JP2012050019A - Node device, information communication system, information processing method, and information processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate time and effort for manually inputting contents into an overlay network.SOLUTION: An information processing method comprises: receiving a packet transmitted from a client device requesting a content and showing a request for a content to a server device; analyzing the received packet; identifying a content requested by the client device based on an analysis result; acquiring the identified content from the server device; determining whether or not the identified content satisfies input conditions to an overlay network based on an analysis result; storing the acquired content into at least one node device when determined to have satisfied the input conditions; and inputting to acquire the content stored by the node device from the overlay network.

Description

  The present invention relates to a technical field of a peer-to-peer (P2P) communication system including a plurality of node devices that can communicate with each other via a network.

  In recent years, a peer-to-peer communication system as disclosed in Patent Document 1 has attracted attention as a system for distributing content. This peer-to-peer communication system is characterized in that the content distribution load is less likely to be concentrated on a specific device as compared with a client-server communication system that is a conventional mainstream form.

JP 2006-197400 A

  In a peer-to-peer communication system, in order to distribute content that has been distributed by the client-server method until now, it is necessary to process the content into the overlay network. In the content input process, for example, the system administrator determines the content to be input, and registers the determined content in the server device for content input. For example, the content input server device assigns identification information to the content and stores the content in one or more node devices. Then, for example, the content can be acquired from the overlay network by making the node device storing the content searchable based on the identification information of the content. However, in the conventional peer-to-peer communication system, the above-described human work is required during the content input process. In other words, since it takes time and effort to input content, it has not been possible to input content efficiently.

  Therefore, the present invention has been made in view of the above points. It is an object of the present invention to provide a node device, an information communication system, an information processing method, and an information processing program that can save time and labor for manually inputting content into an overlay network.

  In order to solve the above problem, the invention according to claim 1 is the node device in the information communication system in which an overlay network is configured by a plurality of node devices connected to the network, and a client device that requests content Based on the analysis result by the receiving means, the receiving means for receiving the packet indicating the request for the content to the server device, the analyzing means for analyzing the packet received by the receiving means, The specifying means for specifying the content requested from the client device, the first acquiring means for acquiring the content specified by the specifying means from the server device, and the specifying based on the analysis result by the analyzing means The content specified by the means is the overlay network. A first determination unit that determines whether or not the input condition is satisfied, and at least one content acquired by the first acquisition unit when the first determination unit determines that the input condition is satisfied And a loading unit that performs a loading process that causes the node device to store the content saved by the node device from the overlay network.

  According to the present invention, when the content requested from the client device and acquired from the server device by the node device satisfies the input condition, the content is input to the overlay network by the node device. Therefore, it is possible to save time and labor for manually inputting content to the overlay network.

  The invention according to claim 2 further comprises second determination means for determining whether or not the content specified by the specifying means can be acquired from the overlay network, and the first acquisition means includes the specifying means. When the second determining means determines that the content specified by the above cannot be acquired from the overlay network, the content specified by the specifying means is acquired from the server device.

  According to the present invention, among the contents that cannot be acquired from the overlay network, the content that satisfies the input condition is input to the overlay network. Therefore, unnecessary input processing can be reduced.

  According to a third aspect of the present invention, the receiving unit receives the packet including specific information for specifying the content requested from the client device, and the specifying unit is configured to receive the packet by analysis by the analyzing unit. The content requested from the client device is identified based on the identification information acquired from the packet received by the means.

  According to the present invention, the requested content can be specified from the content of the packet transmitted from the client device.

  According to a fourth aspect of the present invention, the receiving means includes, as the specific information, identification information for identifying content requested from the client device, and type information indicating a type of content requested from the client device. And the specifying unit specifies the content requested from the client device and the type of the content based on the identification information and the type information acquired by the analysis by the analyzing unit. The first determination unit determines whether or not the type of content specified by the specifying unit is a type of content input to the overlay network, and the input unit is specified by the specifying unit. Is the type of content that is input to the overlay network. When it is determined by said first determination means, and performing the closing process.

  According to the present invention, for example, the administrator determines whether the acquisition efficiency is better when the content is acquired from the overlay network or the server device, and sets the type of content to be input to the overlay network as the input condition can do.

  According to a fifth aspect of the present invention, the node device is a network device that is steadily connected to a network, and is a network device that connects a plurality of networks.

  According to the present invention, by replacing the network device with the node device of the present invention, it is possible to save time and labor for manually inputting content into the overlay network.

  The invention according to claim 6 is characterized in that the at least one node device is a network device that connects a network to which the node device is connected and a network to which the server device is connected.

  According to the present invention, the content transmitted from the server device to the client device is received by the node device that connects the network to which the node device is connected and the network to which the server device is connected. Therefore, the content transmitted from the server device can be reliably input to the overlay network.

  The invention according to claim 7 is characterized in that the network device is a router.

  According to the present invention, by replacing the router with the node device of the present invention, it is possible to save time and labor for manually inputting content into the overlay network.

  According to an eighth aspect of the present invention, the receiving means receives, as the packet, a TCP (Transmission Control Protocol) packet including name information indicating the name of the server device and location information indicating the location of the node device. Received from the client device, the first obtaining unit obtains the content specified by the specifying unit from the server device in which the name information included in the TCP packet received by the receiving unit indicates a name. It is characterized by that.

  Originally, in TCP, content cannot be transmitted / received unless a connection is established between a client device and a server device. According to the present invention, when the client device acquires the location information of one of the node devices when the name of the server device to which the content is requested is resolved by DNS or the like, the client device Connecting. Then, the client device transmits a TCP packet indicating a content request to the node device connected by TCP. The node device that is TCP-connected to the client device can acquire the requested content from the server device and transmit it to the client device based on the name information included in the received TCP packet.

