each link destination linked from the information has been accessed in the past using the requested WWW information as a link source is stored in the requested WWW. Provided in addition to the information, and when access to certain WWW information occurs in the mobile computer, at least obtained by the history information added to the certain WWW information;
Indices relating to the possibility of jumping to each link destination linked from the certain WWW information (for example, a value of a jump probability,
It is characterized by determining WWW information to be prefetched and a device (mobile computer, cache server) to cache the prefetched WWW information on the basis of the jump probability (highest ranking).

The history information can be given as an extension of the HTML format which is a WWW description language, for example.

When the device to be prefetched and cached is a cache server, the cache server is, for example, a nearby cache server. When there are a plurality of cache servers that can be prefetched and cached by the mobile computer, for example, when the cache servers exist hierarchically, the conditions for the WWW information to be prefetched and cached are made different for each cache server. You can also

[0016] Preferably, the decision may be made at the mobile computer and / or at the cache server.

In the mobile computer, the above-mentioned WWW
Several cases can be considered as a case where access to information occurs. For example, a case where a request for access to the certain WWW information is input from a user at a mobile computer (for example, a case where a user clicks a link). Alternatively, the mobile computer may input a request for access to the certain WWW information from a user and actually display the certain WWW information on a display screen of the mobile computer. Also, some cases can be considered for the cache server,
For example, when the cache server receives an acquisition request (for example, an http request) for the certain WWW information transmitted by the mobile computer, the cache server can recognize that access to the certain WWW information has occurred in the mobile computer.

Preferably, the information on each of the link destinations contained in the history information is the requested WWW
The number of times the WWW information of each link destination is accessed using the information as the link source, and the index regarding the possibility of jumping to each link destination is the number of times that the WWW information of each link destination is accessed, and the requested WWW The information may be obtained by dividing by the number of times of access.

The history information includes the requested WWW
In addition to or instead of the number of times the WWW information of each link destination was accessed using the information as the link source, the number of times that the WWW information of each link destination was accessed is the number of times that the requested WWW information was accessed. The value obtained by dividing each value may be included.

[0020] Preferably, the determination may be made in consideration of the data size of WWW information of each link destination linked from the requested WWW information in the history information.

If the data can be compressed, the data size of the compressed data may be described.

Preferably, the determination may be made in consideration of available bandwidth information of a network that is dynamically monitored.

Preferably, the WWW information of the link destination is the first
If the index indicates that there is a jump possibility equal to or more than the reference value of the second link, it is determined that the WWW information is prefetched and cached in the mobile computer, and the WWW information of the link destination is smaller than the first reference value. If the index indicates that the jump possibility is greater than or equal to the reference value, it may be determined that the WWW information is prefetched and cached in the cache server.

Preferably, priority is given to the link destination WWW information having an index indicating a large jump possibility, based on the relationship between the data size of the link destination WWW information and the size that can be stored in the mobile computer. Linked WWW
It may be determined that information is to be prefetched and cached in the mobile computer.

Preferably, the index regarding the possibility of jump is a jump probability from a link source to a link destination,
The history information further includes information relating to the data size of the WWW information of each link destination, and the WWW information of the link destination in which the total sum of the jump probabilities is the maximum as long as the total data size can be stored in the mobile computer. Select the set of
It may be determined that the WWW information is prefetched and cached in the mobile computer.

[0026] Preferably, the determination may be made in accordance with look-ahead policy information describing a predetermined procedure.

For the read-ahead policy information, a dedicated read-ahead policy storage means may be provided on the mobile computer side, and the necessary read-ahead method may be described by a user or a system administrator.

Preferably, the look-ahead policy information includes:
A description including a condition to be satisfied in order for the link destination WWW information to be determined to be prefetched and information indicating a device to be prefetched and cached when the condition is satisfied,
It may be configured to include one or a plurality.

Preferably, in the prefetch policy information, a procedure for prefetching and caching WWW information registered in advance in the display software when the display software of the mobile computer is started is described. Good.

Preferably, the history information is based on a predetermined message including information specifying the link source WWW information and information specifying the link destination WWW information transmitted by each mobile computer, based on the link source WWW information. May be created for each link source WWW information in each information server that holds the link information.

Preferably, when the information server provides the requested WWW information, the information server also adds the link destination WWW information determined to be highly likely to be jumped based on the history information corresponding to the requested WWW information. May be provided.

In the above, the present invention has been grasped as an invention relating to an information distribution system. However, the present invention can also be grasped as an invention relating to each device existing in the information distribution system.

Note that the above-described subclaims and other configurations (examples) of the information distribution system are similarly established in the present invention relating to the mobile computer, the information server device, and the cache server device.

First, when the present invention is grasped as an invention relating to a mobile computer, the present invention (claim 12) relates to a mobile computer connected to the Internet via a wireless network and receiving distribution of WWW information from an information server on the Internet. Then, when access to certain WWW information occurs, at least the WWW information of each link destination linked from the certain WWW information added to the certain WWW information and provided from the information server apparatus is stored in the certain WWW. The mobile computer itself based on an index relating to the possibility of jumping to each link destination linked from the certain WWW information, which is obtained by history information including at least information indicating how much access has been made in the past using the information as a link source. Means for determining WWW information to be prefetched and cached;
Means for caching the pre-read WWW information.

The present invention (claim 13) relates to a mobile computer connected to the Internet via a cache server via a wireless network and receiving WWW information from an information server on the Internet, wherein access to certain WWW information occurs. In this case, at least how much WWW information of each link destination linked from the certain WWW information added to the certain WWW information and provided from the information server apparatus has been accessed using the certain WWW information as a link source in the past. WWW information to be prefetched and cached, based on an index relating to the possibility of jumping to each link destination linked from the certain WWW information, which is obtained from history information including at least information indicating whether the WWW information has been read, and the WW
Means for prefetching the W information to determine a device to be cached, and means for prefetching and caching the WWW information when the own device has WWW information determined to be prefetched, Means for transmitting, to the cache server, a request for prefetching and caching the WWW information when the cache server has WWW information determined to be prefetched.

