JP2010050815A - Aggregation server, distribution server, reception client, distribution system, method thereof, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make compatible high efficiency in distribution of update information and high availability of a system even when a relationship between a server and a client is frequently varied. <P>SOLUTION: An aggregation server includes: a receiving means for receiving, from each distribution server, topology information representing a plurality of distribution routes for update information from the distribution server to a plurality of reception clients corresponding to contents inside the distribution server; and a control means for selecting a selection distribution route so as to partially overlap a part of at least two selection distribution routes when selecting one selection distribution route from among the plurality of distribution routes for each of received topology information, for transmitting a result of the selection to a plurality of distribution servers, and for transmitting a combination instruction indicating a reception client that becomes a starting point of the part and a plurality of update information items to be combined by the reception client to each distribution server that has transmitted the topology information representing the selection distribution route including the part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a distribution system that provides update information of a content to the terminal when a request for update information is made from the terminal for various contents transmitted from a large number of servers.

  In particular, the present invention relates to an aggregation server, a distribution server, a reception client, a distribution system, an aggregation method, a distribution method, a reception method, and a program.

  In recent years, there is an increasing demand among users for mobile terminals such as mobile phones, PDAs, and in-vehicle terminals to exchange large-capacity content such as voice and video using a network while moving.

  Furthermore, there is a demand for distributing and utilizing contents such as information generated by street corner monitoring cameras or various sensors over a network.

  Technologies that meet such demands are being studied. In particular, while various and large amounts of content are distributed, it is important to deliver content information to users in real time without losing the freshness of the content.

  In response to such a demand, a system that distributes update information indicating that content has been updated to a terminal has been studied.

  In this system, when a topology for distributing update information (apparatus connection form indicating a distribution route) is created for each content, and update information is distributed according to the topology, the distribution efficiency of update information deteriorates. End up.

  Therefore, Patent Document 1 describes a method of synthesizing, that is, aggregating update information in order to reduce the distribution frequency of update information.

In the method described in Patent Document 1, update information is once aggregated by an update information distribution system. Information indicating which content update information the client requests is also collected by the update information distribution system. Then, the update information distribution system sets the distribution tree of clients that can aggregate the update information, that is, topology, aggregates the update information, and distributes the aggregated update information according to the topology, thereby improving the distribution efficiency of the update information. ing.
JP 2008-46888 A

  However, the above method cannot sufficiently cope with a situation where the connection between communication devices is frequently changed in the ubiquitous network society.

  For example, in the method described in Patent Document 1, when the relationship between the server and the client frequently changes, there is a problem that the topology is frequently recombined and the availability is deteriorated.

  An object of the present invention is to provide an aggregation server, a distribution server, a reception client, a distribution system, an aggregation method, a distribution method, a reception method, and a program capable of solving the above problems.

  The aggregation server of the present invention is an aggregation server that can communicate with a plurality of distribution servers, and each content server transmits the content from the distribution server to the plurality of receiving clients associated with the content in the distribution server. Receiving means for receiving topology information representing a plurality of delivery paths for update information, and selecting one selected delivery path from the plurality of delivery paths represented by the topology information for each topology information received by the receiving means When selecting, the selected delivery route is selected so that at least a part of at least two of the selected delivery routes overlaps, the result of the selection is transmitted to the plurality of delivery servers, and the start point of the part And a plurality of update information to be combined by the reception client. Of delivery server, at least, and a control means for transmitting to each of the execution distribution server that sent the topology information representing the selected delivery path including said portion.

  The distribution server of the present invention is a distribution server that is communicable with the aggregation server, and distributes update information of content within itself to a plurality of receiving clients associated with the content. Create topology information representing a plurality of distribution paths for the update information to a plurality of receiving clients, transmit the topology information to the aggregation server, and are selected from the plurality of distribution paths from the aggregation server When the selection result indicating the selected distribution route is received, the selected distribution route is selected from the plurality of distribution routes, and when the combination instruction is received from the aggregation, the combination instruction is stored in association with the selected distribution route. Managing means, and combining the selected delivery route selected by the managing means When the indication is associated, the update information is added with the delivery route information indicating the selected delivery route and the synthesis instruction, and the update information with the delivery route information and the synthesis information is added to the selected delivery. When the distribution instruction is associated with the selected distribution route, the distribution route information is attached to the update information, and the update information with the distribution route information is distributed according to the selected distribution route. And distribution means.

  The receiving client of the present invention is a receiving client capable of communicating with the plurality of distribution servers and other receiving clients, and the selected distribution route from the update information storage means and each of the distribution servers or other receiving clients. Update information receiving means for receiving update information to which distribution route information is attached, and the distribution route information attached to the update information, when the own reception client is indicated as a termination, The transfer is stopped, the own receiving client is indicated as a relay location in the distribution route information, the combining instruction is added to the update information, and the own receiving client is indicated in the combining instruction. A relay management unit that stores the update information in the update information storage unit; If the update instruction is added to the update information and the own reception client is not indicated in the combination instruction, or the own reception client relays the distribution route information. If the update instruction is not attached to the update information, the update information is transferred to another receiving client according to the distribution route information, and the update information is stored. When a plurality of update information indicated in the combination instruction is stored in the means, the plurality of update information is combined, and the combined update information is transmitted to other receiving clients according to the distribution route information. Transfer management means for transferring.

  The distribution system of the present invention includes the aggregation server, the plurality of distribution servers, and the plurality of reception clients.

  The aggregation method of the present invention is an aggregation method performed by an aggregation server that can communicate with a plurality of distribution servers, from each distribution server to a plurality of receiving clients associated with the contents in the distribution server. A receiving step of receiving topology information representing a plurality of delivery paths for the content update information, and selecting one selected delivery path from the plurality of delivery paths represented by the topology information for each received topology information When selecting, the selected delivery route is selected so that at least a part of at least two of the selected delivery routes overlaps, the result of the selection is transmitted to the plurality of delivery servers, and the start point of the part And a combination of a plurality of update information to be combined by the receiving client. The view, among the plurality of delivery servers, at least, and a control step of transmitting to each of the execution distribution server that sent the topology information representing the selected delivery path including said portion.

  The distribution method of the present invention is a distribution method performed by a distribution server that is communicable with the aggregation server and that distributes update information of content in itself to a plurality of receiving clients associated with the content, Create topology information representing a plurality of distribution paths for the update information from the own server to the plurality of receiving clients, send the topology information to the aggregation server, and from the aggregation server, among the plurality of distribution paths When the selection result indicating the selected delivery route selected from the above is received, the selected delivery route is selected from the plurality of delivery routes, and when the synthesis instruction is received from the aggregation, the synthesis instruction is selected. A management step of storing in association with the When linked, the update information is attached with the delivery route information indicating the selected delivery route and the composition instruction, and the update information with the delivery route information and the composition information is added to the selected delivery route. If the composition instruction is not associated with the selected delivery route, the delivery route information is attached to the update information, and the update information with the delivery route information is delivered according to the selected delivery route. A delivery step.

  The reception method of the present invention is a reception method performed by a plurality of distribution servers and a reception client that can communicate with other reception clients, and indicates the selected distribution route from each distribution server or other reception client. An update information receiving step for receiving update information to which distribution route information is attached, and when the own reception client is indicated as a termination in the distribution route information attached to the update information, transfer the update information. When the self-receiving client is indicated as a relay location in the distribution route information, the combining instruction is attached to the update information, and the self-receiving client is indicated in the combining instruction Includes a relay management step of storing the update information in the update information storage means, and the self-reception client is indicated as a relay location in the distribution route information. And the update instruction is attached to the update information and the own reception client is not indicated in the combination instruction, or the own reception client is indicated as a relay location in the distribution route information. And the update instruction is not attached to the update information, the update information is transferred to another receiving client according to the delivery route information, and the update information storage means When a plurality of pieces of update information indicated in the combination instruction are stored, the plurality of pieces of update information are combined, and the combined update information is transferred to another receiving client according to the distribution route information. Steps.

  The program of the present invention relates to update information of the contents from each distribution server to a plurality of receiving clients associated with the contents in the distribution server from each distribution server to a computer that can communicate with the plurality of distribution servers. A receiving procedure for receiving topology information representing a plurality of delivery paths, and selecting at least two of the selected delivery paths from a plurality of delivery paths represented by the topology information for each received topology information; The selected delivery route is selected so that at least a part of the selected delivery route overlaps, the result of the selection is transmitted to the plurality of delivery servers, and the receiving client that is the starting point of the part, and the receiving client A plurality of update information to be combined with a combination instruction indicating at least a part of the plurality of distribution servers. And a control step of transmitting to each of the execution distribution server that sent the topology information representing the selected delivery routes including, to the execution.

  The program of the present invention is communicable with the above aggregation server, and also distributes the update information of the content within itself to a plurality of receiving clients associated with the content from the own computer to the plurality of receiving clients. The topology information representing a plurality of distribution paths for the update information to the server is created, the topology information is transmitted to the aggregation server, and the selected distribution path selected from the plurality of distribution paths is selected from the aggregation server. A management procedure for selecting the selected delivery route from the plurality of delivery routes and receiving the composition instruction from the aggregation and storing the composition instruction in association with the selected delivery route when receiving a selection result indicating The combining instruction is associated with the selected delivery route. When the update information, the delivery information indicating the selected delivery route and the synthesis instruction are attached, and the update information with the delivery route information and the synthesis information is delivered according to the selected delivery route, A delivery procedure for attaching the delivery route information to the update information and delivering the update information to which the delivery route information is attached according to the selected delivery route when the combination instruction is not associated with the selected delivery route; Is executed.

