JP2013051500A - Content distribution system, cache server and content distribution method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid network congestion when a content to be distributed through a mobile network has a large volume.SOLUTION: A cache server tentatively stores a copy of at least a portion of a management content among a plurality of management contents stored in a storage device; generates the stored management content list as a first content list; collects a management content list stored in a cache server other than the self-cache server among a plurality of cache servers, as a second content list; using information, included in a management content request message from a mobile terminal, and the first and second content list, discriminating a cache server having the requested management content stored therein; and instructs the discriminated cache server to read out a file or a stream of the requested management content, in consideration of coordination between the plurality of cache servers.

Description

  The present invention relates to a content distribution system for distributing content, a cache server for caching content, and a content distribution system, and in particular, after content including moving images, still images, audio, software, applications, etc. is cached in a mobile network. The present invention relates to a content distribution system, a cache server, and a content distribution method for distributing to various terminals (for example, mobile phones, smartphones, PCs, game machines, etc.).

  The mobile network is scheduled to be increased in speed and capacity by LTE (Long Term Evolution), EPC (Evolved Packet Core) technology, and the like. Along with this progress, it is expected that content distribution for distributing content to various terminals including mobile terminals via the mobile network will become widespread in the future.

  For example, Patent Document 1 describes a technique for ensuring communication quality of content distribution traffic in a content distribution network to which a distributed cache system is applied.

Japanese Patent Laid-Open No. 2007-110368

  The following analysis was made by the present inventors.

  It is predicted that the traffic volume of the data system in the mobile network will increase from the current 8 times to more than 10 times over the next 2013, and the video content will occupy most of it. In addition, with the rapid spread of smartphones, the processing capacity of terminals has become higher, so the size of video content has become larger year by year. In the near future, it is expected that high-definition, high-capacity, high-quality paid managed content will be distributed on mobile networks.

  In a conventional content distribution system that distributes managed content over a mobile network, the device that stores the managed content on the mobile network accepts content requests from all terminals via the packet transfer device, and the packet transfer device. Content is distributed to all terminals via

  However, according to the conventional content distribution system based on such a configuration, the following problems may occur.

  Due to the existence of popular contents and the like, if access concentrates on the management contents stored on the mobile network, the traffic of the mobile network becomes concentrated. At this time, the network may be congested. If the network becomes congested, there is a possibility that the delay until the video is played back on the terminal will be long, the video being played back on the terminal will be stopped, or the packet will be lost frequently and the image will be greatly disturbed. .

  Therefore, according to the conventional content distribution system, the user's QoE (Quality of Experience) may be impaired.

  In the content distribution system described in Patent Document 1, a single CDN router centrally manages which cache server among a plurality of cache servers that cache content is caching the content. . Therefore, when the content distribution request increases, the processing in the CDN router may become a bottle net.

  Thus, when content is distributed via a mobile network, it becomes a problem to avoid network congestion when the content becomes large. An object of the present invention is to provide a content distribution system, a cache server, and a content distribution method that solve such problems.

The content distribution system according to the first aspect of the present invention is:
A storage device for storing a plurality of management contents;
With multiple cache servers on the mobile network,
Each of the plurality of cache servers includes a content temporary storage unit that temporarily stores a copy of at least some of the plurality of management content,
A content list creation unit for creating a list of managed content stored in the content temporary storage unit as a first content list;
A collection unit for collecting a list of managed contents stored in another cache server among the plurality of cache servers as a second content list;
A discriminator for discriminating a cache server that holds the requested managed content using the information included in the message requesting the managed content from the portable terminal, and the first content list and the second content list; ,
A content securing unit that instructs the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
A delivery unit that outputs the read file or stream in accordance with a set protocol.

The cache server according to the second aspect of the present invention is:
A content temporary storage unit that temporarily stores a copy of at least some of the management content stored in a storage device provided on the mobile network; and
A content list creation unit for creating a list of managed content stored in the content temporary storage unit as a first content list;
A collection unit that collects a list of managed content stored in a cache server other than itself among a plurality of cache servers provided in the mobile network, as a second content list;
A discriminator for discriminating a cache server that holds the requested managed content using the information included in the message requesting the managed content from the portable terminal, and the first content list and the second content list; ,
A content securing unit that instructs the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
A delivery unit that outputs the read file or stream in accordance with a set protocol.