Preferably, the apparatus further comprises means for holding information relating to a data size enabling a prefetch cache to the own apparatus, and the history information further includes WWW of each link destination.
Information on the data size of the information may be included, and the determination unit may make the determination in consideration of the information on the data size.

[0037] Preferably, the information processing apparatus may further include means for storing look-ahead policy information describing a procedure of the determination performed by the determining means.

Preferably, there is further provided means for performing processing for notifying a set of the link source WWW information and the link destination WWW information to the information server holding the link source WWW information. You may do so.

Next, when the present invention is grasped as an invention relating to an information server device, the present invention (claim 16) is an information server device which is connected to the Internet and provides WWW information. For each WWW information, a certain W
Means for creating history information including at least information indicating how much of the WWW information of each link destination linked from the WW information has been accessed using the certain WWW information as a link source, and providing the requested WWW information When doing
Means for providing the requested WWW information with the history information added thereto.

Preferably, when the requested WWW information is provided, the link destination WWW information determined to be highly likely to be jumped based on the history information corresponding to the requested WWW information is also provided. Means may be further provided.

Preferably, the history information may be added as an extension of an HTML format which is a WWW description language.

Next, when the present invention is grasped as an invention relating to a cache information server device, the present invention (claim 18)
Is a cache server installed between a mobile computer connected to the Internet via a wireless network and an information server for providing WWW information to the mobile computer, and prefetching and caching information distributed by the information server for the mobile computer. A device, WW specified by a mobile computer
A means for prefetching and caching the W information is provided.

Further, the present invention (claim 19) is provided between a mobile computer connected to the Internet via a wireless network and an information server for providing WWW information to the mobile computer, and distributes the information server. A cache server device for prefetching and caching information for a mobile computer, wherein when a mobile computer accesses certain WWW information, at least the certain WWW
A history including at least information indicating how much the WWW information of each link destination linked from the certain WWW information provided from the information server apparatus added to the information has been accessed in the past using the certain WWW information as a link source Based on an index obtained from the information regarding the possibility of jumping to each link destination linked from the certain WWW information,
Means for prefetching WWW information to be cached, and means for prefetching the WWW information and determining a device to be cached;
WW determined to be prefetched in its own device
Means for prefetching and caching the WWW information when there is W information, and when there is WWW information determined to be prefetched and cached in the mobile computer,
Means for causing the mobile computer to prefetch and cache the WWW information.

Further, each invention relating to the apparatus is also established as an invention relating to a method.

For example, according to the present invention (claim 20), a mobile computer connected to the Internet via a wireless network, an information server for providing WWW information to the mobile computer, and information to be distributed by the information server are stored in the mobile computer. A prefetch cache processing method in an information distribution system including a cache server that performs prefetch caching for
When the information server provides the requested WWW information, each link destination WWW information linked from the requested WWW information indicates how much access has been made in the past using the requested WWW information as a link source. History information containing at least information is provided in addition to the requested WWW information, and when an access to certain WWW information occurs in the mobile computer, at least the history information added to the certain WWW information is obtained. The certain W
W to be prefetched and cached based on an index relating to the possibility of jumping to each link destination linked from the WW information
It is characterized in that a device for caching the WWW information and the pre-read WWW information is determined.

The present invention relating to an apparatus or a method is provided for causing a computer to execute a procedure corresponding to the present invention (or for causing a computer to function as means corresponding to the present invention, or a computer corresponding to the present invention). The present invention is also realized as a computer-readable recording medium in which a program for realizing the function of performing the above is recorded.

In the conventional Web page read-ahead cache method, since no priority control is performed between related pages, inefficient read-ahead is performed by first prefetching and caching a page with a low access frequency. There was a possibility. In particular, in a wirelessly connected mobile computer (mobile terminal device, wireless terminal device) with a low transmission speed, the previous page is displayed, and it may not be possible to pre-read sufficient data before the user selects the next page. . In such a case, if the page with the highest probability of being selected next cannot be preferentially prefetched, the prefetched content is not actually displayed, and the WWW server must be accessed again. Further, since the amount of resources (memory and disk capacity) held by the mobile terminal is generally limited, it may happen that all linked pages cannot be cached. In such a case, it is necessary that the control for preferentially prefetching the page having the highest probability of being selected next be effectively operated.

In the present invention, the information server requests the WW
When providing W information, the WWW information of each link destination linked from the requested WWW information is
When providing the requested WWW information with history information including at least information indicating how much access has been made in the past using the WW information as a link source, and performing the prefetching cache processing, at least the certain WWW It is determined which WWW information is to be prefetched and cached (in which device) based on an index obtained from the history information added to the information and which indicates a jump possibility to each link linked from the certain WWW information. . Further, it is possible to determine which WWW information is to be prefetched and cached (in which device), in consideration of the data size that can be stored and the available bandwidth of the network as needed.

For example, when a WWW page is displayed on the mobile computer, it is possible to perform a prefetch cache control based on the jump probability only for pages having a jump probability equal to or more than a reference value or in order from a page having a high jump probability. . Further, for example, when there is a limit in the disk capacity to be cached, it is possible to perform control such that only the top three pages having a high jump probability are prefetched and cached.

Thus, even with a wireless network connected with a low transmission rate, a cacheable disk, and a mobile computer having an upper limit in memory capacity, the content having a high use probability can be read out first so that the prefetched content can be used. This can contribute to speeding up Web response and reducing traffic volume.

[0051]

Embodiments of the present invention will be described below with reference to the drawings.

According to the present invention, a mobile terminal device (mobile computer) connects to the Internet via a wireless access network, or connects to the Internet via a cache server or the like via a wireless access network, and installs the mobile terminal device on the Internet. An information distribution system or a mobile terminal device, a WWW server, a cache server, or the like, in which communication is performed with a WWW server that has been set.

The present invention is applicable as long as it has the above basic configuration, and various variations of the specific network configuration are conceivable. In particular, there are various variations as to how the wireless access network, the mobile terminal device, the cache server, and the like are included in the system. For example, the wireless access network may be a public network provided by an operator, or may be an element of an intranet within one organization. The cache server or the like may be located, for example, at the boundary between the wireless access network, which is a public network, and the wired network (on the side of the wireless operator), may be located inside an intranet within one organization, or may be a cache server or the like. May exist hierarchically.