  The program of the present invention is an update in which distribution route information indicating the selected distribution route is attached from each distribution server or another receiving client to a computer capable of communicating with the plurality of distribution servers and other receiving clients. When the update information reception procedure for receiving information and the distribution route information attached to the update information indicate that the client itself is terminated, the transfer of the update information is stopped and the distribution route information When the own receiving client is indicated as a relay location, the update instruction is attached to the combining instruction, and the combining instruction indicates the own receiving client, the update information is The relay management procedure stored in the update information storage means, and the self-reception client is indicated as a relay location in the distribution route information, and the update information includes If the combination instruction is attached and the own reception client is not indicated in the combination instruction, or the own reception client is indicated as a relay point in the distribution route information, and the update information includes When the combination instruction is not attached, the update information is transferred to another receiving client according to the distribution route information, and a plurality of pieces of information indicated in the combination instruction are stored in the update information storage unit. When the update information is stored, the plurality of update information is combined, and a transfer management procedure for transferring the combined update information to another receiving client according to the distribution route information is executed.

  According to the present invention, even when the relationship between the server and the client frequently changes, it is possible to achieve both high efficiency of distribution of update information and high availability of the system.

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

(First embodiment)
FIG. 1 is a conceptual diagram showing a network configuration example of an update information distribution system (hereinafter simply referred to as “distribution system”) 1 according to the first embodiment of the present invention.

  The distribution system 1 includes a plurality of update information distribution servers (hereinafter simply referred to as “distribution servers”) 100, an aggregation server 200, and a plurality of update information reception clients (hereinafter simply referred to as “reception clients”) 300; including.

  The distribution server 100 is a computer, for example.

  The distribution server 100 is connected directly or indirectly to one or more other distribution servers 100, the aggregation server 200, and the plurality of receiving clients 300.

  The distribution server 100 receives update information indicating that the content held by the server itself has been updated, among the plurality of reception clients 300, each of the reception clients (hereinafter referred to as “participating clients”) 300a who desire the update information. Send to.

  Each participating client 300a is associated with the content indicated in the update information transmitted to itself.

  The update information is added to the update message and transmitted.

  In the present embodiment, the distribution server 100 creates, for each content, an update graph that represents a transmission path of a content update message, a transmission destination (participating client 300a), and the like. The distribution server 100 stores an update graph for each content.

  The content update message is transferred according to the update graph corresponding to the content.

  Each update graph includes topology information, an aggregation instruction, and update graph participation client information (hereinafter simply referred to as “participation client information”).

  The topology information indicates a topology representing a connection form of the participating client 300a, that is, a transmission path of a content update message corresponding to the topology information.

  The topology information indicates the currently used topology and one or more topology candidates. That is, the topology information represents a plurality of distribution routes of update information from the distribution server 100 to a plurality of receiving clients 300 associated with the contents in the distribution server 100.

  The aggregation instruction represents a plurality of update messages (hereinafter referred to as “combined update messages”) to be aggregated (combined) and a participating client (hereinafter referred to as “execution client”) 300a1 that executes the aggregation.

  That is, the aggregation instruction is information for instructing the execution client 300a1 to aggregate a plurality of synthesized update messages.

  Note that the aggregation instruction is created by the aggregation server 200 and transmitted from the aggregation server 200 to the distribution server 100.

  The participating client information is information necessary for transmitting a content update message to the participating client 300a.

  For example, the client ID, IP address, and port number of the participating client 300a are used as participating client information.

  The aggregation server 200 is, for example, a computer.

  The aggregation server 200 is directly or indirectly connected to one or a plurality of distribution servers 100.

  The aggregation server 200 collects topology information of update graphs from the distribution server 100 for each content. For example, the aggregation server 200 collects the topology information by receiving the topology information of the update graph from each distribution server 100.

  The aggregation server 200 calculates a combination of topologies that can efficiently aggregate (synthesize) update messages based on the topology information of the update graph.

  The receiving client 300 is, for example, a computer.

  The receiving client 300 is connected directly or indirectly to one or more distribution servers 100 and one or more other receiving clients 300.

  The receiving client 300 searches the distribution system 1 for content desired by the user (hereinafter referred to as “desired content”) in accordance with the operation of the user of the receiving client 300 (hereinafter simply referred to as “user”). .

  When the desired content is found, the receiving client 300 connects to the distribution server 100 that owns the desired content according to the operation of the user.

  FIG. 2 is an explanatory diagram showing an overview of the operation of the distribution system 1 and information (messages) exchanged among the distribution server 100, the aggregation server 200, and the receiving client 300 (participating client 300a). . Each message describes a destination.

  In FIG. 2, the receiving client 300 transmits a search message 1001 to the distribution server 100 in accordance with a user operation.

  The search message 1001 describes one or more pieces of information regarding the desired content.

  When the distribution server 100 receives the search message 1001, the distribution server 100 searches for content corresponding to the information related to the content described in the search message 1001.

  Distribution server 100 adds the search result to search response message 1002.

  The distribution server 100 transmits a search response message 1002 to which the search result is added to the transmission source (reception client 300) of the search message 1001.

  When receiving the search response message 1002, the receiving client 300 displays the search result added to the search response message 1002.

  Upon receiving an instruction from the user to request update information about the content indicated in the search result, the reception client 300 functions as a participation client 300a and functions as an update client participation message 300a (hereinafter simply referred to as “participation message”). 1003) is transmitted to the distribution server 100.

  In the participation message 1003, identification information (content ID) of the desired content and information (client ID, IP address, port number) of the participating client 300a are described.

  When distribution server 100 receives participation message 1003, distribution server 100 specifies the desired content identified by the identification information of the desired content described in participation message 1003.

  Subsequently, the distribution server 100 updates an update graph (hereinafter referred to as “corresponding update graph”) corresponding to the desired content based on information of the participating client 300a.

  At this time, the distribution server 100 has a plurality of connection forms, that is, a plurality of topologies, of the distribution server 100, the participating client 300a that has already participated in the update information notification target, and the newly participating participating client 300a. Create the topology information shown.

  That is, this topology information represents a plurality of distribution paths (topologies) of update messages from the distribution server 100 to the participating client 300a already participating in the update information notification target and the newly participating participating client 300a.

  The distribution server 100 appropriately selects a topology to be used in the future from among a plurality of topologies indicated by the topology information, and describes the selection result in the topology information.

  The distribution server 100 updates the topology information in the correspondence update graph to the created topology information.

  Further, the distribution server 100 adds the information of the participating client 300a to the participating client information.

  When the distribution server 100 updates the corresponding update graph, the distribution server 100 transmits an update graph participation response message (hereinafter simply referred to as “participation response message”) 1004 to the participating client 300a.

  The participation response message 1004 includes topology information in the correspondence update graph.

  Further, each distribution server 100 transmits a topology report message 1005 to the aggregation server 200 every preset time.

  Each topology report message 1005 includes an update graph for each content stored in the distribution server 100 that is the transmission source of the topology report message 1005.

  The distribution server 100 may include all the update graphs in its own server in the topology report message 1005 or may include any of the update graphs in its own server in the topology report message 1005.

  Each time the aggregation server 200 receives the topology report message 1005, the aggregation server 200 stores an update graph for each content included in the topology report message 1005.

  The aggregation server 200 calculates combinations (hereinafter referred to as “recommended combinations”) that can aggregate update messages among the combinations of the topologies shown in the respective update graphs at preset time intervals. Ask.

  In the present embodiment, the aggregation server 200 selects at least two selected topologies (selected distribution routes) when selecting one selected topology, that is, a selected distribution route, from a plurality of topologies represented by the topology information for each topology information. The selected topology is selected so that at least a part of each overlaps.

  The aggregation server 200 uses a combination of selected topologies selected for each topology information as a recommended combination.

  When the aggregation server 200 obtains the recommended combination, the aggregation server 200 indicates the reception client that is the starting point of the overlapping portion (the above-described part) of the selected topology as an execution client, and an aggregation instruction that indicates a plurality of update messages that the execution client aggregates. Is generated.

  The aggregation instruction can be generally called a synthesis instruction.

  The aggregation server 200 adds the recommended combination and the aggregation instruction to the topology designation message 1006.

  The aggregation server 200 transmits a topology designation message 1006 to which the recommended combination and the aggregation instruction are added to all the distribution servers 100.

  Upon receiving the topology designation message 1006, each distribution server 100 indicates the recommended combination added to the topology designation message 1006 among a plurality of topologies indicated by the topology information in the update graph for each content in its own server. The selected topology is selected as a topology to be used in the future, and the selection result is described in the topology information.

  Each distribution server 100 stores the aggregation instruction added to the topology designation message 1006 in association with the topology to be used in the future.

  When the content in the distribution server 100 is updated, the distribution server 100 is selected as the topology to be used in the future from the topologies described in the topology information in the update flag corresponding to the updated content. In order for the update message 1007 to be transferred in accordance with the topology (selected topology), the update message 1007 includes metadata update information indicating the update contents of the content metadata, and selected topology information (distribution route) indicating the selected topology. Information) and an aggregation instruction, the update message 1007 is transmitted to the transmission destination (participating client 300a) according to the selected topology.

  When the participating client 300a receives the update message 1007, the participating client 300a obtains metadata update information included in the update message 1007.