The content distribution method according to the third aspect of the present invention is:
A step in which the cache server temporarily accumulates a copy of at least some of the management content stored in a storage device provided on the mobile network;
A content list creation unit that creates a list of accumulated management content as a first content list;
Collecting a list of managed contents stored in a cache server other than itself among a plurality of cache servers provided in the mobile network as a second content list;
Determining the cache server that holds the requested managed content using the information included in the message requesting the managed content from the mobile terminal, and the first content list and the second content list;
Instructing the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
Outputting the read file or stream in accordance with a set protocol.

  According to the content distribution system, the cache server, and the content distribution method according to the present invention, when content is distributed via a mobile network, it is possible to avoid network congestion when the content becomes large.

It is a block diagram which shows the connection structure of the content delivery system which concerns on 1st Embodiment as an example. It is a block diagram which shows the structure of the cache server in the content delivery system which concerns on 1st Embodiment as an example. It is a block diagram which shows the connection structure of the content delivery system which concerns on 2nd Embodiment as an example.

  First, the outline of the present invention will be described. Note that the reference numerals of the drawings attached to this summary are merely examples for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment.

  Referring to FIGS. 1 and 2, the content distribution system of the present invention includes a storage device (121) for storing a plurality of managed contents and a plurality of cache servers (110_1 to 110_N) on a mobile network (150). Each of the plurality of cache servers includes a temporary content storage unit (113) for temporarily storing a copy of at least a part of the plurality of managed content, and the managed content stored in the temporary content storage unit. A content list creation unit (118) that creates a list of the contents as a first content list, and a collection unit that collects a list of managed content stored in another cache server among a plurality of cache servers as a second content list (116) and management content from the portable terminal (170) And a discriminating unit (117) for discriminating a cache server holding the requested management content using the information included in the message requesting the request, the first content list and the second content list, and the requested management A content securing unit (112) for instructing the determined cache server to read the content file or stream in consideration of cooperation between the plurality of cache servers, and a protocol in which the read file or stream is set And a distribution unit (114) that outputs the response according to the above.

  In addition, when the storage device (121) receives a request for management content from the mobile terminal (170) via any of the plurality of cache servers (110_1 to 110_N), the storage device (121) receives the end user information of the mobile terminal from the policy device ( 122), and the resolution of the management content may be set according to the information and sent to the cache server.

  When the management content requested from the mobile terminal (170) is included in the first content list, the determination unit (117) instructs the content temporary storage unit (113) to read the management content. May be. In addition, when the management content requested from the mobile terminal (170) is not included in the first content list and is included in the second content list, the determination unit (117) includes a plurality of cache servers (110_1 to 110_N). ), The content securing unit (112) may be instructed to secure the managed content from the cache server storing the managed content. Further, when the managed content requested from the mobile terminal (170) is not included in either the first content list or the second content list, the determination unit (117) receives the information from the storage device (121). The content securing unit (112) may be instructed to secure managed content.

In the present invention, the following modes are possible.
[Form 1]
This is the same as the content distribution system according to the first aspect.
[Form 2]
When the storage device receives a request for management content from the mobile terminal via any of the plurality of cache servers, the storage device reads out the information of the end user of the mobile terminal from the policy device and determines the resolution of the management content. It may be set according to and sent to the cache server.
[Form 3]
The determination unit may instruct the temporary content storage unit to read out the management content when the management content requested from the portable terminal is included in the first content list.
[Form 4]
When the management content requested from the mobile terminal is not included in the first content list but is included in the second content list, the determination unit determines the management content of the plurality of cache servers. The content securing unit may be instructed to secure the management content from the stored cache server.
[Form 5]
The determination unit secures the management content from the storage device when the management content requested from the mobile terminal is not included in either the first content list or the second content list. You may make it instruct | indicate to the said content securing part.
[Form 6]
The plurality of managed contents may include at least one of a moving image, a still image, sound, audio, software, an application, and data.
[Form 7]
The cache server according to the second aspect is as described above.
[Form 8]
The determination unit may instruct the temporary content storage unit to read out the management content when the management content requested from the portable terminal is included in the first content list.
[Form 9]
When the management content requested from the mobile terminal is not included in the first content list but is included in the second content list, the determination unit determines the management content of the plurality of cache servers. The content securing unit may be instructed to secure the management content from the stored cache server.
[Mode 10]
The determination unit secures the management content from the storage device when the management content requested from the mobile terminal is not included in either the first content list or the second content list. You may make it instruct | indicate to the said content securing part.
[Form 11]
The content distribution method according to the third aspect is as described above.
[Form 12]
In the content distribution method, the cache server may read the management content from its storage unit when the management content requested from the mobile terminal is included in the first content list.
[Form 13]
In the content distribution method, the cache server may include, when the management content requested from the mobile terminal is not included in the first content list but is included in the second content list, among the plurality of cache servers. The management content may be secured from a cache server storing the management content.
[Form 14]
In the content distribution method, when the management content requested from the portable terminal is not included in either the first content list or the second content list, the cache server manages the management server from the storage device. Content may be secured.