FIG. 1 shows an example of a network configuration to which the present invention is applied.

In the example shown in FIG. 1, the mobile terminal device 1 is connected to the wireless base station 12 → the router device 5 → the Internet 6 via the route W.
Connected to WW server 2 or wireless base station 1
2 → Router 5 → Mobile phone network or PHS network 16 →
Access server 18 → WWW via Internet 6
Connected to the server 2 (for example, the user can select which route to take). Note that the router device 5 belongs to the wireless carrier side. Access server 1
Reference numeral 8 denotes a connection device belonging to the Internet provider for dial-up connection or the like. Further, FIG.
Although omitted, a plurality of WWW servers 2 are installed on the Internet. In such a network configuration, communication is performed between the mobile terminal device 1 connected to the Internet 6 and the WWW server 2 installed on the Internet 6 via a wireless access network, and WWW information (Web page data). And the contents of the Web page on the mobile terminal device 1 are displayed.

As will be described later in detail, in this embodiment, the We
The content of page b is provided with jump history information (hereinafter abbreviated as history information) related to a jump history to the linked page, and a prefetch cache is performed based on the history information. In the present embodiment, the mobile terminal device 1
Is provided with a function of prefetching and caching WWW information. In the example of FIG. 1, a case is considered in which a cache server 3 is installed near the mobile terminal device 1 and the cache server 3 also performs a prefetch cache of WWW information. In this case, from the viewpoint of the mobile terminal device 1, the storage device included in the mobile terminal device 1 itself is a (relatively) high-speed, small-capacity primary read-ahead cache, and the cache server 3 is (relatively) a low-speed, large-capacity secondary cache. It is positioned as a prefetch cache. Here, it is assumed that the mobile terminal device 1 controls the look-ahead cache.

The cache server 3 performs, for example, an address translation (NAT) process when the terminal device is in a network operated by a private address, and a function of a firewall for preventing unauthorized access from the outside. It also has a cache function of another method, for example, a function of holding WWW information requested by the terminal device in the past as necessary, and storing WWW information about a pre-registered Web page. The cache server 3 may also have various functions as described above. In this embodiment, the cache server 3 will be described focusing on the prefetch cache function of WWW information.

In the following, the mobile terminal device 1, WWW server 2, and cache server 3 will be mainly described by taking the network configuration of FIG. 1 as an example, but, of course, the mobile terminal device 1 and the WWW server 2 A network configuration different from that shown in FIG.

In the present information distribution system, the user accesses the WWW server 2 on the Internet 6 from the mobile terminal device 1 via a wireless medium such as a cellular phone / PHS, and performs various operations described in HTML. WWW
Information can be obtained.

As described above, in this WWW information, a link can be established between mutually related information, and it is possible to easily jump from one WWW information (Web page) to another WWW information. . Generally, a certain We
The page b is used as an entrance to information (top page). First, the user accesses a desired top page, selects a link to a related page desired by the user on the displayed top page, and selects a corresponding portion (for example, a character (The display part such as a column or an image) is clicked with a mouse, thereby obtaining and displaying the relevant page. Further, the user selects and clicks a link to the desired relevant page with respect to the displayed page. By simply repeating simple operations as appropriate, the configuration is such that pages can be jumped one after another to reach necessary information.

Depending on the Web page, a predetermined service may be received by transmitting a user input from the mobile terminal device 1 to the WWW server 2.

FIG. 2 shows a configuration example of a Web page used in the present embodiment. FIG. 2 assumes a web page for ticket reservation of an airline company as an example. This We
On page b, first, on the top page (airline entrance page), language choices (links to English, Japanese, and Chinese top pages) used in this service are presented, and the user's desired language is displayed. To choose.
For example, if the user selects Japanese (Japanese), a page (Japanese top page) associated with “Japanese” is displayed. On this page, (1) ticket reservation, (2) reservation change, (3)
The option (link to each related page) such as departure / arrival information, (4) mileage service, (5)... Is presented, and the service desired by the user is selected. When the user selects a desired service (for example, the mileage service of (4)), the Web associated with the selected service is selected.
A page b (for example, a mileage service page) is displayed, for example, a service is provided using the Web page, or a jump from the page to another page is performed.

In the present embodiment, in order to speed up the communication and display of such WWW information, a look-ahead cache of the WWW information is performed. Schematically, as shown in FIG. 3, when a certain page is displayed on the mobile terminal device 1, a page linked from the page is displayed on the disk of the nearby cache server 3 or the mobile terminal device 1 or on the disk. It is a pre-read cache on the memory. that time,
Which pages are cached and where are important,
This will be described later.

Here, first, the problem of the conventional read-ahead cache method will be described using a specific example of the Web in FIG. As described above, the WWW access is basically performed by communication between the client device and the WWW server. However, if all the operations are performed, the traffic on the network becomes enormous and the bandwidth of the network is wasted. The access response time is slowed down, and the performance of a WWW server on which access is concentrated is degraded. To avoid this, a conventional cache method uses a cache server or the like near a client device or a client device. WWW information is cached therein. In the conventional look-ahead cache method, for example, when a page on the terminal device side is displayed, another page to which a link is provided is read ahead from the page. This conventional look-ahead method,
If the effect is exhibited, it becomes effective when there is a restriction on the network band, such as when the mobile terminal device 1 is used via wireless access.

However, in the case of Web access using a wireless portable terminal, since the amount of data transferred in a wireless section is limited, content that can be prefetched by the wireless portable terminal itself while the user is reading the previous page. The amount is also limited. In the conventional look-ahead cache method, for example, a formal and uniform method of caching a link destination page in accordance with the order of appearance of links on the page (for example, a certain number or until the memory is full) is used. , No valid look-ahead cache. For example, considering the example of the airline Web in FIG.
When choosing a language to use on the top page (airline entrance page), it is assumed that most users will select Japanese if the Web is a Japanese domestic airline, but first In the case where the page is prefetched only for the link that has appeared, since the first option in this top page is English, the Japanese top page that most users will select is cached prefetched. Instead, the English-language top page that most users would not select would be prefetched and cached, and for most users the prefetching cache process itself would be wasted, just wasting bandwidth on the wireless network. Become. Since the resources in the wireless section are shared with other users, the prefetch cache process is difficult to employ if the prefetch cache process itself is often wasted.

