JP2006244054A - Information processor and method, recording medium, program and information processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more hardly allow breaking-off of reproduction of a content. <P>SOLUTION: In this information processor, an assignment part 182 divides content data instructed with a download into a prescribed number of segments, and divides each segment into parts of the number of servers 52 as transmission nodes. The assignment part 182 assigns transmission of each of the parts constituting the segment to be next downloaded to each of the server 52-1 to the server 52-N. A communication control part 183-1 to a communication control part 183-N respectively generate transmission requirement signals requiring the transmission of the parts assigned to the server 52-1 to the server 52-N, and transmit them to the server 52-1 to the server 52-N via a communication network 53. The information processor can be applied to a streaming distribution system distributing streaming data of a moving image, music or the like. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information processing device and method, a recording medium, a program, and an information processing system, and more particularly, to an information processing device and method, a recording medium, a program, and an information processing system that can stream more efficiently.

  In recent years, services that distribute content such as video (moving images) and music using various communication media such as the Internet are generally performed. Content distribution is performed by, for example, a server that records image data and audio data (hereinafter referred to as content data as appropriate) for reproducing content transmitting content data to clients via the Internet. In a network such as peer-to-peer (Peer To Peer), a client (transmitting device) as a transmission node recording content data transmits content data to a client (receiving device) as a receiving node via the network. Is done by.

  In particular, in recent years, the performance of personal computers and the like, which have been considered to be low as a transmission node, has increased, the reliability as a transmission node has increased, the network bandwidth has become wider, With each node such as a personal computer being always (always) connected to the network, larger data can be transmitted more reliably on the network. Therefore, in addition to download-type and live-type transmission scheme services, more progressive download-type transmission scheme services are provided.

  In a download-type transmission method service, content data that has already been encoded by a device that distributes (transmits) content (hereinafter referred to as a server) is referred to as a device that receives data (hereinafter referred to as a client). ). The client reproduces the content data after receiving the content data transmitted from the server (after downloading of the content data is completed).

  On the other hand, in a live-type transmission method service, for example, a server encodes content data corresponding to a captured video in real time, and immediately transmits the content data obtained by encoding to a client. Then, the client receives the content data transmitted from the server, and at the same time, reproduces the content based on the received content data. That is, the server distributes the content data in a streaming manner, and the client receives the content data transmitted from the server and reproduces it sequentially.

  In the service of the progressive download transmission method, the server transmits content data that has already been encoded to the client. Then, as in the case of the live transmission method, the client receives the content data transmitted from the server, and simultaneously reproduces the content based on the received content data.

  When delivering content (content data) using the progressive download type transmission method, the speed at which the encoded content data is output (bit rate) is the speed at which the client downloads the content data (the bit rate at which the content data is received). When the size is larger than the limit, the client downloads the content data by making the best use of its own (allocated) network bandwidth, and temporarily stores the content data. Even if a problem occurs in the network, a portion (content data) where the content can be viewed continuously can be secured as much as possible.

  For example, in a network where bandwidth is not guaranteed such as the Internet, when a client downloads content data from a server, a packet loss or transmission delay occurs in the middle of transmitting the content data (packet storing the content) on the network. Such a disturbance (problem) occurs, and band degeneration and connection disconnection due to this occur with a certain probability. However, in the progressive download type transmission method, the client downloads (receives) the content data as much as possible using the resources such as the network bandwidth and the hard disk capacity of the hard disk as much as possible. Even if a packet loss or connection disconnection occurs due to continuation of the scene using the already downloaded content data (cached content data) until the connection is reestablished or the bandwidth is restored. It is possible to continue watching the content without losing performance (without interrupting playback).

  By the way, in order to download content data more quickly, a method of dividing and downloading content data has been proposed. For example, there is a method of dividing desired content data into a plurality of data (downloading) using a download application program such as FlashGet and downloading each of the divided data from one server at the same time (simultaneously). Proposed.

  However, since content data is normally downloaded in one session of a TCP (Transmission Control Protocol) session, for example, the maximum transfer rate per session on the server side is limited so that the server is not overloaded. May be. Also, in a TCP session, when packet loss occurs, the maximum throughput is limited in a network where the packet transfer rate is significantly reduced or the delay is large.

  Therefore, when a client downloads content data from one server, even if the content data is divided and downloaded, the client may not be able to effectively use its own bandwidth.

  As a method for solving such a problem, a method is proposed in which content data is divided into a plurality of data, and the divided data is downloaded from a plurality of servers (mirror servers), respectively (for example, see Patent Document 1). . Also, as a method of dividing content data into a plurality of data and downloading them from a plurality of servers, for example, using a download application program such as Star Downloader, the content data is divided into a plurality of data, and each of the plurality of servers The method of downloading from is also proposed. For example, if server A and server B record the same content data A, the client divides content data A into two data, data A and data B, and downloads data A from server A. Then, data B is downloaded from server B.

  As described above, by dividing (dividing) one content data into a plurality of data and downloading the data from a plurality of servers, the client can effectively use the bandwidth possessed by the client. In this case, the speed at which the client downloads the content data is a value (speed) obtained by adding the bandwidths of the servers, so that the content data can be downloaded more quickly.

  In the peer-to-peer network, the possibility that content data can be downloaded is improved by distributing the content data to a plurality of clients connected to the peer-to-peer network.

  In other words, a client serving as a receiving node connected to a peer-to-peer network such as Winny or Bittorrent downloads content data from another client serving as a sending node using, for example, client software corresponding to each network. To do. Here, a client as a transmission node is generally a personal computer, which is inferior in terms of its own bandwidth and CPU (Central Processing Unit) processing capability, that is, content data transmission capability, compared to a dedicated server. Therefore, when a client as a receiving node downloads content data, a sufficient download speed may not be obtained. Therefore, in a peer-to-peer network, a client as a receiving node divides one content data into a plurality of data, and downloads each data from a client as a plurality of transmitting nodes. Make up for the lack of transmission capability of each client.

JP 2003-157197 A

  By the way, the above-described method of downloading content data by dividing it from a plurality of servers (or transmission nodes) is mainly assumed to distribute the content data by a download-type transmission method. Distribution in the transmission system is not in view. For example, in the case of distributing content (content data) in a peer-to-peer network, since a personal computer is used as a transmission node, stability such as transmission capability cannot be guaranteed. From the viewpoint that it is only necessary to be able to download, content distribution is usually performed by a download-type transmission method.

  Accordingly, when content (content data) distributed by a progressive download type transmission method is divided and downloaded from a plurality of servers, content data that can be continuously played out of content data that has been downloaded. The amount is small and the efficiency is very poor.

  For example, as shown in FIG. 1, it is assumed that one piece of content data is divided into data 11-1 to data 11-5 and downloaded from a plurality of servers. Here, in the figure, the horizontal axis indicates the reproduction time of the content data. In addition, among the data 11-1 to data 11-5, the black portion indicates a portion where the download from the server has already been completed, and the white portion indicates a portion where the download from the server has not been completed, that is, still The part which has not been downloaded is shown.

  When content (content data) is reproduced, the content data starts to be reproduced from the portion of the reproduction time t0, and the reproduction ends at the portion of the reproduction time t10. That is, the client reproduces the content using each of the data 11-1 to data 11-5 in the order of the data 11-1 to data 11-5. The client uses this content data as data 11-1 from playback time t0 to playback time t2, data 11-2 from playback time t2 to playback time t4, data 11-3 from playback time t4 to playback time t6, Data 11-4 from reproduction time t6 to reproduction time t8 and data 11-5 from reproduction time t8 to reproduction time t10 are divided. Then, data 11-1 through data 11-5 are downloaded from different servers.

  In the example of FIG. 1, the data from the reproduction time t0 to the reproduction time t1 in the data 11-1, the data from the reproduction time t2 to the reproduction time t3 in the data 11-2, and the data 11 -3, the data from the playback time t4 to the playback time t5 has already been downloaded. In addition, the data from the reproduction time t6 to the reproduction time t7 in the data 11-4 and the data from the reproduction time t8 to the reproduction time t9 in the data 11-5 are already downloaded.

  Therefore, in this case, the client can continuously reproduce the portion corresponding to the content data from the reproduction time t0 to the reproduction time t1 among the content reproduced based on the content data. However, the data from the reproduction time t2 to the reproduction time t3 that has already been downloaded is the data of the portion from the reproduction time t1 to the reproduction time t2 that has not yet been downloaded, that is, the data 11-1. Until the data download is complete, it cannot be used for content playback.

  Similarly, the data from the playback time t4 to the playback time t5 that have already been downloaded, the data from the playback time t6 to the playback time t7, and the data from the playback time t8 to the playback time t9 are also currently recorded. Cannot be used for content playback.

  Here, for example, in FIG. 1, a problem occurs in the server that transmits the data 11-1 to the client, and the server transmits a part of the data from the reproduction time t1 to the reproduction time t2. If the data 11-2 to data 11-5 are completely downloaded, the data 11-2 to data 11-5 can be downloaded from the reproduction time t1 to the reproduction time t2. Until it is completed, it cannot be used to reproduce the content of the corresponding part. That is, the user who operates the client changes the content data from the reproduction time t0 to the reproduction time t1 among the contents to be viewed even though the downloading of the data 11-2 to the data 11-5 is completed. Only the corresponding part can view the content.

  Similarly, when the data transmission speed of the server that transmits the data 11-1 is smaller (slower) than the transmission speed of each of the servers that transmit the data 11-2 to the data 11-5, the data 11-2 Even if the downloading of the data 11-5 is completed, the user reproduces the content only up to the portion corresponding to the portion where the downloading of the data 11-1 is completed among the content reproduced based on the content data. I can't.

  As described above, when one content data is divided (divided) into a plurality of data and the divided data is downloaded from different servers, the content data can be downloaded at a higher speed. Of the completed content data, the amount of content data that can be played continuously is small and the efficiency is low, so the data transmission speed of one server is very low compared to the transmission speed of other servers In addition, when a problem occurs in a network that transmits content data, a server that transmits content data, or the like, there is a problem that playback of content being viewed may be interrupted.

  The present invention has been made in view of such a situation, and when content data is downloaded more quickly and more efficiently, and the content data is distributed by a progressive download type transmission method, Even when a problem occurs in the server, the reproduction of content can be made more difficult to interrupt.

  The information processing apparatus according to the present invention receives the first data to be received from now on, and sequentially receives the second data divided into predetermined predetermined sizes. Is further divided into third data corresponding to each of the transmission devices, thereby assigning each transmission of the third data to each of the corresponding transmission devices, and assigning to each of the transmission devices Transmission means for transmitting each request signal for requesting transmission of each third data to a transmission device corresponding to the third data, and transmission of the third data transmitted from each transmission device. Receiving means for receiving each of them.

  The information processing apparatus further includes storage means for storing information indicating the speed at which the third data is received from the transmitting apparatus, and the assigning means is based on information indicating the speed at which the third data is received from the transmitting apparatus. Further, the size of the third data can be changed, and the second data can be divided into the third data.

  According to the information processing method of the present invention, when the first data to be received is received in turn and the second data is divided into predetermined predetermined sizes, the second data to be received next is received. Is further divided into third data corresponding to each of the transmission devices, thereby assigning each transmission of the third data to each of the corresponding transmission devices, and assigning to each of the transmission devices A transmission control step for controlling transmission of each request signal for requesting transmission of each of the third data to each of the transmission devices corresponding to the third data, and transmission from each of the transmission devices. A reception control step of controlling reception of each of the third data.