  The invention according to claim 9 comprises a client device that requests content, a server device that transmits the requested content, and a plurality of node devices connected to a network, and the plurality of node devices can provide an overlay network. The client device includes a transmission unit that transmits a packet indicating a request for content to the server device to the network, and the node device is transmitted from the client device. Receiving means for receiving the packet; analyzing means for analyzing the packet received by the receiving means; and specifying means for specifying content requested from the client device based on an analysis result by the analyzing means; The server specifies the content specified by the specifying means First determination means for acquiring from a position, first determination means for determining whether the content specified by the specifying means satisfies the input condition to the overlay network based on the analysis result by the analysis means, When it is determined by the first determination unit that the input condition is satisfied, the content acquired by the first acquisition unit is stored in at least one of the node devices, and the content stored by the node device is stored in the Input means for performing input processing that enables acquisition from the overlay network.

  The invention according to claim 10 is an information processing method by the node device in an information communication system in which an overlay network is configured by a plurality of node devices connected to the network, and is transmitted from a client device requesting content. A reception step of receiving a packet indicating a request for content to the server device; an analysis step of analyzing the packet received in the reception step; and an analysis result in the analysis step, the client A specifying step for specifying the content requested from the device, a first acquisition step for acquiring the content specified in the specifying step from the server device, and an analysis result in the analyzing step. A first determination step for determining whether or not the content satisfies the input condition to the overlay network; and when it is determined in the first determination step that the input condition is satisfied, the content is acquired in the first acquisition step A loading step of performing a loading process for storing the content in at least one of the node devices and acquiring the content stored by the node device from the overlay network.

  The invention according to claim 11 is a packet transmitted from a client device that requests content to a computer included in the node device in an information communication system in which an overlay network is configured by a plurality of node devices connected to the network. A receiving step for receiving a packet indicating a request for content to the server device; an analyzing step for analyzing the packet received in the receiving step; and an analysis result in the analyzing step, based on the analysis result from the client device. A specifying step for specifying the requested content; a first acquisition step for acquiring the content specified in the specifying step from the server device; and an analysis result in the analyzing step. A first determination step for determining whether the content satisfies the input condition to the overlay network, and when it is determined in the first determination step that the input condition is satisfied, the first acquisition step A loading step of performing a loading process for storing content in at least one of the node devices and acquiring the content stored by the node device from the overlay network.

  According to the present invention, when the content requested from the client device and acquired from the server device by the node device satisfies the input condition, the content is input to the overlay network by the node device. Therefore, it is possible to save time and labor for manually inputting content to the overlay network.

It is a figure showing an example of outline composition of contents distribution system S concerning one embodiment. It is a figure which shows an example of the operation | movement outline | summary in the content delivery system S which concerns on one Embodiment. It is a figure which shows an example of the operation | movement outline | summary in the content delivery system S which concerns on one Embodiment. It is a figure which shows the example of a schematic structure of router Rm. It is a figure which shows the example of a schematic structure of user terminal Tm-n. It is a flowchart which shows the process example in the process at the time of the connection establishment request | requirement reception of the control part 21 of router Rm in one Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distribution system.

[1. Overview of content distribution system]
First, a schematic configuration of the content distribution system according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a schematic configuration example of a content distribution system S according to the present embodiment. As shown in FIG. 1, in the content distribution system S, a distribution center network NS and a plurality of base networks NLm (m = 1, 2, 3,...) Are connected to a network NW. This network NW, distribution center network NS, and each base network NLm are real-world communication networks.

  The network NW is a network for interconnecting the distribution center network NS and each base network NLm. The network NW is, for example, a WAN (Wide Area Network). The network NW includes, for example, IX (Internet eXchange), ISP (Internet Service Provider), DSL (Digital Subscriber Line) line provider apparatus, FTTH (Fiber To The Home) line provider apparatus, communication line, etc. Is built by. The network NW may be a network dedicated to the content distribution system S.

  The distribution center network NS is, for example, a network constructed in the site of the distribution center. This distribution center network NS is constructed by, for example, a LAN (Local Area Network) or the like. A content distribution server SD is connected to the distribution center network NS. The content distribution server SD is a Web server that transmits content to the user terminal Tm-n or the like in response to an HTTP (HyperText Transfer Protocol) request from the user terminal Tm-n or the like which will be described later. A predetermined domain name is assigned to the content distribution server SD. A plurality of distribution centers may exist. A content distribution server SD to which a domain name is individually assigned may be connected to the network of each distribution center. The content distribution server SD is an example of a server device in the present invention.

  Each base network NLm is a network constructed in the site of the base m. Examples of the base include a company, a store, a school, a hospital, and a cram school. This base network NLm is constructed by a LAN or the like, for example. A plurality of user terminals Tm-n (n = 1, 2, 3...) Are connected to each base network NLm. The user terminal Tm-n is, for example, a personal computer. In FIG. 1, illustration of some base networks NLm and illustration of user terminals Tm-n connected to the base networks NLm are omitted. The user terminal Tm-n is an example of a client device in the present invention.

  A router Rm is steadily connected to each of the distribution center network NS and the base network NLm. The router Rm interconnects the distribution center network NS or the base network NLm and the network NW. The router Rm is, for example, a firewall having a router function, a broadband router, or the like. The router Rm is an example of a node device in the present invention.

  A router DNS (Domain Name System) server SR and a terminal DNS server ST are further connected to the network NW. The router DNS server SR and the terminal DNS server ST are DNS servers that convert a domain name into an IP (Internet Protocol) address of a host corresponding to the domain name. Here, the router DNS server SR is accessed from the router Rm. On the other hand, the terminal DNS server ST is accessed from the user terminal Tm-n.

[2. Overview of peer-to-peer network]
In the content distribution system S, a P2P network PW that is a peer-to-peer network for distributing content to the user terminals Tm-n is constructed. As shown in FIG. 1, the P2P network PW is a logical overlay network constructed on the network NW. The P2P network PW is a network formed by connecting a plurality of routers Rm that constitute the content distribution system S. In the following description, the router Rm connected to the P2P network PW is referred to as a “node”.

  The P2P network PW is realized by a specific algorithm, for example, an algorithm using a DHT (Distributed Hash Table). Each node connected to the P2P network PW is assigned a node ID, which is unique identification information having a predetermined number of digits. The P2P network PW shown in FIG. 1 shows the ID space of the node ID as a ring. The position of each node shown in the ring-shaped ID space of FIG. 1 corresponds to each node ID.

