JP2008234444A - Content distributed storage system, node device, node processing program, and server function control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distributed storage system, a node device, a node processing program, and a server function control method for preventing a user from being disturbed by operation sound. <P>SOLUTION: The content distributed storage system is provided with a plurality of node devices capable communicating with each other via a network so that a plurality of content data are distributed to be stored in a plurality of node devices. Each of the node devices is provided with a server function for transmitting content data related to a provision request to another node device when provision request information showing the provision request for content data is received from another node device via the network, a presence determination means determining whether there is a person in the periphery or not, and a control means stopping the server function while presence of the person is determined in periphery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In this kind of peer-to-peer communication system, there is known a content distributed storage system in which replicas (replicated data) of content data are distributed and distributed (distributed storage) to a plurality of node devices. Access dispersibility is improved. The location of the replica of the content data thus distributed and stored can be efficiently searched using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table)) as disclosed in Patent Document 1, for example. Yes. The DHT is stored in each node device, and node information (for example, including IP addresses and port numbers) indicating a plurality of node devices to which various messages are to be transferred is registered in the DHT. .

When a node device participating in the distributed content storage system desires to acquire desired content data, a message (query) for searching (discovering) the location of the replica of the content data is sent to other node devices. By sending the message, the message is transferred according to the DHT by the relay node device toward the managing node device where the replica of the content data is located, and finally the message arrives at the managing source node. Information indicating the location is acquired from the node device. As a result, the node device that sent the message requests the replica of the content data from the node device that stores the replica of the content data related to the search, and is provided with the replica of the content data. Can do.
JP 2006-197400 A

  By the way, the distribution operation in which the node device that stores the replica of the content data related to the search provides the replica in response to the request of the replica usually performs the operation of the node device that provides the replica. It is done without being informed.

  However, for example, when a distribution operation for providing a replica of the content data is performed in a situation where the user does not operate the node device to perform the content reproduction operation and the surroundings are quiet (particularly at night), the distribution is performed. The operation sound (especially the operation sound of the hard disk drive) becomes particularly noticeable, which is not preferable for the user.

  The present invention has been made in view of the above points and the like, and provides a distributed content storage system, a node device, a node processing program, and a server function control method that can prevent a user from being aware of operation sounds. The task is to do.

  In order to solve the above-described problem, the invention according to claim 1 is provided with a plurality of node devices that can communicate with each other via a network, and a plurality of content data are distributed and stored in the plurality of node devices. When receiving provision request information indicating a content data provision request from another node device via the network, the node device in the system sends the content data related to the provision request to the other node device. And a server function for determining whether or not there is a person in the surroundings, and a control means for stopping the server function while it is determined that a person is present in the surroundings. It is characterized by that.

  According to the present invention, since the server function is stopped while it is determined that there is a person around, it is possible to prevent the user from being aware of the operation sound.

  According to a second aspect of the present invention, in the node device according to the first aspect, the presence determination unit acquires information from a human sensor that senses a person existing in the vicinity, and based on the information, It is characterized by determining whether or not there is a person around.

  According to a third aspect of the present invention, in the node device according to the first or second aspect, information from a sound sensor that detects a surrounding sound is acquired, and based on the information, the surrounding sound exceeds a specified value. The sound judging means for judging whether or not the sound and the control means, when the surrounding sound is equal to or higher than a predetermined value, even while it is judged that there is a person in the surrounding, The server function is continued.

  According to the present invention, when the ambient sound is equal to or higher than the specified value, it is considered that the user does not care about the operation sound, so even if it is determined that there is a person around, the server By continuing the function, it is possible to respond to requests from other node devices.

  According to a fourth aspect of the present invention, in the node device according to any one of the first to third aspects of the present invention, the node device further includes a power-off instruction receiving unit that receives a power-off instruction. It is characterized in that it is determined whether or not there is a person in the surrounding area after being accepted.

  According to a fifth aspect of the present invention, in the node device according to any one of the first to fourth aspects, the control unit is configured to receive content from another node device via the network while the server function is stopped. When provision request information indicating a data provision request is received, information indicating that the content data related to the provision request cannot be provided is transmitted to the other node device.

  According to a sixth aspect of the present invention, in the node device according to any one of the first to fifth aspects, the server function is provided with a request to provide content data from another node device via the network. When the request information is received, a function of transmitting content data related to the provision request to the other node device is included.