  The program of the recording medium of the present invention receives the first data to be received from now on, and sequentially receives the second data divided into predetermined predetermined sizes. Allocating each transmission of the third data to each of the corresponding transmission devices by further dividing the second data into each of the third data corresponding to each of the transmission devices, and to each of the transmission devices A transmission control step for controlling transmission of each of the request signals for requesting transmission of the allocated third data to each of the transmission apparatuses corresponding to the third data, and transmission from the respective transmission apparatuses And a reception control step for controlling the reception of each of the third data.

  The program according to the present invention receives the second data to be received next when the first data to be received is received in turn and the second data is divided into predetermined predetermined sizes. Is further divided into each of the third data corresponding to each of the transmission devices, thereby assigning each transmission of the third data to each of the corresponding transmission devices, and each of the transmission data assigned to each of the transmission devices. A transmission control step for controlling transmission of each request signal for requesting transmission of each of the three data to each of the transmission devices corresponding to the third data, and a third transmission signal transmitted from each of the transmission devices. And a reception control step for controlling the reception of each of the data.

  In the information processing apparatus and method, the recording medium, and the program according to the present invention, when the first data to be received is received in turn, the second data is divided into predetermined predetermined sizes. Then, the second data to be received next is further divided into each of the third data corresponding to each of the transmitting devices, so that each transmission of the third data is assigned to each of the corresponding transmitting devices. Each of the request signals for requesting the transmission of the third data assigned to each of the transmission devices is transmitted to the transmission device corresponding to the third data, and transmitted from each of the transmission devices. , Each of the third data is received.

  The information processing apparatus according to the present invention includes a storage unit that stores first data, and second data obtained by dividing the first data that the other party is to receive from the predetermined data into a predetermined size. When receiving each in turn, transmission of one third data out of the third data, which is transmitted from the other party and the second data that the other party intends to receive next is further divided into a predetermined number Receiving means for receiving a request signal for requesting, acquiring means for acquiring third data requested to be transmitted from the stored first data based on the request signal, and acquired third data Transmission means for transmitting to the other party.

  The information processing method of the present invention is transmitted from the other party when the other party sequentially receives the second data obtained by dividing the first data to be received by the other party into a predetermined size. Reception that controls the reception of a request signal for requesting transmission of one third data out of the third data obtained by dividing the second data to be received by the other party into a predetermined number. Based on the control step, the acquisition step of acquiring the third data requested to be transmitted from the stored first data, and the transmission of the acquired third data to the other party based on the request signal A transmission control step.

  The recording medium program of the present invention transmits the second data obtained by dividing the first data to be received by the other party into a predetermined size in advance when the other party sequentially receives the second data. Controlling reception of a request signal for requesting transmission of one third data among the third data obtained by dividing the second data to be received next by the partner into a predetermined number. Based on the reception control step, the acquisition step of acquiring the third data requested to be transmitted from the stored first data, and the transmission of the acquired third data to the other party based on the request signal And a transmission control step.

  The program of the present invention has been transmitted from the other party when the other party sequentially receives the second data obtained by dividing the first data to be received by the other party into a predetermined size. A reception control step for controlling reception of a request signal for requesting transmission of one third data among the third data obtained by further dividing the second data to be received next by the opponent into a predetermined number And an acquisition step of acquiring the third data requested to be transmitted from the stored first data based on the request signal, and transmission control for controlling transmission of the acquired third data to the other party And causing the computer to execute the steps.

  In the information processing apparatus and method, the recording medium, and the program according to the present invention, the partner sequentially orders the second data obtained by dividing the first data that the partner intends to receive into a predetermined size. Requesting transmission of one third data out of the third data, which is transmitted from the partner and the second data that the partner intends to receive next is further divided into a predetermined number. The request signal to be transmitted is received, and based on the request signal, the third data requested to be transmitted is acquired from the stored first data, and the acquired third data is transmitted to the other party.

  In the information processing system of the present invention, when the receiving device receives the first data to be received in the order of the second data divided into predetermined predetermined sizes, the receiving device receives the next data next. Assigning each transmission of the third data to each of the corresponding transmitting devices by dividing the second data to be further divided into each of the third data corresponding to each of the connected transmitting devices. And a transmission means for transmitting each request signal for requesting transmission of each of the third data assigned to each of the transmission devices to the transmission device corresponding to the third data, and each of the transmission devices. Based on the request signal, the storage means for storing the first data, the reception means for receiving the request signal transmitted from the receiving device. An acquisition means for acquiring the third data requested to be transmitted from the first data, and a transmission means for transmitting the acquired third data to the reception apparatus. It further comprises receiving means for receiving each of the third data transmitted from each of the above.

  In the information processing system of the present invention, when receiving the first data to be received by the receiving device in the order of the second data divided into predetermined predetermined sizes, Next, the second data to be received is further divided into the third data corresponding to each of the connected transmitting apparatuses, so that each transmission of the third data corresponds to the corresponding transmitting apparatus. A request signal for requesting transmission of each of the third data assigned to each of the transmission devices is transmitted to the transmission device corresponding to the third data, and is transmitted by each of the transmission devices. A request signal transmitted from the receiving device is received, and transmission is requested from the stored first data based on the request signal. The third data is acquired, the third data obtained is transmitted to the receiving apparatus. Then, each of the third data transmitted from each of the transmission devices is further received by the reception device.

  The network is a mechanism in which at least two devices are connected and information can be transmitted from one device to another device. The devices that communicate via the network may be independent devices, or may be internal blocks that constitute one device.

  The communication is not only wireless communication and wired communication, but also communication in which wireless communication and wired communication are mixed, that is, wireless communication is performed in a certain section and wired communication is performed in another section. May be. Further, communication from one device to another device may be performed by wired communication, and communication from another device to one device may be performed by wireless communication.

  According to the present invention, content data can be downloaded. In particular, according to the present invention, when content data is downloaded more quickly and efficiently, and the content data is distributed by the progressive download type transmission method, even when a problem occurs in the network or the server. , It is possible to make the reproduction of the content more difficult to interrupt.

  Embodiments of the present invention will be described below. The correspondence relationship between the invention described in this specification and the embodiments of the invention is exemplified as follows. This description is intended to confirm that the embodiments supporting the invention described in this specification are described in this specification. Therefore, although there is an embodiment which is described in the embodiment of the invention but is not described here as corresponding to the invention, it means that the embodiment is not It does not mean that it does not correspond to the invention. Conversely, even if an embodiment is described herein as corresponding to an invention, that means that the embodiment does not correspond to an invention other than the invention. Absent.

  Further, this description does not mean all the inventions described in this specification. In other words, this description is for the invention described in the present specification, which is not claimed in this application, that is, for the invention that will be applied for in the future or that will appear and be added by amendment. It does not deny existence.

  The information processing apparatus according to claim 1, wherein the first data to be received (for example, the content data shown in FIG. 5) is divided into predetermined second predetermined data (for example, the content data illustrated in FIG. 5). When receiving the segments 71-1 to 71-6 and 71 in FIG. 5 in order, the second data to be received next is further transmitted to the transmitting device (for example, the servers 52-1 to 52-1 in FIG. 2). Server 52-N, server 52) third data (for example, part 111-1 to 111-6, part 111, part 112-1 to part 112-6, part 112 shown in FIG. 5) By assigning each transmission of the third data to each of the corresponding transmission devices (for example, the calculation unit 253 in FIG. 8). And a transmission means (for example, the transmission unit 203 in FIG. 7) for transmitting each of the request signals for requesting the transmission of the third data allocated to each of the transmission devices to the transmission device corresponding to the third data. -1 to transmitting section 203-N, transmitting section 203) and receiving means for receiving each of the third data transmitted from the respective transmitting apparatuses (for example, receiving section 204-1 to receiving section in FIG. 7) 204-N, receiving unit 204).

  The information processing apparatus according to claim 2 transmits the third data (for example, part 111-1 to part 111-6, part 111, part 112-1 to part 112-6, part 112 shown in FIG. 5). A storage unit (for example, the reception history storage unit 255 in FIG. 8) that stores information indicating the speed received from the device (for example, the server 52-1 to the server 52-N in FIG. 2 or the server 52) is further provided. (For example, the calculation unit 253 in FIG. 8) changes the size of the third data based on the information indicating the speed at which the third data is received from the transmission device, and converts the second data into the third data. It is characterized by dividing each of the data.

  The information processing method according to claim 3, wherein the first data to be received (for example, the content data shown in FIG. 5) is divided into predetermined second predetermined data (for example, content data shown in FIG. 5). When receiving the segments 71-1 to 71-6 and 71 in FIG. 5 in order, the second data to be received next is further transmitted to the transmitting device (for example, the servers 52-1 to 52-1 in FIG. 2). Server 52-N, server 52) third data (for example, part 111-1 to 111-6, part 111, part 112-1 to part 112-6, part 112 shown in FIG. 5) By assigning each transmission of the third data to each of the corresponding transmitting devices (for example, the steps of FIG. 10). The process of S64 and the process of step S72) and the transmission of the request signal for requesting the transmission of each of the third data assigned to each of the transmission apparatuses to each of the transmission apparatuses corresponding to the third data. A transmission control step for controlling (for example, the processing of step S65 in FIG. 10) and a reception control step for controlling the reception of each of the third data transmitted from the respective transmitting apparatuses (for example, step S66 in FIG. 10). The processing is included.

  Note that the recording medium according to claim 4 and the program according to claim 5 are basically the same processing as the information processing method according to claim 3 described above, and are therefore repeated, so that the description thereof is omitted. To do.

  The information processing apparatus according to claim 6 is a storage unit (for example, the recording unit 223-1 to the recording unit 223-N in FIG. 7, the recording unit) that stores the first data (for example, the content data illustrated in FIG. 5). 223) and second data obtained by dividing the first data to be received by the other party into a predetermined size (for example, segment 71-1 to segment 71-6, segment 71 in FIG. 5) Are received in turn, the third data (for example, the part shown in FIG. 5), which is transmitted from the partner and is divided into a predetermined number of second data to be received next by the partner. 111-1 to part 111-6, part 111, part 112-1 to part 112-6, part 112), receiving means for receiving a request signal for requesting transmission of one third data For example, the third data requested to be transmitted is acquired from the first data stored based on the request signal with the reception units 221-1 to 221-N and the reception unit 221) in FIG. Acquisition means (for example, the acquisition unit 222-1 to acquisition unit 222-N and acquisition unit 222 in FIG. 7) and transmission means for transmitting the acquired third data to the other party (for example, the transmission unit 224 in FIG. 7). -1 to transmitting unit 224-N, and transmitting unit 224).

  The information processing method according to claim 7 is the second data (for example, the first data (for example, the content data shown in FIG. 5) that the other party intends to receive is divided into a predetermined size. , When the partner receives the segment 71-1 to segment 71-6 and the segment 71) in order, the second data transmitted from the partner and to be received next by the partner is further specified. 3rd data (for example, part 111-1 to part 111-6, part 111, part 112-1 to part 112-6, part 112 shown in FIG. 5). A reception control step for controlling reception of a request signal for requesting transmission of data (for example, the processing of step S111 in FIG. 15), and the first data stored based on the request signal. The acquisition step (for example, the process of step S112 in FIG. 15) for acquiring the third data requested to be transmitted, and the transmission control step (for example, FIG. 15) for controlling the transmission of the acquired third data to the other party. 15 step S113).

  Note that the recording medium according to claim 8 and the program according to claim 9 are basically the same processing as the information processing method according to claim 7 described above, and are therefore repeated, so the description thereof is omitted. To do.