  When the transfer instruction (next transmission destination) is not described in the selected topology in the update message 1007 (that is, the self is indicated as a termination), the participating client 300a stops the transfer of the update message 1007.

  When the transfer instruction is described in the selected topology in the update message 1007 (that is, the self is indicated as a relay location) and there is no aggregation instruction, or there is a transfer instruction in the selected topology in the update message 1007, and If there is an aggregation instruction and the self is not described as an execution client in the aggregation instruction, the participating client 300a copies the update message 1007 and transmits the copy to the participating client 300a designated as the transfer destination.

  There is a transfer instruction in the selected topology in the update message 1007, there is an aggregation instruction, self is described as an execution client in the aggregation instruction, and all of the update messages described in the aggregation instruction are self If not, the participating client 300a saves the update message 1007 and then starts counting the time for the update message.

  When all of the update messages described in the aggregation instruction are present, the participating client 300a stops counting the time, aggregates the update message to be aggregated, and updates the aggregated update message according to the selected topology. Send.

  When the time count value indicates a predetermined time, the participating client 300a reads each update message stored in the aggregation instruction stored in itself, aggregates the update message, and aggregates according to the selected topology. An update message 107 is transmitted.

  In addition, when the participating client 300a receives information indicating that a desired content body is requested from the user, the participating client 300a transmits a content request message 1008 to the distribution server 100 corresponding to the desired content.

  The content request message 1008 describes identification information (content ID) of the desired content.

  Upon receiving the content request message 1008, the distribution server 100 adds the content identified by the content identification information in the content request message 1008 to the content request response message 1009, and sends the content request message 1008 from the transmission source (participation) To the client 300a).

  In addition, when the participating client 300a receives an instruction from the user to request that the notification of content update information be canceled, an update graph leaving message (hereinafter simply referred to as “leaving message”) 1010 is sent to the distribution server 100. Send to.

  In the leave message 1010, identification information (content ID) of content desired to be notified of update information and information (client ID, IP address, port number) of the participating client 300 a are described.

  Upon receiving the leave message 1010, the distribution server 100 specifies the content identified by the content identification information described in the leave message 1010.

  Subsequently, the update graph management unit 114 displays the update graph (corresponding update graph) corresponding to the identified content as information on the receiving client 300 (specifically, the participating client 300a) described in the leave message 1010. Update based on.

  At this time, the distribution server 100 shows a plurality of connection forms, that is, a plurality of topologies, between the participating client 300a excluding the participating client 300a desiring to leave from the participating client 300a that has already participated, and the distribution server 100. Create topology information.

  This topology information represents a plurality of distribution paths of update messages from the distribution server 100 to the participating clients 300a excluding the participating clients 300a that want to leave from the participating clients 300a that have already participated.

  The distribution server 100 selects a topology (selected topology) to be used in the future from among a plurality of topologies indicated by the topology information, and describes the selection result in the topology information.

  The distribution server 100 updates the topology information in the correspondence update graph to the created topology information.

  Further, the distribution server 100 deletes the information of the participating client 300a who desires to leave from the participating client information.

  When the distribution server 100 updates the corresponding update graph, the distribution server 100 transmits an update graph leave response message (hereinafter simply referred to as “leave response message”) 1011 to the transmission source (participating client 300a) of the leave message 1010.

  Next, each of the distribution server 100, the aggregation server 200, and the reception client 300 will be described.

  FIG. 3 is a block diagram illustrating a configuration of the distribution server 100.

  The distribution server 100 includes a main control unit 110, an update graph participation client information database (hereinafter referred to as “participating client information DB”) 121, a metadata database (hereinafter referred to as “metadata DB”) 122, and a content database ( Hereafter includes a server information database (hereinafter referred to as “server information DB”) 124, and a network interface (hereinafter referred to as “network IF”) 130.

  The main control unit 110 includes a transmission / reception unit 111, a topology report unit 112, a topology report timer 113, an update graph management unit 114, a search server unit 115, a metadata distribution server unit 116, a metadata generation unit 117, The content server unit 118 is included.

  The main control unit 110 is a main part of a computer that includes a CPU, a RAM, an OS, and the like. The main control unit 110 operates according to a program recorded on a CD-ROM, hard disk, or memory. A CD-ROM, hard disk, or memory can generally be called a computer-readable recording medium.

  The main control unit 110 reads and executes the program from the recording medium, thereby transmitting / receiving unit 111, topology report unit 112, topology report timer 113, update graph management unit 114, search server unit 115, metadata distribution server unit 116, It functions as the metadata generation unit 117 and the content server unit 118.

  The topology report unit 112, the topology report timer 113, the update graph management unit 114, and the participating client information DB 121 are included in the management unit 100a.

  The metadata distribution server unit 116, the metadata generation unit 117, and the metadata DB 122 are included in the distribution unit 100b.

  The metadata distribution server unit 116 and the metadata DB 122 are included in the distribution control unit 100b1.

  The distribution server 100 distributes the update information of the content in itself to a plurality of receiving clients 300 associated with the content, that is, a plurality of participating clients 300a.

  Management unit 100a can generally be referred to as management means.

  The management unit 100a creates topology information representing a plurality of distribution paths (topologies) of update information from the own server to the plurality of participating clients 300a.

  The management unit 100a transmits a topology report message 1005 including the topology information to the aggregation server 200.

  When the management unit 100a receives the topology designation message 1006 from the aggregation server 200, the topology indicated as the selected topology in the topology designation message 1006 from among the plurality of topologies indicated by the topology information (selected topology). ) And describe the selection result in the topology information.

  The management unit 100a stores the aggregation instruction in the topology designation message 1006 in association with the selected topology (selected topology).

  Distribution unit 100b can be generally referred to as distribution means.

  When an aggregation instruction is associated with the selected topology, the distribution unit 100b adds the selected topology information and the aggregation instruction to the update message 1007 with the selected topology information indicating the selected topology and the aggregation instruction. The update message 1007 is distributed according to the selected topology.

  On the other hand, when the aggregation instruction is not associated with the selected topology, the distribution unit 100b adds the selected topology information to the update message 1007 and distributes the update message 1007 with the selected topology information according to the selected topology.

  Participating client information DB 121 can generally be referred to as storage means.

  FIG. 4 is a conceptual diagram showing the data structure of the participating client information DB 121. As shown in FIG.

  The participating client information DB 121 stores topology information, an aggregation instruction, and update graph participating client information for each content stored in the content DB 123 (for each content ID in FIG. 4).

  An update graph is configured by the topology information, the aggregation instruction, and the update graph participation client information.

  In FIG. 4, for example, “n1-n10-n13” in the topology information indicates that the reception clients n1, n10, and n13 are connected in series, and the reception client n1 is connected to the distribution server 100.

  The topology information “n1-n10-n13” also indicates that the receiving clients n1 and n10 are relay locations and the receiving client n13 is a termination.

  On the other hand, the topology information “n1, n10, n13” indicates that the receiving clients n1, n10, and n13 are connected to the distribution server 100 in a star shape.

  The aggregation instruction “n10-n13: C10” associated with the content C1 indicates that the receiving client n10 is an execution client, and the update message of the content C1 and the update message of the content C10 are combined update messages.

  Further, the aggregation instruction “n10-n13: C10” associated with the content C1 also indicates that the receiving client n13 is a separation client that separates the synthesized update message into each of the update messages before synthesis.

  For example, the aggregation instruction “n10-n13: C10” associated with the content C1 is transmitted from the aggregation server 200 in the format “n10-n13: C1, C10”.

  “N10-n13: C1, C10” indicates that n10 is an execution client, the update message of content C1 and the update message of content C10 are combined update messages, and n13 is a separation client.

  When the update graph management unit 114 detects C1 corresponding to the content stored in the own client from the “n10-n13: C1, C10”, the update graph management unit 114 associates the content with the content C1 in the participating client information DB 121 and “n10-n13”. : C10 "is saved. Note that “n10-n13: C1, C10” may be stored instead of “n10-n13: C10”.

  The topology information, the aggregation instruction, the update graph participation client information, and the update graph are as described above.

  FIG. 5 is a conceptual diagram showing the data configuration of the metadata DB 122.

  The metadata DB 122 stores content metadata stored in the content DB 123.

  The metadata is information accompanying the content, and includes, for example, a content ID, a URI, a title, a creator, a creation location, a creation time, a keyword, and the like.

  The content DB 123 stores content that is a target for which the distribution server 100 notifies the reception client 300 of update information.

  The content is, for example, text, sound, photo, video, or the like. When the content is updated, the content DB 123 notifies the metadata generation unit 117 that the content has been updated.

  FIG. 6 is a conceptual diagram illustrating a data configuration of the server information DB 124.

  The server information DB 124 is a database of server information that is used when the search server unit 115 transmits the search response message 1002. The server information DB 124 stores information such as a server ID, an IP address, and a port number that are necessary when the search response message 1002 is transmitted.

  The transmission / reception unit 111 receives and processes messages from the aggregation server 200, the other distribution server 100, and the reception client 300 via the network IF 130.

  When the received message is the participation message 1003, the transmission / reception unit 111 transmits the participation message 1003 to the update graph management unit 114.

  Further, when the received message is the leaving message 1010, the transmission / reception unit 111 sends the leaving message 1010 to the update graph management unit 114.

  Furthermore, when the received message is the topology designation message 1006, the transmission / reception unit 111 sends the topology designation message 1006 to the update graph management unit 114.

