JP5370184B2 - Data distribution method - Google Patents

Description

  The present invention relates to a data distribution method for distributing data from a distribution source device to a plurality of distribution destination devices.

  When distributing a large amount of data (for example, video data), if data is transmitted from a distribution source device to a plurality of distribution destination devices by unicast communication, the load on the distribution source device and the network is significantly increased. For this reason, a system for distributing data using multicast communication has been proposed or put into practical use. However, since the multicast communication itself does not have a function for guaranteeing the arrival of data, a mechanism for retransmitting the distribution data to the distribution destination device that has failed to be received is necessary.

  Patent Document 1 describes an example of a data distribution method for transmitting data for complementation to a distribution destination apparatus that has failed to receive distribution data after distributing distribution data by multicast communication. In the data distribution method described in Patent Document 1, the distribution source device divides the distribution data into a plurality of partial data, and transmits each partial data to a number of distribution destination devices by multicast communication. When the delivery destination device fails to receive the partial data, the delivery destination device requests other delivery destination devices to transmit the necessary partial data by P2P (Peer To Peer) communication. When the other distribution destination apparatus that has received the request has received the requested partial data normally, the other distribution destination apparatus transmits the partial data to the requesting distribution destination apparatus by P2P communication.

JP 2004-72551 A

  However, in the data distribution method described above, there is no guarantee that the distribution destination apparatus that is requested to transmit the partial data normally receives the partial data. For this reason, useless traffic is generated between the delivery destination devices, and it is difficult to complete data complementation at an early stage. Such a problem is particularly noticeable when the proportion of distribution destination apparatuses that normally receive the partial data is small.

  An object of the present invention is to solve the problem that when data that has failed to be received by multicast communication is complemented by P2P communication between delivery destination devices, unnecessary traffic is generated until the completion of the data complementation. It is to provide a delivery method.

A data distribution method according to an aspect of the present invention includes:
The distribution source device adds an error detection code to each partial data constituting the distribution target data and transmits the data to a plurality of distribution destination devices by multicast communication.
Each distribution destination device determines whether or not there is an error in the partial data received from the distribution source device using the error detection code, and transmits the determination result for each partial data to a specific device set in advance. ,
Based on the determination result for each partial data received from each distribution destination device, the specific device requires a distribution destination device that needs to supplement partial data, and a distribution destination device as a transmission source of partial data for the completion And a supplement request request describing the partial data to be transmitted and the distribution destination device to be transmitted is transmitted to the distribution destination device to be the transmission source,
The distribution destination device that has received the complement request request transmits partial data to be transmitted to the distribution destination device to be transmitted by P2P communication in accordance with the complement request request.
The structure is taken.

  Since the present invention is configured as described above, when supplementing data that has failed to receive data by multicast communication with P2P communication between distribution destination devices, no unnecessary traffic is generated and data supplement is completed early. It becomes possible to do.

1 is a block diagram of a data distribution system according to a first embodiment of the present invention. It is a block diagram of the distribution origin apparatus used with the data distribution system concerning the 2nd Embodiment of this invention. It is a block diagram of the delivery destination apparatus used with the data delivery system concerning the 2nd Embodiment of this invention. It is a figure which shows the structural example of delivery object data. It is a figure which shows the structural example of determination result group information. It is a sequence diagram which shows operation | movement of the data delivery system concerning the 2nd Embodiment of this invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
Referring to FIG. 1, the data distribution system according to the first embodiment of the present invention includes a distribution source device 1, a plurality of distribution destination devices 2, and a network 3 that connects these devices so as to communicate with each other. The

  The distribution source device 1 has a function of dividing distribution target data into a plurality of partial data, adding an error detection code to each partial data, and transmitting the data to a plurality of distribution destination devices 2 through the network 3 by multicast communication. Have. Also, the distribution source device 1 receives a determination result indicating whether or not the data has been normally received for each partial data from the distribution destination device 2 through the network 3 by P2P communication, and complements the partial data based on the determination result. A function for determining a combination of a distribution destination device 2 that requires a distribution destination and a distribution destination device 2 that is a transmission source of partial data for complementing the distribution destination device 2 and a distribution destination device 2 that is a transmission source. It has a function of transmitting a complement request request describing partial data and a delivery destination device 2 to be transmitted by P2P communication.