  In the information processing system according to claim 10, the receiving device (for example, the client 51 in FIG. 2) has predetermined first data (for example, the content data illustrated in FIG. 5) to be received. When the second data divided into a predetermined size (for example, segment 71-1 to segment 71-6, segment 71 in FIG. 5) is received in order, the second data to be received next is Further, third data (for example, part 111-1 to part 111- shown in FIG. 5) corresponding to each of the connected transmission apparatuses (for example, server 52-1 to server 52-N, server 52 in FIG. 2). 6, part 111, part 112-1 through part 112-6, and part 112), each transmission of the third data is supported Allocating means (for example, the calculation unit 253 in FIG. 8) to be allocated to each of the transmission devices and the request signal for requesting transmission of each of the third data allocated to each of the transmission devices as the third data. A transmission unit (for example, the transmission unit 203-1 to the transmission unit 203-N and the transmission unit 203 in FIG. 7) for transmitting to the corresponding transmission device, and each of the transmission devices stores a first data. 7 (for example, the recording unit 223-1 to the recording unit 223-N and the recording unit 223 in FIG. 7) and a receiving unit (for example, the receiving unit 221 in FIG. 7) that receives a request signal transmitted from the receiving device. 1 to receiving unit 221-N, receiving unit 221) and acquisition means for acquiring third data requested to be transmitted from the stored first data based on the request signal (for example, FIG. The acquisition unit 222-1 to acquisition unit 222 -N, the acquisition unit 222) and transmission means for transmitting the acquired third data to the reception device (for example, the transmission unit 224-1 to transmission unit 224 -N in FIG. 7). , And a receiving unit that receives each of the third data transmitted from each of the transmitting devices (for example, the receiving unit 204-1 to the receiving unit 204- in FIG. 7). N, receiving unit 204).

  The present invention can be applied to a streaming distribution system that distributes streaming data such as moving images and music.

  Embodiments to which the present invention is applied will be described below with reference to the drawings.

  FIG. 2 is a diagram for explaining a content distribution system according to the present invention. In this content distribution system, the client 51 and the servers 52-1 to 52-N (the servers 52-5 to 52- (N-1) are not shown) are connected to each other via the communication network 53. Has been.

  The network composed of the client 51 and the servers 52-1 to 52-N is a so-called peer-to-peer network, and each of the client 51 and the servers 52-1 to 52-N is connected via the communication network 53. Among the existing devices (client 51 and servers 52-1 to 52 -N), the device that records the desired content data can be searched, and the content data can be downloaded from the searched device. Each of the client 51 and the servers 52-1 to 52 -N transmits the recorded content data via the communication network 53 in response to a request from a device connected via the communication network 53. It can be transmitted to a device that has requested transmission of content data.

  In FIG. 2, for the sake of explanation, a device that receives (downloads) content data is referred to as a client 51, and devices that transmit content data to the client 51 are referred to as servers (servers 52-1 to 52 -N). Hereinafter, when it is not necessary to distinguish each of the servers 52-1 to 52-N, they are simply referred to as servers 52.

  When the user operates the client 51 to download desired content data, the client 51 selects desired content data from the servers 52-1 to 52-N connected via the communication network 53. The recorded server 52 is searched.

  For example, the client 51 generates a search request signal for requesting a search of the server 52 that records predetermined content data, and sends the generated search request signal to the server 52-1 and the server 52 via the communication network 53. -Send to -2.

  Each of the server 52-1 and the server 52-2 receives the search request signal transmitted from the client 51. Then, when the server 52-1 or the server 52-2 records the predetermined content data, the server 52-1 or the server 52-2 generates a signal indicating that the content data is recorded, and sends the generated signal to the communication network 53. To the client 51.

  On the other hand, when the server 52-1 or the server 52-2 does not record the predetermined content data, the server 52-1 or the server 52-2 transmits the received search request signal to the other via the communication network 53. It is transmitted to the server 52. For example, the server 52-1 transmits the received search request signal to the server 52-3 and the server 52-4 via the communication network 53, and the server 52-2 transmits the received search request signal to the communication network. The data is transmitted to the server 52-5 and the server 52-6 via 53.

  Similarly to the case where the server 52-1 or the server 52-2 receives the search request signal, each of the server 52-3 to the server 52-6 receives the search request signal and records its own content data. If the content data is recorded, it is transmitted to the client 51 via the communication network 53. If the content data is not recorded by itself, the received search request signal is The data is transmitted to another server 52 via the communication network 53.

  In this way, a signal indicating that the content data is recorded is transmitted to the client 51 from the server 52 that records the desired content data. The client 51 can search the server 52 that records the desired content data among the servers 52 by receiving the signal indicating that the content data is recorded.

  Then, when the server 52 that records the content data is searched, the client 51 divides the desired content data into a plurality of data, and records each divided data as content data. Download from the server 52 running. For example, when the server 52-1 and the server 52-2 are recording the desired content data, the client 51 designates a division position where the content data is divided into a plurality of data, and each data is assigned to the server 52-. 1 or downloaded from the server 52-2.

  Next, a method in which the client 51 divides and downloads content data will be described with reference to FIGS. 4 and 5, the same reference numerals are given to the portions corresponding to those in FIG. 3, and the description thereof will be omitted as appropriate since it will be repeated.

  For example, when the client 51 divides content data to be received and downloads it from the two servers 52-1 and 52-2, the content data has a predetermined size as shown in FIG. The division positions are designated so that the data is segmented into six pieces of data, that is, the segments 71-1 to 71-6.

  When dividing the content data into the segments 71-1 to 71-6, for example, the segment 71-1 is divided so that the size is smaller than the sizes of the segments 71-2 to 71-6. The division positions may be specified so that the sizes of the segments 71-1 to 71-6 are different, such as specifying the position, and the segments 71-1 to 71-6 have the same size. The division position may be designated so as to be data.

  For example, when the segments 71-1 to 71-6 are divided so as to have the same size, the sizes of the segments 71-1 to 71-6 correspond to the content data, for example. The size of data necessary for reproducing the content for one minute is set. Hereinafter, the segments 71-1 to 71-6 are simply referred to as segments 71 when it is not necessary to individually distinguish them.

  Next, the client 51 designates the division position so that the segment 71 is divided into data of the number of servers 52 that download the content data. Therefore, in the example of FIG. 3, the client 51 divides and downloads the content data from the server 52-1 and the server 52-2, so that each segment 71 is divided into two pieces of data. Specify the data division position. Hereinafter, data obtained by dividing the segment 71 is referred to as a part.

  That is, the client 51 divides the segment 71-1 into the parts 81-1 and 82-1, divides the segment 71-2 into the parts 81-2 and 82-2, and divides the segment 71-3 into the part 81-. 3 and part 82-3.

  Similarly, the client 51 divides segment 71-4 into part 81-4 and part 82-4, divides segment 71-5 into part 81-5 and part 82-5, and segments 71-6 as part 81. -6 and part 82-6.

  Further, the client 51 assigns the transmissions of the parts 81-1 to 81-6 to the server 52-1, and assigns the transmissions of the parts 82-1 to 82-6 to the server 52-2. The client 51 establishes a session (establishes a connection) with each of the server 52-1 and the server 52-2, downloads the parts 81-1 to 81-6 from the server 52-1, and the server 52-2. Part 82-1 through part 82-6 are downloaded respectively.

  That is, the client 51 first downloads the part 81-1 from the server 52-1, and after the download of the part 81-1 is completed, downloads the part 81-2 from the server 52-1. After the download of the part 81-2 is completed, the part 81-3 is downloaded from the server 52-1, and each of the parts 81-4 to 81-6 is sequentially transferred from the server 52-1. to download.

  In addition, the client 51 downloads each of the parts 82-1 to 82-6 from the server 52-2 in parallel with the downloading of the parts 81-1 to 81-6. That is, the client 51 first downloads the part 82-1 from the server 52-2, and after the download of the part 82-1 is completed, the client 51 downloads the part 82-2 from the server 52-2. Then, after the download of the part 82-2 is completed, the part 82-3 is downloaded from the server 52-2. Similarly, the parts 82-4 to 82-6 are sequentially transferred from the server 52-2. to download.

  Hereinafter, when it is not necessary to individually distinguish each of the parts 81-1 to 81-6, they are simply referred to as part 81. Hereinafter, when it is not necessary to distinguish each of the parts 82-1 to 82-6, they are simply referred to as part 82.

  In the following description, the client 51 divides the content data, not the client 51 divides the content data itself, but the content data that the client 51 intends to receive is divided into data of a predetermined size (amount). To specify the size (or division position). Therefore, the client 51 divides the content data from the plurality of servers 52 by designating the position where the content data is divided, that is, by designating the part (part) of the content data that requires transmission. to download.

  By the way, when the segment 71 is divided into parts having the same size and downloaded from the server 52-1 and the server 52-2, the client 51, for example, as shown in FIG. Divide into two equal parts. Here, in the figure, the horizontal axis indicates the reproduction time of the content that is reproduced based on the content data. When the content (content data) is reproduced, the content starts to be reproduced from the portion of the reproduction time t30. The playback ends at the playback time t38.

  In each of the parts 101-1 to 101-6 and the parts 102-1 to 102-6, the black part indicates a part that has already been downloaded from the server 52, and the white part indicates A portion where the download from the server 52 has not been completed, that is, a portion that has not yet been downloaded is shown.

  The client 51 divides the segment 71-1 into parts 101-1 and 102-1 having the same size, and divides the segment 71-2 into parts 101-2 and 102-2 having the same size. Then, the segment 71-3 is divided into a part 101-3 and a part 102-3 having the same size.

  Similarly, the client 51 divides the segment 71-4 into a part 101-4 and a part 102-4 having the same size, and segments 71-5 are divided into a part 101-5 and a part 102- having the same size, respectively. The segment 71-6 is divided into a part 101-6 and a part 102-6 having the same size.

  Then, the client 51 assigns the transmissions of the parts 101-1 to 101-6 to the server 52-1, and assigns the transmissions of the parts 102-1 to 102-6 to the server 52-2. Then, as in the case of FIG. 3, the client 51 downloads the parts 101-1 to 101-6 from the server 52-1 in order from the part 101-1, and sequentially from the part 102-1. Parts 102-1 to 102-6 are downloaded from the server 52-2, respectively.

  Hereinafter, the parts 101-1 to 101-6 are simply referred to as parts 101 when it is not necessary to distinguish them individually. Hereinafter, when it is not necessary to individually distinguish the parts 102-1 to 102-6, they are simply referred to as part 102.

  In the example in FIG. 4, the client 51 has already downloaded the part 101-1 to the part 101-5 from the server 52-1, and the reproduction time t37 from the reproduction time t36 of the part 101-6. The part of the download is complete. Further, in the client 51, the download of the part 102-1 and the part 102-2 from the server 52-2 has already been completed, and the part of the part 102-3 from the reproduction time t33 to the reproduction time t34 is downloaded. Has been completed.

  In this case, the client 51 can continuously reproduce the content by using the segment 71-1 and the segment 71-2 and the data of the segment 71-3 from the reproduction time t32 to the reproduction time t34. . That is, the user can continuously view the content corresponding to the content data from the reproduction time t30 to the reproduction time t34.

  For example, assuming that the portion corresponding to the reproduction time t31 of the content is being reproduced at the present time, the download of the portion of the content data from the reproduction time t30 to the reproduction time t34 has been completed. 2 or the communication network 53, even if the download of the part 102-3 is interrupted, the client 51 can reproduce at least the content corresponding to the reproduction time t34. Therefore, if the download of the part 102-3 is resumed by the end of the reproduction of the content corresponding to the reproduction time t34, the content can be reproduced without interruption.

