JP2005149040A - Peer-to-peer communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video communication system capable of providing peer-to-peer (P2P) streaming service even in a node such as a mobile terminal in which a storage capacity is small and communication quality is unstable as to the P2P service for relaying streaming through a P2P network. <P>SOLUTION: A terminal requiring to join the P2P network releases information concerned with the data loss of data received by the terminal itself and latest information concerned with a data time range to the outside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a video communication system, and more particularly to streaming video relay by a peer-to-peer network.

In the Internet, a file exchange service using a peer-to-peer (hereinafter referred to as P2P) network represented by Napster, Gnutella, and the like has attracted attention. The P2P service does not require a large-scale server such as a server client model, terminals that participate in the P2P service communicate with each other, and each terminal connects to a plurality of other terminals, so that the terminals can communicate with each other. A logical network is configured. P2P not only reduces the load on the server accompanying an increase in the network usage population, but is also being applied to various applications such as distributed computing, collaborative work, and local community formation (see, for example, Patent Document 1).
The P2P service is a file exchange service, that is, a content exchange center by downloading a file. However, a trial service has already been provided for a content exchange service by streaming (hereinafter referred to as P2P streaming).
In P2P streaming, a certain P2P node downloads all files from another node and then releases this file to other nodes as in the file exchange service. Is stored in the buffer, and the stored data is disclosed to other nodes.

Japanese Patent Laid-Open No. 11-275156

At present, as a peer constituting a P2P network, a personal computer that can be always connected and has a large-capacity storage device is mainstream. However, along with recent advances in mobile terminal processing capabilities and network speeds, mobile terminals such as PDAs and mobile phones can create, play, and edit content containing various media data such as video, music, voice, and text. Transfer to terminals has become possible.
Mobile terminals are inferior to PCs in terms of processing speed and data storage. However, as a personal tool, the creation of new added value of P2P service is expected by taking advantage of the characteristics of mobile terminals such as the user's constant portability and the speed of user response.
However, when a mobile terminal is applied as a P2P node, it is often impossible to store all of the content because the buffer capacity of the mobile terminal is small. For this reason, since only a part of the content can be disclosed to the P2P network, even if a node in the P2P network searches for the desired content, how much of the searched content is disclosed to the public. There is a problem of not knowing. In addition, when a mobile terminal is applied as a node of a P2P network, the node usually participates in the P2P network by wireless communication. Therefore, when the throughput of the wireless communication network varies greatly, when relaying streaming between nodes, Data loss can occur. In the conventional P2P streaming technology, the loss of streaming data as described above is not taken into consideration, so even when a node in the P2P network searches for desired content, the quality when the content is received by streaming is not known. There's a problem.

Furthermore, a P2P file exchange service completes one service operation when a node finishes downloading a file from another node, whereas in P2P streaming, the service operation continues during streaming delivery. There is. Therefore, unlike the file exchange service, the P2P streaming service has a problem of how to continue the service when the node leaves the P2P network. When the mobile terminal is a node in the P2P streaming service, the node frequently leaves the P2P network, such as the movement of the terminal, the deterioration of the radio wave reception status, and the stop of the power supply. However, the conventional P2P streaming service has a problem that it is difficult to continue the service of P2P streaming by the mobile terminal because the service continuation at the time of leaving the node assuming such a mobile terminal as a P2P node is not considered.
Also, with conventional P2P streaming, a terminal cannot freely select a P2P streaming relay section and provide a streaming relay service.

  The object of the present invention is made in view of the above circumstances, and in a P2P service in which streaming is relayed by a P2P network, even in a node having a small storage capacity and unstable communication quality, such as a mobile terminal, It is to provide a video communication system that realizes a P2P streaming service.

In order to achieve the above object, an outline of the invention disclosed in the present application is as follows.
A communication device having a network interface unit connected to an external device, which requests a search for video data from another communication device and analyzes the search result, and the communication device selected based on the analysis result All the video data received from or a video data storage means and an analysis unit. In the present application, in particular, the search result includes at least one of information on a time range of the video data and information on a data loss of the video data.
Further, an apparatus connected to the communication apparatus and having a management unit that searches for a content providing candidate terminal in response to a search request includes at least information on a time range of the video data and information on a data loss of the video data. Either one is sent to the communication device.
Further, in the P2P streaming communication system using the communication apparatus of the present invention, a function of newly relaying streaming is provided by taking over the streaming relay function of another node. Alternatively, it is possible to interrupt a section (between two nodes) where streaming distribution has already been performed.