  Furthermore, when the received message is the content request message 1008, the transmission / reception unit 111 sends the content request message 1008 to the content server unit 118.

  Furthermore, when the received message is the search message 1001, the transmission / reception unit 111 sends the search message 1001 to the search server unit 115.

  Further, the transmission / reception unit 111 receives a message from each of the topology report unit 112, the update graph management unit 114, the search server unit 115, the metadata distribution server unit 116, and the content server unit 118.

  The transmission / reception unit 111 transmits the message to the destination (for example, the aggregation server 200, another distribution server 100, or the reception client 300) described in the message via the network IF 130.

  The update graph management unit 114 can generally be referred to as topology information management means.

  When the update graph management unit 114 receives the participation message 1003 from the reception client 300, the update graph management unit 114 specifies the desired content identified by the identification information of the desired content described in the participation message 1003.

  Subsequently, the update graph management unit 114 creates an update graph (corresponding update graph) corresponding to the desired content based on information of the reception client 300 (specifically, the participation client 300a) described in the participation message 1003. Update.

  At this time, the update graph management unit 114 has a plurality of connection modes, that is, a plurality of connection forms of the own server 100, the participating client 300a that has already participated in the update information notification target, and the newly participating participating client 300a. Create topology information indicating the topology.

  Examples of the topology include those that specify a form such as a ring topology and a binary tree topology, and those that specify a topology creation policy such as a minimum hop count topology and a minimum load topology.

  The updated graph management unit 114 appropriately selects a topology to be used in the future (selected topology) from the plurality of topologies indicated by the topology information, and describes the selection result in the topology information.

  The update graph management unit 114 updates the topology information in the corresponding update graph stored in the participating client information DB 121 to the created topology information.

  Further, the update graph management unit 114 adds the information of the participating client 300a to the participating client information in the participating client information DB 121.

  When the update graph management unit 114 updates the corresponding update graph in the participation client information DB 121, the update graph management unit 114 transmits a participation response message 1004 to the participation client 300a.

  The participation response message 1004 includes topology information in the correspondence update graph.

  Furthermore, when the update graph management unit 114 receives the leave message 1010 from the reception client 300 (participating client 300a), the update graph management unit 114 displays an update graph corresponding to the content identification information described in the leave message 1010 as information on the participating client 300a. Update based on.

  At this time, the update graph management unit 114 excludes the participating client 300a that wants to leave from the participating client 300a that has already participated, and a plurality of connection forms of the participating client 300a and the own server 100, that is, a plurality of connection forms. Create topology information indicating the topology of the.

  The updated graph management unit 114 selects a topology to be used in the future from among a plurality of topologies indicated by the topology information, and describes the selection result in the topology information.

  The update graph management unit 114 updates the topology information in the corresponding update graph in the participating client information DB 121 to the created topology information.

  Furthermore, the update graph management unit 114 deletes the information of the participating client 300a who wishes to leave from the participating client information in the participating client information DB 121.

  When the update graph management unit 114 updates the corresponding update graph in the participation client information DB 121, the update graph management unit 114 transmits a leave response message 1011 to the transmission source of the leave message 1010 (participating client 300a).

  Further, when the update graph management unit 114 receives the topology designation message 1006 from the aggregation server 200, the update graph management unit 114 stores the topology designation message 1006 in the participating client information DB 121 so as to match the recommended combination (topology for each content) described in the topology designation message 1006. Update the update graph for each content.

  Specifically, the update graph management unit 114 sets the topology for each content indicated by the recommended combination in the topology for each content in the participating client information DB 121 as a topology to be used in the future (selected topology). .

  Topology report timer 113 can be generally referred to as report start notification means.

  The topology report timer 113 notifies the topology report unit 112 of the topology report trigger at every preset time. The topology reporting opportunity can generally be called a report start notification.

  Topology reporting unit 112 can generally be referred to as reporting means.

  The topology reporting unit 112 includes all topology information or some topology information in the participating client information DB 121 in the topology report message 1005 and transmits it to the aggregation server 200 in response to the notification from the topology report timer 113.

  In response to the notification from the metadata generation unit 117, the metadata distribution server unit 116 sets the updated topology to the receiving client 300 (participating client 300a) described in the participating client information DB 121 with respect to the updated content. The update message 1007 is transmitted including the metadata update information, the selected topology information, and the aggregation instruction associated with the selected topology information so that the update message 1007 is transferred as described. .

  When the aggregation instruction is not associated with the selected topology information, the metadata distribution server unit 116 transmits the metadata update information and the selected topology information included in the update message 1007.

  For example, in the situation where the selected topology shown in FIG. 4 is “n1-n10-n13”, when the content C1 is updated, the metadata distribution server unit 116 sends the selected topology “ An update message 1007 with selected topology information indicating “n1-n10-n13” and an aggregation instruction “n10-n13: C10” associated with the selected topology is transmitted.

  When the content server unit 118 receives the content request message 1008 from the receiving client 300 (specifically, the participating client 300a), the content server unit 118 adds the content specified by the content request message 1008 to the content request response message 1009, Transmit to the receiving client 300.

  When the search server 115 receives the search message 1001 from the receiving client 300, the search server unit 115 collates the metadata DB 122 with the keyword added to the search message 1001, and adds metadata that matches the search message 1001 to the search response message 1002. To the receiving client 300.

  Further, when receiving the search message 1001 from the receiving client 300, the search server unit 115 copies and transmits the received search message 1001 to the distribution server 100 described in the server information DB 124.

  The metadata generation unit 117 can be generally referred to as generation means.

  When the metadata generation unit 117 receives a content update notification from the content DB 123, the metadata generation unit 117 checks the update content of the corresponding content in the content DB 123 and updates the corresponding metadata in the metadata DB 122. In the present embodiment, the updated metadata is used as update information.

  Furthermore, when the metadata generation unit 117 receives a content update notification from the content DB 123, the metadata generation unit 117 notifies the metadata distribution server unit 116 of the content update for the corresponding content.

  Distribution control unit 100b1 can be generally referred to as distribution control means.

  In response to the notification from the metadata generation unit 117, the distribution control unit 100b1 sends metadata update information, selected topology information, and an aggregation instruction associated with the selected topology information for the updated content. It is included in the update message 1007 and transmitted according to the selected topology.

  When the aggregation instruction is not associated with the selected topology information, the distribution control unit 100b1 includes the metadata update information and the selected topology information for the updated content in the update message 1007 according to the selected topology. Send.

  FIG. 7 is a block diagram showing the configuration of the aggregation server 200.

  Aggregation server 200 includes a main controller 210, a topology information database (hereinafter referred to as “topology information DB”) 221, and a network interface (hereinafter referred to as “network IF”) 230.

  The main control unit 210 includes a transmission / reception unit 211, an aggregation pattern calculation unit 212, and an aggregation pattern calculation timer 213.

  The main control unit 210 is a main part of a computer configured with a CPU, a RAM, an OS, and the like. The main control unit 210 operates in accordance with a program recorded on a CD-ROM, hard disk or memory.

  The main control unit 210 functions as the transmission / reception unit 211, the aggregation pattern calculation unit 212, and the aggregation pattern calculation timer 213 by reading and executing the program from the recording medium.

  The aggregation pattern calculation unit 212, the aggregation pattern calculation timer 213, and the topology information DB 221 are included in the control unit 200a.

  The topology information DB 221 can be generally called storage means.

  FIG. 8 is a conceptual diagram showing the data configuration of the topology information DB 221. As shown in FIG.

  The topology information DB 221 stores an update graph for each content transmitted from the distribution server 100 for each distribution server 100.

  Transmitter / receiver 211 can be generally referred to as receiving means.

  The transmission / reception unit 211 receives and processes a message from the distribution server 100 via the network IF 230.

  If the received message is the topology report message 1005, the transmission / reception unit 211 sends the topology report message 1005 to the aggregation pattern calculation unit 212.

  Furthermore, the transmission / reception unit 211 receives a message (for example, topology designation message 1006) from the aggregation pattern calculation unit 212, and transmits the message to the distribution server 100 serving as the destination described in the message via the network IF 230. .

  Aggregation pattern calculation section 212 can be generally referred to as calculation means.

  When the aggregation pattern calculation unit 212 receives the topology report message 1005 from the distribution server 100, the aggregation pattern calculation unit 212 registers an update graph for each content included in the topology report message 1005 in the topology information DB 221.

  Further, the aggregation pattern calculation unit 212 reads all the topology information for each distribution server 100 stored in the topology information DB 221 triggered by the notification from the aggregation pattern calculation timer 213, and for each content shown in each update graph. Then, a recommended combination is calculated from each combination of topologies.

  At this time, when selecting one selected topology for each topology information, the aggregation pattern calculation unit 212 maximizes the dispersion value of the number of overlapping links between receiving clients in the selected topology from among the combinations of selected topologies. And a combination is selected as a recommended combination.

  By selecting the topology combination of the update graph in this way, the number of links that can aggregate the update message can be maximized among the topology configuration combinations permitted by the distribution server 100.

  Furthermore, the aggregation pattern calculation unit 212 generates an aggregation instruction according to the recommended combination.

  Furthermore, the aggregation pattern calculation unit 212 adds the recommended combination and the aggregation instruction to the topology designation message 1006.

  The aggregation pattern calculation unit 212 transmits the topology designation message 1006 to which the recommended combination and the aggregation instruction are added to all the distribution servers 100.