  As described above, by dividing the content data into the segments 71 and downloading, the content data (cached content data) used for continuously playing the content increases every time the download of the segment 71 is completed. To do. Here, the segment 71 is divided into N parts having the same size, and cached, which is used to continuously play back the content when downloaded from the server 52-1 to the server 52-N, respectively. If the speed at which the content data increases (hereinafter referred to as the cache increase speed) is M1, the cache increase speed M1 is approximated by the expression (1) (approaches the value expressed by the expression (1)).

  M1≈min (Si) × N (1)

  Here, Si is a download speed at which the client 51 downloads a part from the server 52-i (where 1 ≦ i ≦ N), and min (Si) indicates the lowest download speed among S1 to SN. . Here, the download speed refers to a bit rate at which the client 51 downloads data (part) from the server 52.

  Therefore, for example, in the example of FIG. 4, the download speed S2 of the part 102 is smaller (slower) than the download speed S1 of the part 101, and the segment 71 is divided into two parts (part 101 and part 102). Therefore, the cache increase speed M1 in the example of FIG. 4 is “2 (S2)” ((S2) × 2) from the equation (1).

  On the other hand, as shown in FIG. 1, when the content data is divided into a plurality of data (segment 71 in the example of FIG. 4) and the divided data is downloaded from the server 52, the cache increase speed M2 is, for example, It is approximated by equation (2).

  M2≈S1 (2)

  Here, S1 indicates the download speed of the data at the part where the reproduction of the content is started. That is, in the example of FIG. 1, it becomes the download speed of the data 11-1. In more detail, in the example of FIG. 1, when the download of the data 11-1 is completed, for example, until the download of the data 11-2 is completed, the cache increase speed M2 is Download speed.

  Therefore, it is assumed that the download speeds of all parts or data are equal, that is, Si in equation (1) is equal to S1 in equation (2) (eg, “Si = S1”). When the cache increase speed M1 and the cache increase speed M2 are compared, the value of M1 is “NS1” (S1 × N), and the value of M2 is S1, so that the value of M1 is N of the value of M2. Doubled.

  In this way, the content data is divided into segments 71, and further, the segments 71 are divided into a plurality of parts each having the same size, and each part is downloaded from a plurality of servers 52, thereby increasing the cache increase rate. Can be bigger. As a result, the client 51 can store (secure) more cached content data that is used to continuously play back content, which causes a problem in the server 52 and the communication network 53. In such a case, it is possible to further reduce the possibility that the reproduction of the content is interrupted.

  By the way, in FIG. 4, since the part 101-4 and the part 101-5 are not downloaded, the part from the reproduction time t34 to the reproduction time t35 of the part 102-3 is not downloaded. It cannot be used as data for reproducing the corresponding content.

  This is because, even though the download speed of part 101 and the download speed of part 102 are different, segment 71 is divided (divided) into part 101 and part 102 of the same size. Therefore, as shown in FIG. 5, by determining the size of each part according to the download speed of the part, the cache increase rate can be further increased. That is, the amount of content data (cached content data) that can be used for continuous content playback relative to the amount of content data that has been downloaded by changing the size of the part according to the part download speed The ratio of can be increased.

  In FIG. 5, the horizontal axis indicates the playback time of the content that is played back based on the content data. When playing back the content (content data), playback of the content starts from the playback time t50 portion. Playback ends at time t53.

  Also, among the parts 111-1 to 111-6 and the parts 112-1 to 112-6, the black part indicates a part that has already been downloaded from the server 52, and the white part indicates the server 52. The part which has not been downloaded from, that is, the part which has not been downloaded yet is shown.

  The client 51 first divides the segment 71-1 into a part 111-1 and a part 112-1 having the same size. Then, the client 51 assigns the transmission of the part 111-1 to the server 52-1, assigns the transmission of the part 112-1 to the server 52-2, downloads the part 111-1 from the server 52-1, and transmits the part 112-1. -1 is downloaded from the server 52-2.

  Next, when the download of the part 111-1 and the part 112-1 is completed, the client 51 transfers the segment 71-2 to the part 111- based on the download speed of the part 111-1 and the download speed of the part 112-1. 2 and part 112-2. Here, for example, when the download speed of the part 111-1 is higher than the download speed of the part 112-1, the client 51 is set so that the size of the part 111-2 is larger than the size of the part 112-2. The segment 71-2 is divided into a part 111-2 and a part 112-2.

  In more detail, when the download of part 111-1 and part 112-1 is completed, the client 51 determines the segment 71-2 based on the download speed of part 111-1 and the download speed of part 112-1. Or segment 71-6 is divided into part 111-2 to part 111-6 and part 112-2 to part 112-6, respectively.

  Then, the client 51 assigns the transmission of the part 111-2 to the server 52-1, assigns the transmission of the part 112-2 to the server 52-2, downloads the part 111-2 from the server 52-1, and the part 112. -2 is downloaded from the server 52-2.

  When the downloading of the part 111-2 and the part 112-2 is completed, the client 51, like the case where the segment 71-2 is divided into the part 111-2 and the part 112-2, is the part 111-2 and the part 112-. 2, segment 71-3 is divided into part 111-3 and part 112-3, part 111-3 is downloaded from server 52-1, and part 112-3 is downloaded from server 52-. Download from 2.

  Further, the client 51 assigns each of the segments 71-4 to 71-6 to the part 111 based on the download speed of each of the parts 111-3 to 111-5 and the parts 112-3 to 112-5. -4 to part 111-6 and part 112-4 to part 112-6.

  Then, the client 51 downloads the parts 111-4 to 111-6 in order from the server 52-1, and downloads the parts 112-4 to 112-6 in order from the server 52-2. To do. Hereinafter, each of the parts 111-1 to 111-6 is simply referred to as a part 111 when it is not necessary to individually distinguish them. Hereinafter, each of the parts 112-1 to 112-6 will be simply referred to as a part 112 when it is not necessary to individually distinguish them.

  In the example of FIG. 5, the client 51 has already downloaded the parts 111-1 to 111-4 from the server 52-1, and the server 112-of the parts 112-1 to 112-4. Download from 2 is complete. Therefore, in this case, the client 51 can continuously reproduce the content by using the content data of the segments 71-1 to 71-4. That is, the user can continuously view the content corresponding to the content data from the reproduction time t50 to the reproduction time t52.

  For example, assuming that the portion corresponding to the reproduction time t51 of the content is being reproduced at the present time, since the portion of the content data from the reproduction time t50 to the reproduction time t52 has been downloaded, the server 52 and the communication Even if a problem occurs in the network 53 and the download of the part 111 or the part 112 is interrupted, the client 51 can reproduce at least the part corresponding to the content reproduction time t52. Therefore, if the download of the part 111 or the part 112 is resumed before the reproduction of the portion corresponding to the content reproduction time t52 is completed, the content can be reproduced without interruption.

  Here, as shown in FIG. 5, the segment 71 to be downloaded next is divided into N parts based on the download speed of each of the N parts constituting one segment 71 that has already been downloaded. Then, the cache increase speed M3 when the parts are downloaded from the servers 52-1 to 52-N can be approximated by the equation (3) (each of the servers 52-1 to 52-N). When the variance of the transmission capability is minimal, it approaches the value represented by equation (3)).

  M3≈ΣSi (3)

  In Equation (3), Si is a download speed at which the client 51 downloads a part from the server 52-i (where 1 ≦ i ≦ N), and Σ is Si obtained by changing i from 1 to N. Represents the sum (total) of

  Therefore, for example, in the example of FIG. 5, if the download speed of part 111 is S1, and the download speed of part 112 is S2, M3 is (S1 + S2).

  Also, the download speed of part 101 in FIG. 4 is equal to the download speed of part 111 in FIG. 5 (for example, S1). Furthermore, the download speed of part 102 in FIG. 4 and the download speed of part 112 in FIG. Are compared (for example, S2), the cache increase rate M1 in the example of FIG. 4 is compared with the cache increase rate M3 in the example of FIG. At this time, for example, if S1 is larger than S2, the value of M1 is “2 (S2)” (S2 × 2), the value of M3 is (S1 + S2), and the value of M3 is “ It becomes larger by (S1-S2) "((S1 + S2) -2 (S2)). Therefore, content that can be used for continuous content reproduction with respect to the amount of content data that has been downloaded by changing the size of the part of the segment to be downloaded next in accordance with the download speed of the already downloaded part. The ratio of the amount of data can be increased. That is, the portion of content data that has been downloaded that cannot be used for continuous content playback can be reduced, and the amount of cached content data can be made closer to the amount of content data that has been downloaded. .

  In this way, by determining the size of each part according to the download speed of the part, the cache increase speed can be further increased. As a result, the client 51 can store (reserve) more content data used to continuously play back content, so that when a problem occurs in the server 52 or the communication network 53, The possibility that content reproduction is interrupted can be further reduced.

  Next, FIG. 6 is a block diagram illustrating an example of the configuration of the client 51.

  The CPU 131 executes various processes according to a program recorded in a ROM (Read Only Memory) 132 or a recording unit 138. A RAM (Random Access Memory) 133 appropriately stores programs executed by the CPU 131 and data. The CPU 131, the ROM 132, and the RAM 133 are connected to each other by a bus 134.

  An input / output interface 135 is also connected to the CPU 131 via the bus 134. Connected to the input / output interface 135 are an input unit 136 composed of a keyboard, mouse, switch, and the like, and an output unit 137 composed of a display, a speaker, a lamp, and the like. The CPU 131 executes various processes in response to commands input from the input unit 136.

  The recording unit 138 connected to the input / output interface 135 is configured by a hard disk, for example, and records programs executed by the CPU 131 and various data. The communication unit 139 includes a network card, for example, and communicates with an external device via a communication network 53 such as the Internet or other networks.

  In addition, the communication unit 139 may acquire a program via the communication network 53 and cause the recording unit 138 to record the program.

  The drive 140 connected to the input / output interface 135 drives the magnetic disk 161, the optical disk 162, the magneto-optical disk 163, or the semiconductor memory 164 when they are mounted, and programs and data recorded there. Get etc. The acquired program and data are transferred to the recording unit 138 and recorded as necessary.

  Since the server 52 is configured in the same manner as the client 51, the description thereof is omitted.

  FIG. 7 is a block diagram illustrating functional configurations of the client 51 and the server 52 that are realized by the CPU 131 of the client 51 and the CPU of the server 52 executing programs.

  When the user instructs the client 51 to download predetermined content data, the client 51 establishes a connection with the server 52 in order to communicate with the server 52 that records the content data instructed to be downloaded by the user. . In the following, as an example in which the client 51 establishes a connection with the server 52, a case where a connection is established in a so-called two way will be described. However, a connection can be established in a so-called three way.

  That is, the client 51 generates a communication request signal for requesting the start of communication, and transmits the generated communication request signal to the server 52 via the communication network 53. The server 52 receives the communication request signal transmitted from the client 51. When the server 52 receives the communication request signal, the server 52 generates a response signal indicating that the communication request signal has been received, and transmits the generated response signal to the client 51 via the communication network 53.

  Since the response signal is transmitted from the server 52, the client 51 receives the response signal transmitted from the server 52. Since the connection with the server 52 is established by receiving the response signal, the client 51 divides the content data instructed to be downloaded by the user into segments, and further divides the segments into parts. The transmission is assigned to one of the servers 52-1 to 52-N, respectively. Then, the client 51 generates a transmission request signal for requesting transmission of a part (content data) assigned to each of the servers 52.