According to the present invention, when content is exchanged by P2P streaming, even when the mobile terminal becomes a node of the P2P network such as a PDA or a mobile phone, and the mobile terminal becomes a node of the P2P network so that the fluctuation of the communication situation is large It is possible to search for and distribute the content.
In addition, since each terminal can take over the streaming relay function instead of a certain terminal relaying streaming distribution, even when a mobile terminal with a high frequency of withdrawal becomes a node of the P2P network Thus, the overall distribution efficiency and stability of the P2P streaming communication system can be improved. Furthermore, since each terminal can provide a streaming relay function by interrupting an arbitrary streaming distribution section, the flexibility of the network configuration of the P2P streaming communication system is increased, and the content fee by providing the resources of the terminal A new P2P service model such as discounts can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The configuration of the P2P streaming distribution system according to the first embodiment of the present invention will be described with reference to FIGS. It should be noted that the subsequent processing of the server and the terminal device can be realized by reading a program for executing the subsequent processing, or by a cooperative operation of hardware and software processing, in addition to an implementation method using a hardware configuration. Nor.
FIG. 3 is a configuration of the P2P streaming communication system according to the first embodiment of the present invention. In the figure, the central server 200 is a server device that performs node registration, node search, and public content search. Terminals 100, 300, 301, and 302 are individual communication devices that constitute a P2P network. The terminals 300, 301, and 302 have the same configuration as the terminal 100. In the present specification, the terminals constituting the P2P network are referred to as “terminals” in the case of meaning as a communication device, and “nodes” in the sense of being a logical network entity constituting the P2P network. Shall be described. FIG. 1 is a diagram illustrating functional blocks of a terminal 100 configuring a P2P streaming communication system according to Embodiment 1 of the present invention. In the figure, the control unit 101 controls processing in each module in the terminal 100. The network interface unit 102 provides a communication function for the terminal 100 to access the P2P network.

  In the present invention, a wireless communication path such as a wireless LAN or a cellular phone network is mainly assumed as a communication path of the network interface 102 unit. However, the communication path is a wired communication path such as Ethernet (registered trademark), DSL, or FTTH. Also good. The message processing unit 103 creates and analyzes messages for transmitting information and data between the central server 200 and other nodes. The node information processing unit 104 analyzes node information and content information received from the central server 200 and manages information related to content data stored in the content storage unit 105. The stream relay unit 106 controls buffering of the received streaming content to the content storage unit 105, transmission of the buffered streaming content, and the like. The stream analysis unit 107 analyzes the received stream and the content stored in the content storage unit 105. The connection determining unit 108 performs processing related to determining whether to connect to another node. The query processing unit 109 transmits a query request message for content search, analyzes a received query response message, and the like. FIG. 2 is a diagram illustrating functional blocks of the central server 200 configuring the P2P streaming system according to the first embodiment of the present invention. In the figure, a network interface unit 201 provides a communication function for the central server 200 to communicate with a terminal. The message processing unit 202 creates and analyzes a message for transmitting information and data between the central server 200 and the node. The login management unit 203 performs node login and logout processing. The query processing unit 204 analyzes a query request from a node, searches for a node or published content, and creates a query response. The node information management unit 205 performs management such as addition, update, and deletion of information related to nodes and content information disclosed by each node.

  A flow of the P2P streaming service in the first embodiment of the present invention will be described with reference to FIGS. The terminal 100 participating in the P2P network first logs into the central server 200. This processing sequence is shown in FIG. The terminal 100 establishes a TCP session with the central server and transmits a login request M401. The login request M401 stores login information such as a login user name of the terminal 100 and a login password. When the central server 200 receives the login request message M401, the message processing unit 202 analyzes the login request message M401, extracts login information, passes the login information to the login processing unit 204, and performs login processing of the terminal 100 in the login processing unit 204 ( S401). If the login process S401 is successful, the node information management unit 205 adds node information with the terminal 100 as a node of the P2P network (S402). The login processing unit 204 transmits a login response message M402 to the terminal 100. When the terminal 100 confirms that the login is completed by receiving the login response message M402, the terminal 100 transmits the node information of the terminal 100 and the content information that the terminal 100 discloses to the P2P network by streaming to the central server 200 as a message M403. In the central server 200, the node information management unit 205 adds node information and public content information based on the message M403 (S403).