  Aggregation pattern calculation timer 213 can generally be referred to as operation start notification means.

  The aggregation pattern calculation timer 213 notifies the aggregation pattern calculation unit 212 of the trigger of the aggregation combination calculation at every preset time. This opportunity can generally be called an operation start notification.

  Control unit 200a can generally be referred to as control means.

  The control unit 200a calculates a recommended combination triggered by the notification from the aggregation pattern calculation timer 213, and further generates an aggregation instruction according to the recommended combination.

  The control unit 200a adds the recommended combination and the aggregation instruction to the topology designation message 1006.

  The control unit 200a transmits the topology designation message 1006 to which the recommended combination and the aggregation instruction are added to all the distribution servers 100.

  FIG. 9 is a block diagram illustrating a configuration of the reception client 300.

  The reception client 300 includes a main control unit 310, a server information database (hereinafter referred to as “server information DB”) 321, and a network interface (hereinafter referred to as “network IF”) 330.

  The main control unit 310 includes a transmission / reception unit 311, a content client unit 312, a search client unit 313, an update graph join / leave unit 314, an update graph client unit 315, an aggregation waiting buffer 316, a message creation unit 317, A buffer timer 318.

  The main control unit 310 is a main part of a computer that includes a CPU, a RAM, an OS, and the like. The main control unit 310 operates according to a program recorded on a CD-ROM, hard disk, or memory.

  The main control unit 310 reads and executes the program from the recording medium, thereby transmitting / receiving unit 311, content client unit 312, search client unit 313, update graph joining / leaving unit 314, update graph client unit 315, aggregation waiting buffer 316, It functions as a message creation unit 317 and a buffer timer 318.

  The message creation unit 317 and the buffer timer 318 are included in the transfer management unit 300a.

  The server information DB 321 is equivalent to the server information DB 124 in the distribution server 100 illustrated in FIG. 6 and is a database used when the search client unit 313 transmits the search message 1001.

  The server information DB 321 stores information such as a server ID, an IP address, and a port number that are necessary when the search message 1001 is transmitted.

  The transmission / reception unit 311 can be generally referred to as update information receiving means.

  The transmission / reception unit 311 receives and processes a message from each of the distribution server 100 and the reception client 300 via the network IF 330.

  When the received message is the content request response message 1009, the transmission / reception unit 311 sends the content request response message 1009 to the content client unit 312.

  Further, when the received message is the search response message 1002, the transmission / reception unit 311 sends the search response message 1002 to the search client unit 313.

  Furthermore, when the received message is the participation response message 1004, the transmission / reception unit 311 sends the participation response message 1004 to the update graph participation / leaving unit 314.

  Further, when the received message is the leaving response message 1011, the transmitting / receiving unit 311 sends the leaving response message 1011 to the update graph participation leaving unit 314.

  Furthermore, when the received message is the update message 1007, the transmission / reception unit 311 sends the update message 1007 to the update graph client unit 315.

  Further, the transmission / reception unit 311 receives a message from each of the content client unit 312, the search client unit 313, the update graph client unit 315, and the message creation unit 317, and distributes the destination described in the message The message is transmitted to the server 100 or the receiving client 300 via the network IF 330.

  When the content client unit 312 receives information requesting the content body from the user for the content for which the update message 1007 has been received, the content client unit 312 transmits a content request message 1008 to the distribution server 100 having the content. .

  When the content client unit 312 receives the content request response message 1009, the content client unit 312 obtains the content added to the content request response message 1009.

  The search client unit 313 creates a search message 1001 that describes one or more pieces of information related to the desired content when searching for the desired content according to the user's operation.

  The search client unit 313 transmits a search message 1001 to one or a plurality of distribution servers 100 described in the server information DB 321.

  Here, the information regarding the content includes, for example, a content ID, URI, title, creator, creation location, creation time, keyword, and the like.

  When the search client unit 313 receives the search response message 1002, the search client unit 313 displays content metadata described in the search response message 1002.

  When participating in the content distribution target described in the search response message 1002 received by the search client unit 313, the update graph participation / leaving unit 314 transmits a participation message 1003 to the distribution server 100 having the content.

  Further, when the update graph participation / removal unit 314 receives the participation response message 1004, it accepts the update message 1007 thereafter.

  Further, when the update graph participation leaving unit 314 stops the notification of the update message 1007, the update graph participation / leave unit 314 transmits a leave message 1010 to the distribution server 100 that is the transmission source of the update message 1007.

  Furthermore, the update graph participation leaving unit 314 stores the leave response message 1011 in the aggregation waiting buffer 316 after a certain time has elapsed after sending the leave message 1011 to the distribution server 100 that is the transmission source of the update message 1007. If there is a buffer corresponding to the update message, the buffer is deleted.

  The update graph client unit 315 can be generally called a relay management unit.

  When the update graph client unit 315 receives the update message 1007, the update graph client unit 315 obtains metadata update information included in the update message 1007.

  At this time, if the transfer instruction is not described in the selected topology in the update message 1007, the update graph client unit 315 stops the transfer of the update message 1007.

  When there is a transfer instruction in the selected topology in the update message 1007, there is an aggregation instruction, and the own client is described as an execution client in the aggregation instruction, the update graph client unit 315 stores the aggregation waiting buffer 316 in the aggregation waiting buffer 316. A buffer corresponding to the aggregation instruction is created, and the update message 1007 is stored in the buffer. This buffer is created for each combination of aggregation instructions.

  When there is a transfer instruction in the selected topology in the update message 1007 and there is no aggregation instruction, or there is a transfer instruction in the selected topology in the update message 1007 and there is an aggregation instruction, and the self is in the aggregation instruction. When not listed as an execution client, the update graph client unit 315 copies the update message 1007 and passes the copy to the message creation unit 317.

  The aggregation waiting buffer 316 can be generally referred to as update information storage means.

  Further, the aggregation waiting buffer 316 stores the update message 1007 when the update message 1007 is stored in the already created buffer and another update message 1007 to be aggregated does not exist in the other buffer. The time count of the buffer timer 318 for the buffer is started.

  Also, the aggregation waiting buffer 316 resets the buffer timer 318 if another update message 1007 to be aggregated exists in another buffer when the update message 1007 is stored in the created buffer, A plurality of update messages 1007 to be aggregated are passed to the message creation unit 317.

  Further, when the aggregation waiting buffer 316 receives a timer expiration notification from the buffer timer 318, the aggregation waiting buffer 316 passes the update message 1007 stored in the buffer corresponding to the buffer timer 318 to the message creation unit 317.

  When the message creation unit 317 obtains the update message 315 from the update graph client unit 315, the message creation unit 317 transmits the update message 1007 to the reception client 300 according to the selected topology.

  Further, the message creation unit 317 aggregates a plurality of update messages 1007 obtained from the aggregation waiting buffer 316, and transmits the update messages 1007 to the reception client 300 according to the selected topology.

  Buffer timer 318 can generally be referred to as counting means.

  The buffer timer 318 has one or a plurality of timers, and operates or resets the timer corresponding to the buffer created in the aggregation waiting buffer 316 on a one-to-one basis according to the notification from the aggregation waiting buffer 316.

  Further, when there is a timer that has passed a predetermined time, the buffer timer 318 notifies the aggregation waiting buffer 316 of the buffer information corresponding to the timer, and resets the timer.

  Transfer management unit 300a can be generally referred to as transfer management means.

  When the buffer timer 318 counts a predetermined time, the transfer management unit 300a transmits the update message in the aggregation wait buffer 316 even if all the update messages indicated in the aggregation instruction are not stored in the aggregation wait buffer 316. The combined update message is transferred to the receiving client 300 according to the selected topology.

  Next, the operation will be described.

  FIG. 10 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 receives the participation message 1003 from the receiving client 300.

  When the distribution server 100 starts to operate, first, the transmission / reception unit 111 is in a state of waiting for communication from the aggregation server 200, another distribution server 100, or the reception client 300 (hereinafter referred to as “idle state”) (step). 400).

  When the distribution server 100 receives the participation message 1003 from the receiving client 300 in the idle state (step 401), the distribution server 100 updates the topology information and the participation client information in the participation client information DB 121 of the content corresponding to the participation message 1003 ( Step 402).

  Subsequently, the distribution server 100 transmits a participation response message 1004 including topology information to the transmission source (reception client 300) of the participation message 1003 (step 403), and then returns to the idle state (step 400).

  FIG. 11 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 receives the leave message 1010 from the receiving client 300.

  When the distribution server 100 receives the leaving message 1010 from the receiving client 300 in the idle state (step 411), the distribution server 100 updates the topology information and the participating client information in the participating client information DB 121 corresponding to the leaving message 1010 (step 412). .

  Subsequently, the distribution server 100 transmits a leave response message 1011 to the transmission source (reception client 300) of the leave message 1010 (step 413), and then returns to the idle state (step 400).

  FIG. 12 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 updates the content.

  When the distribution server 100 updates the content in the idle state (step 421), the updated content is transmitted to the receiving client 300 described in the participating client information DB 121 as described in the selected topology information. The update message 1007 is transmitted including the metadata update information, the topology information, and the aggregation instruction so that the update message 1007 is transferred (step 422), and then returns to the idle state (step 400). ). The topology information indicates the selected topology.

  FIG. 13 is a flowchart showing the operation of the distribution server 100 when the topology report timer 113 expires in the distribution server 100.