Furthermore, when caching read-ahead contents in the memory or disk of a wireless portable terminal, there is generally an upper limit to the memory or disk capacity of the wireless portable terminal, and data of a Web page containing a large amount of image data and the like is generally required. Has a limitation that only a certain amount can be cached. (Recently, in consideration of this, a protocol for thinning out and delivering image data for mobile terminals has been proposed, but even if these are used, the mobile terminal side There is still an upper limit on the amount of content that can be cached.) For example, in the case where the linked page is prefetched and cached until the memory becomes full according to the order of appearance of the links on the page, the airline Wen of FIG.
In the example of b, although most users (for example, 70% of the accessing users) select the mileage service (4) on the Japanese top page, the options (1) to (3) are cached in order. If the memory of the wireless portable terminal becomes full at this point, most of the user's requests cannot be answered, and the prefetch cache processing itself is wasted as in the above example.

Therefore, when performing prefetch caching on the mobile terminal device 1 in the present information distribution system, prefetching access to contents that are not actually accessed even when caching should be avoided as much as possible. There is a need for a mechanism for prefetching and caching content that is likely to be read with priority as much as possible.

In order to realize this, in the present embodiment, history information indicating which related page linked / selected by a user who has selected / accessed a certain WWW page next is introduced. . Then, a page to be prefetched and cached (and its cache destination) is determined based on the history information. In the present embodiment, this determination is made in accordance with a “read ahead policy” described later.

Hereinafter, this history information will be described with reference to the top page of the airline company in FIG. 2 as an example.

FIG. 4 shows an example in which history information is added to each page of the airline Web in FIG.

As shown in FIG. 4, the history information added to each page includes the number-of-times-of-access information (T
total-Hit) and count information (item) for each of the pages linked to the page.

The access number information is the number of times the page has been accessed (the number of hits). Conventionally, a counter process for counting the number of hits has been performed by a WWW server. For example, a count value obtained by the conventional counter process can be used as the access count information. The example of FIG. 4 shows a case where the airline top page has hit 1000 hits so far.

The count information item (i) indicates the number of times that the page i linked to the page a has been selected / accessed (that is, the number of jumps from the page a to the page i) with the page a as the previous page. Information. In the example of FIG. 4, the English top page is selected 40 times, the Japanese top page is selected 930 times, and the Chinese top page is selected 30 times.

In the present embodiment, the history information is described (in the WWW server side) in an area in which the HTML data is extended. When the client obtains the page, the client can obtain the history information of the page from a predetermined extension area of the HTML data.

On the client side, by referring to the history information (access number information and count information) of the acquired page, the user accessing the page accesses the next page (jumps to which page).
It is possible to determine whether the possibility is high. of course,
On the client side, various types of information (for example, jump probability) can be obtained by appropriately processing the information provided as the history information.

The history information includes access frequency information,
Other information of the count information may be added, or a value obtained by processing them (for example, a jump probability obtained by dividing the count information by the access number information) may be added.

Next, a method of creating the count information item (i) will be described.

Hereinafter, several examples of the method of creating the count information will be described. However, the present invention does not particularly limit the method of creating the count information, and various methods of creating the count information can be considered.

Generally, Web described in HTML data of a certain page # 1 acquired from a certain WWW server # 1
b. According to the resource information (for example, the URL of the page of the link destination), the Web browser of the mobile terminal device 1 makes a request to obtain the next page # 2 to the corresponding WWW server # 2. In the WWW server # 1 holding the page # 1, the counter processing for updating the "count information" for the link destination page # 2 requested as the next page in the history information of the original Web page # 1 is performed. Will be needed. In this case, the WWW server # 1 holding the previous page and the WWW server holding the next page
W server # 2 may be the same or different.

For this reason, in the present embodiment, the mobile terminal device 1 includes, in the page acquisition request (http request), information for specifying the page that is the link source of the page (for example, the link source page). URL).

For example, in the example of the airline shown in FIG. 4, when the Japanese top page is selected on the airline entrance page, the mobile terminal device 1 sends the http request for the “Japanese top page” to indicate that the immediately preceding page is Information indicating that it is an “airline entrance page” is added, and the information is transmitted to a WWW server holding the “airline entrance page”.

When the airline entrance page and the next page in each language are stored in the same WWW server, the WWW server sets the “Japanese top page” from the http request of the mobile terminal device 1. Since it is possible to know that the request was made and that the previous page was the "airline entrance page", the count information corresponding to the "Japanese top page" in the history information of the "airline entrance page" Increment item (2).

On the other hand, when the airline entrance page and the top page of each language are stored in different servers, the WWW server sends
You can know that the "Japanese top page" was requested and that the previous page was the "airline entrance page", but since the "airline entrance page" is not what you own, A history information update request in which the link source is the “airline entrance page” and the link destination is the “Japanese top page” is transmitted to the WWW server holding the “airline entrance page”. The WWW server holding the “airline entrance page” receiving the history information update request,
The count information item (2) corresponding to the “Japanese top page” in the history information of the “airline entrance page” is incremented.

Further, in this embodiment, the link destination page selected by the user may be cached in the mobile terminal device 1 in advance. In this case, no http request for the WWW page is transmitted. Therefore, in such a case, the history information update request described above may be transmitted from the mobile terminal device 1 to the WWW server holding the link source page.

When the cache server 3 is provided, the following may be performed. That is, the cache server 3 receives the http request transmitted from the inside of the mobile terminal device 1, transfers the requested page to the mobile terminal device 1 if the requested cache page is cached, and If the cached page is not cached, h
Transfer the http request to the WWW server. Therefore, when the requested page is cached and the http request includes the information of the link source page, the cache server 3 transmits the history information update request to the WWW holding the link source page. What is necessary is just to transmit to a server.

With the above processing, the WWW server holding the link source page can create and update the count information for each link of each page.