An example of the structure of the node information managed by the node information management unit 205 and the content information disclosed by the node in the central server 200 is shown in FIG.
In FIG. 7, the user name, node IP address, network type, number of lower nodes, and shared content information are stored as node information. The user name is the same as the login name. The IP address is the IP address of the terminal 100 that is a P2P node. The number of lower nodes is the number of destination terminals when the terminal 100 is transmitting streaming content to other terminals.
In FIG. 7, along with the node information, content information disclosed by the node is described. The public content information includes information such as content name, media type, supported codec, content average bit rate, content time range, reception throughput, reception loss rate, cumulative reception loss rate, hop count, total content time, source address, etc. Stored. The content name describes the URL of the content published by each node. In the media type, all media types included in the content such as Video and Audio are described. In the corresponding codec, all codecs necessary for content reproduction are described. The average bit rate of the content is a value obtained by dividing the transmitted data size (number of bits) by the total content time.

  The content time range is a time range of content that the terminal 100 discloses to other nodes. If the memory capacity of the terminal 100 is not sufficient, all the streaming data received by the terminal 100 cannot be buffered. The content time range describes the time range of streaming content buffered at that node. For example, when 50 seconds from the beginning of the content is buffered and can be transmitted to another terminal, “0 to 50 seconds” is described.

In this way, each node publishes the content time range, thereby making it possible to search for streaming content in response to a request regarding content time. Therefore, even when the mobile terminal has a small buffer capacity and the entire streaming content cannot be buffered, it can be a P2P streaming node. Therefore, many mobile terminals can participate in this P2P service and publish content.
The total content time is the total time of the published content. When the end time of content is unknown, such as live content, the total content time is not described.
The host address is the IP address of the transmission source node of the content received by streaming. The number of hops describes how many terminals are relayed to the terminal 100 from the original content source. It can be said that the higher the number of hops, the higher the possibility of being affected by processing delays and data loss in the intermediate relay. When the hop number is 0, it indicates that the node is transmitting the original public content.

The reception loss rate describes the loss rate of received data when the terminal 100 is receiving content from another node by streaming. As will be described later, the terminal 100 buffers the received streaming content and transfers the buffered content to the other terminal in response to a request from the other terminal. Therefore, the loss rate of received data means the loss rate of content data that can be disclosed.
By describing the loss rate of the received content data, it is possible to estimate the quality when another terminal receives the content from the terminal 100 by streaming.

Here, when the number of hops is 2 or more, that is, when the public content is streamed through one or more nodes, the cumulative reception loss rate described in the public content information in FIG. Data loss in all relay sections until data reaches the node needs to be accumulated. An example of the accumulation of data loss is shown in FIG.
In FIG. 10, the streaming content originating from node A is relayed to node D via nodes B and C. In each section, the lower node can measure or estimate the reception loss rate using the sequence number of the received data. In the figure, it is assumed that the reception loss rates between the nodes A and B, the nodes B and C, and the nodes CD are measured as X, Y, and Z, respectively. As will be described later, the lower nodes of each section periodically transmit the latest information on the values of X, Y, and Z to the central server 200. In the central server 200, the reception loss rate of the public content information of each node, La, Lb, Lc, and Ld are La = 0, Lb = La + (1-La) × X, and Lc = Lb + (1-Lb), respectively. XY and Ld = Lc + (1−Lc) × Z are calculated and updated and managed by the node information management unit 205, respectively. As described above, when the content transmitted by streaming passes through a plurality of nodes, the central server 200 determines the data loss rate of the content published by each node based on the reception loss rate information measured at each node. Infer. It goes without saying that calculations other than those described above may be used as long as they represent values obtained by accumulating the loss rates so far.

The cumulative reception loss rate may be estimated by the node information processing unit 104 of the terminal 100. That is, based on the cumulative reception loss rate in the public content information (FIG. 7) of the transmission source node and the reception loss rate between the transmission node and the local node, which is disclosed by the central server, the local node receives as described above. The cumulative reception loss rate of the received data is estimated, and this estimated value is transmitted to the central server 200 as the public content information of FIG. In this case, the central server 200 does not need to estimate the cumulative reception loss rate described above, and the node information management unit 205 only needs to update and manage the public content information received from each terminal.
As described above, the P2P streaming communication system according to the first embodiment is characterized in that each node discloses information on the quality of content that can be distributed to other nodes to the outside. With this feature, even when the mobile terminal becomes a P2P streaming node by wireless communication and the quality of streaming content received by the node deteriorates, other nodes can improve the content quality during content search. Therefore, it is possible to search for streaming contents according to the request.
As described above, the information management unit 205 of the central server 200 adds or deletes information about nodes participating in the P2P network and contents published by each node, and updates values based on the node information as described above. Manage.