  Each node holds a routing table using DHT. This routing table is referred to as a “DHT routing table”. The DHT routing table defines various message transfer destinations on the P2P network PW. Specifically, a plurality of pieces of node information including node IDs, IP addresses, and port numbers of nodes that are moderately separated in the ID space are registered in the DHT routing table. One node connected to the content distribution system S stores the minimum necessary node information as a DHT routing table. By transferring various messages between the nodes, node information about nodes that do not store node information is acquired.

  In the P2P network PW, various contents having different contents are distributed and stored in a plurality of nodes. Hereinafter, a node that stores content is referred to as a “content holding node”. Examples of the content include a web page, still image data, moving image data, audio data, text data, and an electronic document. Each content is given a content ID, which is identification information unique to each content. Attribute information such as the content ID of each content is described in the content catalog information. The content catalog information is created by any node and distributed to all nodes. The DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  The location of the content that is distributed and stored is stored as index information by a node that manages (stores) the location of the content. Hereinafter, the node that manages the location of the content is referred to as a “root node”. The index information includes a set of node information of the node that stores the content, content ID of the content, and the like. Such a root node is determined to be a node having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, the node ID with the highest number of upper digits that match.

  Then, when a certain node tries to acquire a certain content, the node generates a search message. Hereinafter, a node from which content is to be acquired is referred to as a “user node”. The search message includes the content ID of the content to be acquired, the IP address of the user node, and the like. The search message is a message for searching for a content holding node. A search message is sent to other nodes according to the DHT routing table stored by the user node. That is, the user node sends a search message toward the root node. As a result, the search message finally arrives at the root node by DHT routing using the content ID as a key.

  The root node that has received the search message acquires index information corresponding to the content ID included in the search message from the index information cache. The root node returns a reply message including the acquired index information to the user node that is the transmission source of the search message. The user node that has acquired the index information in this way can download (acquire) the content based on the index information. The user node transmits a content request message to the content holding node based on the IP address and port number of the content holding node included in the index information. The content request message includes the content ID of the content to be acquired. The content holding node that has received the content request message transmits (uploads) the content corresponding to the content ID included in the content request message to the user node. In this way, the user node downloads the content.

  The user node generates a publish message when acquiring and storing content from the content holding node. The publish message is a message for informing the root node that the content has been saved. The publish message includes the content ID of the content and node information of the node device that stores the content. The publish message is sent toward the root node. As a result, the publish message arrives at the root node by DHT routing using the content ID as a key, like the search message. Then, the root node receives the publish message. The root node stores index information including a set of node information and content ID included in the publish message in the index information cache area. Thus, the user node becomes a new content holding node that holds the content.

[3. Content distribution and content input to P2P network]
Next, content distribution in the content distribution system S and content input to the P2P network will be described with reference to FIGS.

  In the content distribution system S, content distributed from the content distribution server SD to the user terminal Tm-n is input to the P2P network PW. Content input refers to storing content in at least one router Rm among a plurality of routers Rm so that the content can be acquired from the P2P network PW. The content requested for the first time from the user terminal Tm-n in the content distribution system S is stored only by the content distribution server SD. Therefore, the content request from the user terminal Tm-n is transferred to the content distribution server SD by the router Rm, and the requested content is transmitted from the content distribution server SD to the user terminal Tm-n. At this time, in the process in which the content is transferred by the router Rm, the router Rm automatically inputs the content. When the user terminal Tm-n requests the content once input to the P2P network PW, the content is acquired from the P2P network PW by the router Rm that has received the request. Then, the content acquired from the P2P network PW is transmitted to the user terminal Tm-n. Thereby, the user terminal Tm-n can efficiently acquire the content, and the load on the content distribution server SD can be reduced. In addition, since content is automatically input without human intervention, it is possible to input content efficiently. However, the router Rm inputs the requested content to the P2P network PW only for requests that conform to the P2P operation rule among the requests from the user terminal Tm-n. That is, only content corresponding to a request that conforms to the P2P operation rule as an input condition is placed in a state that can be acquired from the P2P network PW by the P2P operation. The P2P operation means that each router Rm acquires content from the P2P network PW by transmitting and receiving P2P control messages such as a search message, a reply message, and a content request message.

  When the user terminal Tm-n requests content, the user terminal Tm-n transmits a packet indicating the content request to the content distribution server SD. Here, a packet indicating a content request is referred to as a “content request packet”. The content request packet reaches the content distribution server SD via a plurality of routers Rm. At this time, the router Rm analyzes the content request packet when transferring the content request packet toward the content distribution server SD. The router Rm specifies the requested content based on the analysis result of the content request packet, and determines whether or not the P2P operation rule is met. Based on the determination result, the router Rm determines whether the requested content is retrieved from the P2P network PW or acquired from the content distribution server SD. Further, the router Rm determines from the search result from the P2P network PW that the requested content is acquired from the content distribution server SD even when the requested content cannot be acquired from the P2P network PW. When the router Rm acquires the requested content from the content distribution server SD, the router Rm transfers the acquired content toward the user terminal Tm-n. At this time, when the router Rm determines that the content of the content distribution server SD conforms to the P2P operation rule based on the analysis result of the content request packet, the router Rm inputs the content to the P2P network PW.

  If all the content from the content distribution server SD is input to the P2P network PW, ideally all the content should be finally acquired from the P2P network PW. However, the capacity in which the router Rm can store content is also limited. Therefore, when the storage capacity is not sufficient, the router Rm must delete the content stored in the past in order to store new content, for example. Therefore, the router Rm separates the request from the user terminal Tm-n into a request to input content and a request not to input content. With the P2P operation rule, for example, it is possible to distinguish between content that is acquired more efficiently from the content distribution server SD and content that is acquired more efficiently from the P2P network PW. Thereby, user terminal Tm-n can acquire a content more efficiently.

