JP2005025655A - Contents distribution system and user's terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to always utilize contents data of a contents distribution device whose constant operation cannot be guaranteed by previously dispersing and caching contents in respective user's terminal devices and distributing necessary contents between the use's terminal devices. <P>SOLUTION: A user's terminal to which contents are downloaded functions also as a cache device and the cached contents are distributed. When a user's terminal device 3-1 caches the contents of the contents distribution device 2, both the devices 2, 3-1 return the contents ID lists of contents owned by the devices 2, 3-1 themselves in response to an inquiry from a user's terminal device 3-2. Thereby the user's terminal device 3-2 can grasp the contents owned by both the devices 2, 3-1 from the received lists and download necessary contents from the device 2 or 3-1. Even when only either one of the devices 2, 3-1 is operated, the contents ID list can be received from the operating device 2 or 3-1 and the contents can be acquired from the device 2 or 3-1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a content distribution technology using a network, and more particularly to a content distribution system and a user terminal device in which content data is distributed and cached (stored) in devices on the network.

  In general, in a wide area network system represented by the Internet, content data downloaded by a client from a web server is cached in a proxy server on the route, and the next time the client makes a distribution request for the same content data, A technique for reducing the frequency of access to a web server by distributing content data stored in a proxy server is used.

The downloaded content data is also cached on the client, and only the content data updated on the web server after the client caches is sent from the proxy server to the client, so that the communication volume between the proxy server and the client is reduced. The technology is also known. (See Patent Document 1)
Japanese Patent Application Laid-Open No. 11-249977

  However, in the technique described in Patent Document 1, even if there are many clients and each client caches content data, a client uses content data cached in another client. It is not possible. Also, if the client who wants to use the content knows in advance the location of the proxy server that caches the content data, the content can be used by accessing the proxy server. Unusable when the server is not running.

  The present invention was devised to solve the above problems, and its purpose is to distribute and cache content data among user terminal devices existing on the network and to be necessary between the user terminal devices. An object of the present invention is to provide a content distribution system that can always use content data of a content distribution device that cannot guarantee operation at all times, and a user terminal device that constitutes this network system.

  In order to achieve the above object, a content distribution system according to the present invention includes one or more content distribution devices and a plurality of user terminal devices that download content data from the one or more content distribution devices. In the system, the user terminal device downloads the communication means for communicating with another device, the content download means for downloading content data from the other device using the communication means, and the content download means. Content cache means for caching content data, and managing the content data cached in the content cache means in correspondence with the content ID, and when there is an inquiry about content data currently held from another device A content management unit that returns the content ID of the corresponding content data to the inquiry source device using the communication unit; and the content cache that uses the communication unit when a content data transmission request is received from another device. Content distribution means for transmitting the corresponding content data cached in the means to the transmission request source device. Here, the other devices include a content distribution device and other user terminal devices.

  In the content distribution system configured as described above, each user terminal device caches content data downloaded from other devices in its own device, and manages the content data in association with the content ID. When there is an inquiry about the content data currently held from another device, the content ID of the corresponding content data is returned to the inquiry source device. When there is a content data transmission request from another device, the corresponding content data cached in the own device is transmitted to the transmission requesting device.

  That is, in this content distribution system, each user terminal device that has downloaded content data simultaneously functions as a cache device (a proxy device for the content distribution device), and the content data cached in the own device (downloaded content data) Is transmitted to the content data transmission request source.

  Therefore, according to this content distribution system, as the number of user terminal devices that have downloaded content data increases, the number of user terminal devices that function as a cache device for the content data increases. Content data that can be distributed between user terminal devices also increases, and a large number of content data distributed and cached among a large number of user terminal devices can be distributed between user terminal devices.

  In this way, content data that cannot be guaranteed to operate at all times can be distributed and cached among user terminal devices that exist on the network, and necessary content data can be distributed among user terminal devices. The content data of the device can always be used.