Next, a processing sequence in which the terminal 100 searches for streaming content via the central server 200 and performs streaming reception from the terminal 300 will be described with reference to FIG.
In the terminal 100, the user inputs information related to the desired content, such as a content name or a content search keyword, through the user interface unit 110. The query processing unit 203 (see FIG. 2) creates and sends a query request message M500 to the central server 200. The query request message M500 stores search information input by the user.

In the central server 200, when the query request message M500 is received, the query processing unit 203 analyzes it, extracts a content name, a keyword, and the like, and passes them to the node information management unit 205. The node information management unit 205 searches the node information described above for the content that matches the query condition such as the content name and keyword and the node that publishes the content (S500). The search result may include a plurality of content or a plurality of nodes as content provision candidate terminals for the same content. The central server 200 returns this query processing (S500) result to the terminal 100 as a query response message M501.
In the terminal 100, when the query response message M501 is received, the query processing unit 109 analyzes it. The connection determination unit 108 finally selects one content from the query result and the transmission source terminal 300 of the content (S501).

  As a content selection method in step S501, content information and node information of a plurality of search results included in the query response message M501 are presented to the user through the user interface unit 110, and the content and its distribution source node are displayed by the user's own interaction. There is a method of determining the terminal 300 that is. Alternatively, by setting some selection criteria on the terminal 100 in advance, the terminal 100 can automatically select one content from a plurality of query results.

  For example, if the terminal 100 is set in advance so as to give priority to streaming delivery from the beginning of the content, the terminal 100 automatically selects a content whose transmission content time range in FIG. Similarly, if the terminal 100 is set so as to place the highest priority on the streaming quality, the quality can be improved by selecting a peer having a small number of hops and reception loss rate as the terminal 300 in the public content information of FIG. The choice of streaming delivery can be expected.

On the other hand, if a confirmation process for the user is put in, content distribution more suited to the user's preference can be realized.
When the terminal 100 determines the content to be viewed and the terminal 300 that is the distribution source (S501), the terminal 100 transmits a content distribution request message M502 to the terminal 300. When the terminal 300 receives the message M502, the stream relay unit 106 analyzes it and returns a content distribution request response message M503. Here, the messages M502 and M503 include information such as the URL of the content, the start time of the streaming content, and the port number for distribution necessary for starting streaming. Further, the request / response message pair described above may not be single as shown in FIG. As a protocol for the above content delivery request and response message, an existing streaming control protocol such as RFC2326 (RealTime Streaming Protocol (RTSP)) defined by The Internet Engineering Task Force (IETF), or a proprietary control protocol is used. realizable.

  When the information necessary for streaming delivery is exchanged between the terminal 100 and the terminal 300 by the above-described messages of M502 and M503, and both are ready for streaming transmission / reception, the terminal 300 starts streaming delivery to the terminal 100 ( S502). In the terminal 300, the content data buffered in the content storage unit 105 (FIG. 1) is analyzed in the streaming analysis unit 107, subjected to data conversion processing as necessary, and sent to the communication network through the streaming relay unit 106. Is done. As this data conversion processing, for example, reassignment of sequence numbers, addition of head header information, and the like are conceivable.

  When the terminal 100 receives the streaming data from the terminal 300, the streaming relay unit 105 sends the received data to the streaming analysis unit 107. The streaming analysis unit 107 analyzes and reproduces the received data (S503), and at the same time, sends the content information as a result of the analysis to the content information processing unit 104, and further buffers the received data in the content storage unit 105. Here, when the buffer size of the content storage unit 105 is not sufficient and there is no remaining capacity for new buffering, new writing to the buffer is stopped or old data is deleted. Buffer new data. The content information processing unit 104 always manages the latest information of the content time range of the buffered data (S504).