  Next, an embodiment and its operation will be described in detail with reference to FIGS. In the following embodiment, the configuration in the case where the content is a moving image is shown as an example, but the same configuration is also used in the case where the content is a still image, audio, audio, software, application, data, or the like. be able to.

(Embodiment 1)
The content distribution system according to the first embodiment will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a content distribution system according to the present embodiment.

  FIG. 1 shows a configuration when a 3G mobile packet network is used as a mobile network and an xGSN device is used as a packet transfer device.

  Referring to FIG. 1, the content distribution system includes a storage device 121, a policy device 122, an xGSN device 190_1 to 190_N, a cache server 110_1 to 110_N, an RNC device 195_1 to 195_L, 197_1 to 197_L, and a base on the mobile network 150. Station devices 180_1 to 180_M, 181_1 to 181_M, 182_1 to 182_M, and 183_1 to 183_M are provided.

  In FIG. 1, the storage device 121 on the mobile network 150 stores various management contents that the operator owns or that the operator has secured by contracting with a content provider. In the following description, these managed contents are called MC (Managed Content). The content is a compression-encoded bitstream or a compression-encoded bitstream of content including at least one of moving images, still images, audio, audio, etc., but is a Web screen, software, application, data Etc. Moreover, although the portable terminal 170 is used as a terminal, other terminals can also be used.

  N (N ≧ 2) xGSN apparatuses 190_1 to 190_N are arranged on the mobile network 150. The RNC devices 195_1 to 195_L (L ≧ 2) are connected to the xGSN device 190_1. Similarly, RNC devices 197_1 to 197_L are connected to the xGSN device 190_N. Note that L RNC devices are also connected to the xGSN device 190_2, but are not shown in FIG. 1 for the sake of space. Furthermore, M base station apparatuses (M ≧ 2) are connected to each RNC apparatus. For example, M base station apparatuses 180_1 to 180_M are connected to the RNC apparatus 195_1.

  In FIG. 1, one cache server is connected to the GGSN unit of each xGSN device. For example, the cache server 110_1 is connected to the xGSN device 190_1. Here, the xGSN device means that the SGSN function unit and the GGSN function unit are configured in the same place.

  The portable terminal 170 issues a distribution connection request message describing the URL of the requested content. Then, the base station device in which the mobile terminal 170 is located (in the case of FIG. 1, any of the base station devices 181_1 to 181_M) receives the connection request message and manages the base station device. A connection request message is sent to the device (in the case of FIG. 1, RNC device 195_L).

  The RNC device 195_L receives the connection request message from the base station device, and stores the connection request message, the IP address of the distribution server, the IP address of the mobile terminal 170, and the like in the payload portion of the GTP packet. Further, the RNC device 195_L transfers the GTP packet to the xGSN device 190_1 that collects the RNC devices 195_1 to 195_L.

  Next, the xGSN device 190_1 receives the GTP packet.

  The cache server 110_1 is connected to the Gi interface of the GGSN function unit of the xGSN device 190_1, for example. Similarly, the cache server 110_N is connected to the Gi interface of the GGSN function unit of the xGSN device 190_N. Further, the cache servers 110_1 to 110_N are connected to each other so that the contents can be linked.

  Next, the configuration of the cache server 110_1 connected to the xGSN device 190_1 will be described with reference to the drawings. FIG. 2 is a block diagram illustrating an example of the configuration of the cache server 110_1. Since the other cache servers 110_2 to 110_N have the same configuration as the cache server 110_1, the description thereof is omitted.

  Referring to FIG. 2, the cache server 110_1 includes a control signal transmission / reception unit 111, an analysis unit 115, a collection unit 116, a determination unit 117, a content securing unit 112, a content temporary storage unit 113, a content list creation unit 118, and a distribution unit. 114.

  The control signal transmission / reception unit 111 receives a GTP packet storing a connection request message from the mobile terminal 170, a received IP address of the mobile terminal 170, a URL of the requested content, and the like from the xGSN device 190_1.