  Next, an outline of content distribution and input operations will be described. 2 and 3 are diagrams illustrating an example of an operation outline in the content distribution system S according to the present embodiment. For example, the user terminal T2-1 displays a certain web page on the screen. When the user selects a link to the content from the displayed Web page, the user terminal T2-1 acquires the URL (Uniform Resource Locator) of the selected link. Further, the user terminal T2-1 extracts a domain name indicating the server that requested the content from the acquired URL. Then, as illustrated in FIG. 2, the user terminal T2-1 resolves the acquired domain name. Specifically, the user terminal T2-1 transmits an inquiry message including the domain name to the terminal DNS server ST (FIG. 2 (1)).

  It is assumed that the domain name included in the inquiry message received by the terminal DNS server ST is the domain name of the content distribution server SD. In this case, the terminal DNS server ST does not convert the domain name into the IP address of the content distribution server. Instead, the terminal DNS server ST converts, for example, the IP address of the router R5 among the plurality of routers Rm by DNS round robin. Then, the terminal DNS server ST returns the IP address of the router R5 to the user terminal T2-1 (FIG. 2 (2)). In order to perform such processing, the terminal DNS server ST stores the domain name of the content distribution server SD and the IP address of each router Rm in association with each other. Except for this point, the content distribution server SD has the same configuration and function as a general DNS server.

  The reason why the IP address of the router Rm is returned to the user terminal Tm-n will be described. In TCP (Transmission Control Protocol), a TCP connection is established between a client and a server. The client can acquire the content only from the server that established the TCP connection. That is, even if any router Rm stores the content requested by the user terminal Tm-n, the user terminal Tm-n cannot acquire the content unless it is from the content distribution server SD. Therefore, the IP address of the router Rm is returned so that the user terminal Tm-n establishes a TCP connection with the router Rm. The user terminal Tm-n can acquire the content from the content distribution server SD or the content from the P2P network PW via the router Rm that has established the TCP connection. In this case, when viewed from the user terminal Tm-n, the router Rm is a server. Also, when viewed from the content distribution server SD, the router Rm becomes a client.

  Since the user terminal T2-1 receives the IP address of the router R5, the user terminal T2-1 establishes a TCP connection with the router R5. Then, the user terminal T2-1 transmits an HTTP request TCP packet to the router R5 (FIG. 2 (3)). The TCP packet of this HTTP request is a content request packet. In the HTTP request line of the TCP payload of this content request packet, the URL acquired from the Web page is set as the request URL. In the Host header field of the TCP payload of the content request packet, the domain name of the content distribution server is set as information indicating the request destination server. The IP address of the router R5 is set as the destination IP address in the IP header of the content request packet. The request URL is an example of identification information in the present invention. The extension portion of the content included in the request URL is an example of type information in the present invention. The domain name included in the Host header field is an example of name information in the present invention. The IP address of the router Rm set as the destination IP address is an example of location information in the present invention.

  The router R5 that has received the content request packet analyzes the content of the content request packet and determines whether or not the communication from the user terminal T2-1 is communication that conforms to the P2P operation rule (FIG. 2 (4)). ). In analyzing the content request packet, the router R5 identifies the format of the content request packet based on information set in the header of the content request packet. Then, the router R5 acquires information for specifying communication contents from the content request packet according to the specified format. For example, the router R5 includes, as communication contents, a transport layer protocol, an application layer protocol, a content requesting server, a requested content type, a data size, a content position on the server, and the like. It is determined whether or not the P2P operation rule is met. As an example, if all of the conditions that the protocol is TCP and HTTP, the content request destination is the content distribution server SD, the content type is a moving image, and the data size is 10 Mbytes or more, it is determined that the P2P operation rule is satisfied.

  When the router R5 determines that the P2P operation rule is met, the router R5 searches the P2P network PW for the requested content. Then, the router R5 determines whether or not the requested content has been retrieved from the P2P network PW. That is, the router R5 determines whether or not the requested content can be acquired from the P2P network PW. For example, the router R5 determines whether or not the requested content attribute information is described in the content catalog information. Further, for example, the router R5 determines whether there is a content holding node by searching for the content holding node of the requested content.

  When the requested content is not obtainable from the P2P network PW (FIG. 2 (5)), the router R5 transfers the content request packet received from the user terminal T2-1 to the content distribution server SD (FIG. 2 ( 6)). In order to perform this transfer, the router R5 needs to acquire the IP address of the content distribution server SD. Therefore, the router R5 transmits an inquiry message including the domain name set in the Host header field of the TCP payload of the received content request packet to the router DNS server SR. Unlike the terminal DNS server ST, the router DNS server has the same configuration and function as a general DNS server. Therefore, the router DNS server SR returns the IP address of the content distribution server SD.

  The content distribution server SD that has received the HTTP request returns the content corresponding to the URL set in the HTTP request line to the router R5 (FIG. 2 (7)). The router R5 transmits the content received from the content distribution server SD to the user terminal T2-1 (FIG. 2 (8)).

  Further, since the content conforms to the P2P operation rule, the router R5 inputs the content received from the content distribution server SD into the P2P network PW (FIG. 2 (9)). With this input process, the content transmitted from the content distribution server SD to the user terminal T2-1 is stored by, for example, the router R3 and can be searched from the P2P network PW. If the content does not conform to the P2P operation rule, the processes of FIGS. 2 (6) to 2 (8) are performed, but the process of FIG. 2 (9) is not performed.

  Thereafter, for example, the user terminal T1-2 tries to acquire the same content as the content acquired by the user terminal T2-1. Therefore, as shown in FIG. 3, the user terminal T1-2 makes an inquiry to the terminal DNS server ST as in the case of the user terminal T2-1 (FIG. 3 (10)), and returns the IP address. (FIG. 3 (11)). At this time, the user terminal T1-2 receives the IP address of the router R4, for example. Therefore, the user terminal T1-2 establishes a TCP connection with the router R4 and transmits a content request packet to the router R4 (FIG. 3 (12)).