  The invention of a node processing program according to a seventh aspect is characterized in that a computer is caused to function as the node device according to any one of the first to sixth aspects.

  The invention according to claim 8 is a content distributed storage system comprising a plurality of node devices capable of communicating with each other via a network, and a plurality of content data being distributed and stored in the plurality of node devices. A server function for transmitting content data related to the provision request to the other node device when receiving provision request information indicating a content data provision request from the other node device via the network; It is characterized by comprising presence determining means for determining whether or not a person is present in the surroundings, and control means for stopping the server function while it is determined that a person is present in the surroundings.

  The invention according to claim 9 is a server function of the node device in a content distributed storage system comprising a plurality of node devices capable of communicating with each other via a network, and a plurality of content data being distributed and stored in the plurality of node devices. In the control method, when provision request information indicating a content data provision request is received from another node device via the network, the content data related to the provision request is transmitted to the other node device. The node device having a server function includes a step of determining whether a person exists in the surroundings and a step of stopping the server function while it is determined that a person exists in the surroundings. It is characterized by.

  According to the present invention, since the server function is stopped while it is determined that there is a person in the vicinity, it is possible to prevent the user from being aware of the operation sound.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the 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 distributed storage system.

[ 1. Configuration of distributed content storage system ]
First, with reference to FIG. 1 and the like, a schematic configuration and the like of the content distributed storage system according to the present embodiment will be described.

  FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the distributed content storage system according to the present embodiment.

  As shown in the lower frame 101 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4a, 4b, DSL (Digital Subscriber Line) line operators (devices) 5a, 5b, FTTH (Fiber To The Home) (line device) 6 and communication line (for example, telephone line, optical cable, etc.) 7 etc., a network such as the Internet (real world communication network, an example of communication means) 8 is constructed. ing. Note that a router for transferring data (packets) is appropriately inserted in the network (communication network) 8 in the example of FIG.

  A plurality of node devices (hereinafter referred to as “nodes”) Nn (n = 1, 2, 3,...) Are connected to such a network 8. Each node Nn is assigned a unique manufacturing number and an IP (Internet Protocol) address. Such serial numbers and IP addresses are not duplicated among a plurality of nodes.

  The content distributed storage system S according to the present embodiment is a peer-to-peer network system formed by participation of any of a plurality of nodes Nn, as shown in the upper frame 100 of FIG. It has become. A network 9 shown in the upper frame 100 of FIG. 1 is an overlay network 9 (logical network) that forms a virtual link formed using the existing network 8. The overlay network 9 is realized by a specific algorithm, for example, an algorithm using a DHT (Distributed Hash Table).

  Each node Nn participating in the content distributed storage system S (in other words, the overlay network 9) is assigned a node ID, which is unique identification information consisting of a predetermined number of digits. For example, a value (for example, the bit length is 160 bits) obtained by hashing an IP address or a manufacturing number individually assigned to each node Nn with a common hash function (for example, SHA-1 etc.), as shown in FIG. Therefore, they are arranged in a uniform ID space without being distributed.

  In addition, participation in the content distributed storage system S is performed by any node Nn (for example, the node N8) that has not participated in any node Nn (for example, a contact node that always participates in the system S) that has not participated. This is done by sending a participation message indicating a participation request.

  As described above, the node ID obtained (hashed) by the common hash function has a very low probability of having the same value if the IP address or the manufacturing number is different. The node ID needs to have a number of bits that can accommodate the maximum number of nodes that can be operated. For example, if a 128-bit number is used, 2 ^ 128 = 340 × 10 ^ 36 nodes can be operated. Since the hash function is publicly known, detailed description thereof is omitted.

  Each node Nn holds a routing table using DHT. This routing table defines the transfer destinations of various messages on the content distributed storage system S, specifically, a node including the node ID, IP address, and port number of a node Nn that is moderately separated in the ID space Multiple pieces of information are registered.

  One node Nn participating in the content distributed storage system S registers the minimum necessary node information of the nodes Nn among all the nodes Nn participating in the system S in the routing table, With respect to the node Nn that does not know (store) the node information, various messages are transferred between the nodes Nn to be delivered.

  Here, the routing table using DHT will be described in detail with reference to FIGS.

  FIG. 2 is a diagram illustrating an example of a routing table using the DHT held by the node N2, and FIG. 3 is a conceptual diagram illustrating an example of an ID space of the DHT.