  The client 51 transmits the generated transmission request signal to the server 52 via the communication network 53, respectively. The server 52 receives the transmission request signal transmitted from the client 51 and transmits the part (part) requested from the client 51 in the recorded content data to the client 51 via the communication network 53. To do. Then, the client 51 receives the content data (part) transmitted from the server 52.

  The client 51 is configured to include a management unit 181, an allocation unit 182, communication control units 183-1 to 183 -N, and a reconfiguration unit 184.

  The management unit 181 controls (mediates) data exchange between an upper layer such as an application program (not shown) and the allocation unit 182 and the reconfiguration unit 184. The management unit 181 includes a registration control unit 201 and a content output unit 202.

  When the user instructs download of desired content data, for example, the management unit 181 sends the number of servers 52 as transmission nodes connected to the client 51 via the communication network 53 from the application program, that is, the user Node information is supplied, including the number of servers 52 that record the desired content data, the IP (Internet Protocol) address of the server 52, the data transmission capability determined from the processing capability of the server 52, etc. Is done. In addition, the application program notifies the management unit 181 of the node data, the information specifying the content data instructed to be downloaded by the user, the size of the content data (data size), the number of segments into which the content data is divided, 1 Initial setting information including the size (data size) of one segment is supplied.

  Further, after the application program supplies the node information to the management unit 181, when a server 52 that records content data desired by the user is newly detected, the application program sends a new information to the management unit 181. Additional node information including the detected IP address of the server 52 and the transmission capability of the server 52 is supplied.

  The registration control unit 201 of the management unit 181 supplies node information, initial setting information, or additional node information supplied from the application program to the allocation unit 182. In addition, the content output unit 202 of the management unit 181 supplies the content data (packet storing the content data) supplied from the reconfiguration unit 184 to the application program.

  The allocation unit 182 stores the node information supplied from the management unit 181. When the additional node information is supplied from the management unit 181, the allocating unit 182 updates the node information so that the information included in the supplied additional node information is included in the stored node information. The assigning unit 182 stores the initial setting information supplied from the management unit 181 and supplies the initial setting information to the communication control units 183-1 to 183-N.

  Furthermore, when the connection between the client 51 and each of the servers 52-1 to 52-N is established, the assignment unit 182 receives a connection from each of the communication control units 183-1 to 183-N. A signal indicating that has been established is supplied. The allocation unit 182 specifies the part of the content data allocated to the server 52 when a signal indicating that the connection is established is supplied from each of the communication control units 183-1 to 183-N. The allocation information including the information to be generated is generated, and the generated allocation information is supplied to each of the communication control units 183-1 to 183-N.

  In other words, from the assignment unit 182 to each of the communication control unit 183-1 to the communication control unit 183-N, the server 52-1 to the server 52 with which each of the communication control unit 183-1 to the communication control unit 183-N communicates. Allocation information including information identifying the part of the content data allocated to each of -N is supplied. Hereinafter, when it is not necessary to individually distinguish each of the communication control units 183-1 to 183-N, they are simply referred to as a communication control unit 183.

  The allocation unit 182 updates the reception history based on the reception information supplied from each of the communication control units 183-1 to 183-N. Here, the reception information is information including information for identifying a part received by the communication control unit 183 from the server 52, a download speed of the part, and the like. Each time the control unit 183 completes downloading (reception) of a part, reception information including the download speed of the part is supplied. Although details of the reception history will be described later, the reception history includes reception information for each segment (part) of each server 52.

  The communication control unit 183-1 controls transmission / reception of data with the server 52-1. The transmission control unit 183-1 includes a transmission unit 203-1 and a reception unit 204-1.

  The communication control unit 183-1 temporarily stores the initial setting information supplied from the assigning unit 182, and generates a communication request signal in order to establish a connection with the server 52-1. The transmission unit 203-1 of the communication control unit 183-1 transmits the communication request signal generated by the communication control unit 183-1 to the server 52-1 via the communication network 53.

  The receiving unit 204-1 of the communication control unit 183-1 receives the response signal transmitted from the server 52-1. When the communication control unit 183-1 receives the response signal, the communication control unit 183-1 generates a signal indicating that the connection has been established, and supplies the signal indicating that the generated connection has been established to the allocation unit 182.

  When the allocation information is supplied from the allocation unit 182, the communication control unit 183-1 generates a transmission request signal including the allocation information. The transmission unit 203-1 of the communication control unit 183-1 transmits the transmission request signal generated by the communication control unit 183-1 to the server 52-1 via the communication network 53.

  The receiving unit 204-1 of the communication control unit 183-1 receives the content data transmitted from the server 52-1. More specifically, the receiving unit 204-1 of the communication control unit 183-1 receives a packet storing content data (part thereof) transmitted from the server 52-1. The communication control unit 183-1 supplies the packet storing the received content data to the reconfiguration unit 184.

  Further, when the server 52-1 transmits the requested content data (part thereof), an end notification signal indicating that the transmission of the part has ended is transmitted from the server 52-1, so that the communication control unit 183-1 is transmitted. The receiving unit 204-1 receives the end notification signal transmitted from the server 52-1. When receiving the end notification signal, the communication control unit 183-1 generates reception information including the download speed of the received part and supplies the generated reception information to the allocation unit 182.

  Each of the communication control units 183-2 to 183-N controls data transmission / reception with each of the servers 52-2 to 52-N. The communication control units 183-2 through 183-N include transmission units 203-2 through 203-N and reception units 204-2 through 204-N, respectively.

  Each of the communication control units 183-2 to 183 -N temporarily stores the initial setting information supplied from the allocation unit 182, and establishes connections with the servers 52-2 to 52 -N, respectively. In order to establish, a communication request signal is generated. The transmission unit 203-2 to the communication control unit 183-N of the communication control unit 183-2 transmits the communication request signal generated by each of the communication control unit 183-2 to the communication control unit 183-N. The data is transmitted to the servers 52-2 to 52-N via the communication network 53.

  Each of the receiving unit 204-2 through the communication control unit 183-2 through the receiving unit 204-N through the communication control unit 183-N receives a response signal transmitted from each of the server 52-2 through the server 52-N. . Upon receiving the response signal, each of the communication control units 183-2 to 183 -N generates a signal indicating that the connection has been established, and assigns the generated signal indicating that the connection has been established to the allocating unit 182. To supply.

  When the allocation information is supplied from the allocation unit 182, each of the communication control units 183-2 to 183 -N generates a transmission request signal including the allocation information. The transmission unit 203-2 of the communication control unit 183-2 to the transmission unit 203-N of the communication control unit 183-N are respectively transmission request signals generated by the communication control unit 183-2 to the communication control unit 183-N. Is transmitted to the servers 52-2 to 52-N via the communication network 53.

  The receiving unit 204-2 of the communication control unit 183-2 to the receiving unit 204-N of the communication control unit 183-N receives the content data transmitted from the server 52-2 to the server 52-N. More specifically, the reception unit 204-2 of the communication control unit 183-2 to the reception unit 204-N of the communication control unit 183-N transmit content data (from the server 52-2 to the server 52-N) ( Each of the packets storing the part) is received. The communication control units 183-2 to 183 -N supply the packet storing the received content data to the reconfiguration unit 184.

  Further, when each of the servers 52-2 to 52-N transmits the requested content data (part thereof), an end notification that the transmission of the parts from each of the servers 52-2 to 52-N has ended. Since the signal is transmitted, the reception unit 204-2 of the communication control unit 183-2 to the reception unit 204-N of the communication control unit 183-N terminates transmitted from the server 52-2 to the server 52-N. Receive a notification signal. Upon receiving the end notification signal, the communication control units 183-2 to 183 -N generate reception information including the download speed of the received part and supply the generated reception information to the allocation unit 182. To do.

  Hereinafter, when it is not necessary to distinguish each of the transmission unit 203-1 to the transmission unit 203-N, they are simply referred to as the transmission unit 203. Hereinafter, each of the receiving units 204-1 to 204-N is simply referred to as the receiving unit 204 when it is not necessary to individually distinguish them.

  The reconfiguration unit 184 temporarily stores the content data parts (packets) supplied from the communication control unit 183 as necessary, and reconfigures the stored parts into a continuous content data stream. The reconstruction unit 184 includes an output control unit 205 and a storage unit 206.

  When the packet is supplied from the communication control unit 183, the output control unit 205 of the reconstruction unit 184 checks a sequence number indicating the order of reproduction of content data included in the header of the packet. Then, the output control unit 205 of the reconstruction unit 184 has a sequence number included in the packet that is the same as the sequence number to be output stored in the output control unit 205 of the reconstruction unit 184. The packet supplied from the communication control unit 183 is supplied to the management unit 181.

  For example, the sequence number included in the header of the packet is a value representing the start point position of the part stored in the packet. That is, for example, the position of the content data is represented by a value that is incremented every time the data increases by 1 KB, with the leading position of the content data being “0”, and the position of the content data corresponding to the leading position of the part is The start point position of the part. For example, when the start position of the part stored in the packet is “0”, the sequence number of the packet is “0”.

  Therefore, for example, when the sequence number to be output stored in the output control unit 205 of the reconstruction unit 184 is “0” and the sequence number of the packet supplied from the communication control unit 183 is “0”. The output control unit 205 of the reconfiguration unit 184 supplies the packet having the sequence number “0” supplied from the communication control unit 183 to the management unit 181.

  Further, when the output control unit 205 of the reconstruction unit 184 supplies the packet to the management unit 181, the output control unit 205 updates the sequence number to be output. For example, the output control unit 205 of the reconstruction unit 184 supplies a packet with a sequence number “0” to the management unit 181, and the size (size) of the part stored in the packet is “1100 KB”. In this case, the output control unit 205 of the configuration unit 184 increases the sequence number to be output by 1100 to “1100”.

  On the other hand, if the sequence number of the packet supplied from the communication control unit 183 is not the same as the sequence number to be output, the output control unit 205 of the reconfiguration unit 184 determines that the packet supplied from the communication control unit 183 is The data is supplied to the storage unit 206 of the reconstruction unit 184 without being supplied to the management unit 181.

  In addition, the output control unit 205 of the reconfiguration unit 184 acquires, from the storage unit 206, a packet whose sequence number is the same as the sequence number to be output among the packets stored in the storage unit 206. To the management unit 181.

  The storage unit 206 of the reconstruction unit 184 temporarily stores the packet supplied from the output control unit 205 of the reconstruction unit 184. Further, the storage unit 206 of the reconstruction unit 184 supplies the stored packet to the output control unit 205 of the reconstruction unit 184.

  Each of the servers 52-1 to 52-N includes a receiving unit 221-1 to a receiving unit 221-N, an acquiring unit 222-1 to an acquiring unit 222-N, a recording unit 223-1 to a recording unit 223-N, and Transmitters 224-1 to 224-N are provided.

  Each of the reception units 221-1 to 221 -N receives the communication request signal or the transmission request signal transmitted from the client 51, and acquires the received communication request signal or the transmission request signal. Thru | or each acquisition part 222-N.

  Each of the acquisition units 222-1 to 222 -N receives a response signal indicating that the communication request signal has been received when the communication request signal is supplied from each of the reception units 221-1 to 221 -N. The generated response signal is supplied to each of the transmission units 224-1 to 224-N.