  In addition, the user terminal device of the present invention includes a communication unit for communicating with another device, a content download unit for downloading content data from the other device using the communication unit, and a content downloaded by the content download unit. Content cache means for caching data, and managing the content data cached in the content cache means in association with the content ID, and when there is an inquiry about content data currently held from another device, the communication Content management means for returning the content ID of the corresponding content data to the inquiry source device using the means, and the content cache using the communication means when there is a content data transmission request from another device And content delivery means for transmitting the content data corresponding cached in stage transmission requesting device, comprising a.

  The user terminal device configured as described above caches content data downloaded from other devices in its own device, and manages the content data in association with the content ID. When there is an inquiry about the content data currently held from another device, the content ID of the corresponding content data is returned to the inquiry source device. When there is a content data transmission request from another device, the corresponding content data cached in the own device is transmitted to the transmission requesting device.

  That is, the user terminal device that has downloaded the content data simultaneously functions as a cache device (a proxy device for the content distribution device), and transmits the content data cached in the own device (a copy of the downloaded content data) to the content data. Send to requester.

  Therefore, if a content distribution system is constructed by using this user terminal device as a terminal device on the user side, as the number of user terminal devices that have downloaded content data increases, the user terminal device that functions as a cache device for the content data is increased. It will increase. Content data that can be distributed between user terminal devices also increases, and a large number of content data distributed and cached among a large number of user terminal devices can be distributed between user terminal devices.

  In this way, content data that cannot be guaranteed to operate at all times can be distributed and cached among user terminal devices that exist on the network, and necessary content data can be distributed among user terminal devices. The content data of the device can always be used.

  In the content distribution system and the user terminal device of the present invention, the user terminal device uses the communication means to make an inquiry about the currently held content data to all other devices that can communicate with the own device. It is desirable to have content inquiry means.

  If configured as described above, the possibility of detecting another device that holds the target content data is maximized, so the availability of the content data is significantly improved.

  In the content distribution system and the user terminal device of the present invention, the content ID is preferably information that can specify a storage location of the original data of the downloaded content data.

  If comprised as mentioned above, the apparatus of the inquiry origin of content data can specify the preservation | save place of the original data of the content data which the said inquiry destination holds based on the content ID returned from the apparatus of inquiry destination Therefore, if necessary, the original content data can be downloaded by accessing the content distribution apparatus storing the original data.

  In the content distribution system and the user terminal device of the present invention, when the user terminal device returns the content ID to the inquiry source device, the content data corresponding to the content ID is cached. It is desirable to include cache attribute information adding means for adding information (attribute information, identifier, flag, etc.) indicating this to the transmission data.

  When configured as described above, when a response is received from a plurality of inquiry destination devices, the content data inquiry device can select which device based on the flag set in each of the returned transmission data. It is possible to determine whether to download the content data.

  As described above, according to the content distribution system and the user terminal device of the present invention, the content data is distributed and cached among the user terminal devices existing on the network, and is necessary between the user terminal devices. Since the content data can be distributed, it is possible to always use the content data of the content distribution apparatus that cannot guarantee operation at all times.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram conceptually showing a configuration example of a content distribution system according to the present invention.

  FIG. 1 shows a system configuration having devices 2, 3 (3-1, 3-2) that can communicate with each other via the Internet 1. Here, description will be made assuming that the device 2 is a content distribution device and the devices 3 (3-1, 3-2) are user terminal devices. In addition, each device 2, 3 (3-1, 3-2) can share, search, and use data and information directly by using a mutual storage unit, so-called peer-to-peer method. It is assumed that communication is performed by the above, and each device 2, 3 (3-1, 3-2) is notified in advance of the address of each device by a location server (not shown).

  FIG. 2 is a block diagram conceptually showing a configuration example of the user terminal device 3 (3-1, 3-2).

  The user terminal device 3 (3-1, 3-2) stores a communication unit 4 that communicates with other devices via the Internet 1, various programs used by the own device, content data downloaded from other devices, and the like. It has the memory | storage part 5 and the control part 6 which controls the whole apparatus. The storage unit 5 has a cache area 5a for caching (saving) downloaded content data.