  The analysis unit 115 reads the content of the connection request message stored in the payload portion of the GTP packet, extracts information such as the received IP address of the mobile terminal 170 and the URL of the requested content, and the requested content URL, The received IP address of the portable terminal 170 is output to the distribution unit 114 and the determination unit 117.

  The collection unit 116 inputs the content list of the content stored in the cache server 110_1 from the content list creation unit 118, and inputs the content list of the content stored in the cache servers 110_2 to 110_N other than the cache server 110_1 from the control signal transmission / reception unit 111. These are output to the determination unit 117. The collection unit 116 may collect the content list at predetermined time intervals, may be performed when a connection request is received from the mobile terminal 170, or a collection request is received from another cache server. You may go when there is.

  The determination unit 117 inputs the received IP address of the mobile terminal 170, the URL of the requested content, and the like from the analysis unit 115. Further, the determination unit 117 inputs from the collection unit 116 a content list of content stored in the cache server 110_1 and a content list of content stored in the cache servers 110_2 to 110_N other than the cache server 110_1. The determination unit 117 determines whether the content requested by the mobile terminal 170 is accumulated in the cache server 110_1 or whether the cache servers 110_2 to 110_N other than the cache server 110_1 are accumulated.

  When the cache server 110_1 stores the content requested by the mobile terminal 170, the determination unit 117 instructs the temporary content storage unit 113 and the distribution unit 114 to read and distribute.

  On the other hand, when the cache servers 110_2 to 110_N other than the cache server 110_1 store the content requested by the mobile terminal 170, the determination unit 117 stores the URL of the requested content in the content securing unit 112. The cache server is informed of the IP address of the cache server, and instructed to secure the contents from the cache server through cooperation between the cache servers.

  Note that if neither the cache server 110_1 nor the cache server 110_2 to 110_N other than the cache server 110_1 has accumulated the content requested by the mobile terminal 170, the determination unit 117 secures the content from the storage device 121. The content securing unit 112 is instructed.

  The content securing unit 112 inputs the requested content URL and content securing instruction from the determination unit 117. If the cache servers 110_2 to 110_N store the content requested by the mobile terminal 170, the content securing unit 112 inputs the IP address of the corresponding cache server from the determination unit 117. On the other hand, when the storage device 121 stores the content requested by the portable terminal 170, the content securing unit 112 inputs the IP address of the storage device 121 from the determination unit 117. The content securing unit 112 secures a copy of the requested content from the cache server or the storage device 121 and outputs it to the content temporary storage unit 113. The temporary content storage unit 113 stores the content. Here, when reading the requested content from the storage device 121, the content securing unit 112 searches the storage device 121 for the content using the URL of the requested content.

  In addition, when the content securing unit 112 receives an instruction to secure content from the cache servers 110_2 to 110_N via the control signal transmission / reception unit 111, the content securing unit 112 reads the content from the temporary content storage unit 113 and reads the cache servers 110_2 to 110_2. 110_N.

  The storage device 121 reads user information from the policy device 122 based on the received IP address or telephone number of the mobile terminal 170 when searching for content according to the requested content URL, and uses the user's usage plan or QoE policy. To extract. Thereby, the storage device 121 sets the resolution of the content to be read and the setting of QoE when distributing the content, reads the content, and outputs the content to the content securing unit 112.

  When the content read instruction is input from the determination unit 117, the temporary content storage unit 113 reads the content file corresponding to the requested content URL and outputs the content file to the distribution unit 114. In addition, the temporary content storage unit 113 reads the content file requested from the content securing unit 112 and outputs the content file to the content securing unit 112.

  The content list creation unit 118 creates a list of all the content stored in the content temporary storage unit 113 as needed, and when there is a request from the cache servers 110_2 to 110_N at predetermined time intervals. Alternatively, the content list is output when requested by the collection unit 116.

  The distribution unit 114 inputs URL information of the requested content from the analysis unit 115, inputs a content distribution instruction from the determination unit 117, inputs a file of the requested content from the content temporary storage unit 113, and further performs QoS. , The packet of a predetermined protocol (for example, TCP) is generated, the QoS setting is set in the header portion of the packet, the packet is sent to the xGSN device 190_1, and the QoS set via the xGSN device 190_1 is transmitted. To the portable terminal 170.

  Various modifications can be made in the present embodiment.