  When the topology report timer 113 expires in the idle state (step 431), the distribution server 100 includes a part or all of the contents of the participating client information DB 121 in the topology report message 1005 and transmits it to the aggregation server 200 ( Step 432) and then return to the idle state (step 400).

  FIG. 14 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 receives the topology designation message 1006 from the aggregation server 200.

  When the distribution server 100 receives the topology designation message 1006 from the aggregation server 200 in the idle state (step 441), the distribution server 100 updates the participating client information DB 121 based on the recommended combination and the aggregation instruction described in the topology designation message 1006. (Step 442), and then returns to the idle state (Step 400).

  FIG. 15 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 receives the content request message 1008 from the receiving client 300.

  When the distribution server 100 receives the content request message 1008 from the receiving client 300 in the idle state (step 451), the distribution server 100 adds the content specified by the content request message 1008 to the content request response message 1009, and receives the content request message 1008. (Step 452), and then returns to the idle state (step 400).

  FIG. 16 is a flowchart showing the operation of the distribution server 100 when the distribution server 100 receives the search message 1001 from the receiving client 300.

  When the distribution server 100 receives the search message 1001 from the receiving client 300 in the idle state (step 461), the distribution server 100 collates the metadata DB 122 with the keyword added to the search message (step 462), and searches for suitable metadata. It is added to the response message 1002 and transmitted to the receiving client 300 (step 463).

  Further, the distribution server 100 copies and transmits the received search message 1001 to the server described in the server information DB 124 (step 464), and then returns to the idle state (step 400).

  FIG. 17 is a flowchart showing the operation of the aggregation server 200 when the aggregation server 200 receives the topology report message 1005 from the distribution server 100.

  When the aggregation server 200 starts operating, first, the transmission / reception unit 211 enters a state of waiting for communication from the distribution server 100 (hereinafter referred to as “idle state”) (step 500).

  When the aggregation server 200 receives the topology report message 1005 from the distribution server 100 in the idle state (step 501), the aggregation server 200 registers the update graph for each content included in the topology report message 1005 in the topology information DB 221 to thereby change the topology. The information DB 221 is updated (step 502), and then returns to the idle state (step 500).

  FIG. 18 is a flowchart showing the operation of the aggregation server 200 when the aggregation pattern calculation timer 213 in the aggregation server 200 expires.

  When the aggregation pattern calculation timer 213 expires in the idle state (step 511), the aggregation server 200 reads all the update graphs for each distribution server 100 stored in the topology information DB 221 and updates some or all of the contents. For the combination of graph topologies, a recommended combination that can be aggregated by the update message 1007 is calculated (step 512), and the recommended combination is added to the topology designation message 1006 and transmitted to all the distribution servers 100 (step 513). Thereafter, the process returns to the idle state (step 500).

  FIG. 19 is a flowchart showing the operation of the receiving client 300 when the receiving client 300 desires the distribution server 100 to participate in the update graph.

  When the reception client 300 starts operation, first, the transmission / reception unit 311 enters a state of waiting for communication from the distribution server 100 or the reception client 300 (hereinafter referred to as “idle state”) (step 600).

  The receiving client 300 transmits a participation message 1003 in order to participate in the update graph of the distribution server 100 in the idle state (step 601).

  Subsequently, the receiving client 300 receives the participation response message 1004 from the distribution server 100 (step 602), and returns to the idle state (step 600).

  FIG. 20 is a flowchart illustrating an operation of the receiving client 300 when the receiving client 300 desires to leave the participating update graph.

  The receiving client 300 transmits a leave message 1010 to the distribution server 100 having the content in order to cancel the notification of the content update in the idle state (step 611).

  Subsequently, the receiving client 300 receives the withdrawal response message 1011 from the distribution server 100 (step 612).

  Further, when there is a buffer (related buffer) related to the notification of the updated update (YES in Step 613), the receiving client 300 deletes the related buffer existing in the aggregation waiting buffer 316 (Step 614), and then Returning to the idle state (step 600).

  If there is no related buffer (NO in step 613), the receiving client 300 returns to the idle state (step 600).

  FIG. 21 is a flowchart showing the operation of the receiving client 300 when the receiving client 300 receives the update message 1007 from the distribution server 100.

  When receiving the update message 1007 in the idle state (step 621), the receiving client 300 obtains the metadata update information included in the update message 1007 (step 622).

  Furthermore, when there is no transfer instruction in the selected topology in the update message 1007 (NO in step 623), the receiving client 300 returns to the idle state (step 600).

  When there is a transfer instruction in the selected topology (YES in step 623), and there is no aggregation instruction, or there is a transfer instruction in the selected topology, there is an aggregation instruction, and the aggregation instruction is executed by itself If not described as a client (NO in step 624), the receiving client 300 copies the update message 1007, transmits the copy to the receiving client 300 designated as the transfer destination (step 625), and enters the idle state. Return (step 600).

  There is a transfer instruction in the selected topology in the update message 1007, there is an aggregation instruction, and the self is described as an execution client in the aggregation instruction (YES in step 624), and the update described in the aggregation instruction If all of the messages are not present in the buffer within the message (NO in step 626), the receiving client 300 starts the buffer timer 318 corresponding to the buffer (step 627).

  Thereafter, regardless of the result of step 626, the receiving client 300 stores the update message 1007 in the corresponding buffer of the aggregation waiting buffer 316 (step 628).

  At this time, if all the update messages to be aggregated are not prepared in the buffer (NO in step 629), the receiving client 300 returns to the idle state (step 600).

  When all the update messages to be aggregated are gathered in the buffer (YES in Step 629), the receiving client 300 resets the buffer timer 318 (Step 630), aggregates the target update message, and displays the aggregated update message. Then, it transmits according to the selected topology (step 631) and returns to the idle state (step 600).

  FIG. 22 is a flowchart showing the operation of the reception client 300 when the buffer timer 318 has expired in the reception client 300.

  When the buffer timer 318 expires in the idle state (step 641), the receiving client 300 reads and aggregates the update message from the buffer of the aggregation wait buffer 316 corresponding to the timer, and transmits the aggregated update message according to the selected topology. (Step 642), the state returns to the idle state (Step 600).

  FIG. 23 is a flowchart showing the operation of the receiving client 300 when the receiving client 300 requests the content body from the distribution server 100.

  In the idle state, the receiving client 300 transmits a content request message 1008 to the distribution server 100 having the desired content (step 651), and receives the content request response message 1009 as a reply to obtain the content body. (Step 652), the state returns to the idle state (Step 600).

  FIG. 24 is a flowchart showing the operation of the receiving client 300 when the receiving client 300 searches for content.

  In the idle state, the receiving client 300 creates a search message 1001 that describes one or more pieces of information about the desired content, transmits the search message 1001 to one or more distribution servers 100 (step 661), and returns the response. When the search response message 1002 is received from the distribution server 100, the content metadata described in the search response message 1002 is displayed (step 662), and the state returns to the idle state (step 600).

  Note that the operation contents of each step according to the flowcharts described in FIGS. ).

  In the present embodiment, each distribution server 100 creates a plurality of update graph topologies in advance for the receiving client 300 that receives the update information of the content distributed by the distribution server 100.

  The aggregation server 200 collects the topology information of the update graph for each content from the distribution server 100.

  The aggregation server 200 obtains a recommended combination and an aggregation instruction based on the topology information.

  The aggregation server 200 transmits the recommended combination and the aggregation instruction to each distribution server 100.

  For this reason, even when the relationship between the server and the client frequently changes, it is possible to provide a distribution system that achieves both high efficiency of distribution of update information and high availability of the system.

  Note that this effect is that an aggregation server including the transmission / reception unit 211 and the control unit 200a, a distribution server including the management unit 100a and the distribution unit 100b, an aggregation waiting buffer 316, a transmission / reception unit 311, an update graph client unit 315, and a transfer management. It can also be played by a receiving client including the unit 300a.

  In this embodiment, the aggregation server 200 periodically obtains a recommended combination and an aggregation instruction.

  In this case, even if the topology information changes, it is possible to periodically change the recommended combination and the aggregation instruction.

  Further, in this embodiment, the aggregation server 200 sets a combination of selected topologies that has a maximum dispersion value of the number of overlapping links between receiving clients in the selected topology as a recommended combination.

  In this case, it is possible to obtain a selection topology that is optimal for aggregation of update messages.

  In addition, the distribution server 100 transmits the instruction (selected topology or aggregation instruction) from the aggregation server 200 together with the update information in the update message 1007 and transmits it to the reception client 300.

  Further, the receiving client 300 distributes and aggregates the update message 1007 in accordance with the instruction placed on the update message 1007.

  In this case, the update message 1007 can be distributed and aggregated as instructed from the aggregation server 200.

  In the present embodiment, the distribution server 100 periodically transmits topology information to the aggregation server 200.

  In this case, it becomes possible to notify the aggregation server 200 of changes in the topology information periodically.

  Further, in the present embodiment, when update information is generated, the distribution server 100 transmits an instruction from the aggregation server 200 together with the update information in an update message 1007 and transmits it to the reception client 300.

  In this case, the update information can be transmitted to the reception client 300 along with an instruction from the aggregation server 200 in an update message 1007 at an appropriate timing.

  Further, in the present embodiment, the distribution server 100 updates the topology information in accordance with the change of the participating client when receiving the participation message or receiving the leaving message.

  In this case, it becomes possible to update the topology information in accordance with changes in participating clients.