  In the terminal 100, the content information processing unit 104 periodically transmits the buffered content information to the central server 200 (M504). The content information of M504 is the latest information of the node information and public content information shown in FIG. As described above, for the reception loss information, the central server 200 estimates the reception loss information accumulated at each node based on the reception loss information periodically sent from each node, and calculates the accumulated reception loss rate. The node information management unit 205 manages reception loss information while making it public as the cumulative reception loss rate in FIG. Alternatively, as described above, the cumulative reception loss rate is estimated at each node, and is periodically transmitted to the central server 200 as the public content information in FIG. 7 (M504). Similarly, the terminal 300 periodically transmits public content information to the central server 200 (M505). In the public content information M505 from the terminal 300, since the terminal 100 is a lower node, the number of lower nodes in the node information described in FIG. The central server 200 sequentially updates the node information and public content information received periodically from each terminal in the node information management unit 205 (S505).

As described above, the terminal 100 searches for the desired content via the central server 200, searches for the terminal 300 that is the distribution source of the content, and receives content from the terminal 300 by streaming. The terminal 100 accumulates received data during content reception, and periodically transmits public content information such as a reception loss rate and a content time range to the central server 200. Through such processing, the terminal 100 can receive the content by streaming, and at the same time, it can transmit the received content to other terminals by disclosing information on the data loss and time range of the received data. it can.

Next, a sequence of processing for terminating streaming reception when the terminal 100 does not distribute content received by streaming to another terminal, that is, when the terminal 100 does not have a lower node, will be described with reference to FIG. .
As described in FIG. 5, it is assumed that the terminal 100 is receiving content from the terminal 300 by streaming (S502). When the terminal 100 finishes receiving the streaming content, the terminal 100 transmits a streaming distribution end request message M600 to the terminal 300. The terminal 300 transmits a streaming distribution end request message M601 to the terminal 100. For example, the RTSP “TEARDOWN” message described above is used as the M600 and M601 message protocol.
Thereafter, the terminal 300 performs a distribution end process S600, and the terminal 100 performs a reception end process S601. Specifically, these processes include a stop of a transmission / reception loop and release of network resources.

  Thereafter, the terminal 100 and the terminal 300 transmit a peer information update message to the central server 200 (M602, M603). The terminal 100 notifies the central server of the deletion of the public content information by a message M602 because the streaming content received so far is terminated. Further, since the terminal 300 finishes streaming delivery to the terminal 100, the message M603 notifies that the number of lower nodes of the node information corresponding to the terminal 300 described in FIG. The central server 200 reflects the notifications of these messages M602 and M603 and updates the node information (S602).

Next, a processing sequence for ending streaming reception when the terminal 100 has a lower node will be described with reference to FIG. If the terminal 100 has a lower node and the streaming reception is terminated, streaming distribution to other terminals cannot be continued. Therefore, when the terminal 100 has a lower node, the lower node is notified of the end of distribution, and the lower node searches for other nodes that can distribute the same content as the streaming content received from the terminal 100, Switch to receiving from this node. Hereinafter, this flow will be described with reference to FIG.
In FIG. 8, the terminal 100 relays and distributes the streaming content (see FIG. 5) received from the terminal 300 to the terminal 301 (S801). When the terminal 100 ends the streaming content reception according to the flow described in FIG. 6 (S601), the terminal 100 transmits a streaming distribution end request message M800 to the terminal 301. When the terminal 301 receives the message M800, the terminal 301 transmits an end-of-life response message M801 to the terminal 100.

Thereafter, the terminal 100 executes a distribution end process S801, and the terminal 301 executes a reception end process S802. Specifically, these processes include stopping a transmission / reception loop and releasing network resources.
Then, the terminal 100 and the terminal 301 transmit a node information update message to the central server 200 (M802, M803). Since the terminal 100 ends the streaming delivery to the terminal 301, the message M802 requests the central server 200 that the number of lower nodes of the node information of the terminal 100 described in FIG. The terminal 301 notifies the central server of the deletion of the public content information by a message M803 because the streaming content received so far is terminated. The central server 200 reflects the notifications of these messages M802 and M803 and updates the node information (S803).
Thereafter, the terminal 301 performs reconnection processing S804 between the central servers 200. In the reconnection process S804, in order to continue receiving content by streaming, a node that can distribute the same content is searched for and reconnected to this node. The processing of the reconnection processing S804 is the same as the flow up to content reception described with reference to FIG. In this reconnection process, when a node capable of distributing the same content is not searched, the continuation of content reception is stopped or the reception is changed to reception of other content.