  Although FIG. 1 shows a configuration in which one cache server is connected to one xGSN device, a configuration in which one cache server is connected to a plurality of xGSN devices can be adopted, and one xGSN device can be used. Alternatively, a plurality of cache servers can be connected.

  The storage device 121 can also be connected to the cache server devices 110_1 to 110_N.

  Furthermore, in FIG. 1, although it was set as the structure which uses the xGSN apparatus which integrated the SGSN apparatus and the GGSN apparatus, the structure which isolate | separated the SGSN apparatus and the GGSN apparatus can also be taken. In the case of this configuration, it is possible to adopt a configuration in which at least one cache server is connected to either the SGSN device or the GGSN device.

  Further, the mobile terminal 170 may be any of a mobile phone, a smartphone, a tablet, and a PC in which a data communication card is mounted. The mobile terminal 170 may be any other terminal as long as it can communicate with the mobile 3G network.

(Embodiment 2)
A content distribution system according to a second embodiment will be described with reference to the drawings. FIG. 3 is a block diagram illustrating an example of the configuration of the content distribution system according to the present embodiment. FIG. 3 shows a configuration in which an LTE (Long Term Evolution) / EPC (Evolved Packet Core) network 250, which is a 3.9 generation mobile network, is used as the mobile network 250 instead of the 3G mobile network 150 shown in FIG. Indicates. In LTE, the functions of the base station device and the RNC device are degraded, and only the eNodeB device is provided.

  Referring to FIG. 3, the content distribution system includes a distribution server device 120 on the Internet 145, S / P-GW devices 290_1 to 290_N, cache servers 410_1 to 410_N, and eNodeB on the mobile LTE / EPC network 250. Devices 260_1 to 260_M, 261_1 to 261_M, and 262_1 to 262_M are provided.

  In EPC, an S / P-GW (Serving / Packet Data-Gateway) device is connected to an eNodeB device. Here, the S / P-GW device means that the S-GW device and the P-GW device are integrated. FIG. 3 shows a configuration in which M eNodeB devices are connected to one S / P-GW device. For example, eNodeB devices 260_1 to 260_M are connected to the S / P-GW device 290_1.

  Here, one cache server is connected to each S / P-GW apparatus. For example, the cache server 410_1 is connected to the S / P-GW apparatus 290_1. The cache servers 410_1 to 410_N are connected to each other so that the contents can be linked.

  The portable terminal 170 describes the IP address of the distribution server device 120 and issues a distribution connection request message. Then, the eNodeB device in which the mobile terminal 170 is located (in the case of FIG. 3, one of the eNodeB devices 261_1 to 261_M) receives the connection request message. Any of the eNodeB devices 261_1 to 261M stores the connection request message, the IP address of the distribution server device 120, the IP address of the mobile terminal 170, etc. in the payload portion of the GTP protocol, and sends the GTP packet to the S / P-GW device 290_2. Forward.

  The cache server 410_1 has the same configuration as the cache server 110_1 illustrated in FIG. However, in this embodiment, the connection destination of the control signal transmission / reception unit 111 is the S / P-GW apparatus 290_1. Therefore, the control signal transmission / reception unit 111 receives the connection request message from the portable terminal 170, the GTP packet storing the IP address, and the location information of the portable terminal 170 from the S / P-GW apparatus 290_1. Note that the cache servers 410_2 to 410_N other than the cache server 410_1 also perform the same exchanges with the S / P-GW apparatuses connected thereto.

  Various modifications can be made in the present embodiment.

  In FIG. 3, the S / P-GW apparatus in which the S-GW apparatus and the P-GW apparatus are integrated is used. However, a structure in which the S-GW apparatus and the P-GW apparatus are separated can be used. In the case of this configuration, a configuration in which at least one cache server is connected to either the S-GW device or the P-GW device can be used.

  In addition, the mobile terminal 170 may be any of a mobile phone, a smartphone, and a PC in which a data communication card is mounted. The portable terminal 170 may be any other terminal as long as it can communicate with the mobile 3.9G network.

  In the content distribution systems according to the first and second embodiments described above, the cache server temporarily stores a copy of the content for the management content held by the operator or the management content held by the operator contracting with the content provider. By collecting the content list that is stored by itself and the content list that is stored by a cache server other than itself, the content requested by the terminal is requested in consideration of cooperation between cache servers or cooperation between proxy servers. The cache server or proxy server having the determined content is determined, and the requested content is read from the determined cache server or proxy server and distributed.

  According to such a content distribution system, for example, the following effects are brought about.