  In this embodiment, when the update message is stored in the buffer for a predetermined time, the reception client 300 aggregates the update message in the buffer and transfers the update message to another reception client 300 according to the selected topology.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  In the second embodiment, in the aggregation server 200, an aggregation pattern calculation unit 212a is used instead of the aggregation pattern calculation unit 212 shown in FIG. Since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

  When the aggregation pattern calculation unit 212 a receives the topology report message 1005 from the distribution server 100, the aggregation pattern calculation unit 212 a registers an update graph for each content included in the topology report message 1005 in the topology information DB 221.

  Further, the aggregation pattern calculation unit 212a reads all the topology information for each distribution server 100 stored in the topology information DB 221 in response to the notification from the aggregation pattern calculation timer 213, and for each content shown in each update graph. Then, a recommended combination is calculated from each combination of topologies.

  At this time, when selecting one selected topology for each topology information, the aggregation pattern calculation unit 212a obtains a combination that minimizes the variance value of the order of the selected topology from the combinations of the selected topologies, and determines the combination. Select as a recommended combination.

  By selecting the topology combination of the update graph in this way, the link load of the receiving client 300 can be distributed among the topology configuration combinations allowed by the distribution server 100.

  Furthermore, the aggregation pattern calculation unit 212a generates an aggregation instruction according to the recommended combination.

  Furthermore, the aggregation pattern calculation unit 212a adds the recommended combination and the aggregation instruction to the topology designation message 1006.

  The aggregation pattern calculation unit 212a transmits the topology designation message 1006 to which the recommended combination and the aggregation instruction are added to all the distribution servers 100.

  In the present embodiment, the aggregation server 200 finds a combination in which the distribution value of the order of the selected topology is the minimum among the combinations of selected topologies, that is, a combination that can distribute the load of the receiving client 300, and the combination is determined as the distribution server 100. Send to.

  For this reason, even when the relationship between the server and the client frequently changes, it is possible to provide a distribution system that can make the load on the receiving client 300 uniform.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

It is a conceptual diagram which shows the network structure of the delivery system 1 of the 1st Embodiment of this invention. It is a sequence diagram for demonstrating the outline | summary of operation | movement of the delivery system. 2 is a block diagram illustrating a configuration of a distribution server 100. FIG. It is a conceptual diagram which shows the structure of participating client information DB121. It is a conceptual diagram which shows the structure of metadata DB122. It is a conceptual diagram which shows the structure of server information DB124. 2 is a block diagram showing a configuration of an aggregation server 200. FIG. It is a conceptual diagram which shows the structure of topology information DB221. 2 is a block diagram showing a configuration of a receiving client 300. FIG. 6 is a flowchart illustrating an operation of the distribution server 100 when the distribution server 100 receives a participation message from the reception client 300. 6 is a flowchart showing an operation of the distribution server 100 when the distribution server 100 receives a leave message from the receiving client 300. It is a flowchart which shows operation | movement of the distribution server 100 when the distribution server 100 updates a content. 6 is a flowchart showing an operation of the distribution server 100 when a topology report timer 113 expires in the distribution server 100. 6 is a flowchart showing an operation of the distribution server 100 when the distribution server 100 receives a topology designation message from the aggregation server 200. 6 is a flowchart showing an operation of the distribution server 100 when the distribution server 100 receives a content request message from the receiving client 300. 6 is a flowchart showing an operation of the distribution server 100 when the distribution server 100 receives a search message from the receiving client 300. 4 is a flowchart illustrating an operation of the aggregation server 200 when the aggregation server 200 receives a topology report message from the distribution server 100. 6 is a flowchart illustrating an operation of the aggregation server 200 when an aggregation pattern calculation timer 213 expires in the aggregation server 200. 6 is a flowchart illustrating an operation of the receiving client 300 when the receiving client 300 desires the distribution server 100 to participate in the update graph. It is a flowchart which shows the operation | movement of the receiving client 300 when leaving | separating from the update graph which the receiving client 300 participates is desired. 4 is a flowchart showing an operation of the receiving client 300 when the receiving client 300 receives an update message from the distribution server 100. 6 is a flowchart illustrating an operation of the reception client 300 when a buffer timer 318 expires in the reception client 300. 6 is a flowchart showing an operation of the receiving client 300 when the receiving client 300 requests a content body from the distribution server 100. It is a flowchart which shows operation | movement of the receiving client 300 when the receiving client 300 searches content.

Explanation of symbols

1 Update information distribution system 1
100 update information distribution server 100a management unit 100b distribution unit 100b1 distribution control unit 110 main control unit 111 transmission / reception unit 112 topology report unit 113 topology report timer 114 update graph management unit 115 search server unit 116 metadata distribution server unit 117 metadata generation unit 118 Content server part 121 Update graph participation client information DB
122 Metadata DB
123 Content DB
124 Server information DB
130 Network Interface 200 Aggregation Server 200a Control Unit 210 Main Control Unit 211 Transmission / Reception Unit 212 Aggregation Pattern Calculation Unit 213 Aggregation Pattern Calculation Timer 221 Topology Information DB
230 Network interface 300 Update information reception client 300a Transfer management unit 310 Main control unit 311 Transmission / reception unit 312 Content client unit 313 Search client unit 314 Update graph join / leave unit 315 Update graph client unit 316 Aggregation wait buffer 317 Message creation unit 318 Buffer timer 321 Server information DB
330 Network interface

Claims (23)