  Each distribution destination device 2 receives each partial data constituting the distribution target data from the distribution source device 1 through the network 3 by multicast communication, and uses the error detection code to determine whether or not the received partial data has an error. It has a function to judge. Also, each distribution destination device 2 receives the determination request for each partial data in its own device by the P2P communication to the distribution source device 1 and, when receiving the supplement request from the distribution source device 1, the supplement request In accordance with the request, it has a function of transmitting partial data to be transmitted to another distribution destination apparatus 2 to be transmitted by P2P communication.

  The data distribution system according to the present embodiment configured as described above operates as follows.

  First, the distribution source device 1 adds an error detection code to each partial data constituting the distribution target data and transmits the partial data to a plurality of distribution destination devices 2 through the network 3 by multicast communication.

  Each distribution destination device 2 determines whether or not there is an error in the partial data received from the distribution source device 1 using an error detection code, and the determination result for each partial data is P2P communication to a predetermined specific device. Send by. The specific device can be, for example, the distribution source device 1. The specific device can be any one of the plurality of distribution destination devices 2. Hereinafter, the operation will be described assuming that the distribution source device 1 is a specific device.

  The distribution source device 1 distributes the distribution destination device 2 that needs to supplement partial data and the transmission source of partial data for complementation based on the determination result for each partial data received from each distribution destination device 2. A combination with the destination device 2 is determined.

  The algorithm for determining this combination is arbitrary. As an example, the load may be distributed to a plurality of distribution destination devices 2 so that the load of the partial data transmission processing is not concentrated on a specific distribution destination device 2. This method of load distribution is arbitrary. As an example, for each partial data that has not been normally received by at least one distribution destination device 2, the distribution source device 1 complements up to the present time among the distribution destination devices that have normally received the partial data. It is possible to use a method in which the delivery destination device 2 having the smallest amount of partial data transmission is determined as the transmission source of the partial data for complementation. In addition, when there are a plurality of delivery destination devices 2 with the smallest amount of partial data transmission for complementation up to the present time, the delivery destination device 2 with the earlier determination result reception time is transmitted with the partial data for complementation. It may be determined based on the original. This is because the distribution destination device 2 that has transmitted the determination result earlier is expected to have a smaller load.

  The distribution source device 1 may be included in a candidate of a partial data transmission source for complementation, assuming that the device itself is one distribution destination device that has received all the partial data normally. . In this case, the distribution source device 1 may be included in the candidates only for partial data that cannot be normally received by all the distribution destination devices 2. In this case, partial data for complementation is transmitted from the distribution source device 1 to the distribution destination device 2 by P2P communication.

  Subsequently, according to the above determination, the distribution destination device 2 sends a supplement request request describing the partial data to be transmitted and the distribution destination device 2 to be transmitted to the distribution destination device 2 to be the transmission source. Through P2P communication.

  The distribution destination apparatus 2 that has received the complement request request transmits the partial data to be transmitted to the distribution destination apparatus 2 to be transmitted through the network 3 by P2P communication in accordance with the complement request request.

  As described above, according to the present embodiment, when supplementing partial data that has failed to receive data by multicast communication with P2P communication between the distribution destination devices 2, no unnecessary traffic is generated and data supplementation is completed early. It becomes possible.

  The reason is that a specific device, based on the determination result received from each distribution destination device, a distribution destination device that needs to supplement partial data, and a distribution destination device that is a transmission source of partial data for complementation, Is transmitted to the distribution destination device that is the transmission source, and a complementary request request that describes the partial data that is the transmission target and the distribution destination device that is the transmission target is transmitted. This is because the distribution destination device that normally receives the partial data transmits the partial data to the distribution destination device that needs to supplement the partial data by P2P communication.

[Second Embodiment]
Next, a data distribution system according to the second embodiment of the present invention will be described with reference to FIG. 2 and FIG. FIG. 2 is a block diagram of a distribution source device used in the data distribution system according to the second embodiment of the present invention. FIG. 3 is a block diagram of a distribution destination device used in the data distribution system according to the second embodiment of the present invention.

<Distribution source device>
First, the configuration of a distribution source device used in the data distribution system according to the second embodiment of the present invention will be described with reference to FIG.