  2 and 3, for convenience of explanation, the bit length of the node ID is 2 bits × 3 digits = 6 bits, and each digit is represented by a quaternary number (an integer from 0 to 3) (actually, A longer bit length is used, and each digit is also divided into, for example, 4 bits and expressed by a hexadecimal number of 0 to f).

  In the example of FIG. 2, the routing table using DHT is composed of level 1 to level 3 tables (divided into a plurality of levels), and each level table entry includes node information for each area. The node ID is registered in association with the IP address and port number of the node Nn corresponding to the node ID. Each area in the table of each level is an area obtained by dividing the DHT node ID space. For example, as shown in FIG. 3, in the level 1, the entire ID space of the DHT is divided into four, and the area where the node IDs “000” to “033” are present is the 0XX area, “100” to “133” The area where the node ID exists is the 1XX area, the area where the node IDs "200" to "233" exist is the 2XX area, and the area where the node ID "300" to "333" exists is the 3XX area. . In level 2, the area of level 1 (that is, the area from 0XX to 3XX) is further divided into four, for example, the area of 1XX is divided into four, and the area where the node IDs “100” to “103” exist is 10X. Area, an area where node IDs “110” to “113” exist are 11X areas, an area where node IDs “120” to “123” exist are 12X areas, and node IDs “130” to “133” exist The area in which is present is defined as a 13X area.

  For example, if the node ID of the node N2 is “122”, as shown in FIG. 2, the table of the 1XX area at the level 1 of the node N2 (the area where the self (that is, the own node) exists) The area where the self node ID and IP address (the IP address is own, so it is not necessary to register it in the routing table) etc. is registered and does not exist (that is, 0XX area, 2XX area) , And 3XX area), node IDs and IP addresses of other arbitrary nodes Nn are registered.

  Further, in the table of the 12X area (the area where the self exists) in the level 2 of the node N2, as shown in FIG. 2, the own node ID and the IP address (the IP address is own) In the areas where the self does not exist (that is, the 10X area, the 11X area, and the 13X area), etc., nodes of other arbitrary nodes Nn, respectively, are registered. ID, IP address, etc. are registered.

  Further, in the level 3 of the node N2, as shown in FIG. 2, the node IDs and IP addresses having node IDs “120” to “122” are registered in the routing table. Is not necessary).

  In the example of FIGS. 2 and 3, since the bit length of the node ID is 3 digits × 2 bits, it can be covered by a table of three levels of levels 1 to 3, but if the bit length of the node ID increases, (For example, if the bit length of the node ID is 16 digits × 4 bits, a table for 16 levels is required).

  Thus, in the routing table using DHT in the present embodiment, the area becomes narrower as the level increases.

  In addition, such DHT is given, for example, when a non-participating node participates in the content distributed storage system S.

  By the way, in the content distributed storage system S, each copy data (hereinafter referred to as “replica”) of various contents (for example, movies and music) having different contents is distributed and stored (stored) in a plurality of nodes Nn. )

  For example, the node N1 and the node N5 store a replica of the content data of the movie whose title is XXX, while the node N3 stores a replica of the content data of the movie whose title is YYY. , Distributed and stored in a plurality of nodes Nn (hereinafter referred to as “content holding nodes”).

  In addition, information such as a content name (title) and a content ID (identification information unique to each content) is added to each replica of the content data. This content ID is generated, for example, by hashing a content name + an arbitrary numerical value (or may be the first few bytes of the content data) with a hash function common to the node ID (node ID) Placed in the same ID space). Alternatively, the system administrator may give a unique ID value (same bit length as the node ID) for each content. In this case, the content catalog information in which the correspondence between the content name and the content ID is written is distributed to all the nodes Nn.

  Further, the location of the replica of the content data thus distributed and stored, that is, the index information including the set of the IP address of the node Nn storing the replica of the content data and the content ID corresponding to the content data Is stored (stored in the index cache) and managed by a node Nn (hereinafter referred to as “root node” or “root node of content (content ID)”) which is a management source of the location of the replica of the content data It is like that.

  For example, the index information about the replica of the content data of the movie with the title XXX is managed by the node N4 that is the root node of the content (content ID), and the index information about the replica of the content data of the movie with the title YYY is The node N6 that is the root node of the content (content ID) is managed (that is, the location of the replica is managed for each content data).