In the above example, the count information item (i) is updated every time a page is accessed or a link is selected. Instead, the access behavior of a certain user on the mobile terminal device 1 is changed. May be monitored, and after all accesses have been completed, a history information update request is transmitted collectively to update all relevant count information at once.

In addition, as long as it is a method that can collect the global count information without contradiction, the update frequency of the information and the update method may be any.

Next, the configuration of the WWW server 2 will be described.

FIG. 6 shows a configuration example of the WWW server 2.

The WWW server 2 holds the WWW data including the history information of each WWW page acquired as described above.

Here, it is preferable to hold the data size information of each link destination page in addition to the history information of each link destination for use in the “prefetch policy” described later. This information is used for controlling, for example, not to cache a large-capacity page including an image.
If a process such as thinning an image can be performed by a recent Web protocol for mobile terminals, it is also possible to describe the fact and list a plurality of size information.

Next, the configuration of the mobile terminal device 1 will be described.

FIG. 7 shows a configuration example of the mobile terminal device 1 which performs a prefetch cache process. It should be noted that in FIG.
The modules related to the b-access are omitted, and the description will focus on the modules related to the prefetch cache processing.

The mobile terminal device 1 has a prefetch cache storage unit 71, a memory size register 72, and a prefetch policy storage unit 73 as modules related to the prefetch cache process.

The prefetch cache storage unit 71 prefetches and caches WWW information.
Any storage medium such as a disk may be used.

The memory size register 72 holds the size information of the cache area of the prefetch cache storage unit 71. This size information is used to determine whether or not cache processing is possible.

The prefetch policy information storage unit 73 stores each W
The read-ahead policy information serving as a reference for how to pre-fetch and cache the WWW information (link destination page) linked from the WW information (link source page) is held. In the prefetch policy information, for example, a description indicating criteria such as what conditions the jump probability of the link destination page and the data size of the link destination page satisfy when executing the prefetch cache process is described.

In addition to the above, the mobile terminal device 1 has a function of transmitting a cache command including information designating a page to be prefetched to the cache server 3 when the cache server 3 performs prefetch caching. A function of transmitting the history information update request described above is provided as necessary.

FIG. 8 shows an example of the description grammar of the prefetch policy information. In this example, the grammar of the look-ahead policy is defined from the condition part based on information about the page such as the jump probability and size information of the linked page and the action part indicating where and in what order the look-ahead is cached. (Ie, policy)
Is described in the form of if ... then ...). FIG.
, Policy: = if (<condition>) then <action>
Indicates that when the condition described in the condition part <condition> is satisfied, the prefetch cache processing described in the action part <action> is performed. In addition,
policy: = <action> indicates that the prefetch cache process described in <action> is unconditionally performed.

In FIG. 8, with respect to the condition part, an attribute value (feature amount) of a page for which it is determined whether or not to perform prefetch caching, a reference value thereof, and a comparison method thereof are described. An example is given. For example, <condition>:
= size_of <page ID> lt SIZE represents a condition that the size of a page described in <page ID> is smaller than a reference value (SIZE). <condition>: = Prob_of <page ID> g
e PROB represents a condition in which the jump probability (for example, a value obtained by dividing the count information item (i) by the access count information Total-Hit) of the page described in <page ID> is equal to or greater than the reference value (PROB). <condition>: = Ran
k_of <page ID> eq NUM represents a condition in which the rank of the page described in <page ID> (for example, the order of count information or jump probability) is equal to the reference value (NUM).

FIG. 8 shows an example in which the action section describes the ID of the page to be prefetched and the position (apparatus) for prefetching and caching.

<Action>: = Cache <page ID> at <Cache_lo
cation> pre-reads the content (WWW information) of the page described in <page ID>, and <Cache_
location>. <Action>: = No-Cache <page ID>
Indicates that the page described in <page ID> is not to be prefetched and cached.

The position of the prefetch cache (<Cache
_Location>) includes information (TERM) indicating the mobile terminal device itself or the ID (p
Roxy ID) is described. For example, a URL is used as information (page ID) for specifying a page.

It should be noted that various features other than those described above can be used as the feature amounts used in the condition part.

In the above description, only static information such as jump probability and size information is used. For example, if the traffic amount of the wireless link is a certain level or more, prefetching is performed by referring to dynamic information such as not performing prefetch cache processing. Extension such as caching can be easily performed.

It is also possible to use a condition part in which a plurality of conditions are combined by and or or. A plurality of actions can be described in the action section.
Furthermore, a plurality of if ... then ... sentences are written together,
, Then ... else if ... then ... can be used.

Of course, the description grammar of the prefetch policy information described above is an example, and various description grammars can be considered.

Here, as to who decides the contents of the prefetch policy information, there are several methods as exemplified below. The end user arbitrarily describes the prefetching policy information and sets it in the mobile portable terminal 1. -The telecommunications carrier determines the read-ahead policy in consideration of the network usage rate. In this case, for example, the pre-reading policy information created by the communication carrier is held in a predetermined server managed by the communication carrier, and the user can use the mobile portable terminal 1.
Is activated, the mobile terminal 1 accesses the predetermined server to acquire the prefetch policy information, and stores the information in the prefetch policy storage unit 73. When the user operates in the corporate network, the administrator of the corporate network sets the prefetch policy information. The method of distributing the prefetch policy information to each terminal device is the same as in the above-described example of the communication carrier.

A specific example of the prefetch policy information and the prefetch cache process will be described later.

Next, the configuration of the cache server 3 will be described.

FIG. 9 shows a configuration example of the cache server 3 according to the present embodiment. Note that, in FIG. 9, modules related to normal cache are omitted, and the description will focus on modules related to prefetch cache processing.

When the mobile terminal device 1 controls the prefetch cache, the mobile terminal device 1 transmits the prefetch cache information in accordance with the contents of the prefetch policy information of the mobile terminal device 1 and the contents of the history information of the WWW page corresponding to the link source. A cache command may be given to the cache server 3 (the WWW information instructed from the mobile terminal device 1 (if necessary)
Cache), so as shown in FIG.
A cache instruction register 91 is provided, and holds a cache instruction from the mobile terminal device 1 side. Then, according to the cache instruction (if the cache processing order is designated by the cache instruction, according to the cache processing order), the specified WWW information is obtained (if not already cached, from the corresponding WWW server). The data is stored in the cache area 92.