  The distribution source device 1 is a device having a function of transmitting distribution target data to the distribution destination device 2, and is installed in, for example, a center device that multicasts video data to a large number of movie theaters or distribution bases via a satellite or the like. Server device.

  The distribution source device 1 includes an arithmetic processing unit 11, a storage unit 12, a communication interface unit (hereinafter referred to as a communication I / F unit) 13, and an operation input unit 14 as main functional units.

  The communication I / F unit 13 includes a dedicated data communication circuit, and has a function of performing data communication with various devices such as the distribution destination device 2 connected via the communication line and the network 3. The operation input unit 14 includes an operation input device such as a keyboard and a mouse, and has a function of detecting an operator operation and outputting the operation to the arithmetic processing unit 11.

  The storage unit 12 includes a storage device such as a hard disk or a memory, and has a function of storing processing information and programs 12P necessary for various processes in the arithmetic processing unit 11. The program 12P is a program that realizes various processing units by being read and executed by the arithmetic processing unit 11, and is read in advance from an external device or a recording medium via a data input / output function such as the communication I / F unit 13. And stored in the storage unit 12. Main processing information stored in the storage unit 12 includes distribution target data 12A and determination result group information 12B.

  The distribution target data 12A is data distributed from the distribution source device 1 to the distribution destination device 2, for example, video data. FIG. 4 is a configuration example of the distribution target data 12A. This distribution target data 12A is composed of a plurality of partial data having a size equal to or smaller than a size that can be transmitted at once by multicast communication. Each partial data is composed of a data body and management data. The data body is the data itself to be distributed, such as video data. The management data includes a data ID indicating which distribution target data the partial data belongs to, and a number indicating the number of partial data from the top of the partial data. The data ID is an identifier that uniquely identifies the distribution target data.

  The determination result group information 12B is information obtained by adding management information to the determination result received from the distribution destination device 2. FIG. 5 is a configuration example of the determination result group information 12B. The determination result group information 12B includes a determination result 22C for each distribution destination device, management information 121 for each distribution destination device, and a complementation necessary data determination result 122.

  The determination result 22C for each distribution destination device sets, for each partial data constituting the distribution target data 12A, a “positive” flag indicating that the distribution destination device has received the partial data normally. If the partial data is not normally received, the data is set with an “error” flag indicating that. The supplementation necessary data determination result 122 sets a “necessary” flag indicating that if there is a distribution destination apparatus 2 that needs to supplement the partial data for each partial data constituting the distribution target data 12A. If there is no distribution destination apparatus 2 that needs to complement the partial data, the data is set with an “unnecessary” flag indicating that. The management information 121 for each distribution destination device is a portion that stores an identifier of the distribution destination device and load information as a determination material when determining a transmission source of complementary data.

  The arithmetic processing unit 11 includes a processor such as a CPU and its peripheral circuits, and reads and executes the program 12P from the storage unit 12, thereby realizing various processing units by cooperating the hardware and the program 12P. It has a function. As main processing units realized by the arithmetic processing unit 11, there are a multicast distribution unit 11A and a P2P communication unit 11B.

  The multicast distribution unit 11A adds an error detection code to each partial data constituting the distribution target data 12A stored in the storage unit 12 based on an instruction input from the operation input unit 14 or an external device, and performs communication. The I / F 13 is used to transmit to a plurality of distribution destination apparatuses 2 through the network 3 by multicast communication.

  The P2P communication unit 11B uses the communication I / F unit 13 to receive the determination result 22C for each distribution destination device 2 from the distribution destination device 2 through the network 3 by P2P communication, and the determination for each distribution destination device 2. Based on the result 22C, the function of determining the combination of the distribution destination device 2 that needs partial data complementation and the distribution destination device 2 that is the transmission source of partial data for complementation, and the transmission source according to this determination A function of transmitting a complement request request describing the partial data to be transmitted and the distribution destination device 2 to be transmitted to the distribution destination device 2 using the communication I / F unit 13 by P2P communication And have.

<Delivery destination device>
Next, with reference to FIG. 3, the structure of the delivery destination apparatus used with the data delivery system concerning the 2nd Embodiment of this invention is demonstrated.