  Further, each of the acquisition units 222-1 to 222 -N receives the transmission request signal from each of the reception units 221-1 to 221 -N, the recording unit 223-1 to the recording unit 223. The part of the content data requested to be transmitted is acquired from the content data recorded in each of -N, and the acquired part (content data) is stored in, for example, a TCP packet. At this time, each of the acquisition units 222-1 to 222 -N assigns a sequence number to the packet storing the part based on the transmission request signal, and stores the sequence number in the packet header. . Each of the acquisition units 222-1 to 222 -N supplies a packet storing the content data part to each of the transmission units 224-1 to 224 -N.

  Each of the recording units 223-1 to 223-N records content data. Each of the recording units 223-1 to 223-N supplies the recorded content data (a part (part) thereof) to each of the acquisition units 222-1 to 222-N.

  Each of the transmission unit 224-1 to transmission unit 224-N transmits the packet or the response signal stored in the content data supplied from each of the acquisition unit 222-1 to acquisition unit 222-N to the communication network 53. To the client 51 via

  Hereinafter, each of the reception units 221-1 to 221 -N is simply referred to as a reception unit 221 when it is not necessary to individually distinguish them. Hereinafter, the acquisition units 222-1 to 222 -N will be simply referred to as the acquisition unit 222 when it is not necessary to individually distinguish them.

  Further, hereinafter, each of the recording units 223-1 to 223-N is simply referred to as a recording unit 223 when it is not necessary to individually distinguish them. Furthermore, hereinafter, each of the transmission units 224-1 to 224-N is simply referred to as a transmission unit 224 when it is not necessary to distinguish them individually.

  FIG. 8 is a block diagram illustrating a functional configuration of the assignment unit 182 of FIG.

  The allocation unit 182 is configured to include a setting unit 251, a node information storage unit 252, a calculation unit 253, a reallocation control unit 254, and a reception history storage unit 255.

  The setting unit 251 supplies the node information supplied from the management unit 181 to the node information storage unit 252 for storage. Further, when the additional node information is supplied from the management unit 181, the setting unit 251 supplies the supplied additional node information to the node information storage unit 252, and causes the node information storage unit 252 to store the additional node information based on the additional node information. Update node information.

  Further, the setting unit 251 supplies the initial setting information supplied from the management unit 181 to the calculation unit 253 and the communication control unit 183. When the signal indicating that the connection has been established is supplied from the communication control unit 183, the setting unit 251 generates a signal instructing the start of downloading content data and supplies the signal to the calculation unit 253.

  The node information storage unit 252 stores the node information supplied from the setting unit 251 under the control of the setting unit 251. As described above, the node information includes the number of servers 52 as transmission nodes, the transmission capability of the servers 52, the IP address of the server 52, and the like. Further, the node information storage unit 252 updates the stored node information based on the additional node information supplied from the setting unit 251 under the control of the setting unit 251.

  The calculation unit 253 temporarily stores the initial setting information supplied from the setting unit 251. In addition, when the setting unit 251 receives a signal instructing the start of downloading content data, the calculation unit 253 refers to the initial setting information and the node information stored in the node information storage unit 252. The content data instructed to be downloaded is divided into a plurality of segments in accordance with the initial setting information, and each segment is further divided into the number of parts of the server 52 as a transmission node included in the node information. More specifically, the calculation unit 253 designates a division position at which the content data instructed to be downloaded is divided into a plurality of segments according to the initial setting information, and further, the number of servers 52 as transmission nodes is determined for each segment. Specify the division position to divide into parts.

  Then, the calculation unit 253 transmits the part of the first segment (for example, the segment 71-1 in the example of FIG. 5) including the data (content data) of the part to start reproduction to different servers. 52, the allocation information for specifying the allocated part is generated. Then, the calculation unit 253 supplies the generated allocation information to the communication control unit 183.

  Hereinafter, the segment including the data (content data) of the portion where playback is started is referred to as the first segment, in the order of downloading from the first segment (in the order of playback), nth (where n is (Integer) segment.

  Further, the calculation unit 253 instructs reassignment for downloading the parts of the second and subsequent segments (for example, the segment 71-2 to the segment 71-6 in the example of FIG. 5) from the reassignment control unit 254. When a signal is supplied, a segment that has not yet been downloaded with reference to the initial setting information, the node information stored in the node information storage unit 252 and the reception history stored in the reception history storage unit 255 Is re-divided into the number of parts of the server 52 as the transmission node included in the node information (re-designation of the division position). Then, the calculation unit 253 allocates the transmission of the part of the segment to be downloaded next to each different server 52, and generates allocation information for specifying the allocated part. Then, the calculation unit 253 supplies the generated allocation information to the communication control unit 183.

  Hereinafter, the process of re-dividing the second and subsequent segments into a plurality of parts and allocating the transmission of each part to the server 52 is also referred to as reassignment.

  The reallocation control unit 254 supplies the reception information supplied from the communication control unit 183 to the reception history storage unit 255, and the reception history storage unit 255 stores the reception history storage unit 255 based on the supplied reception information. Update the received reception history.

  The reassignment control unit 254 updates the reception history storage unit 255 to update the reception history, generates a signal instructing reassignment, and supplies the generated signal instructing reassignment to the calculation unit 253. In addition, when the download of the content data is completed (terminated), the reallocation control unit 254 generates a signal indicating that the download of the content data is completed, and supplies the signal indicating that the generated download is complete to the setting unit 251. .

  The reception history storage unit 255 stores a reception history. As described above, the reception history includes reception information for each segment (part) of each server 52. The reception history storage unit 255 updates the stored reception history based on the reception information supplied from the reallocation control unit 254 under the control of the reallocation control unit 254.

  Next, referring to the flowchart of FIG. 9, when content data is divided into two segments, the content data received by the client 51 to be described later, and the server 52 receives the content data requested from the client 51. An outline of the transmission process will be described. In the description of the flowchart of FIG. 9, the client 51 explains the process of downloading the content data part from one server 52. In practice, however, the client 51 includes a plurality of servers. The process of downloading the part of the content data from 52 is executed.

  When the initial setting information is supplied from the management unit 181 to the assignment unit 182, the assignment unit 182 stores the supplied initial setting information and supplies the initial setting information to the communication control unit 183 in step S <b> 11. When the initial setting information is supplied from the assigning unit 182 to the communication control unit 183, the communication control unit 183 generates a communication request signal and establishes the communication network 53 in order to establish a connection with the server 52 in step S12. To the server 52.

  In step S41, the server 52 receives the communication request signal transmitted from the client 51, and generates a response signal indicating that the communication request signal has been received. In step S <b> 42, the server 52 transmits the generated response signal to the client 51 via the communication network 53.

  In step S <b> 13, the communication control unit 183 receives the response signal transmitted from the server 52. Thereby, since the connection between the client 51 and the server 52 is established, in step S14, the communication control unit 183 generates a signal indicating that the connection is established and supplies the signal to the assignment unit 182.

  When a signal indicating that a connection has been established is supplied from the communication control unit 183 to the allocation unit 182, the allocation unit 182 generates allocation information and supplies the generated allocation information to the communication control unit 183 in step S <b> 15. To do. In step S <b> 16, the communication control unit 183 generates a transmission request signal including the allocation information supplied from the allocation unit 182, and transmits the generated transmission request signal to the server 52 via the communication network 53.

  In step S <b> 43, the server 52 receives the transmission request signal transmitted from the client 51. In step S <b> 44, the server 52 transmits the part of the content data requested to be transmitted from the client 51 to the client 51 via the communication network 53.

  In step S <b> 17, the communication control unit 183 receives the part transmitted from the server 52 and supplies it to the reconfiguration unit 184. The reconfiguration unit 184 temporarily stores the part supplied from the communication control unit 183 as necessary, and supplies the part to the application program via the management unit 181.

  When the transmission of the part is completed, the server 52 transmits an end notification signal indicating that the transmission of the part is completed to the client 51 via the communication network 53 in step S45. In step S <b> 18, the communication control unit 183 receives the end notification signal transmitted from the server 52. In step S <b> 19, the communication control unit 183 generates reception information and supplies it to the allocation unit 182.

  In step S <b> 20, the assigning unit 182 updates the reception history based on the reception information supplied from the communication control unit 183. Then, the assignment unit 182 performs reassignment in order to download the part of the second segment, generates assignment information, and supplies it to the communication control unit 183. Note that the processing from step S21 to step S24 and the processing from step S46 to step S48 are the same as the processing from step S16 to step S19 and the processing from step S43 to step S45, respectively, and therefore description thereof is omitted. To do.

  In this way, the client 51 divides the content data into a plurality of segments, and further divides each segment into a plurality of parts and downloads it from the server 52. Further, the server 52 transmits a part (part) requested from the client 51 of the recorded content data to the client 51.

  When the initial setting information and the node information are supplied from the management unit 181 to the setting unit 251 of the allocating unit 182, the client 51 performs a process of updating the node information (a process of updating the node information described later). The process of receiving content data is executed.

  First, with reference to the flowchart of FIG. 10, the details of the content data reception processing by the client 51 described in FIG. 9 will be described.

  In step S <b> 61, the setting unit 251 supplies the initial setting information supplied from the management unit 181 to the calculation unit 253 and the communication control unit 183. The calculation unit 253 stores the initial setting information supplied from the setting unit 251.

  In step S <b> 62, the communication control unit 183 establishes a connection with the server 52. That is, the communication control unit 183 stores the initial setting information supplied from the setting unit 251 and further generates a communication request signal. The transmission unit 203 of the communication control unit 183 transmits the communication request signal generated by the communication control unit 183 to the server 52 via the communication network 53. Then, when a response signal is transmitted from the server 52 according to this, the receiving unit 204 of the communication control unit 183 receives the response signal transmitted from the server 52. When receiving the response signal, the communication control unit 183 generates a signal indicating that the connection has been established, and supplies the signal to the allocation unit 182.

  When a signal indicating that a connection has been established is supplied from the communication control unit 183, in step S63, the setting unit 251 generates a signal instructing the start of download, and generates a signal instructing the start of the generated download. , And supplied to the calculation unit 253.

  When a signal instructing the start of download is supplied from the setting unit 251 to the calculation unit 253, the start of download is instructed. In step S64, the calculation unit 253 stores the stored initial setting information and the node The node information stored in the information storage unit 252 is referred to generate allocation information, and the generated allocation information is supplied to the communication control unit 183.

  For example, the initial setting information includes information in which the size of one segment is “2300 KB” and the number of segments into which content data is divided is “6”, and is included in the node information. When the number of servers 52 as nodes is “2”, the calculation unit 253 sets the size of one segment to 2300 KB, and, as shown in FIG. 1 to segment 71-6 (the division position is designated so as to be divided into segment 71-1 to segment 71-6).

  Next, the calculation unit 253 divides the segment 71 into the number of servers 52 as transmission nodes (designates a division position). That is, the calculation unit 253 designates the division position so that the segment 71 is divided into two parts 111 and 112. At this time, the calculation unit 253 divides the segment 71 so that the sizes of the part 111 and the part 112 are equal. Therefore, in this case, the calculation unit 253 divides the segment 71 so that the sizes of the part 111 and the part 112 are 1150 KB (2300/2), respectively.

  When the segment 71 is divided, the calculation unit 253 assigns the transmission of the part 111 to, for example, the server 52-1, and assigns the transmission of the part 112 to the server 52-2 different from the server 52-1. Then, the calculation unit 253 generates allocation information for specifying the part 111-1 and allocation information for specifying the part 112-1. The calculation unit 253 supplies the generated allocation information for specifying the part 111-1 to the communication control unit 183-1 and supplies the allocation information for specifying the part 112-1 to the communication control unit 183-2. Supply.