  Under the control of the control unit 6, the communication unit 4 functions as communication means in the claims. The cache area 5a functions as content cache means. The control unit 6 itself functions as a content download unit, a content distribution unit, a content inquiry unit, a cache attribute information addition unit, and the like.

  Next, an operation example of the content distribution system configured as described above will be described with reference to FIGS.

  In FIG. 3, it is assumed that the content distribution apparatus 2 publishes content (Content) A on the Internet 1. Further, it is assumed that the user terminal device 3-1 has already downloaded the content A (ContentA) from the content distribution device 2 and has the cache (content A copy data) in the cache area 5a.

  At this time, it is assumed that the user terminal device 3-2 makes an inquiry (search) of the currently held content to the content distribution device 2 and the user terminal device 3-1. Then, the content distribution apparatus 2 returns a list of content IDs of the content data currently owned by itself (see FIG. 4A) to the user terminal device 3-2. The content ID is information that can specify the storage location of the original data of each content data (specifically, address information such as URL (Uniform Resource Locator) or URN (Uniform Resource Name) of the content data) and the content data It includes cache attribute information indicating whether or not it is cached. Since all the content data held by the content distribution device 2 is original data, the cache attribute information is null in this case. That is, the content ID in the list returned by the content distribution apparatus 2 is composed only of information that can specify the storage location of the original data of the content data.

  The user terminal device 3-1 also returns a list of content IDs of the content data that it currently owns (see FIG. 4B) to the user terminal device 3-2. As shown in FIG. 4B, the content ID in the list returned by the user terminal device 3-1 has a cache attribute to indicate that the content data corresponding to the content ID is cached. The attribute code “CACHED” is attached as information. Further, the user terminal device 3 that has further cached the cached content data (re-cache, re-cache) shows the cache attribute information “CACHED”, for example, “CACHED” in order to indicate which device has cached the data. -A "," CACHED-B "," CACHED-A, B ", etc., and a code (" -A "," -B ", etc.) corresponding to the cached device is further added. Here, “CACHED-A” is the data cached by the device A, and “CACHED-A, B” is the data cached by the device A and is further cached by the device B. Indicates that there is. The cache attribute information is set when the content ID is returned to the inquiry source device.

  The user terminal device 3-2 receives a list of content IDs from the content distribution device 2 and the user terminal device 3-1, and what kind of content each of the two devices 2 and 3-1 owns. I can grasp it. For example, in the case where it is desired to use the content A, the content A is held in both the content distribution device 2 and the user terminal device 3-1 in this example. Thus, the content A can be downloaded. At this time, as a method of selecting a transmission request destination, a method of selecting a device that has responded first, a device whose content ID cache attribute information is not “CACHED”, that is, content distribution possessing original content A There is a method for selecting the device 2. Also, both the content distribution device 2 and the user terminal device 3-1 are selected at the same time, the first half of the content A is downloaded from the content distribution device 2, and the latter half is downloaded from the user terminal device 3-1. In other words, one piece of content A can be acquired from both devices 2, 3-1.

  The above description of the operation is for the case where both the content distribution device 2 and the user terminal device 3-1 are operating. According to this system, the content distribution device 2 and the user terminal device 3- The user terminal device 3-2 can download the content A even when either one of the devices 2, 3-1 is not operating.

  That is, when either one of the content distribution device 2 and the user terminal device 3-1 is not operating, the user terminal device 3-2 is one of the devices 2, 3- A list of content IDs is received from 1, and the content held by the device 2 or 3-1 is grasped. In this example, since the contents A are held in both the apparatuses 2 and 3-1, by making a transmission request for the contents A to the one apparatus 2 or 3-1, which has returned the list of contents IDs. The content A can be downloaded.

  In the above example, in order to simplify the description, a system configuration in which two user terminal devices 3 exist for one content distribution device 2 is shown. A system configuration in which the above user terminal devices 3 exist or a system configuration in which a plurality of user terminal devices 3 exist for a plurality of content distribution devices 2 can be adopted.