Note that, in addition to the above, the cache server 3
Has the function of transmitting the history information update request described above as necessary.

In the following, a description will be given of some examples of specific examples of the prefetch policy information and the prefetch cache process in which various things can be considered.

<Specific Example 1> FIG. 10A shows that, if the jump probability of a certain linked page exceeds 50%, the page is prefetched and cached in the mobile terminal device 1, and the jump probability of a certain linked page is read. Is an example in which a policy is described in which the page is cached in the cache server 3 if the value exceeds 20%.

In this case, after displaying the WWW page serving as the link source, the mobile terminal device 1 checks the jump probability for each link based on the history information of the page, and finds a page whose jump probability exceeds 50%. If found, an http request (not including the link source page information) for the corresponding page is sent to the corresponding WWW server for prefetching and caching. 20% jump probability
Is generated, and a cache instruction including the list is transmitted to the cache server indicated by proxy1.

For example, in the case of history information as shown in FIG. 10B, the page corresponding to link 3 is cached in the mobile terminal device 1 itself, and the corresponding cache server stores the link 2 page and the link 3 page. A cache instruction will be sent to cache the two.

If the history information obtained from the WWW server does not include the data of the jump probability, the mobile terminal device 1 counts up the count information item for each link.
(I) and access number information (Tot) for the page
al-Hit) may be used to calculate each jump probability (this is the same for other examples).

<Specific Example 2> FIG. 11A shows an example of a prefetch policy in consideration of the restriction on the cache area of the mobile terminal device 1. That is, the jump probability is first and the data size is 300K in the link source page.
B, and caches the linked page in the mobile terminal device 1 only when the condition of B or less is satisfied,
This is an example in which a policy is described in which, when such a condition is not satisfied, the linked page having the highest jump probability is cached by the cache server.

Note that the data size condition can be determined as a function of the value of the memory size register 72.

For example, in the case of history information as shown in FIG. 11B, a page corresponding to link 2 is cached in the mobile terminal device 1 itself. Also, for example, FIG.
In the case of history information as shown in (c), a cache command is transmitted to the cache server to cache the link 3 page.

Note that, in the order of the jump probability, if the data can be stored in the mobile terminal device by referring to the data size of the link destination page, if the data cannot be stored in the mobile terminal device, it is possible to decide to perform prefetch caching in the cache server. It is. In addition, it is also possible to select a combination of linked pages so that the sum of the jump probabilities is the highest within a range in which the sum of the data sizes can be stored in the mobile terminal device and decide to cache them in the mobile terminal device in advance. It is possible. In addition, others can be determined to be prefetched and cached in the cache server. At that time, other conditions for prefetching and caching can be weighted.

<Specific Example 3> The conditions for the prefetch cache are as follows.
It's not just about landing page attributes.
For example, in an environment where the available band information of the wireless link can be dynamically monitored on the mobile terminal device 1 side, it is possible to configure a prefetch policy using the information. FIG. 12A shows an example of such a policy configuration. As a condition for prefetching and caching in the mobile terminal device 1 itself, a condition that the jump probability exceeds 50% in FIG. Is weighted on the condition that the security can be secured.

In this case, the data transfer amount monitor information of the wireless section is obtained from the monitor device incorporated in the mobile terminal device 1 or another monitor device (not shown) (for example, the router device 5 or the wireless base station 12). Jump probability is 50% only if this satisfies the specified condition
Go ahead to pages beyond. If the wireless section is congested, caching is not performed even if the link jump probability is high.

As described above, in this embodiment, a policy for prefetching and caching can be arbitrarily set using various information, and flexible WWW access can be realized.

Further, by expanding the look-ahead policy description of the present embodiment, it becomes possible to cope with various network forms and use forms.

<Specific Example 4> For example, FIG. 13 shows an example of extension to a case where cache servers are hierarchically arranged. In the example of FIG. 13A, for each linked page, if the data size is less than 300 MB, the data is prefetched and cached in the cache server indicated by proxy1, and 300M
If the value is equal to or more than B and less than 600 MB, the prefetch cache is performed in the cache server indicated by proxy2.

For example, in the case of the history information as shown in FIG. 13B, a cache command is transmitted to the cache server indicated by proxy1 so as to cache the page of link 2, and the cache instruction of link 1 is transmitted to the cache server indicated by proxy2. A cache instruction will be sent to cache two of the page and the page of link 3.

As described above, the conditions for prefetching cache can be individually specified for each cache server.

Also, a WWW page (bookmar) registered in advance in the WWW browser on the mobile terminal device 1
If there is k), it is also possible to describe a control that the information is preferentially cached on the cache server. In FIG. 14, when the mobile terminal device 1 connects to the network and starts the WWW browser, a cache command is transmitted to the cache server so as to prefetch and cache a WWW page (bookmark) registered in advance in the WWW browser. Control may be performed.

Further, when a cache command is issued to the cache server side, there is already data cached within a predetermined time using the WWW data already cached on the cache server side and the cached time information. In such a case, it is possible to control transmission of the cache command on the mobile terminal device 1 side or ignore the cache command on the cache server side.

For this purpose, for example, if Already cached (ID) and Cached_time
It is sufficient to record the time cached on the cache server side at the same time as performing expansion such as 24 hours then….

By performing these controls in combination, it is possible to cache data that is accessed more frequently at an appropriate level and reduce data traffic in the entire network.

Of course, the specific example described above is only an example.
Various other variations are conceivable. It is also possible to prefetch and cache a page of a link hierarchy further ahead of the WWW page that has been prefetched and cached. For example, when accessing the top page, it is possible to prefetch and cache the page that has the highest jump possibility from the top page, and also prefetch and cache the page that has the highest jump possibility from this prefetched page. It is. In that case, whether or not to prefetch and cache the linked page two or more layers ahead is determined by the probability that the linked page will be selected (for example, the probability of all jump probabilities up to the linked page). Product).