In the reconnection process S804 described above, the content continuously distributed from another node is such that the content received by the terminal 301 from the terminal 100 and the content newly received are temporally continuous, and Search for a content distribution source node whose content quality is the same or higher. The processing of the reconnection processing S804 is the same as the flow up to content reception described with reference to FIG. If a node capable of distributing such content is not found, the content resumption is continued at the expense of the time continuity and quality continuity of the content by the reconnection process, or the content reception is continued. Cancel.
As described above, in the P2P streaming system according to the present embodiment, when a certain node stops the current streaming reception while relaying streaming to the lower node, the lower node is notified of the end of distribution. The lower node determines whether to search for or stop the streaming destination. When the lower node continues streaming, the lower node searches for another node capable of delivering content from the same time as the streaming content received from the terminal 100, and switches to reception from this node. To do. The feature of this embodiment is that when a certain node leaves the P2P service, when continuing the streaming of the subordinate node, based on the published content time information and content quality information, in terms of time and quality It is a feature that content is selected so as to maintain continuity, and it goes without saying that separation procedures other than those described above may be used as long as this continuity can be realized.
FIG. 9 is a diagram illustrating a processing sequence for the terminal 100 to leave the P2P network. When the terminal 100 leaves the P2P network, the terminal 100 transmits a logout request message M900 to the central server 200. When the central server 200 receives the logout request message M900, the message processing unit 202 analyzes this, and the login management unit 204 performs logout processing of the terminal 100 (S900). In the central server 200, the node information management unit 205 deletes node information corresponding to the terminal 100 (S902). The terminal 100 releases resources for communication with the central server 200 (S901).

  As described above, in the P2P streaming communication system according to the first embodiment, each terminal can exchange contents by streaming. In the P2P streaming system according to the mobile phone 1 of the present invention, even if the buffer size of the terminal and the quality of the communication path are insufficient by disclosing the time range of the content, the loss rate of the received data, etc., the user's It is possible to search for content according to the request.

In the P2P streaming network according to the first embodiment, it is assumed that a mobile terminal such as a PDA or a mobile phone is used as a terminal participating in the P2P network. However, mobile terminals are often accessed via a wireless communication network, unlike PCs that are always connected via a wired communication network. In a wireless communication network, a variation in throughput is often large. Therefore, when a node transmits content to another node, if the radio wave reception status of that node deteriorates, content transmission to a lower node is affected.
Therefore, in the first embodiment, a terminal participating in the P2P network takes over the streaming relay function of another terminal (for example, the radio wave reception status is bad) and provides a function of newly relaying streaming. A process of taking over this streaming relay function from another node will be described with reference to FIGS.

In FIG. 12, content is distributed from the terminal 1103 to the terminal 1102 by streaming, and the terminal 1102 distributes the received content to the terminal 1101 by streaming. Here, the reception throughput of the terminal 1102 is reduced, and the process in which the terminal 100 receives content from the terminal 1103 by streaming instead of the terminal 1102 and distributes the content to the terminal 1101 by streaming will be described with reference to FIG. .
In FIG. 11, as shown in FIG. 12, content is distributed from the terminal 1103 to the terminal 1102 by streaming (S1101), and the terminal 1102 distributes the received content to the terminal 1101 by streaming (S1102). The terminal 100 transmits a relay takeover request message M1100 to the central server 200. When the central server 200 receives the relay takeover request message M1100, the central server 200 searches for a relay handover node (terminal 1102) having a reduced reception throughput from the streaming delivery currently being performed (S1100). The searched result is transmitted to terminal 100 as relay takeover response message M1101. The message M1101 includes the addresses of the upper node (terminal 1103) and the lower node (terminal 1101) of the relay handover node 1102.

The terminal 100 sends the same data distribution request message as the streaming data transmitted to the terminal 1102 to the terminal 1103 (M1102). Upon receiving the distribution request message M1102, the terminal 1103 transmits a distribution request response message M1104 to the terminal 100, and starts streaming distribution S1103 to the terminal 100. The terminal 100 buffers the streaming data received from the terminal 1103. The terminal 100 transmits a relay switching request message M1106 to the terminal 1101. The terminal 1101 returns a relay switching response message M1107 to the terminal 100. Upon receiving the relay switching response message M1107, the terminal 100 performs streaming distribution of the data received through the streaming distribution S1103 to the terminal 1100 (S1104). The terminal 1100 receives this, switches the streaming distribution S1102 to S1104 at an appropriate timing, and reproduces it (S1105). The terminal 1100 transmits a distribution end request message M1108 of the streaming distribution S1102 to the terminal 1102. Upon receiving the distribution end request message M1108, the terminal 1102 transmits a distribution end response message M1109 to the terminal 1101 and ends the streaming distribution S1102 (S1107). Upon receiving the distribution end response message M1109, the terminal 1101 ends the reception of the streaming distribution S1102 (S1108).