  The distribution destination device 2 is a device having a function of receiving data distributed from the distribution source device 1, and is installed in, for example, a movie theater or distribution base that receives video data distributed from a center device through a satellite or the like. Consists of server devices.

  The distribution destination device 2 includes an arithmetic processing unit 21, a storage unit 22, and a communication I / F unit 23 as main functional units.

  The communication I / F unit 23 includes a dedicated data communication circuit and has a function of performing data communication with various devices such as the distribution source device 1 connected via the communication line and the network 3.

  The storage unit 22 includes a storage device such as a hard disk or a memory, and has a function of storing processing information and programs 22P necessary for various processes in the arithmetic processing unit 21. The program 22P is a program that realizes various processing units by being read and executed by the arithmetic processing unit 21, and is read in advance from an external device or a recording medium via a data input / output function such as the communication I / F unit 23. And stored in the storage unit 22. Main processing information stored in the storage unit 22 includes distribution meta information 22A, received data 22B, and a determination result 22C.

  The distribution meta information 22A includes information such as the data ID of data distributed from the distribution source device 1, the size of partial data, and the number of partial data. The distribution meta information 22A is stored in the storage unit 22 prior to distribution. The distribution meta information 22A may be transmitted from the distribution source device 1 to each distribution destination device 2 by multicast communication or unicast communication, or input from an external device connected to the distribution destination device 2 without communication. And remember it.

  The reception data 22 </ b> B is distribution target data distributed from the distribution source device 1.

  The determination result 22 </ b> C is data indicating the reception status of each partial data of the distribution data distributed from the distribution source device 1. In the determination result 22C, for each partial data constituting the reception data 22B, a “positive” flag indicating that the partial data is normally received is set, and the partial data is normally received. If not, an “error” flag indicating that is set.

  The arithmetic processing unit 21 includes a processor such as a CPU and its peripheral circuits, and reads and executes the program 22P from the storage unit 22, thereby realizing various processing units by cooperating the hardware and the program 22P. It has a function. As main processing units realized by the arithmetic processing unit 21, there are a multicast reception unit 21A and a P2P communication unit 21B.

  The multicast receiving unit 21A has a function of receiving each partial data of distribution target data distributed from the distribution source device 1 by multicast communication using the communication I / F unit 23, and whether or not there is an error in the received partial data. And a function of creating a determination result 22C.

  The P2P communication unit 21 </ b> B uses the communication I / F unit 23 to receive the function of transmitting the determination result 22 </ b> C to the distribution source device 1 and the supplement request from the distribution source device 1 through the communication I / F unit 23. In accordance with this supplement request, the communication I / F unit 23 is used to transmit the partial data to be transmitted to another distribution destination device 2 to be transmitted by P2P communication.

<Operation of Second Embodiment>
Next, the operation of the data distribution system according to the second embodiment of the present invention will be described with reference to FIG. In the following, a case where the distribution source device 1 distributes distribution target data VD composed of a total of n partial data D1 to Dn to a plurality of distribution destination devices 2 will be described as an example. Corresponding to the data ID of the distribution target data VD, distribution meta information 22A including the size of the partial data D1 to Dn and the number of partial data n is stored in advance in the storage unit 22 of each distribution destination device 2. It shall be. Furthermore, it is assumed that the communication addresses of the distribution source device 1 and each distribution destination device 2 are distributed to each device in advance in association with the identifiers of these devices. In addition, it is assumed that the same unicast address is assigned to the plurality of distribution destination apparatuses 2.

  First, the multicast distribution unit 11A of the distribution source device 1 transmits each partial data constituting the distribution target data VD as one packet to the plurality of distribution destination devices 2 through the network 3 by multicast communication (step S11). The payload of each packet includes partial data and checksum data as an error detection code. Further, as described above, the partial data includes a data body and management data including a partial data number and a data ID.