  That is, since the root node is divided for each content, load distribution is achieved, and replicas of the same (same content) content data (same content ID) are stored in a plurality of content holding nodes, respectively. Even in such a case, the index information of the content data can be managed by one root node. For this reason, each root node recognizes the number of content data replicas managed by itself in the content distribution storage system S (in other words, the number of content holding nodes storing the replicas).

  Further, such a root node is determined to be, for example, a node Nn having a node ID closest to the content ID (for example, the higher-order digits match more).

  When a user of a certain node Nn wants to acquire desired content data, a node Nn (hereinafter referred to as a “user node”) from which the content data is desired to be acquired is selected by the user (for example, to all the nodes Nn). Content catalog information (for example, the content name is selected) that is distributed from the content catalog information (content name, content ID, etc. are described and selected from, for example, a content catalog management server (not shown)) A content location inquiry (search) message (query) including the content ID and its own IP address is generated and sent to other nodes Nn according to the routing table using its own DHT. That is, the user node sends a content location inquiry (search) message to the root node (to the root node). As a result, the content location inquiry (search) message finally arrives at the root node by DHT routing using the content ID as a key.

  Here, the user node is not limited to a case where a content name or the like is selected from the content catalog information by the user, but a content input request (save request) message (specific new content data) from a content management server such as a system administrator, for example. The content location inquiry (search) message (query) is also sent to the root node. The content input request (save request) message (also referred to as a pre-push message) secures (preserves) a predetermined number of replicas of new content data (content data before being published by the content catalog information) in the content distributed storage system S, for example. To be distributed to any of a plurality of nodes Nn. When a predetermined number or more of replicas are stored in the content distributed storage system S, the content catalog information describing the content name, content ID, etc. of the new content data is distributed (published thereby) to each node Nn. It will be. Alternatively, content catalog information in which attribute information of new content data to be newly input is described is distributed in advance to all nodes Nn, and the publication date of the new content data is set in the content catalog information. Until the release date, it is made not to be disclosed (cannot be used) to the users of each node Nn, and when the release date has passed, even in nodes Nn other than each node Nn that has previously stored new content data by the input request, The new content data can be requested.

  Thus, it can be said that the acquisition and storage of the replica in response to the content input request (save request) message is for provision to other nodes Nn.

  The content ID included in the content location inquiry (search) message may be generated by the user node by hashing the content name with the common hash function.

  FIG. 4 is a conceptual diagram showing an example of the flow of a content location inquiry (search) message sent from a user node in the ID space of the DHT.

  In the example of FIG. 4, for example, the node N2, which is a user node, refers to its own DHT level 1 table and is closest to the content ID included in the content location inquiry (search) message (for example, the upper digit is For example, the IP address and port number of the node N3 having a node ID that more matches) are acquired, and the content location inquiry (search) message (query) is transmitted to the IP address and port number.

  On the other hand, the node N3 receives the content location inquiry (search) message, refers to the DHT level 2 table, and is closest to the content ID included in the content location inquiry (search) message. The IP address and port number of, for example, the node N4 having a node ID (for example, the higher digits match more) are acquired, and the content location inquiry (search) message is transferred to the IP address and port number.

  On the other hand, the node N4 receives the content location inquiry (search) message, refers to the table of the level 3 of its own DHT, and is closest to the content ID included in the content location inquiry (search) message. If the node ID (for example, the higher-order digits match more) is itself, that is, if it recognizes that it is the root node of the content ID, it corresponds to the content ID included in the content location inquiry (search) message The index information to be acquired is acquired from the index cache, and the index information is returned to the user node that is the transmission source of the content location inquiry message. As a result, the user node sends a content transmission request message (an example of provision request information indicating a content data provision request) to the content holding node, for example, the node N1 that stores a replica of desired content data. It is possible to receive the provision of a replica of the content data from the transmission.

  Alternatively, the node N4 that is the root node sends a content transmission request message (including the IP address of the user node, etc. to the content holding node indicated by the IP address included in the index information. Request information indicating a data replica transmission request). As a result, the user node can receive a replica of the content data from the content holding node, for example, the node N1.

  The user node obtains the index information from the relay node that caches the same index information as the root node (for example, the cache node of the node N3) until the content location inquiry message reaches the root node. It can also be acquired (received).