As described above, the P2P streaming system according to Embodiment 1 is characterized in that an arbitrary terminal takes over the streaming relay function instead of another terminal. With this feature, it is possible to improve the distribution efficiency and stability of the P2P streaming network because the relay of streaming distribution provided by the terminal having a low reception throughput can be taken over by another terminal having a high reception throughput. It becomes possible.
In the P2P streaming system according to the first embodiment, a terminal participating in the P2P network provides a streaming relay function by interrupting an arbitrary node into an existing streaming relay section.
In FIG. 13, content is distributed from the terminal 1301 to the terminal 1300 by streaming. Here, the terminal 100 interrupts the streaming interval between the terminal 1301 and the terminal 1300, and as shown in the lower part of the figure, the terminal 100 receives the content from the terminal 1300 by streaming, and distributes the received data to the terminal 1300 for streaming. Will be described with reference to FIG.

  In FIG. 14, content is distributed from the terminal 1301 to the terminal 1300 by streaming as shown in FIG. 13 (S1402). The terminal 100 transmits to the central server 200 a route information request message M1400 that relays the desired content (or keyword specification). Upon receiving the route information request message M1400, the central server 200 searches a series of route information relaying the content designated by the terminal 100 by streaming from the currently distributed streaming (S1400). The result is transmitted to the terminal 100 as a route information response message M1401. The message M1401 includes node information that relays and distributes the content designated by the terminal 100 and route information.

  The terminal 100 presents the route information and node information included in the message M1401 to the user. An example of the user's presentation is shown in FIG. In FIG. 15, a circle represents a node that relays streaming, and a numerical value in the circle represents a resource status of each node. FIG. 15 shows five levels, where 5 indicates that resources such as the memory capacity, CPU speed, and remaining power of the node are abundant, and that the smaller the numerical value, the less the resource of the node. In FIG. 15, the line connecting the nodes represents the state of the communication path (link). The number beside the link represents the quality of the communication path. In the figure, there are five levels. The larger the value, the better the communication state.

The user selects a route section where the user's terminal 100 is to be interrupted from the information presented as shown in FIG. 15 (S1401). Here, it is assumed that the user has selected a section in which streaming distribution (S1402) is performed from terminal 1301 to terminal 1300.
The terminal 100 transmits to the terminal 1301 a streaming distribution request message M1402 having the same data as the streaming distribution S1402 from the terminal 1301 to the terminal 1300. Upon receiving the distribution request message M1402, the terminal 1301 transmits a distribution response message M1403 to the terminal 100, and starts streaming distribution S1403. The terminal 100 buffers the streaming data received from the terminal 1301. The terminal 100 transmits a relay switching request message M1404 to the terminal 1300. The terminal 1300 returns a relay switching response message M1405 to the terminal 100. Upon receiving the relay switching response message M1405, the terminal 100 performs streaming distribution of the data received through the streaming distribution S1403 to the terminal 1300 (S1404). The terminal 1300 receives this and switches from streaming delivery S1402 to S1404 at an appropriate timing and reproduces it (S1405). The terminal 1300 transmits a distribution end request message M1406 of the streaming distribution S1402 to the terminal 1301. Upon receiving the distribution end request message M1406, the terminal 1301 transmits a distribution end response message M1407 to the terminal 1300, and ends the streaming distribution S1402 (S1106). Upon receiving the distribution end response message M1407, the terminal 1300 ends the reception of the streaming distribution S1402 (S1407).

  As described above, in the P2P streaming communication system according to the first embodiment, any terminal can interrupt an existing streaming distribution section and provide a relay function. This function enables application to a new service such as a content discount service by providing terminal resources (CPU capability, communication traffic).