  The multicast receiver 21A of each distribution destination device 2 receives the packet transmitted from the distribution source device 1 by multicast communication, and stores it in the storage unit 22 (step S21). At that time, the multicast reception unit 21A determines whether or not the received partial data has an error using the checksum data, generates a determination result 22C, and stores the determination result 22C in the storage unit 22. The determination result 22C is composed of flags equal to the number of partial data indicated by the delivery meta information 22A. In the initial state, all flags are set to “false”. When the multicast reception unit 21A receives a packet and determines that there is no error in the partial data in the packet by the error determination based on the checksum data, the multicast reception unit 21A extracts the management data from the partial data, and the data ID and the partial data number And confirm. Then, the multicast reception unit 21A operates the flag corresponding to the confirmed partial data number in the determination result 22C corresponding to the confirmed data ID to change from “wrong” to “correct”. On the other hand, when the multicast receiving unit 21A determines that the partial data has an error, the corresponding flag is left as “false”. The multicast reception unit 21A receives the P2P communication unit 21B when all the flags in the determination result 22C have been operated or when a predetermined time has passed since the first flag operation even if the operation has not been completed. Send notification of completion.

  When receiving the notification of reception completion from the multicast receiving unit 21A, the P2P communication unit 21B of each distribution destination device 2 generates a packet including the determination result 22C and the data ID stored in the storage unit 22, and the distribution source device 1 To the P2P communication unit 11B (step S22).

  When receiving the packet including the determination result 22C and the data ID from each distribution destination device 2, the P2P communication unit 11B of the distribution source device 1 stores the determination result 22C in the location of the determination result group information 12B of the storage unit 12. (Step S12). Specifically, the determination result 22C is stored in the order received, and the identifier of the distribution destination apparatus 2 that has transmitted the determination result 22C is described in the management information 121 corresponding to the determination result 22C. Then, when the reception of the determination results from all the delivery destination devices is completed or a predetermined period of time has elapsed since the reception of the first determination result even if the reception of the determination results is not completed, the partial data is based on the determination result group information 22B The combination of the distribution destination device 2 that needs to be complemented and the distribution destination device 2 that is the transmission source of the partial data for the complementation is determined (step S13). This determination is performed by the following method, for example.

  First, the P2P communication unit 11B needs to complement a list of partial data that is not normally received by at least one distribution destination device 2 by taking the logical product of the flags of all the determination results 22C corresponding to the same partial data. A data determination result 122 is generated. In this embodiment, the supplemental necessary data determination result 122 including the necessary flag and the unnecessary flag is generated. However, the generation of the necessary flag and the unnecessary flag is omitted, and the partial data supplemented with P2P from the erroneous flag. And a distribution destination device as a transmission source of partial data may be determined from the positive flag.

  Next, the P2P communication unit 11 </ b> B pays attention to the first partial data that is determined to be required to be complemented based on the complementation necessary data determination result 122. Next, let the noticed partial data be the transmission target partial data, and the delivery destination apparatus 2 having the determination result that the flag corresponding to the noticed partial data is “false” as the transmission target delivery destination apparatus. In addition, among the distribution destination devices that have normally received the focused partial data, the distribution destination device 2 that has the smallest amount of partial data transmission for complementation up to the present time is transmitted to the partial data for the complementation. Determine the original. At the time when attention is paid to the first partial data, the transmission amount of all the partial data is zero. When there are a plurality of delivery destination apparatuses 2 with the smallest transmission amount in this way, any one of the delivery destination apparatuses 2 is determined as a transmission source of partial data for complementation. Or you may determine the delivery destination apparatus 2 with the earlier reception time of a determination result as the transmission source of the partial data for the said complement.

  Next, when the P2P communication unit 11B determines a certain distribution destination device 2 as a transmission source, the P2P communication unit 11B adds the partial data to be complemented to the management information 121 corresponding to the determination result 22C of the determined distribution destination device 2. The number and information (for example, ID) of the distribution destination device 2 that transmits the partial data are described. For example, when there are two delivery destination devices 2 X and Y that require complementation of the first partial data, and the transmission destination of the supplementary data is determined as the delivery destination device Z, management corresponding to the delivery destination device Z The information 121 describes [1] → [X, Y]. Here, [] in the first half is information for specifying partial data to be transmitted, and [] in the second half is information for specifying delivery destination information to be transmitted.

  The P2P communication unit 11B performs the same processing as described above for other partial data determined to be supplemented in the supplementary necessary data determination result 122, and complements the partial data to be transmitted. Therefore, a combination with a transmission destination device that distributes the partial data is determined. In the case of the second and subsequent partial data, the transmission source is determined so that the load is not biased to a specific distribution destination device in consideration of the transmission amount of the distribution destination device previously determined as the transmission source. For example, the transmission amount of the distribution destination device in which the information [1] → [X, Y] is described in the management information 121 is counted as “2 units”, and the distribution destination device with a smaller load is determined as the transmission source. .