  The router R4 determines that the communication conforms to the P2P operation rule (FIG. 3 (13)). Therefore, the router R4 searches the requested content from the P2P network PW, and determines whether the requested content has been retrieved. Since it becomes clear that the router R3 stores the content, the router R4 determines that the content has been searched (FIG. 3 (14)). Therefore, the router R4 acquires content from the router R3 (FIG. 3 (15)), and transmits the acquired content to the user terminal T1-2 (FIG. 3 (16)).

[4. Configuration and function of each device]
Next, the configuration and function of each apparatus will be described with reference to FIGS. FIG. 4 is a diagram illustrating a schematic configuration example of the router Rm. FIG. 5 is a diagram illustrating a schematic configuration example of the user terminal Tm-n.

[4.1 Router configuration]
As shown in FIG. 4, the router Rm includes a control unit 21 including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and the like. In addition, the router Rm includes a storage unit 22 composed of an HD (hard disk) or the like for storing and storing various data and various programs. Furthermore, the router Rm is a communication unit for controlling communication of information with other routers Rm, content distribution servers SD, user terminals Tm-n, etc. through the network NW, distribution center network NS, base network NLm, etc. 23. The control unit 21, the storage unit 22, and the communication unit 23 are connected to each other via a bus 24.

  The storage unit 22 stores a DHT routing table, a routing table used for routing at the network layer level, content catalog information, and index information. A routing table used for routing at the network layer level is referred to as an “L3 routing table”. The storage unit 22 stores the IP address of the router DNS server SR and the like as the DNS server IP address. The storage unit 22 stores the downloaded content in association with the content ID.

  The storage unit 22 stores P2P operation rule definition information indicating a P2P operation rule. The P2P operation rule definition information is created by an administrator, for example. Then, for example, the P2P operation rule definition information is distributed from a predetermined router Rm to all routers Rm. The P2P operation rule definition information includes, for example, the transport layer protocol, the application layer protocol, the domain name of the server that requests the content, the extension indicating the content type, the data size of the content, and the location of the content on the server Are set as conditions for the P2P operation. The administrator may set one of these conditions as a P2P operation condition, or may combine a plurality of conditions as a P2P operation condition. When a plurality of conditions are set as conditions for the P2P operation, the communication contents conform to the P2P operation rules when the communication contents satisfy all the conditions.

  Further, the storage unit 22 stores an operating system and various programs (including the information processing program of the present invention). Various programs may be downloaded from a predetermined server device or the like, for example. Various programs may be recorded on a recording medium such as a DVD (Digital Versatile Disc) and read from the recording medium via a drive.

  The control unit 21 reads and executes a program stored in the storage unit 22 or the like by the CPU, thereby receiving means, analysis means, first acquisition means, first determination means, input means, second determination means, identification means. Function as.

[4.2 User terminal configuration]
As shown in FIG. 5, each user terminal Tm-n includes a control unit 31 as a computer including a CPU having a calculation function, a working RAM, a ROM that stores various data and programs, and the like. In addition, each user terminal Tm-n includes a storage unit 32 configured by an HD or the like for storing and saving various data, various programs, and the like, and a buffer memory 33 that temporarily stores received content and the like. . Furthermore, each user terminal Tm-n includes a decoder unit 34 that decodes encoded video data (video information), audio data (audio information), and the like included in the content. Furthermore, each user terminal Tm-n performs a predetermined drawing process on the decoded video data or the like and outputs it as a video signal, and outputs the video signal output from the video processing unit 35 to the video signal. And a display unit 36 such as a CRT or a liquid crystal display for displaying an image on the basis thereof. Furthermore, each user terminal Tm-n converts the decoded audio data into an analog audio signal by D (Digital) / A (Analog) conversion, amplifies this by an amplifier, and outputs it, And a speaker 38 that outputs an audio signal output from the sound processing unit 37 as a sound wave. Furthermore, each user terminal Tm-n includes a communication unit 39 for controlling communication of information with the router Rm, the content distribution server SD, and the like through the network NLm. Furthermore, each user terminal Tm-n receives an instruction from the user, and inputs an instruction signal corresponding to the instruction to the control unit 31 (for example, a keyboard, a mouse, a remote controller or an operation panel). It has. The control unit 31, the storage unit 32, the buffer memory 33, the decoder unit 34, the communication unit 39, and the input unit 40 are connected to each other via a bus 41.

  The storage unit 32 stores, for example, the IP address of the terminal DNS server ST as the DNS server IP address. The storage unit 32 stores the IP address of the router Rm connected to the same base network NLm as the user terminal Tm-n itself as the default gateway IP address. The storage unit 32 stores downloaded content. The storage unit 32 stores an operating system, a browser, and other various application programs. The various application programs may be downloaded from a predetermined server device, for example. Various application programs may be recorded on a recording medium such as a DVD (Digital Versatile Disc) and read from the recording medium via a drive.

  The control unit 31 functions as a second acquisition unit, a solution unit, and a transmission unit when the CPU reads and executes a program stored in the storage unit 32 or the like.

[5. Operation of content distribution system]
Next, the operation of the content distribution system S in this embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing a processing example in the connection establishment request reception processing of the control unit 21 of the router Rm in this embodiment.

  The user terminal Tm-n makes an inquiry to the terminal DNS server ST, thereby acquiring the IP address of one of the routers Rm as the IP address of the server such as the content distribution server SD that is the content request destination. Next, the user terminal Tm-n transmits a connection establishment request packet for establishing a TCP connection to the router Rm as the default gateway. The IP address of the router Rm acquired from the terminal DNS server ST is set as the destination IP address of this packet. Each router Rm that has received the connection establishment request packet forwards the received packet toward the router Rm indicated by the destination IP address based on the L3 routing table. The connection establishment request reception process is started when the router Rm indicated by the destination IP address receives a connection establishment request packet.

  The control unit 21 of the router Rm that has received the connection establishment request packet establishes a TCP connection with the user terminal Tm-n that is the transmission source of the connection establishment request packet based on the TCP protocol (step S1). Then, since the user terminal Tm-n transmits a content request packet, the control unit 21 receives the content request packet (step S2).