  For example, as shown in FIG. 11, the allocation information includes information for specifying the content data to be downloaded, information indicating the size of the segment into which the content data is divided, information for specifying the segment, and the start position of the part And information indicating the end point position of the part.

  In the example of FIG. 11, the content data to be downloaded includes information that is content data A, and information that includes a segment size that divides the content data is 2300 KB.

  Further, “1/6” is included as information for specifying a segment. Here, “1/6” indicates that the segment specified by this information is the first (first) segment of the six segments constituting the content data. Therefore, for example, in FIG. 5, the first segment is a segment 71-that includes data at a position where reproduction is started among the segments 71 constituting the content data, that is, data corresponding to the recurrent time t50. Say 1.

  Further, the allocation information shown in FIG. 11 includes information where the start position of the part is “0” and information where the end position of the part is “1150”. Here, the start point position and end point position of the part are represented by values that are incremented every time the data increases by 1 KB, with the leading position of the content data being “0”. Therefore, in this case, the part having the start point position “0” and the end point position “1150” is data of 1150 KB from the top of the content data. That is, this part is data having a size of 1150 KB, with the beginning of the content data being the beginning (starting position) of the part.

  Returning to the description of the flowchart of FIG. 10, in step S65, the communication control unit 183 generates a transmission request signal including the allocation information supplied from the calculation unit 253, and the transmission unit 203 of the communication control unit 183 controls the communication control. The transmission request signal generated by the unit 183 is transmitted to the server 52 via the communication network 53.

  When the server 52 receives the transmission request signal, the server 52 transmits the part of the content data requested to be transmitted. Accordingly, the reception unit 204 of the communication control unit 183 is transmitted from the server 52 in step S66. Receive the content data part. Then, the communication control unit 183 supplies the received part to the reconstruction unit 184.

  In addition, when the transmission of the content data part is completed in the server 52, the server 52 transmits an end notification signal. Therefore, the reception unit 204 of the communication control unit 183 is transmitted from the server 52 in step S67. Receives an end notification signal.

  In step S68, the communication control unit 183 generates part reception information received by the reception unit 204 of the communication control unit 183, and supplies the generated reception information to the allocation unit 182. For example, in step S68, the communication control unit 183 generates reception information illustrated in FIG.

  The received information includes information for identifying a server as a transmitting node that has transmitted the part, information for identifying a segment including the received part, information indicating a start position of the received part, and an end point of the received part Information indicating the position, information indicating the download speed of the downloaded part, and information indicating the magnitude of fluctuation in throughput of the process of downloading the part are included.

  In FIG. 12, the reception information includes information specifying a server as a transmission node, which is “server P”, and information specifying a segment which is “1/6”. Here, “1/6” represents the first segment among the six segments constituting the content data. The received information includes information indicating the start position of the part that is “0”, information indicating the end position of the part that is “1150”, information indicating the download speed that is “3 Mbps”, and “0 Mbps”. Information indicating the magnitude of the variation in throughput is included.

  As described above, the part whose start point position is “0” and end point position is “1150” is data of 1150 KB from the top of the content data. Further, the received information may include a variance value of the variation in throughput instead of the magnitude (absolute value) of the variation in throughput.

  Returning to the description of FIG. 10, in step S69, the reallocation control unit 254 supplies the reception information supplied from the communication control unit 183 to the reception history storage unit 255, and updates the reception history to the reception history storage unit 255. Let

  Here, for example, as shown in FIG. 13, the reception history includes the reception information of the parts constituting each segment. In FIG. 13, the reception information of the parts constituting the first segment and the reception information of the parts constituting the second segment are included. In addition, as the reception information of the parts constituting the first segment, the reception information of the parts received from “Server P” and the reception information of the parts received from “Server Q” are included.

  Of the reception information of the parts constituting the first segment, the reception information of the part received from “Server P” includes information indicating the start point position of the part “0”, and the end point position of the part “1150”. , Information indicating the download speed of “3 Mbps”, and information indicating the magnitude of the variation in throughput of “0 Mbps” are included, and the reception information of the part received from “Server Q” includes: Information indicating the start position of the part that is “1150”, information that indicates the end position of the part that is “2300”, information that indicates the download speed that is “2 Mbps”, and the magnitude of the fluctuation of the throughput that is “0 Mbps” Contains information to indicate.

  In addition, as the reception information of the part constituting the second segment, the reception information of the part received from “Server P” and the reception information of the part received from “Server Q” are included. Among the reception information of the parts constituting the second segment, the reception information of the part received from “Server P” includes the information indicating the start position of the part “2300” and the end position of the part “3680”. , Information indicating the download speed of “3 Mbps”, and information indicating the magnitude of the variation in throughput of “0 Mbps” are included, and the reception information of the part received from “Server Q” includes: Information indicating the start position of the part that is “3680”, information that indicates the end position of the part that is “4600”, information that indicates the download speed that is “3 Mbps”, and the magnitude of the fluctuation of the throughput that is “1 Mbps” Contains information to indicate.

  Returning to the description of FIG. 10, in step S <b> 70, the reallocation control unit 254 refers to the reception history stored in the reception history storage unit 255 and determines whether or not the download of the content data is completed (finished). To do. For example, when the reception history storage unit 255 stores the reception history shown in FIG. 13, the content data is divided into six segments, and the download of the first segment and the second segment is completed. However, since the download of the third to sixth segments has not been completed, the reallocation control unit 254 determines that the download of the content data has not been completed.

  If it is determined in step S70 that the download of the content data has not been completed, the process proceeds to step S71, and the reallocation control unit 254 generates a signal for instructing reallocation to reallocate transmission of the part, A signal instructing the generated reallocation is supplied to the calculation unit 253.

  When a signal for instructing reassignment is supplied from the reassignment control unit 254 to the calculation unit 253, in step S72, the calculation unit 253 is instructed to reassign part transmission. Referring to the node information stored in the storage unit 252 and the reception history stored in the reception history storage unit 255, segments that have not yet been downloaded are divided into parts, and allocation information for each part is generated. To do. Then, the calculation unit 253 supplies the generated allocation information to the communication control unit 183, returns to step S65, and repeats the above-described processing.

  For example, in the content data illustrated in FIG. 5, when the download of the segment 71-1 is finished and the download of the segments 71-2 to 71-6 is not finished, the calculation unit 253 receives the node information and the reception With reference to the history, each of the segments 71-2 to 71-6 is divided into the numbers indicated by the number of servers 52 as transmission nodes included in the node information.

  For example, when the number of servers 52 as transmission nodes included in the node information is “2”, the calculation unit 253 divides each of the segments 71-2 to 71-6 into two parts. At this time, the size of the part is determined by, for example, calculating Equation (4) based on the part download speed included in the reception history.

  Pi = Vi × D / (ΣVi) (4)

  Here, Pi represents the size of the part assigned to the server 52-i (where 1 ≦ i ≦ N), and Vi represents the download speed of the part downloaded from the server 52-i last time. . Σ represents taking the sum (total) of Vi by changing i from 1 to N, and D represents the size of the segment.

  Therefore, for example, the size of the segment 71 shown in FIG. 5 is 2300 KB, the download speed from the server 52-1 of the part 111-1 is “3 Mbps”, and the download from the server 52-2 of the part 112-1 is performed. The speed is “2 Mbps”, and the segments 71-2 through 71-6 are further divided into parts 111-2 through 111-6 and parts 112-2 through 112-6, respectively. -2 to part 111-6 are downloaded from the server 52-1, and when the parts 112-2 to 112-6 are downloaded from the server 52-2, the sizes of the parts 111-2 to 111-6 are as follows. From the formula (4), it is calculated as 1380 KB (3 × 2300 / (2 + 3)).

  Then, when dividing the segments 71-2 to 71-6, the calculation unit 253 allocates transmission of the part 111 to the server 52-1, and allocates transmission of the part 112 to the server 52-2. Then, the calculation unit 253 generates allocation information for specifying the part 111-2 and allocation information for specifying the part 112-2, respectively. The calculation unit 253 supplies the generated allocation information for specifying the part 111-2 to the communication control unit 183-1 and supplies the allocation information for specifying the part 112-2 to the communication control unit 183-2. Supply.

  In addition, when dividing a segment into parts, it was explained that the size of the part is determined based on the size of the segment and the download speed. For example, using the magnitude of the fluctuation of the throughput included in the reception history The part size allocated to the server 52 may be changed. In this case, for example, a larger part (transmission) is assigned to the server 52 with less variation in throughput. That is, a part (transmission) that is smaller than the transmission capability of the server 52 is assigned to the server 52 with a large variation in throughput.

  When reassignment is performed, when the node information in the node information storage unit 252 is updated and the server 52 as a new transmission node is added, the download speed from the newly added server 52 is determined in advance. Equation (4) is calculated using the given value, and reallocation is performed. Therefore, for example, when the information of the server 52-3 is newly added to the node information, the expression (4) is calculated by setting the value of the download speed V3 to 2 Mbps in the expression (4), for example. Furthermore, it is also possible to perform reassignment processing every time a predetermined time elapses.

  Returning to the description of FIG. 10, if it is determined in step S70 that the download of the content data has been completed, the content data reception process ends.

  In this way, the client 51 divides the content data into a plurality of segments (specifies the division position to be divided), and further divides each segment into a plurality of parts (specifies the division position to be divided). Each transmission of the parts to be configured is assigned to a different server 52. Then, the client 51 downloads each assigned part from the server 52.

  In this way, the content data is divided into a plurality of segments, each segment is further divided into a plurality of parts, and each part constituting one segment is downloaded from a different server 52. 51 can download content data more quickly.

  In addition, each segment is divided into multiple parts, and the size of each part is determined according to the download speed of the part downloaded last time, so the content data can be downloaded more efficiently. As a result, the ratio of the amount of content data that can be used for continuous content reproduction to the amount of content data that has been downloaded can be further increased. Thereby, when a problem occurs in the server 52 and the communication network 53, it is possible to further reduce the possibility that the reproduction of the content is interrupted.

  Next, referring to the flowchart of FIG. 14, when initial setting information and node information are supplied from the management unit 181 to the setting unit 251 of the allocation unit 182, the processing is executed in parallel with the content data reception process. The node information update process performed by the client 51 will be described.

  In step S91, the setting unit 251 supplies the node information supplied from the management unit 181 to the node information storage unit 252, and stores the supplied node information in the node information storage unit 252. The node information includes the number of servers 52 connected to the client 51 via the communication network 53 and recording content data desired by the user, the IP address of the server 52, the transmission capability of the server 52, and the like. ing.

  In step S <b> 92, the setting unit 251 determines whether additional node information is supplied from the management unit 181. If it is determined in step S92 that the additional node information has been supplied, the process proceeds to step S93, where the setting unit 251 supplies the additional node information supplied from the management unit 181 to the node information storage unit 252, and the node information storage unit In 252, the node information is updated based on the supplied additional node information, and the process proceeds to step S 94.

  For example, in step S <b> 93, the setting unit 251 stores the node information stored in the node information storage unit 252 including information such as the transmission capability and IP address of the newly detected server 52 included in the additional node information. The node information storage unit 252 updates the node information so that the node information is added to the node information.

  On the other hand, if it is determined in step S92 that the additional node information is not supplied, the node information is not updated, so the process of step S93 is skipped and the process proceeds to step S94.

  In step S94, the setting unit 251 determines whether or not the content data has been completed based on the signal indicating that the download has been completed, which is supplied from the reallocation control unit 254. If it is determined in step S94 that the download has been completed, it is not necessary to update the node information, and the node information update process ends.