  In this way, the user node that has acquired and stored the replica of the content data notifies the root node that the replica has been stored (in other words, the user node holds the replica of the content data. A publish (registration notification) message containing a content ID of the content data, its own IP address, etc. (in order to make it public to other nodes Nn participating in the system S) Therefore, a registration message indicating a registration request such as an IP address is generated, and the publish message is transmitted 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 in the same manner as the content location inquiry (search) message, and the root node receives the IP included in the received publish message. Index information including a set of addresses and content IDs is registered (stored in the index cache area). In this way, the user node becomes a new content holding node that holds a replica of the content data.

  Note that the index information including the set of the IP address and the content ID included in the publish message is also registered (cached) in the relay node on the transfer route to the root node.

  Further, the replica of the content data stored as described above is deleted in response to a deletion instruction from the user. When the replica is deleted, the content ID corresponding to the deleted replica and A deletion notification message including the IP address of the own node (own node Nn) is transmitted toward the root node. As a result, the deletion notification message arrives at the root node by DHT routing using the content ID as a key, like the publish message, and the root node is included in the deletion notification message from its own index information. The IP address or the like associated with the content ID to be deleted is deleted.

  Note that the IP address or the like associated with the content ID included in the deletion notification message is also deleted at the relay node in the transfer route up to the root node.

[ 2. Configuration and function of node Nn ]
Next, the configuration and function of the node Nn will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 5, each node Nn includes a control unit 11 as a computer including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and various data (for example, content data). Storage unit 12 composed of an HD or the like for storing and storing (storing) various programs and the like, a buffer memory 13 for temporarily storing a replica of received content data, and the like. A decoder unit 14 for decoding (data expansion, decoding, etc.) encoded video data (video information) and audio data (audio information) included in a replica of the content data, and the decoded video data, etc. A video processing unit 15 that performs a predetermined drawing process and outputs the video signal; After a display unit 16 such as a CRT or a liquid crystal display for displaying video based on the video signal output from the video processing unit 15 and D (Digital) / A (Analog) conversion of the decoded audio data into an analog audio signal Between the audio processing unit 17 that amplifies this by an amplifier and outputs it, the speaker 18 that outputs the audio signal output from the audio processing unit 17 as a sound wave, and other nodes Nn and various servers through the network 8 A communication unit 20 for performing communication control of information, and an input unit (for example, a keyboard, a mouse, or an operation panel) 21 that receives an instruction from the user and gives an instruction signal corresponding to the instruction to the control unit 11 And a human sensor (for example, a moving body sensor or an infrared sensor) 22 for detecting a person existing in the surroundings, and a surrounding sound. A sound sensor (for example, a sound collecting microphone) 23 to be detected, and the control unit 11, the storage unit 12, the buffer memory 13, the decoder unit 14, and the communication unit 20 are connected to each other via a bus 24 ( The input unit 21, the human sensor 22 and the sound sensor 23 are connected to the bus 24 via an interface (I / F). As the node Nn, a personal computer, an STB (Set Top Box), a TV receiver, or the like can be applied. In addition, the storage unit 12 stores the IP address, port number, and the like of a contact node that is an access destination when participating in the content distribution storage system S.

  In such a configuration, the control unit 11 performs overall control by reading and executing a program stored in the storage unit 12 or the like by the CPU, and the above-described user nodes by participating in the content distributed storage system S, Content holding having a server function (an example of a server function that operates for another node Nn) that performs an operation of providing a replica of content data related to a provision request from a relay node, a root node, a cache node, and another node Nn Processing as at least one of the nodes is performed.

  Further, the control unit 11 is presence determination means for determining whether or not there is a person around, a surrounding sound is a specified value (the specified value is stored in advance in the ROM or the storage unit 12, etc. It functions as a sound judging means for judging whether or not it is about 30 dB or more, and a control means for stopping the server function while judging that there is a person around.

  Here, whether or not there is a person around is determined based on information from the human sensor 22. Whether or not the surrounding sound is equal to or higher than the specified value is determined based on the level of the sound detected by the sound sensor 23. Since the human sensor 22 and the sound sensor 23 are known, detailed description thereof is omitted.

  In addition, when the surrounding sound is equal to or higher than the specified value, the control unit 11 is considered that the user does not care about the operating sound (the operating sound related to the content data replica providing operation). It is desirable to continue the server function even while it is determined that exists.