  Next, the control unit 21 analyzes the communication content based on the content of the received content request packet (step S3). For example, the control unit 21 specifies the transport layer protocol based on the protocol number set in the IP header. For example, the control unit 21 specifies the protocol of the application layer based on the destination port number set in the TCP header. Further, for example, the control unit 21 specifies a request destination server based on the domain name set in the Host header field of the TCP payload. Further, for example, the control unit 21 specifies the requested content and the position of the requested content on the server based on the path name of the content set in the request line of the TCP payload. Further, for example, the control unit 21 specifies the type of content based on the content extension included in the content path name set in the request line of the TCP payload. The data size of the content cannot be specified only by the content of the content request packet. Therefore, the control unit 21 acquires an HTTP header related to the requested content from the server that requested the content. And the control part 21 specifies the data size of a content based on the content length set to the acquired HTTP header. Note that these analyzes are performed only on information corresponding to the conditions set in the P2P operation rule.

  Next, the control unit 21 determines whether the communication conforms to the P2P operation rule based on the analysis result of the communication content (step S4). Specifically, the control unit 21 makes a determination based on the communication content determined from the analysis result and the information set in the P2P rule definition information. At this time, when it is determined that at least one of the communication contents does not conform to the P2P operation rule (step S4: NO), the control unit 21 does not input the content requested from the user terminal Tm-n. In this case, the control unit 21 establishes a connection with the server that requests the content (step S5). Specifically, the control unit 21 transmits to the router DNS server SR an inquiry message including the domain name of the server that requested the content acquired from the received content request packet. Next, the control unit 21 receives the IP address converted from the domain name by the router DNS server SR from the router DNS server SR. This IP address is, for example, the IP address of the content distribution server SD. Then, the control unit 21 transmits a connection establishment request packet in which the received IP address is set as the destination IP address. As a result, the control unit 21 establishes a connection with the server that requests the content.

  Next, the control unit 21 transfers the content request packet received from the user terminal Tm-n to the server that requests the content (step S6). Therefore, the control unit 21 rewrites the destination IP address of the content request packet with the IP address received from the router DNS server SR.

  Next, the control unit 21 receives the content transmitted in response to the content request packet from the server that requested the content (step S7). Next, the control unit 21 transmits the received content to the requesting user terminal Tm-n (step S8). When the process of step S8 is completed, the control unit 21 ends the connection establishment request reception process.

  In step S4, if the control unit 21 determines that all the communication contents specified from the content request packet conform to the P2P operation rule (step S4: YES), the control unit 21 transmits the content requested from the user terminal Tm-n to the P2P network. Search from PW (step S9). Specifically, the control unit 21 generates the content ID of the requested content by hashing the path name acquired from the received content request packet. Next, the control unit 21 searches the content catalog information for attribute information including the generated content ID. Then, when the attribute information including the generated content ID can be searched from the content catalog information, the control unit 21 transmits a search message including the generated content ID to the root node. Then, the control unit 21 receives an answer message from the root node.

  Next, the control unit 21 determines whether or not the content has been searched (step S10). When the attribute information including the generated content ID cannot be searched from the content catalog information, or the response message received from the root node includes one index information of the content holding node. If not, it is determined that the content could not be searched (step S10: NO). In this case, the control unit 21 transmits the content received from the server to the user terminal Tm-n by performing the same processing as the processing of steps S5 to S8 (steps S11 to S14).

  Next, the control unit 21 inputs the content received from the server into the P2P network PW (step S15). Specifically, the control unit 21 arbitrarily selects node information of one or more routers Rm from the DHT routing table. Then, based on the selected node information, the control unit 21 transmits a content storage request message including the content received from the server and the generated content ID to one or more routers Rm. In addition, the control unit 21 updates the content catalog information by adding the attribute information of the content received from the server to the content catalog information. For example, the control unit 21 adds attribute information including a content ID, a content path name, a content data size, a content last update date, and the like. The control unit 21 distributes the updated content catalog information to all routers Rm. This distribution may be performed by, for example, overlay multicast.

  The router Rm that has received the content storage request message causes the storage unit 22 to store the content included in the content storage request message. Then, the router Rm that stores the content transmits a publish message in which the content ID included in the received content storage request message is set to the root node.

  Note that the control unit 21 may store the content received from the server in the storage unit 22 and transmit a publish message for the content. That is, the router Rm that has received the content from the server may be the content holding node for the content. In this case, the control unit 21 does not need to transmit the content storage request message to the other router Rm. When finishing the process of step S15, the control unit 21 ends the connection establishment request reception process.

  In step S10, when the answer message received from the root node includes the index information of the content holding node, the control unit 21 determines that the content can be searched (step S10: YES). In this case, the control unit 21 acquires the content requested from the user terminal Tm-n from the P2P network PW (step S16). Specifically, the control unit 21 transmits a content request message to the content holding node based on the index information included in the answer message. And the control part 21 receives the content transmitted from the content holding node. Next, the control unit 21 transmits the content acquired from the P2P network PW to the requesting user terminal Tm-n (step S17). When the process of step S17 is completed, the control unit 21 ends the connection establishment request reception process.

  Note that the content input to the P2P network PW may be updated or deleted from the content distribution server SD. In such a case, it is necessary to reflect the update or deletion of the content in the content distribution server SD on the P2P network PW. For example, if the content can be retrieved from the P2P network PW, the control unit 21 acquires an HTTP header related to the requested content from the server.

  When the status code indicating that no content exists is set in the acquired HTTP header, the control unit 21 transfers the received HTTP header to the requesting user terminal Tm-n. Further, the control unit 21 deletes the requested content from the P2P network PW. Specifically, the control unit 21 deletes the requested content attribute information from the content catalog information. Further, the control unit 21 distributes the updated content catalog information to all the routers Rm. In addition, the control unit 21 distributes a deletion message including the content ID of the requested content to all the routers Rm. The router Rm that has received the deletion message deletes the content corresponding to the content ID included in the deletion message from the storage unit 22.