  On the other hand, if it is determined in step S94 that the download has not been completed, the process returns to step S92 and the above-described processing is repeated.

  In this way, the client 51 updates the stored node information. In this way, by updating the node information every time additional node information is supplied, the client 51 can divide and download desired content data from more servers 52.

  As described with reference to the flowchart of FIG. 9, when the client 51 establishes a connection with the server 52, a transmission request signal is transmitted to the server 52, requesting transmission of the part of the content data from the client 51. It will be. The server 52 executes content data transmission processing each time a transmission request signal is transmitted from the client 51.

  With reference to the flowchart of FIG. 15, the content data transmission processing by the server 52 will be described.

  In step S <b> 111, the reception unit 221 receives the transmission request signal transmitted from the client 51, and supplies the received transmission request signal to the acquisition unit 222.

  In step S112, the acquisition unit 222 refers to the transmission request signal supplied from the reception unit 221, acquires the content data part requested for transmission from the storage unit 223, and acquires the acquired content data part. The data is supplied to the transmission unit 224. In addition, the acquisition unit 222 supplies the content data part to the transmission unit 224, generates an end notification signal indicating that the transmission of the content data has ended, and supplies the generated end notification signal to the transmission unit 224.

  For example, when the transmission request signal including the allocation information shown in FIG. 11 is supplied from the reception unit 221, the acquisition unit 222 starts from the content data A stored in the recording unit 223 from the top of the content data A. The data up to this point is acquired (extracted) as a part. More specifically, in step S112, the acquisition unit 222 stores the part acquired from the storage unit 223 in, for example, a TCP packet, and supplies the packet to the transmission unit 224. For example, the acquisition unit 222 stores a sequence number having the same value as the start point position of the part to be stored in the header of the packet storing the part.

  In step S <b> 113, the transmission unit 224 transmits the part of the content data supplied from the acquisition unit 222 to the client 51 via the communication network 53.

  In step S114, the transmission unit 224 transmits the end notification signal supplied from the acquisition unit 222 to the client 51 via the communication network 53, and the content data transmission process ends.

  In this way, the server 52 acquires the part of the content data requested to be transmitted from the client 51 and transmits it to the client 51. Thus, by acquiring the part requested to be transmitted from the client 51 as a part from the content data and transmitting it to the client 51, the load on the server 52 can be reduced. It can be transmitted to the client 51 more efficiently.

  As described above, according to the present invention, content data is divided into a plurality of segments, each segment is further divided into a plurality of parts, and each part constituting one segment is downloaded from a different server. As a result, the client can download the content data more quickly.

  In addition, according to the present invention, each segment is divided into a plurality of parts, and the size of each part is determined according to the download speed of the part downloaded last time. The content can be downloaded well, and even when a problem occurs in the network or the server, the reproduction of the content can be made more difficult to interrupt.

  The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a recording medium in a general-purpose personal computer or the like.

  As shown in FIG. 6, this recording medium is distributed to provide a program to the user separately from the computer, and includes a magnetic disk 161 (including a flexible disk) on which the program is recorded, an optical disk 162 (CD- ROM (Compact Disc-Read Only Memory), DVD (including Digital Versatile Disc)), magneto-optical disk 163 (including MD (Mini-Disc) (trademark)), or semiconductor memory 164, etc. In addition, the program is configured by a ROM 132 in which a program is recorded, a hard disk included in the recording unit 138, and the like provided to the user in a state of being incorporated in a computer in advance.

  The program for executing the series of processes described above is installed in a computer via a wired or wireless communication medium such as a local area network, the Internet, or digital satellite broadcasting via an interface such as a router or a modem as necessary. You may be made to do.

  Further, the client 51 has been described as being connected to the peer-to-peer network. However, a server 52 or a center server called a so-called super node is provided on the peer-to-peer network, and the client 51 is connected to the super node or the center server. The node information of the other server 52 may be acquired.

  Furthermore, for example, as shown in FIG. 16, the client 51 may be connected to a server-client network to download content data.

  In this case, a client 51, a management server 302, and distribution servers 303-1 to 303-3 are connected to the communication network 301. When the client 51 downloads the content data, the client 51 records the content data desired by the client 51 from the management server 302 (for example, the distribution server 303-1 to the distribution server 303-3). Information such as the IP address and the transmission capability of the distribution server. The client 51 refers to the information acquired from the management server 302, divides the desired content data into a plurality of segments, further divides the segment into a plurality of parts, and transmits each part to the distribution server. Assigned to 303-1 to distribution server 303-3, respectively. Then, the client 51 downloads the part to which transmission is assigned from each of the distribution server 303-1 to the distribution server 303-3.

  In the present specification, the step of describing the program stored in the recording medium is not limited to the processing performed in chronological order according to the described order, but is not necessarily performed in chronological order. It also includes processes that are executed individually.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

It is a figure explaining the method of dividing and downloading the conventional content data. It is a figure explaining the content delivery system which concerns on this invention. It is a figure explaining the method of dividing and downloading content data. It is a figure explaining the method of dividing and downloading content data. It is a figure explaining the method of dividing and downloading content data. It is a block diagram which shows the example of a structure of a client. It is a block diagram which shows the structure of the function of a client and a server. It is a block diagram which shows the structure of the function of an allocation part. It is a flowchart explaining the process of reception of content data by a client, and the process in which a server transmits the content data requested | required from the client in the case of dividing content data into two segments. It is a flowchart explaining the reception process of content data. It is a figure explaining allocation information. It is a figure explaining received information. It is a figure explaining history information. It is a flowchart explaining the process of update of node information. It is a flowchart explaining the transmission process of content data. It is a figure explaining the content delivery system which concerns on this invention.

Explanation of symbols

  51 clients, 52-1 to 52 -N, 52 servers, 131 CPU, 132 ROM, 133 RAM, 138 recording unit, 161 magnetic disk, 162 optical disk, 163 magneto-optical disk, 164 semiconductor memory, 182 allocation unit, 183-1 Through 183-N, 183 communication control unit, 203-1 through 203-N, 203 transmission unit, 204-1 through 204-N, 204 reception unit, 221-1 through 221-N, 221 reception unit, 222-1 through 222-N, 222 acquisition unit, 223-1 to 223-N, 223 recording unit, 224-1 to 224-N, 224 transmission unit, 251 setting unit, 252 node information storage unit, 253 calculation unit, 254 reallocation control Section, 255 reception history storage section

Claims (10)

In an information processing device that receives data transmitted from each of a plurality of transmission devices connected via a communication network,
When receiving first data to be received from now on and second data divided into predetermined predetermined sizes in order, the second data to be received next is further transmitted Allocating means for allocating each transmission of the third data to each of the corresponding transmitting devices by dividing each of the third data corresponding to each of the devices;
Transmitting means for transmitting each of the request signals for requesting transmission of each of the third data assigned to each of the transmitting devices to the transmitting device corresponding to the third data;
An information processing apparatus comprising: a receiving unit configured to receive each of the third data transmitted from each of the transmission apparatuses. Storage means for storing information indicating a rate at which the third data is received from the transmission device;
2. The allocation unit according to claim 1, wherein, based on the information, the size of the third data is changed, and the second data is divided into the third data. Information processing device. In an information processing method of an information processing device that receives data transmitted from each of a plurality of transmission devices connected via a communication network,
When receiving first data to be received from now on and second data divided into predetermined predetermined sizes in order, the second data to be received next is further transmitted Assigning each transmission of the third data to each of the corresponding transmitting devices by dividing each of the third data corresponding to each of the devices;
A transmission control step for controlling transmission of each of the request signals for requesting transmission of each of the third data assigned to each of the transmission devices to each of the transmission devices corresponding to the third data;
A reception control step of controlling reception of each of the third data transmitted from each of the transmission devices. A program for reception processing for receiving data transmitted from each of a plurality of transmission devices connected via a communication network,
When receiving first data to be received from now on and second data divided into predetermined predetermined sizes in order, the second data to be received next is further transmitted Assigning each transmission of the third data to each of the corresponding transmitting devices by dividing each of the third data corresponding to each of the devices;
A transmission control step for controlling transmission of each of the request signals for requesting transmission of each of the third data assigned to each of the transmission devices to each of the transmission devices corresponding to the third data;
And a reception control step for controlling reception of each of the third data transmitted from each of the transmission devices. A recording medium on which a computer-readable program is recorded. In a program for causing a computer to perform reception processing for receiving data transmitted from each of a plurality of transmission devices connected via a communication network,
When receiving first data to be received from now on and second data divided into predetermined predetermined sizes in order, the second data to be received next is further transmitted Assigning each transmission of the third data to each of the corresponding transmitting devices by dividing each of the third data corresponding to each of the devices;
A transmission control step for controlling transmission of each of the request signals for requesting transmission of each of the third data assigned to each of the transmission devices to each of the transmission devices corresponding to the third data;
A reception control step of controlling the reception of each of the third data transmitted from each of the transmission devices. Storage means for storing first data;
When the other party sequentially receives second data obtained by dividing the first data to be received by the other party into predetermined sizes, the other party has been transmitted from the other party. Receiving means for receiving a request signal for requesting transmission of one third data among the third data obtained by dividing the second data to be received next into a predetermined number;
Acquiring means for acquiring third data requested to be transmitted from the stored first data based on the request signal;
An information processing apparatus comprising: transmission means for transmitting the acquired third data to the partner. When the other party sequentially receives the second data obtained by dividing the first data to be received by the other party into a predetermined size, the other party has been transmitted from the other party. A reception control step for controlling reception of a request signal for requesting transmission of one third data among the third data obtained by further dividing the second data to be received into a predetermined number;
Obtaining the third data requested to be transmitted from the stored first data based on the request signal;
A transmission control step of controlling transmission of the acquired third data to the other party. When the other party sequentially receives the second data obtained by dividing the first data to be received by the other party into a predetermined size, the other party has been transmitted from the other party. A reception control step for controlling reception of a request signal for requesting transmission of one third data among the third data obtained by further dividing the second data to be received into a predetermined number;
Obtaining the third data requested to be transmitted from the stored first data based on the request signal;
And a transmission control step for controlling transmission of the acquired third data to the other party. A recording medium on which a program for causing a computer to execute information processing is recorded. When the other party sequentially receives the second data obtained by dividing the first data to be received by the other party into a predetermined size, the other party has been transmitted from the other party. A reception control step for controlling reception of a request signal for requesting transmission of one third data among the third data obtained by further dividing the second data to be received into a predetermined number;
Obtaining the third data requested to be transmitted from the stored first data based on the request signal;
A program causing a computer to execute a transmission control step of controlling transmission of the acquired third data to the other party. In an information processing system including a plurality of transmission devices connected via a communication network and a reception device that receives data transmitted from each of the transmission devices,
The receiving device is:
When the first data to be received from now on and the second data divided into predetermined predetermined sizes are received in order, the second data to be received next is further connected. Allocating means for allocating each transmission of the third data to each of the corresponding transmitting devices by dividing each of the third data corresponding to each of the transmitting devices being
Transmission means for transmitting each request signal for requesting transmission of each of the third data assigned to each of the transmission devices to the transmission device corresponding to the third data,
Each of the transmitting devices
Storage means for storing the first data;
Receiving means for receiving the request signal transmitted from the receiving device;
Obtaining means for obtaining the third data requested to be transmitted from the stored first data based on the request signal;
Transmitting means for transmitting the acquired third data to the receiving device;
The receiving device is:
An information processing system, further comprising receiving means for receiving each of the third data transmitted from each of the transmitting devices.

Images