  When the P2P communication unit 11B determines a distribution destination device that is a transmission source for all partial data that needs to be complemented, the P2P communication unit 11B creates a complement request according to the determination, and the distribution destination device 2 of the corresponding transmission source by P2P communication. (Step S14). Specifically, paying attention to each of the management information 121 of FIG. 5, the following processing is performed.

  It is determined whether or not the focused management information 121 describes a combination of partial data to be distributed and a distribution destination device to be distributed. If not described, the processing for this management information 121 is finished. If it is described, a supplement request request describing the partial data to be transmitted and the delivery destination device to be transmitted is generated with reference to all the described combinations, and this supplement request is The information is transmitted to the distribution destination device 2 specified by the identifier described in the management information 121. For example, if [1] → [X, Y] and [6] → [X] are described in the management information 121 corresponding to a certain distribution destination apparatus Z, the first partial data is stored in the distribution destination apparatus. A supplement request request is transmitted to X and Y, and the sixth partial data is transmitted to the distribution destination device X, and a supplement request request is transmitted to the distribution destination device Z.

  Each distribution destination device 2 that has transmitted the determination result to the distribution source device 1 is on standby because there is a possibility that a supplement request request addressed to itself is transmitted from the distribution source device 1. In addition, the distribution destination apparatus 2 that has not been able to normally receive some partial data by multicast communication is on standby because there is a possibility that complementary data may be transmitted.

  When the P2P communication unit 21B of the distribution destination device 2 receives the complement request request addressed to itself from the distribution source device 1 (step S23), the storage unit stores the partial data to be transmitted according to the received supplement request. The data is read out from the 22 received data 22B, a packet is generated, and is transmitted to the distribution destination device to be transmitted by P2P communication. The P2P communication unit 21B of the distribution destination device 2 that has received the partial data addressed to the own device completes the missing partial data in the received data 22B with the received partial data. For transmission / reception of complementary data by P2P communication between the distribution destination apparatuses 2, for example, TCP may be used in the upper layer, and data reachability may be guaranteed in the transport layer. Further, UDP may be used for the upper layer, and an error detection code may be added to the partial data for transmission, and the data reachability may be guaranteed by the retransmission function in the application layer. In addition, when it is necessary to transmit a plurality of partial data to a delivery destination device to be transmitted, it may be transmitted in one packet or may be transmitted in a plurality of packets.

  The distribution source device 1 may be included in a candidate of a partial data transmission source for complementation, assuming that the device itself is one distribution destination device that has received all the partial data normally. . In this case, the distribution source device 1 may be included in the candidates only for partial data that cannot be normally received by all the distribution destination devices 2.

  As described above, according to the present embodiment, the distribution of data from the distribution source device 1 to the plurality of distribution destination devices 2 can be efficiently performed without imposing a load on the distribution source device 1 and each specific distribution destination device 2. It becomes possible.

  INDUSTRIAL APPLICABILITY According to the present invention, the present invention can be applied to uses such as distribution of video data to movie theaters and distribution bases such as digital cinema and large-capacity video on demand distribution. Further, the present invention can be applied not only to video data but also to data distribution at multiple locations.

DESCRIPTION OF SYMBOLS 1 Distribution origin apparatus 2 Distribution destination apparatus 3 Network 11 Operation processing part 11A Multicast distribution part 12 Storage part 12A Distribution object data 12B Determination result group information 12P Program 13 Communication I / F part 14 Operation input part 21 Operation processing part 21A Multicast receiving part 22 storage unit 22A distribution meta information 22B received data 22C determination result 22P program 23 communication I / F unit

Claims (10)