In the above description, it is assumed that the cache server 3 for prefetch caching is provided. However, it is also possible to provide the prefetch caching only on the mobile terminal device itself without providing the cache server 3 for prefetch caching. . In this case, the mobile terminal device only needs to determine whether or not to cache certain WWW information in advance, and there is no need to describe the cache destination in the description of the prefetch policy. You can do it.)

The above description has been made on the assumption that the mobile terminal device holds the prefetch policy information and controls the policy of the prefetch cache based on the policy information. It is also possible to perform policy control. For example, in addition to controlling the policy of the prefetch cache on the mobile terminal device side as before, each cache server holds its own cache policy and applies the cache policy to the prefetched WWW page to autonomously It is also possible to pre-read the page in advance. Also, for example, instead of controlling the policy of the prefetch cache on the mobile terminal device side,
Each cache server holds its own cache policy, performs policy control, prefetches and caches itself,
And / or cause the mobile terminal to prefetch cache (e.g., the cache server sends the WWW page (after obtaining it as needed) to the mobile terminal);
You can also say Further, it is possible to perform control such that the WWW server itself determines prefetching based on the jump probability of the link page and sends the prefetched page to the mobile terminal device and / or the cache server side.

Of course, when a device other than the mobile terminal device performs the policy control, it is not possible to take into account the resources of the mobile terminal device (such as the amount of available storage area), so it is necessary to perform appropriate error processing. . In the case where policy control is performed at a plurality of locations, it is necessary to set a rule for determining which is prioritized in the case of inconsistency.

If these detailed controls are determined, in the present embodiment, it becomes possible to perform control by placing the prefetch policy information at an arbitrary position in the system.

As described above, in the present embodiment, when a mobile portable terminal is used, it is possible to determine which page is to be prefetched and cached based on the jump probability and the data size of each link destination page in the link source page. The policy can be set arbitrarily, and the user's WWW access speed can be increased, and unnecessary increase in prefetch traffic can be prevented, so that the use probability of the entire wireless network can be increased. Also, multiple cache servers work together,
The present invention can be easily extended to various modes such as reflecting the status information of the wireless network or setting a cache policy reflecting the preference of each terminal user.

The functions of the present embodiment can be realized as software.

Further, in the present embodiment, a computer which records a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means or for causing a computer to realize predetermined functions) is recorded. It can also be implemented as a readable recording medium.

The present invention is not limited to the above-described embodiments, but can be implemented with various modifications within the technical scope.

[0144]

According to the present invention, even if a mobile terminal is connected to a wireless network having a low transmission speed and has an upper limit in the capacity of a disk or memory that can be cached, contents having a high use probability are preferentially read ahead. The cache can be cached, the availability of the prefetched content is increased, and the speed of Web response can be increased and the traffic amount can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the overall configuration of a data distribution system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a Web page

FIG. 3 is a diagram for explaining basic processing of a prefetch cache of a WWW page;

FIG. 4 is a diagram showing an example of jump history information of a WWW page.

FIG. 5 is a diagram for explaining creation of jump history information of a link destination of a WWW page;

FIG. 6 is a diagram showing a configuration example of a WWW server according to the embodiment;

FIG. 7 is a diagram showing a configuration example of a mobile terminal device according to the embodiment.

FIG. 8 is a diagram illustrating an example of a grammar for describing a prefetch cache policy;

FIG. 9 is a diagram showing a configuration example of a cache server according to the embodiment;

FIG. 10 is a diagram showing an example of a description of a prefetch cache policy and an example of an operation corresponding to the example;

FIG. 11 is a diagram showing a description example of a prefetch cache policy and another example of an operation corresponding thereto;

FIG. 12 is a diagram showing a description example of a prefetch cache policy and still another example of an operation corresponding thereto;

FIG. 13 is a diagram showing a description example of a prefetch cache policy and still another example of an operation corresponding to the description example;

FIG. 14 is a diagram showing still another example of the operation of the prefetch cache.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mobile terminal device 2 ... WWW server 3 ... Cache server 5 ... Router device 6 ... Internet 12 ... Wireless base station 16 ... Cellular phone / PHS network 18 ... Access server 71 ... Look-ahead cache storage unit 72 ... Memory size register 73 ... Look-ahead Policy storage unit 91: Cache instruction register 92: Cache area

Continuing on the front page (72) Inventor Noriyasu Kato 1 Toshiba-cho, Komukai-shi, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba R & D Center Co., Ltd. Inside Toshiba R & D Center (72) Inventor Yoshinari Kumagi 1 at Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside Toshiba R & D Center (72) Inventor Yasuo Masahata Sachi-ku, Kawasaki-shi, Kanagawa No. 1 Muko Toshiba Town F-term in Toshiba R & D Center (Reference) 5B082 AA00 GC04 HA02 HA08

Claims (20)