  First, traffic on the network can be reduced and network congestion due to concentration of access to popular content can be prevented.

  Second, by reducing the traffic, the delay until the video is played back on the terminal is suppressed, the video playing back on the terminal is prevented from being stopped, and the user's QoE (Quality of Experience) is improved. Can keep.

  Third, the first and second effects can be achieved without modifying the terminal at all.

  It should be noted that the disclosures of prior art documents such as the above patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiment can be changed and adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

110_1 to 110_N, 410_1 to 410_N Cache server 111 Control signal transmission / reception unit 112 Content securing unit 113 Content temporary storage unit 114 Distribution unit 115 Analysis unit 116 Collection unit 117 Determination unit 118 Content list creation unit 120 Distribution server device 121 Storage device 122 Policy device 145 Internet 150 Mobile network 170 Portable terminal 180_1-180_M, 181_1-181_M, 182_1-182_M, 183_1-183_M Base station device 190_1-190_N xGSN device 195_1-195_L, 197_1-197_L RNC device 250 Mobile LTE / EPC network 260_1-260_M, 261_1-261_M, 262_1-262_M eNodeB devices 290_1-2 0_N S / P-GW apparatus

Claims (10)

A storage device for storing a plurality of management contents;
With multiple cache servers on the mobile network,
Each of the plurality of cache servers includes a content temporary storage unit that temporarily stores a copy of at least some of the plurality of management content,
A content list creation unit for creating a list of managed content stored in the content temporary storage unit as a first content list;
A collection unit for collecting a list of managed contents stored in another cache server among the plurality of cache servers as a second content list;
A discriminator for discriminating a cache server that holds the requested managed content using the information included in the message requesting the managed content from the portable terminal, and the first content list and the second content list; ,
A content securing unit that instructs the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
A content delivery system comprising: a delivery unit that outputs the read file or stream in accordance with a set protocol.   When the storage device receives a request for management content from the mobile terminal via any of the plurality of cache servers, the storage device reads out the information of the end user of the mobile terminal from the policy device and determines the resolution of the management content. The content distribution system according to claim 1, wherein the content distribution system is set according to the content and sent to the cache server.   The discriminating unit instructs the temporary content storage unit to read out the managed content when the managed content requested from the portable terminal is included in the first content list. Item 3. The content distribution system according to Item 1 or 2.   When the management content requested from the mobile terminal is not included in the first content list but is included in the second content list, the determination unit determines the management content of the plurality of cache servers. 4. The content distribution system according to claim 1, wherein the content securing unit is instructed to secure the management content from an accumulated cache server.   The determination unit secures the management content from the storage device when the management content requested from the mobile terminal is not included in either the first content list or the second content list. The content distribution system according to claim 1, wherein the content securing unit is instructed.   6. The content according to claim 1, wherein the plurality of management contents include at least one of a moving image, a still image, audio, audio, software, an application, and data. Distribution system. A content temporary storage unit that temporarily stores a copy of at least some of the management content stored in a storage device provided on the mobile network; and
A content list creation unit for creating a list of managed content stored in the content temporary storage unit as a first content list;
A collection unit that collects a list of managed content stored in a cache server other than itself among a plurality of cache servers provided in the mobile network, as a second content list;
A discriminator for discriminating a cache server that holds the requested managed content using the information included in the message requesting the managed content from the portable terminal, and the first content list and the second content list; ,
A content securing unit that instructs the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
A cache server, comprising: a distribution unit that outputs a read file or stream according to a set protocol.   The discriminating unit instructs the temporary content storage unit to read out the managed content when the managed content requested from the portable terminal is included in the first content list. Item 8. The cache server according to Item 7.   When the management content requested from the mobile terminal is not included in the first content list but is included in the second content list, the determination unit determines the management content of the plurality of cache servers. 9. The cache server according to claim 7, wherein the content securing unit is instructed to secure the management content from an accumulated cache server. A step in which the cache server temporarily accumulates a copy of at least some of the management content stored in a storage device provided on the mobile network;
A content list creation unit that creates a list of accumulated management content as a first content list;
Collecting a list of managed contents stored in a cache server other than itself among a plurality of cache servers provided in the mobile network as a second content list;
Determining the cache server that holds the requested managed content using the information included in the message requesting the managed content from the mobile terminal, and the first content list and the second content list;
Instructing the determined cache server to read out the requested management content file or stream in consideration of cooperation between the plurality of cache servers;
And a step of outputting the read file or stream in accordance with a set protocol.

Images