  Then, as the number of user terminal devices 3 increases, the availability of content data held in the content distribution device 2 is increased.

  That is, according to this content distribution system, as the number of user terminal devices 3 that have downloaded content data increases, the number of user terminal devices 3 that function as cache devices for the content data increases. The content data that can be distributed between the user terminal devices 3 also increases, and a large number of content data that is distributed and cached among a large number of user terminal devices 3 can be distributed between the user terminal devices 3.

  In this way, content data is distributed and cached among a plurality of user terminal devices 3 existing on the Internet 1, and necessary content data can be distributed between these user terminal devices 3, The content data of the content distribution device 2 that cannot always guarantee operation can be used at all times.

  Further, the device that is the source of the content data can specify the storage location of the original data of the content data held by the inquiry destination based on the content ID returned from the inquiry destination device. The original content data can be downloaded by accessing the content distribution apparatus storing the original data. For example, as shown in FIG. 5, as a result of device D inquiring content data, as a device that holds the target content A, a plurality of copies are made through a plurality of devices A and B. If only the device C holding the content A can be found, the data may be deteriorated due to repeated copying, so the original content A is downloaded after the operation of the content distribution device is resumed. can do.

1 is a system configuration diagram conceptually showing a configuration example of a content distribution system according to the present invention. It is a block diagram which shows notionally the structural example of the user terminal device in FIG. It is operation | movement explanatory drawing of the content delivery system shown in FIG. (A) is a figure which shows the example of the list of content ID in a content delivery apparatus. (B) is a figure which shows the example of the list | wrist of content ID in a user terminal device. It is another operation | movement explanatory drawing of the content delivery system concerning this invention.

Explanation of symbols

1: Internet (network)
2: Content distribution device 3 (3-1, 3-2): User terminal device 4: Communication unit (communication means)
5: Storage unit 6: Control unit (content download unit, content distribution unit, content inquiry unit, cache attribute information addition unit)
5a: Cache area (content cache means)

Claims (8)

A content distribution system having one or more content distribution devices and a plurality of user terminal devices that download content data from the one or more content distribution devices,
The user terminal device
Communication means for communicating with other devices;
Content download means for downloading content data from another device using the communication means;
Content cache means for caching the content data downloaded by the content download means;
The content data cached in the content cache unit is managed in association with the content ID, and when there is an inquiry about the content data currently held from another device, the corresponding content is used using the communication unit Content management means for returning the content ID of the data to the inquiry source device;
Content distribution means for transmitting corresponding content data cached in the content cache means to the transmission request source apparatus using the communication means when there is a content data transmission request from another device;
Content distribution system with The user terminal device
2. The content distribution system according to claim 1, further comprising content inquiry means for making an inquiry about content data currently held with respect to all other apparatuses communicable with the own apparatus using the communication means. The content distribution system according to claim 1, wherein the content ID is information that can specify a storage location of original data of the downloaded content data. The user terminal device
2. A cache attribute information adding unit that adds information indicating that content data corresponding to the content ID is cached to transmission data when the content ID is returned to the inquiry source device. The content delivery system in any one of -3. Communication means for communicating with other devices;
Content download means for downloading content data from another device using the communication means;
Content cache means for caching the content data downloaded by the content download means;
The content data cached in the content cache unit is managed in correspondence with the content ID, and when there is an inquiry about the content data currently held from another device, the corresponding content is used using the communication unit Content management means for returning the content ID of the data to the inquiry source device;
Content distribution means for transmitting corresponding content data cached in the content cache means to the transmission request source apparatus using the communication means when there is a content data transmission request from another device;
A user terminal device comprising: 6. Content distribution means according to claim 5, further comprising content inquiry means for inquiring content data currently held for all other apparatuses communicable with the own apparatus using said communication means. The user terminal apparatus according to claim 6, wherein the content ID is information that can specify a storage location of original data of the downloaded content data. 6. A cache attribute information adding unit for adding information indicating that content data corresponding to the content ID is cached to transmission data when the content ID is returned to the inquiry source device. The user terminal device in any one of -7.

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