  In addition, as an example of the server function, as described above, firstly, the provision operation of the replica of the content data related to the provision request from another node Nn is performed. When the content input request message described above is received, the content location inquiry (search) message is transmitted to the root node as described above to obtain index information, and based on this, the content data related to the input request The function of acquiring and storing the replica of the other node Nn is also an operation for the other node Nn, and the operation sound of the hard disk drive may be conspicuous at the time of the operation. Also good.

  The node processing program may be downloaded from a predetermined server on the network 8, for example, or recorded on a recording medium such as a CD-ROM and read via the drive of the recording medium. You may be made to do.

[ 3. Operation of Content Distributed Storage System S ]
Next, the operation of the distributed content storage system S will be described with reference to FIGS.

  FIG. 6 is a flowchart showing main processing in the control unit 11 of the node Nn. FIG. 7A is a flowchart showing a normal operation, and FIG. 7B is a flowchart showing a silent operation. FIG. 8 is a flowchart showing details of the content data acquisition process. FIG. 9 is a flowchart showing details of message reception processing in normal operation. FIG. 10 is a flowchart showing details of the message reception process in the silent operation.

  The process shown in FIG. 6 is started when, for example, the power is turned on (ON) in an arbitrary node Nn, and after the initial setting is performed, the participation process to the content distributed storage system S is executed. In this participation process, the control unit 11 of the node Nn obtains the IP address and port number of the contact node from the storage unit 12, connects to the contact node via the network 8 based on this, and indicates the participation request A message (including its own node ID and node information) is transmitted. Thereby, the routing table using DHT is transmitted to the node Nn from the other nodes Nn participating in the system S, and the routing table using its own DHT based on the received routing table. And the participation in the content distributed storage system S is completed. Note that a method for generating a routing table using DHT is not directly related to the present invention, and thus detailed description thereof is omitted. Further, information such as the IP address of the contact node is stored in the storage unit 12 in an initial state when the node Nn is shipped or when software is first installed, for example.

  When the participation process to the distributed content storage system S is thus completed, the control unit 11 has received a power-off (OFF) instruction (for example, a power-off operation instruction from the user via the input unit 21) (according to the power-off instruction) (Step S1), and when there is no power off instruction (Step S1: NO), normal operation is performed (Step S2) (Normal operation is not performed until a power off instruction is issued). If the power-off instruction is accepted (step S1: YES), the mode is switched to the power saving mode (step S3), and the process proceeds to step S4.

  By switching to the power saving mode, the control unit 11 transmits and receives various data (for example, various messages and replicas of content data described above) to and from other nodes Nn via the communication unit 20. Leave only necessary power (for example, power supplied to the control unit 11, the storage unit 12, and the communication unit 20) and turn off other power sources such as the display unit 16 (do not leave the overlay network 9 (maintain participation) )). This is to enable data transmission / reception between the nodes Nn even after the user gives a power-off instruction for stable operation of the content distribution storage system S.

  In step S <b> 4, the control unit 11 acquires information related to surrounding sounds from the sound sensor 23. Then, based on the acquired information, the control unit 11 determines whether or not the surrounding sound is equal to or higher than a specified value (for example, whether the sound level detected by the sound sensor 23 is equal to or higher than a specified value). Judgment is made (step S5), and if it is equal to or greater than the prescribed value (step 5: YES), it is considered that the surrounding sound is loud and the user is not particularly conscious of the operation sound, so the process proceeds to step S6 (normal operation (server If the function is not more than the specified value (step 5: NO), the process proceeds to step S7.

  In the normal operation (server function) in step S6, the content data acquisition process corresponding to the content search instruction in step S21 described later is not performed, but the other processes are the same as the normal operation in step S2. After the normal operation, the process returns to step S4.

  On the other hand, in step S <b> 7, the control unit 11 acquires information from the human sensor 22. Based on the acquired information, the control unit 11 determines whether there is a person around (that is, after the power-off instruction is received) (step S8), and there is a person around the person. If not (step S8: NO), the process proceeds to step S6 (continues normal operation (server function)). If there is a person around (step S8: YES), the process proceeds to step S9 (silent operation). To stop the server function).

  After the silent operation in step S9, the process returns to step S4, and the server function is stopped while it is determined that there is a person around.

  Next, in the normal operation in step S2 or step S6, as shown in FIG. 7A, the control unit 11 first determines whether or not there has been a content search instruction from the user via the input unit 21 (step S21). When there is a content search instruction from the user (for example, from the content catalog information displayed on the display unit 12, the user selects the content name of the desired content data by the input unit 21 and issues a content search instruction) (Step S21: YES), the process proceeds to step S22, and if there is no content search instruction (step S21: NO), the process proceeds to step S23.