In the P2P streaming communication system according to the second embodiment of the present invention, there is no special communication device like the central server 200 in the first embodiment, and content search and node information management performed by the central server 200 in the first embodiment are performed. All functions are performed at each terminal. In other words, each terminal is an information exchange mode in which information is propagated between terminals one after another by exchanging content information and nodes only with some peripheral terminals. Query request messages sent by a node are propagated one after another, and each terminal analyzes the query request message, and if there is content that matches the search conditions in its own terminal, the search result To the query source. The same applies to node information that is periodically updated. That is, node information is propagated one after another between terminals, but each terminal acquires only node information related to the content that it discloses and manages it within its own terminal. Node information not related to itself may be simply transferred to the peripheral nodes.
Such a form has already been realized under the name of pure type P2P, such as Gnutella, and can also be applied as a P2P streaming communication system using only terminals without using a central server in the present invention.

  As described above, in the second embodiment, content information and node information exchange and relay for realizing the above-described P2P streaming are performed between nodes without using a device having a server function for relaying content information exchange between nodes. It is characterized by constructing a P2P streaming network by relaying on the network. According to this feature, since the server device is not required, it is possible to realize the P2P streaming described in the present application at a small scale and at a low cost as compared with the first embodiment. For this reason, it becomes possible to easily share the streaming video in a relatively small community such as close friends or people gathered in a certain place.

The block diagram which shows the structure of the terminal of the P2P streaming communication system by Embodiment 1 of this invention. The block diagram which shows the structure of the central server of the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the structure of the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the login process of the terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow until the streaming reception of the terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the streaming reception end (when a lower node does not exist) of the terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the example of the node information in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the end of the streaming reception of a terminal (when a low-order node exists) in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the logout process of a terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the concept of the data reception loss rate in node information in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the process in which the terminal takes over a relay function from another terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the concept of the process in which the terminal takes over a relay function from another terminal in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the concept of the process which a terminal interrupts between other 2 terminals and provides a relay function in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the flow of the process in which the terminal interrupts between other 2 terminals and provides a relay function in the P2P streaming communication system by Embodiment 1 of this invention. The figure which shows the example of a GUI display of the node structure of a P2P network in the P2P streaming communication system by Embodiment 1 of this invention.

Explanation of symbols

100, 300, 301 ... terminal 101 ... control unit 102 ... network interface unit (terminal)
103 ... Message processing unit (terminal)
104 ... node information processing unit 105 ... content storage unit 106 ... stream relay unit 107 ... stream analysis unit 108 ... connection determination unit 109 ... query processing unit (terminal)
110: User interface unit 200: Central server 201: Network interface unit (central server)
202 ... Message processing unit (central server)
203 ... Query processing unit (central server)
204... Login processing unit 205... Node information management unit.

Claims (9)

A network interface unit for receiving video data and information about the video data;
A query processing unit for requesting other communication devices to search for video data and analyzing the search results;
Storage means for storing all or part of video data received via the network interface unit from the communication device selected based on the analysis result;
An analysis unit for analyzing the video data stored by the storage means,
The search result includes at least one of information on a time range of the video data and information on a data loss of the video data. 2. The communication apparatus according to claim 1, wherein the video data is transmitted through the interface unit while receiving the video data through the network interface unit. The query processing unit obtains information about a distribution source of video data received by the receiving unit and information about data loss in a communication path from the distribution source, and sends the data distribution source and information about the data loss to the information processing unit. The communication apparatus according to claim 2, wherein the communication apparatus transmits to the outside via a network interface unit. The said query process part estimates the information regarding the cumulative data loss of the said video data to receive based on the received information regarding the data loss and the information regarding a delivery origin, The said data processing part characterized by the above-mentioned. Communication equipment. The query processing unit acquires time information of video data stored in the storage unit, and transmits the time information to the outside via the network interface unit. A communication device according to claim 1. When receiving at least one of time information of video data or information on cumulative data loss via the network interface unit,
6. The communication apparatus according to claim 2, wherein the query processing unit searches the stored video data based on the time information or the information on the accumulated data loss. A network interface connected to the terminal;
A query processing unit for analyzing a search request received from a terminal via the network processing unit;
A search unit for content based on the result of the analysis, and a management unit for searching for a candidate terminal for providing the content,
The management unit outputs information related to data loss of the content and information related to content time received by each provision candidate terminal, together with the search result, to the terminal via the network interface unit. Communication device. 8. The communication apparatus according to claim 7, wherein the management unit estimates information related to accumulated data loss based on information related to data loss of the content received via the network interface unit. 9. The communication apparatus according to claim 8, wherein the management unit uses time information of video data as the search request.

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