  On the other hand, when the status code indicating that the content exists is set in the acquired HTTP header, the control unit 21 is set in the last update date set in the HTTP header and the content catalog information. Compare the last update date of the content. Then, when the last update date has been updated, the control unit 21 deletes the old content that is the requested content from the P2P network PW in the same manner as described above. And the control part 21 acquires the updated content which is the requested | required content from a server, and transmits to user terminal Tm-n. In addition, the control unit 21 inputs the updated content to the P2P network PW.

  In the above embodiment, the P2P operation rule allows the case where the protocol is TCP and HTTP. However, P2P operation rules may be set to allow protocols other than these protocols.

  For example, when the P2P operation rule permits a connectionless protocol such as UDP (User Datagram Protocol), a part of the operation of the content distribution system S is different from the above embodiment. An operation when the P2P operation rule permits UDP will be described. As the protocol for the application layer, for example, a uniquely designed protocol may be used as a protocol for transmitting and receiving content. In this case, for example, a path name as communication information identification information, a communication identifier, and the like are set in the payload of a packet indicating a content request. The communication identifier is information for identifying one session of communication between the client and the server. As the communication identifier, for example, identification information arbitrarily generated by the user terminal Tm-n is set. Note that a packet indicating a request for content in this case is also referred to as a “content request packet”. In addition, as a response to the content request packet, for example, a part of the content, a communication identifier, and the like are set in the payload of each packet constituting the content. As the communication identifier in this case, the communication identifier set in the content request packet received by the content distribution server SD is set as it is. Note that a packet constituting the content is referred to as a “content packet”.

  Whether or not the user terminal Tm-n needs to acquire the IP address of the content requesting server from the domain name of the requesting server depends on the application layer protocol. Even when it is necessary to acquire the IP address of the server from the domain name, a DNS server that converts the domain name of the content distribution server SD into the IP address of the router Rm is unnecessary. The user terminal Tm-n may make an inquiry to a general DNS server.

  The user terminal Tm-n transmits a content request packet to the router Rm as a default gateway. In the destination IP address of the content request packet, the IP address of the server that requests the content, for example, the content distribution server SD is set.

  The router Rm that has received the content request packet analyzes the communication content and determines whether the communication conforms to the P2P operation rule. When the router Rm determines that the communication does not conform to the P2P operation rule, the router Rm forwards the content request packet to the content distribution server SD based on the L3 routing table. That is, the router Rm performs a normal operation as a router. On the other hand, when the router Rm that has received the content request packet determines that the communication conforms to the P2P operation rule, the router Rm identifies the requested content based on the path name set in the content request packet. Then, the router Rm retrieves the requested content from the P2P network PW based on the content path name. When the requested content can be retrieved from the P2P network PW, the router Rm acquires the requested content from the P2P network PW. Then, the router Rm transmits the acquired content to the requesting user terminal Tm-n.

  On the other hand, when the requested content cannot be retrieved from the P2P network PW, the router Rm forwards the content request packet to the content distribution server SD based on the L3 routing table. However, in this case, the router Rm acquires, for example, the destination IP address, the source IP address, the content path name, and the communication identifier from the received content request packet. Then, the router Rm associates the acquired information and stores it in the storage unit 22 as communication management information. Each router Rm that has received the content request packet performs the above-described processing, so that the content request packet finally reaches the content distribution server SD. The content distribution server SD transmits each content packet constituting the requested content to the router Rm, for example, the router R5, connected to the distribution center network NS.

  The router R5 that has received the content packet acquires the destination IP address, the transmission source IP address, and the communication identifier from the content packet. The router R5 then sends the destination IP address of the communication management information = the source IP address of the content packet, the source IP address of the communication management information = the destination IP address of the content packet, and the communication identifier of the communication management information = the content packet. It is determined whether or not communication management information that satisfies the condition of a communication identifier is stored. When the router R5 determines that the communication management information satisfying the condition is not stored, the router R5 transfers the received content packet toward the requesting user terminal Tm-n. If the router R5 receives a content packet that conforms to the P2P operation rule, the router R5 determines that communication management information that satisfies the condition is stored. Therefore, the router R5 searches the P2P network PW for content configured by the received content packet based on the path name included in the communication management information that satisfies the condition. Unless the router R5 transfers the received content packet to the other router Rm, the other router Rm cannot input the content. Therefore, the router R5 cannot search for content. Therefore, the router R5 suspends transfer of the received content packet. When the router R5 receives all the content packets, the router R5 inputs the content configured by the content packets into the P2P network PW. This charging method is the same as in the above embodiment. The router R5 transfers each content packet toward the requesting user terminal Tm-n after the content input is completed.

  When the router Rm other than the router R5 receives the content packet, the router Rm tries to perform the same processing as the router R5. However, the content constituted by the received content packet has already been input by the router R5. Therefore, the routers Rm other than the router R5 can search for content from the P2P network PW. In this case, the router Rm transfers the received content packet toward the requesting user terminal Tm-n. In addition, the router Rm deletes the communication management information corresponding to the content packet from the storage unit 22. Upon receiving all the content packets, the requesting user terminal Tm-n restores the requested content based on the content packet.

  In the case of UDP, in order to determine whether or not the communication content conforms to the P2P operation rule, any router Rm needs to receive the content request packet. In addition, in order to input content to the P2P network PW, any router Rm needs to receive all content packets. The router Rm that can receive these packets is the router Rm connected to the distribution center network NS and the network NW. There is a case where a route through which a packet transmitted and received between the user terminal Tm-n and the content distribution server SD is transferred in the network NW is changed. Even in this case, these packets can be received by the router Rm connected to the distribution center network NS and the network NW.

  In the above embodiment, the router Rm analyzes the content request packet to determine whether or not the content from the content distribution server SD is to be input to the P2P network PW. However, when a content packet from the content distribution server SD to the user terminal Tm-n passes through the router Rm, the router Rm may analyze the content packet to determine whether to input it. The format of the IP header, TCP header, UDP header, etc. is basically the same between the content packet and the content request packet, but the format of the payload portion may be different. Therefore, the router Rm performs analysis corresponding to the format of the payload portion of the content packet.