  In the content data acquisition process in step S22, as shown in FIG. 8, the control unit 11 performs a content location inquiry (search) process (step S221). In the content location inquiry (search) process, the control unit 11 sends a content location inquiry (search) message including the content ID of the content data related to the content search instruction to another content according to the routing table using its own DHT. Transmit to the node Nn (that is, the node Nn having the node ID closest to the content ID (for example, the higher digit matches more)) (send toward the root node of the content ID), and the content ID Get index information from the root node.

  Next, the control unit 11 transmits the above-described content transmission request message to the content holding node based on the IP address or the like included in the acquired index information (step S222). In response to this, if the content holding node is in a normal operation, the content holding node transmits a replica of the content data specified by the content transmission request message to the user node. In this case, a content data provision impossible message is transmitted to the user node.

  A replica of the content data transmitted from the content holding node is received through the communication unit 20 and stored in the buffer memory 13. Then, when a predetermined amount of the replica data is accumulated in the buffer memory 13, the control unit 11 stores and saves the replica data from the buffer memory 13 to the storage unit 12 (for example, writes it in a predetermined area of the HD). (Step S223). In this way, the replica data is sequentially sent from the buffer memory 13 to the storage unit 12 and stored therein.

  Next, the control unit 11 determines whether or not all the data of the replica has been stored and stored (step S224), and if not all stored and stored (step S224: NO), the control unit 11 returns to step 223 and returns to If the process is continued and all the data is stored and saved (step S224: YES), the process proceeds to step S225. Note that when the data amount of the replica is small, the buffer memory 13 may be configured to store and save all data in the storage unit 12 after the data has been collected.

  In step S225, the control unit 11 transmits the above-described publish message including the content ID of the content data related to the stored replica to the other node Nn according to the routing table using its own DHT (in this case 7) and returns to the process of FIG. 7A. As a result, the publish message arrives at the root node by DHT routing using the content ID as a key, and the root node includes index information including a set of the IP address and the content ID included in the received publish message. Register.

  Next, in step S23, the control unit 11 determines whether or not a message transmitted from another node Nn has been received. If the message has not been received (step S23: NO), step S25 is performed. If the message is received (step S23: YES), the process proceeds to step S24 to perform message reception processing.

  In the other processing in step S25, for example, content data reproduction processing according to a reproduction instruction from the user via the input unit 21 (content data replicas are a decoder unit 14, a video processing unit 15, a display unit 16, The data is reproduced and output via the audio processing unit 17 and the speaker 18), the content data deletion process according to the deletion instruction is performed, and the process returns to the process of FIG. 6.

  In the message reception process in step S24, as shown in FIG. 9, the control unit 11 determines whether or not the received message is a content location inquiry message (step S241). (Step S241: NO), the process proceeds to Step S246. On the other hand, if it is a content location inquiry message (step S241: YES), the control unit 11 stores the index information (index information corresponding to the content ID included in the content location inquiry message) in the index cache. (Step S242: YES), the index information is transmitted to the user node that is the transmission source of the content location inquiry message (step S242: YES). S243), the process returns to the process of FIG. On the other hand, when the index information is not stored (step S242: NO), the control unit 11 determines whether or not the own (own node Nn) is the root node (that is, refer to the own routing table). Then, it is determined whether or not the node ID closest to the content ID included in the content location inquiry message is itself (step S244), and if it is not the root node (that is, it is a relay node) (Step S244: NO), the process proceeds to Step S245. If the node itself is the root node (Step S244: YES), the process returns to the process of FIG.

  In step S245, the control unit 11 sets the received content location inquiry message to another node Nn (that is, the node ID closest to the content ID included in the content location inquiry message) according to the routing table using its own DHT. Transfer (send toward the root node of the content ID) to return to the processing of FIG. 7A.

  In step S246, the control unit 11 determines whether or not the received message is a content input request message. If the received message is not a content input request message (step S246: NO), the process proceeds to step S248. On the other hand, if it is a content input request message (step S246: YES), the content data acquisition process shown in FIG. 8 is performed as in step S22 (step S247).