An aggregation server that can communicate with a plurality of distribution servers,
Receiving means for receiving, from each distribution server, topology information representing a plurality of distribution paths for update information of the content from the distribution server to a plurality of receiving clients associated with the content in the distribution server;
When selecting one selected delivery route from among a plurality of delivery routes represented by the topology information for each topology information received by the receiving means, at least a part of at least two of the selected delivery routes is overlapped , Selecting the selected distribution route, transmitting the selection result to the plurality of distribution servers, and indicating the reception client that is the starting point of the part and a plurality of update information that the reception client combines. An aggregation server including: a control unit that transmits the combination instruction to each of the execution distribution servers that transmitted the topology information representing the selected distribution path including at least a part of the plurality of distribution servers. In the aggregation server according to claim 1,
The control means includes
Storage means for storing each topology information received by the receiving means;
An operation start notification means for periodically issuing an operation start notification;
When the operation start notification is issued by the operation start notification unit, at least a part of at least two of the selected distribution routes overlap when selecting the one selected distribution route for each topology information in the storage unit. As described above, the selected distribution route is selected, the result of the selection is transmitted to the plurality of distribution servers, and the combination instruction is transmitted to at least each of the execution distribution servers among the plurality of distribution servers. An aggregation server, including an arithmetic means. In the aggregation server according to claim 2,
When the computing unit selects the one selected delivery route for each topology information, a dispersion value of the number of overlapping links between the receiving clients in the selected delivery route from the combination of the selected delivery routes. An aggregation server that obtains a combination that maximizes and selects a selected delivery route indicated by the combination. A distribution server that is communicable with the aggregation server according to any one of claims 1 to 3, and that distributes update information of content in itself to a plurality of receiving clients associated with the content. ,
Create topology information representing a plurality of distribution paths for the update information from the own server to the plurality of receiving clients, send the topology information to the aggregation server, and from the aggregation server, among the plurality of distribution paths When the selection result indicating the selected delivery route selected from the above is received, the selected delivery route is selected from the plurality of delivery routes, and when the synthesis instruction is received from the aggregation, the synthesis instruction is selected. Management means for storing in association with
When the combination instruction is associated with the selected distribution route selected by the management unit, the update information is added with distribution route information indicating the selected distribution route and the combination instruction, and the distribution route information Update information to which composite information is added is distributed according to the selected distribution route, and when the combination instruction is not associated with the selected distribution route, the distribution route information is attached to the update information, and the distribution route information A distribution server that distributes the update information to which the information is attached according to the selected distribution route. In the delivery server according to claim 4,
The management means includes
Storage means;
Topology information management means for creating the topology information and storing the topology information in the storage means;
A report start notification means for periodically issuing a report start notification;
Reporting means for transmitting the topology information in the storage means to the aggregation server when the report start notification is issued by the report start notification means,
The topology information management means, when receiving the selection result from the aggregation server, selects the selected distribution path from the plurality of distribution paths, and receives the combination instruction when receiving the combination instruction from the aggregation. A distribution server that stores the storage means in association with the selected distribution route. In the delivery server according to claim 4 or 5,
The delivery means includes
Generating means for generating the update information;
When the update information is generated by the generation unit, if the combination instruction is associated with the selected distribution route, the distribution route information and the combination instruction are attached to the update information, and the distribution route information And the update information with the combined information distributed according to the selected distribution route, and when the combination instruction is not associated with the selected distribution route, the distribution route information is added to the update information, and the distribution route A distribution server comprising: distribution control means for distributing update information to which information is attached according to the distribution route. In the delivery server according to any one of claims 4 to 6,
When the management means receives a participation message for requesting notification of the update information from a new receiving client, the management means associates the new receiving client with the content and updates the topology information. A distribution server that transmits topology information to the aggregation server. In the delivery server according to any one of claims 4 to 7,
When the management unit receives a leave message indicating that the update information notification is to be stopped from any of the reception clients already associated with the content, the management unit cancels the association between the reception client and the content. Then, the distribution server updates the topology information and transmits the updated topology information to the aggregation server. A plurality of distribution servers according to any one of claims 4 to 8, and a reception client capable of communicating with other reception clients,
Update information storage means;
Update information receiving means for receiving update information to which distribution route information indicating the selected distribution route is attached from each distribution server or other receiving client;
If the delivery route information attached to the update information indicates that the own reception client is the end, the transfer of the update information is stopped, and the delivery route information indicates the own reception client as a relay location. And, when the update instruction is attached to the update information and the own reception client is indicated in the combination instruction, the relay management stores the update information in the update information storage means. Means,
When the self-received client is indicated as a relay location in the distribution route information, the combining instruction is attached to the update information, and the self-receiving client is not indicated in the combining instruction, or When the self-reception client is indicated as a relay location in the distribution route information and the combining instruction is not attached to the update information, the update information is sent to another receiving client according to the distribution route information. And when the plurality of pieces of update information indicated in the combination instruction are stored in the update information storage means, the plurality of pieces of update information are combined, and the combined update information is Transfer management means for transferring to other receiving clients in accordance with the distribution route information. The receiving client according to claim 9,
The transfer management means includes a counting means for counting an elapsed time since the update information is stored in the update information storage means, and when the counting means counts a predetermined time, the update information storage means Even if not all the update information indicated in the update instruction is stored, the update information in the update information storage means is combined, and the combined update information is received according to the distribution route information. Inbound client to forward to client. The aggregation server according to any one of claims 1 to 3,
A plurality of distribution servers according to any one of claims 4 to 8,
A distribution system comprising: a plurality of receiving clients according to claim 9. An aggregation method performed by an aggregation server that can communicate with a plurality of distribution servers,
A receiving step of receiving, from each distribution server, topology information representing a plurality of distribution paths for the update information of the content from the distribution server to a plurality of receiving clients associated with the content in the distribution server;
The selected delivery so that at least a part of at least two of the selected delivery routes overlaps when selecting one selected delivery route from a plurality of delivery routes represented by the topology information for each received topology information A route is selected, a result of the selection is transmitted to the plurality of distribution servers, and a combination instruction indicating a reception client that is a part of the starting point and a plurality of update information that is combined by the reception client is displayed. An aggregation method including: a control step of transmitting topology information representing a selected distribution path including at least a part of the plurality of distribution servers to each of the execution distribution servers. The aggregation method according to claim 12,
The control step includes
A storage step of storing each received topology information in a storage means;
An operation start notification step for periodically issuing an operation start notification;
When the operation start notification is issued, the selected delivery route is selected such that at least a part of at least two of the selected delivery routes overlaps when selecting the one selected delivery route for each topology information in the storage means. And a transmission control step of transmitting the result of the selection to the plurality of distribution servers and transmitting the combination instruction to at least each of the execution distribution servers among the plurality of distribution servers. The aggregation method. Distribution performed by a distribution server that can communicate with the aggregation server according to any one of claims 1 to 3 and that distributes update information of content within itself to a plurality of receiving clients associated with the content. A method,
Create topology information representing a plurality of distribution paths for the update information from the own server to the plurality of receiving clients, send the topology information to the aggregation server, and from the aggregation server, among the plurality of distribution paths When the selection result indicating the selected delivery route selected from the above is received, the selected delivery route is selected from the plurality of delivery routes, and when the synthesis instruction is received from the aggregation, the synthesis instruction is selected. A management step to store in association with
When the combination instruction is associated with the selected distribution route, the distribution information indicating the selected distribution route and the combination instruction are attached to the update information, and the distribution route information and the combination information are attached. Update information is distributed according to the selected distribution route, and when the combination instruction is not associated with the selected distribution route, the distribution route information is attached to the update information, and the update information with the distribution route information is added. And a delivery step of delivering according to the selected delivery route. The distribution method according to claim 14,
The management step includes
A topology information management step of creating the topology information and storing the topology information in a storage means;
A report start notification step for periodically issuing a report start notification;
When the report start notification is issued, a reporting step of transmitting the topology information in the storage means to the aggregation server;
When the selection result is received from the aggregation server, the selected distribution route is selected from the plurality of distribution routes, and when the combination instruction is received from the aggregation, the combination instruction is associated with the selected distribution route. And a storage management step in the storage means. A plurality of distribution servers according to any one of claims 4 to 8, and a reception method performed by a reception client capable of communicating with other reception clients,
An update information receiving step for receiving update information to which distribution route information indicating the selected distribution route is attached from each distribution server or other receiving client;
If the delivery route information attached to the update information indicates that the own reception client is the end, the transfer of the update information is stopped, and the delivery route information indicates the own reception client as a relay location. And when the update instruction is attached to the update information and the own reception client is indicated in the combination instruction, the relay management step of storing the update information in the update information storage means When,
When the self-received client is indicated as a relay location in the distribution route information, the combining instruction is attached to the update information, and the self-receiving client is not indicated in the combining instruction, or When the self-reception client is indicated as a relay location in the distribution route information and the combining instruction is not attached to the update information, the update information is sent to another receiving client according to the distribution route information. And when the plurality of pieces of update information indicated in the combination instruction are stored in the update information storage means, the plurality of pieces of update information are combined, and the combined update information is A transfer management step of transferring to another receiving client in accordance with the distribution path information. The reception method according to claim 16, wherein
The transfer management step includes:
A counting step of counting an elapsed time since the update information is stored in the update information storage means;
When the elapsed time reaches a predetermined time, even if not all the update information indicated in the update instruction is stored in the update information storage means, the update information in the update information storage means is combined, A transfer step of transferring the combined update information to another receiving client according to the distribution route information. To a computer that can communicate with multiple distribution servers,
A reception procedure for receiving, from each distribution server, topology information representing a plurality of distribution paths for update information of the content from the distribution server to a plurality of receiving clients associated with the content in the distribution server;
The selected delivery so that at least a part of at least two of the selected delivery routes overlaps when selecting one selected delivery route from a plurality of delivery routes represented by the topology information for each received topology information A route is selected, a result of the selection is transmitted to the plurality of distribution servers, and a combination instruction indicating a reception client that is a part of the starting point and a plurality of update information that is combined by the reception client is displayed. And a control procedure for transmitting to each of the execution distribution servers that have transmitted topology information representing the selected distribution route including at least a part of the plurality of distribution servers. The program according to claim 18, wherein
The control procedure is:
A storage procedure for storing each received topology information in a storage means;
An operation start notification procedure for periodically issuing an operation start notification;
When the operation start notification is issued, the selected delivery route is selected such that at least a part of at least two of the selected delivery routes overlaps when selecting the one selected delivery route for each topology information in the storage means. And a transmission control procedure for transmitting a result of the selection to the plurality of distribution servers and transmitting the combination instruction to at least each of the execution distribution servers among the plurality of distribution servers. ,program. A computer that can communicate with the aggregation server according to any one of claims 1 to 3 and that distributes update information of content in itself to a plurality of receiving clients associated with the content,
Create topology information representing a plurality of distribution routes for the update information from the own computer to the plurality of receiving clients, send the topology information to the aggregation server, and from the aggregation server, among the plurality of distribution routes When the selection result indicating the selected delivery route selected from the above is received, the selected delivery route is selected from the plurality of delivery routes, and when the synthesis instruction is received from the aggregation, the synthesis instruction is selected. A management procedure to store in association with
When the combination instruction is associated with the selected distribution route, the distribution information indicating the selected distribution route and the combination instruction are attached to the update information, and the distribution route information and the combination information are attached. Update information is distributed according to the selected distribution route, and when the combination instruction is not associated with the selected distribution route, the distribution route information is attached to the update information, and the update information with the distribution route information is added. And a delivery procedure for delivering according to the selected delivery route. The program according to claim 20,
The management procedure is as follows:
A topology information management procedure for creating the topology information and storing the topology information in a storage means;
A report start notification procedure for periodically issuing a report start notification,
When the report start notification is issued, a reporting procedure for transmitting the topology information in the storage means to the aggregation server;
When the selection result is received from the aggregation server, the selected distribution route is selected from the plurality of distribution routes, and when the combination instruction is received from the aggregation, the combination instruction is associated with the selected distribution route. A storage management procedure in the storage means. A plurality of distribution servers according to any one of claims 4 to 8, and a computer capable of communicating with other receiving clients,
An update information reception procedure for receiving update information with distribution route information indicating the selected distribution route from each distribution server or other receiving client;
If the delivery route information attached to the update information indicates that the own reception client is the end, the transfer of the update information is stopped, and the delivery route information indicates the own reception client as a relay location. And, when the update instruction is attached to the update information and the own reception client is indicated in the combination instruction, the relay management procedure for storing the update information in the update information storage means When,
When the self-received client is indicated as a relay location in the distribution route information, the combining instruction is attached to the update information, and the self-receiving client is not indicated in the combining instruction, or When the self-reception client is indicated as a relay location in the distribution route information and the combining instruction is not attached to the update information, the update information is sent to another receiving client according to the distribution route information. And when the plurality of pieces of update information indicated in the combination instruction are stored in the update information storage means, the plurality of pieces of update information are combined, and the combined update information is A transfer management procedure for transferring to another receiving client according to the distribution route information. The program according to claim 22,
The transfer management procedure includes:
A counting procedure for counting an elapsed time since the update information is stored in the update information storage means;
When the elapsed time reaches a predetermined time, even if not all the update information indicated in the update instruction is stored in the update information storage means, the update information in the update information storage means is combined, A transfer procedure for transferring the synthesized update information to another receiving client in accordance with the distribution route information.

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