The distribution source device adds an error detection code to each partial data constituting the distribution target data and transmits the data to a plurality of distribution destination devices by multicast communication.
Each distribution destination device determines whether or not there is an error in the partial data received from the distribution source device, using the error detection code, and transmits a determination result for each partial data to a specific device set in advance. ,
Based on the determination result for each partial data received from each distribution destination device, the specific device needs a distribution destination device that needs to supplement partial data, and a distribution destination device as a transmission source of partial data for the completion And a supplement request request describing the partial data to be transmitted and the distribution destination device to be transmitted is transmitted to the distribution destination device to be the transmission source,
The data distribution method, wherein the distribution destination device that has received the complement request request transmits partial data to be transmitted to the distribution destination device to be transmitted by P2P communication in accordance with the complement request request. The data distribution method according to claim 1, wherein the specific device is the distribution source device. The distribution source device transmits partial data for complementing partial data that cannot be normally received by all the distribution destination devices from the own device to the distribution destination device by P2P communication. The data distribution method according to claim 1 or 2. The specific device has, for each partial data that is not normally received by at least one distribution destination device, out of the partial data for complementation up to the present time among the distribution destination devices that have normally received the partial data. The data delivery method according to any one of claims 1 to 3, wherein a delivery destination device having the smallest transmission amount is determined as a transmission source of partial data for complementation. When there are a plurality of distribution destination devices with the smallest amount of partial data transmission for complementation up to the present time, the specific device selects the distribution destination device with the earlier determination result reception time as partial data for the supplementation The data distribution method according to claim 4, wherein the data transmission method is determined as a transmission source. Consists of a distribution source device and a plurality of distribution destination devices connected to each other via a network,
The distribution source device is:
A multicast distribution means for adding an error detection code to each partial data constituting the distribution target data and transmitting the data to a plurality of distribution destination devices by multicast communication;
Based on the determination result received from the distribution destination device and indicating whether or not the data has been received normally for each partial data, the distribution destination device that needs to supplement the partial data and the transmission source of the partial data for the complementation P2P communication means for determining a combination with a distribution destination device to be transmitted and transmitting a complement request request describing the partial data to be transmitted and the distribution destination device to be transmitted to the distribution destination device as the transmission source And
The delivery destination device is:
Multicast receiving means for receiving the partial data from the distribution source device and determining whether or not the received partial data has an error using the error detection code;
When the determination result for each partial data in its own device is transmitted to the distribution source device and the complement request request is received from the distribution source device, the partial data to be transmitted is transmitted to the P2P communication according to the complement request request A data distribution system comprising: P2P communication means for transmitting to a distribution destination device to be transmitted by A multicast distribution means for adding an error detection code to each partial data constituting the distribution target data and transmitting the data to a plurality of distribution destination devices by multicast communication;
Based on the determination result received from the distribution destination device and indicating whether or not the data has been received normally for each partial data, the distribution destination device that needs to supplement the partial data and the transmission source of the partial data for the complementation P2P communication means for determining a combination with a distribution destination device to be transmitted and transmitting a complement request request describing the partial data to be transmitted and the distribution destination device to be transmitted to the distribution destination device as the transmission source A distribution source device comprising: Multicast receiving means for receiving each partial data constituting distribution target data from the distribution source device together with an error detection code, and determining whether or not the received partial data has an error using the error detection code;
When the determination result for each partial data is transmitted to a specific device set in advance, and a complement request request describing the partial data to be transmitted and the distribution destination device to be transmitted is received from the specific device Comprises a P2P communication means for transmitting partial data to be transmitted to a distribution destination device to be transmitted by P2P communication in accordance with the complement request. Computer
A multicast distribution means for adding an error detection code to each partial data constituting the distribution target data and transmitting the data to a plurality of distribution destination devices by multicast communication;
Based on the determination result received from the distribution destination device and indicating whether or not the data has been received normally for each partial data, the distribution destination device that needs to supplement the partial data and the transmission source of the partial data for the complementation P2P communication means for determining a combination with a distribution destination device to be transmitted and transmitting a complement request request describing the partial data to be transmitted and the distribution destination device to be transmitted to the distribution destination device as the transmission source Program to function as. Computer
Multicast receiving means for receiving each partial data constituting distribution target data from the distribution source device together with an error detection code, and determining whether or not the received partial data has an error using the error detection code;
When the determination result for each partial data is transmitted to a specific device set in advance, and a complement request request describing the partial data to be transmitted and the distribution destination device to be transmitted is received from the specific device Is a program for functioning as a P2P communication means for transmitting partial data to be transmitted to a distribution destination device to be transmitted by P2P communication according to the complement request.

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