  In the above embodiment, the router Rm that constitutes the P2P network PW is connected to the distribution center network NS and each base network NLm. However, the routers Rm may not be connected to all these networks. For example, when the P2P operation rule allows a connection-type protocol, an arbitrary router connected to the network NW can be set as the router Rm. This is because the terminal DNS server ST can connect the user terminal Tm-n to an arbitrary router. For example, when the P2P operation rule permits a connectionless protocol, at least one router Rm may be connected to the distribution center network NS and the network NW.

  In the above embodiment, the node device of the present invention is applied to the router. However, the node device of the present invention may be applied to a network device having a function of relaying information, such as a proxy server, a load balancer, and a web accelerator.

  Moreover, in the said embodiment, although the peer to peer network using DHT was applied to the overlay network, it is not restricted to this. For example, another peer-to-peer system or a system using an overlay network may be applied. As a peer-to-peer system that does not use DHT, for example, there is a hybrid peer-to-peer system.

21 control unit 22 storage unit 23 communication unit Rm router 31 control unit 32 storage unit 33 buffer memory 39 communication unit Tm-n user terminal SD content distribution server SR router DNS server ST terminal DNS server NLm base network NS distribution center network NW Network PW P2P network S Content distribution system

Claims (11)

The node device in the information communication system in which an overlay network is configured by a plurality of node devices connected to the network,
Receiving means for receiving a packet transmitted from a client device requesting content and indicating a request for content to the server device;
Analyzing means for analyzing the packet received by the receiving means;
Identification means for identifying the content requested from the client device based on the analysis result by the analysis means;
First acquisition means for acquiring content specified by the specifying means from the server device;
First determination means for determining whether the content specified by the specifying means satisfies the input condition to the overlay network based on the analysis result by the analysis means;
When the first determination unit determines that the input condition is satisfied, the content acquired by the first acquisition unit is stored in at least one node device, and the content stored by the node device is stored. An input means for performing an input process enabling acquisition from the overlay network;
A node device comprising: A second determination unit that determines whether the content specified by the specifying unit can be acquired from the overlay network;
When the second determination unit determines that the content specified by the specifying unit cannot be acquired from the overlay network, the first acquisition unit determines the content specified by the specification unit as the server device. The node device according to claim 1, wherein the node device is acquired from: The receiving means receives the packet including specific information for specifying content requested from the client device;
2. The content specifying unit requested by the client device based on the specific information acquired from the packet received by the receiving unit by the analysis by the analyzing unit. Alternatively, the node device according to claim 2. The receiving means receives the packet including, as the specific information, identification information for identifying content requested from the client device, and type information indicating the type of content requested from the client device,
The specifying unit specifies the content requested from the client device and the type of the content based on the identification information and the type information acquired by the analysis by the analyzing unit,
The first determination unit determines whether or not the type of content specified by the specifying unit is a type of content to be input to the overlay network;
The input unit performs the input process when the first determination unit determines that the type of content specified by the specifying unit is the type of content input to the overlay network. The node device according to claim 3.   5. The node device according to claim 1, wherein the node device is a network device that is regularly connected to a network, and is a network device that connects a plurality of networks. 6. .   The node device according to claim 5, wherein the at least one node device is a network device that connects a network to which the node device is connected and a network to which the server device is connected.   The node device according to claim 5, wherein the network device is a router. The receiving means receives, as the packet, a TCP (Transmission Control Protocol) packet including name information indicating the name of the server device and location information indicating the location of the node device from the client device,
The said 1st acquisition means acquires the content specified by the said specification means from the said server apparatus in which the said name information contained in the said TCP packet received by the said reception means shows a name. The node device according to any one of 1 to 7. An information communication system comprising a client device that requests content, a server device that transmits the requested content, and a plurality of node devices connected to the network, and an overlay network is configured by the plurality of node devices. And
The client device is
Transmission means for transmitting a packet indicating a request for content to the server device to the network;
The node device is
Receiving means for receiving the packet transmitted from the client device;
Analyzing means for analyzing the packet received by the receiving means;
Identification means for identifying the content requested from the client device based on the analysis result by the analysis means;
First acquisition means for acquiring content specified by the specifying means from the server device;
First determination means for determining whether the content specified by the specifying means satisfies the input condition to the overlay network based on the analysis result by the analysis means;
When the first determination unit determines that the input condition is satisfied, the content acquired by the first acquisition unit is stored in at least one node device, and the content stored by the node device is stored. An input means for performing an input process enabling acquisition from the overlay network;
An information communication system comprising: An information processing method by the node device in an information communication system in which an overlay network is configured by a plurality of node devices connected to the network,
A reception step of receiving a packet transmitted from a client device requesting content and indicating a request for content to the server device;
An analysis step of analyzing the packet received in the reception step;
A specifying step of specifying content requested from the client device based on an analysis result in the analyzing step;
A first acquisition step of acquiring the content specified in the specifying step from the server device;
A first determination step of determining whether the content specified in the specifying step satisfies a condition for input to the overlay network based on an analysis result in the analysis step;
When it is determined in the first determination step that the input condition is satisfied, the content acquired in the first acquisition step is stored in at least one of the node devices, and the content stored by the node device is stored. A loading step for performing a loading process that enables acquisition from the overlay network;
An information processing method comprising: A computer included in the node device in the information communication system in which an overlay network is configured by a plurality of node devices connected to the network,
A reception step of receiving a packet transmitted from a client device requesting content and indicating a request for content to the server device;
An analysis step of analyzing the packet received in the reception step;
A specifying step of specifying content requested from the client device based on an analysis result in the analyzing step;
A first acquisition step of acquiring the content specified in the specifying step from the server device;
A first determination step of determining whether the content specified in the specifying step satisfies a condition for input to the overlay network based on an analysis result in the analysis step;
When it is determined in the first determination step that the input condition is satisfied, the content acquired in the first acquisition step is stored in at least one of the node devices, and the content stored by the node device is stored. A loading step for performing a loading process that enables acquisition from the overlay network;
An information processing program for executing

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