[Claims] An information distribution system in which a mobile computer connects to the Internet via a wireless network and receives WWW information from an information server on the Internet, wherein the information server provides the requested WWW information. The requested WWW information includes history information including at least information indicating how much the WWW information of each link destination linked from the requested WWW information has been accessed in the past using the requested WWW information as a link source. In the case where access to certain WWW information occurs in the mobile computer, at least to each link destination linked from the certain WWW information obtained by the history information added to the certain WWW information Caches the mobile computer itself based on the index regarding the jump possibility of the Information distribution system, characterized in that to determine the can WWW information. 2. A mobile computer connected to the Internet via a wireless network, an information server for providing WWW information to the mobile computer, and a cache server for prefetching and caching information delivered by the information server for the mobile computer. An information distribution system comprising: when an information server provides requested WWW information, each link destination WWW information linked from the requested WWW information uses the requested WWW information as a link source in the past. And providing history information including at least information indicating how much access has been made to the requested WWW information. When an access to certain WWW information occurs in the mobile computer, at least the certain WWW information Each resource linked from the certain WWW information obtained from the added history information Based on the indicator of jump potential for click destination information distribution system and determining the device to cache the WWW information WWW information and prefetching to be read-ahead cache. 3. The information distribution system according to claim 2, wherein said determination is made in said mobile computer and / or said cache server. 4. The information related to each link destination included in the history information is the number of times the WWW information of each link destination has been accessed using the requested WWW information as a link source. 4. The index relating to jump possibility is obtained by dividing the number of times the WWW information of each link destination is accessed by the number of times the requested WWW information is accessed, respectively. 2. The information distribution system according to claim 1. 5. The method according to claim 1, wherein the determination is made in consideration of a data size of WWW information of each link destination linked from the requested WWW information. Information distribution system described. 6. The information distribution system according to claim 1, wherein said determination is made in consideration of available bandwidth information of a dynamically monitored network. 7. If the index indicates that the WWW information of the link destination has a jump possibility greater than or equal to the first reference value, it is determined that the WWW information is prefetched and cached in the mobile computer, and If the index indicates that the WWW information has a jump possibility equal to or more than a second reference value smaller than the first reference value, it is determined that the WWW information is prefetched and cached in the cache server. Item 7. The information distribution system according to any one of Items 2 to 6. 8. A link destination WWW having an index indicating a large jump possibility is preferentially given to the link destination WWW information.
8. The mobile computer according to claim 1, wherein a decision is made to prefetch and cache the WWW information of the link destination in the mobile computer based on a relationship between a data size of the information and a size that can be stored in the mobile computer. 2. The information distribution system according to claim 1. 9. The determination is made in accordance with look-ahead policy information describing a predetermined procedure, and the look-ahead policy information includes, in advance, when the display software of the mobile computer is activated, 9. The information distribution system according to claim 1, wherein a procedure for prefetching and caching the registered WWW information can be described. 10. The history information includes information specifying the link source WWW information transmitted by each mobile computer and a link destination WWW.
The information is generated for each link source WWW information in each information server holding the link source WWW information based on a predetermined message including information specifying the WWW information. 10. The information distribution system according to any one of items 9 to 9. 11. When the information server provides requested WWW information, the information server also adds WWW information of a link destination determined to be highly likely to be jumped based on the history information corresponding to the requested WWW information. The information distribution system according to any one of claims 1 to 10, wherein the information distribution system is provided. 12. A mobile computer connected to the Internet via a wireless network and receiving delivery of WWW information from an information server on the Internet. When an access to certain WWW information occurs, at least the certain WWW information The WWW information of each link destination linked from the certain WWW information provided and provided from the information server apparatus is based on history information including at least information indicating how much access has been made in the past using the certain WWW information as a link source. The certain WWW obtained
The mobile computer itself includes means for determining WWW information to be prefetched and cached, and means for caching the prefetched WWW information, based on an index regarding the possibility of jumping to each link destination linked from the information. Mobile computer featuring. 13. A mobile computer connected to the Internet via a cache server via a wireless network and receiving WWW information delivered from an information server on the Internet. When an access to certain WWW information occurs, at least the certain WWW A history including at least information indicating how much the WWW information of each link destination linked from the certain WWW information provided from the information server apparatus added to the information has been accessed in the past using the certain WWW information as a link source The certain WWW obtained by information
WWW to be prefetched and cached based on the index regarding the possibility of jumping to each link destination linked from the information
Information, means for prefetching the WWW information to determine a device to be cached, and WW determined to be prefetched and cached in its own device.
Means for prefetching and caching the WWW information when there is W information, and means for prefetching and caching the WWW information when there is WWW information determined to be prefetched and cached in the cache server. Means for transmitting a request to the cache server. 14. The apparatus according to claim 1, further comprising means for holding information relating to a data size enabling a prefetch cache to the own apparatus, wherein the history information further includes information relating to a data size of WWW information of each link destination, 13. The method according to claim 12, wherein the determining unit performs the determination in consideration of information on the data size.
Or the mobile computer according to 13. 15. A system further comprising means for performing processing for notifying a set of WWW information serving as a link source and WWW information serving as a link destination to an information server holding WWW information serving as a link source. 3. The method according to claim 1, wherein
5. The mobile computer according to any one of 4. 16. An information server device connected to the Internet and providing WWW information, wherein WWW information of each link destination linked from certain WWW information is stored for each WWW information held by its own device.
Means for creating history information including at least information indicating how much access has been made in the past using the WW information as a link source; and providing the requested WWW information when providing the requested WWW information.
Means for providing the W information with the history information added thereto. 17. A means for providing, when providing requested WWW information, linked WWW information determined to have a high possibility of jumping based on the history information corresponding to the requested WWW information. 17. The information server device according to claim 16, further comprising: 18. A read-ahead cache for a mobile computer, which is installed between a mobile computer connected to the Internet via a wireless network and an information server for providing WWW information to the mobile computer. A cache server device, comprising: means for prefetching and caching WWW information specified by a mobile computer. 19. A read-ahead cache for a mobile computer, provided between a mobile computer connected to the Internet via a wireless network and an information server for providing WWW information to the mobile computer. A cache server device that, when an access to certain WWW information occurs in the mobile computer, at least links provided from the certain WWW information provided from the information server device in addition to the certain WWW information An index relating to the possibility of jumping to each link destination linked from the certain WWW information, which is obtained from history information including at least information indicating how much the previous WWW information has been accessed in the past using the certain WWW information as a link source WWW information to be prefetched and cached based on Means for prefetching information to determine a device to be cached, and WW determined to be prefetched and cached in its own device
Means for prefetching and caching the WWW information when there is W information; and when the mobile computer has WWW information determined to be prefetched and cached,
Means for prefetching and caching information. 20. A mobile computer connected to the Internet via a wireless network, an information server for providing WWW information to the mobile computer, and a cache server for prefetching and caching information distributed by the information server for the mobile computer. A prefetch cache processing method in an information distribution system including: when an information server provides requested WWW information, WWW information of each link destination linked from the requested WWW information is the requested WWW information. History information including at least information indicating how much access was made in the past with the link source as the link source, provided in addition to the requested WWW information, and when an access to certain WWW information occurred in the mobile computer, at least The history information added to the certain WWW information, That on the basis of the index relating jump potential for each link destination linked from WWW information, read-ahead caching method characterized by determining the apparatus to cache the WWW information WWW information and prefetching to be read-ahead cache.