  In step S248, the control unit 11 determines whether or not the received message is a content transmission request message. If the received message is not a content transmission request message (step S248: NO), the process proceeds to step S250. On the other hand, if it is a content transmission request message (step S248: YES), content data provision (upload) processing is performed (server function is executed) (step S249), and the processing returns to FIG. 7A. In the content providing process, a replica of the content data specified by the received content transmission request message is sequentially transmitted to the user node that is the transmission source of the content transmission request message for each block of a predetermined data unit. It will be.

  In step S250, the control unit 11 determines whether or not the received message is a publish message. If the received message is not a publish message (step S250: NO), the process proceeds to step S254. On the other hand, if it is a publish message (step S250: YES), index information including a set of IP address and content ID included in the received publish message and content ID is registered (stored in the index cache area) (step S251). .

  Next, the control unit 11 determines whether or not it is a root node (step S252), similarly to step S244 above, and if it is not the root node (that is, is a relay node) (step S252: (NO), it progresses to step S253, and when self is a root node (step S252: YES), it returns to the process of FIG. 7 (A).

  In step S253, the control unit 11 transfers the received publish message to another node Nn (that is, the node Nn having the node ID closest to the content ID included in the publish message) according to its own routing table. (Send out toward the root node of the content ID), and return to the processing of FIG.

  In the other message reception process in step S254, the process when another message (for example, a participation message or a deletion notification message) is received is performed, and the process returns to the process of FIG.

  On the other hand, in the silent operation in step S9 shown in FIG. 6, as shown in FIG. 7B, compared with the normal operation shown in FIG. It is determined whether or not the message has been received (step S91). If a message has been received (step S91: YES), a message reception process is executed (step S92). Note that the other processes in step S93 shown in FIG. 7B are the same as the other processes in step S25 shown in FIG.

  The message reception process in step S92 is executed as shown in FIG. 10, but the process in the case where the received message is a content input request message (step (step 9)) compared with the message reception process (FIG. 9) during normal operation. S927) differs from the processing (step S929) in the case where the received message is a content transmission request message.

  In the message reception process shown in FIG. 9, if the received message is a content input request message, a content data acquisition process is performed (step S247). However, in the message reception process shown in FIG. Therefore, if the received message is a content input request message, the content data input rejection message (information indicating that content data related to the input request cannot be input) is sent to the server that is the source of the content input request message. ) Is returned (step S927). This is intended to realize silence by rejecting the process of downloading the content data and writing it to the hard disk in response to the input request. Instead of transmitting the content data input rejection message to the server, the control unit 11 randomly selects another node Nn registered in the routing table using its own DHT, for example, and selects the selected node Nn. Thus, the received content input request message may be transferred. The node Nn that has received the transfer of the content input request message acquires index information by sending a content location inquiry (search) message to the root node of the content ID based on the content ID included in the message, A replica of the content data is acquired and stored from the content holding node indicated by the index information, and a publish message is sent to the root node. As a result, a content holding node can be secured instead of the node Nn whose server function is stopped. Alternatively, the content data acquisition process may be performed after the server function is restored without transmitting the content data input rejection message and transferring the content input request message.

  In the message reception process shown in FIG. 9, when the received message is a content transmission request message, the server function transmits a replica of the content data to the user node that is the transmission source of the content transmission request message ( In step S249), since the server function is stopped in the message reception process shown in FIG. 10, if the received message is a content transmission request message, the message is sent to the user node that is the transmission source of the content transmission request message. Thus, the content data provision impossible message (information indicating that the content data related to the provision request cannot be provided) is transmitted to the user node that is the transmission source of the content transmission request message (step S929).

  The processes other than step S929 shown in FIG. 10 are the same as the processes other than step S249 shown in FIG.

  Further, in the above-described processing, when the presence of the person is detected by the human sensor 22 when a person approaches while the server function is operating (content data is being transmitted or received), the control unit 11 immediately The function may be configured to stop, or the server function may be configured to stop after the session ends. When the server function is immediately stopped, there is a merit that is not noticed by a person. On the other hand, when the server function is stopped after the session is finished, there is a merit that stable operation is easy as a system.

  As described above, according to the above-described embodiment, while it is determined that there is a person in the surrounding area, the message transmission / reception function is continued and only the server function is stopped. While stable operation of the system S, operation sound (for example, when a distribution operation for providing a replica of content data is performed or when a replica of the content data is stored in response to an input request is performed) It is possible to prevent the user from being conscious of the operation sound related to reading and writing data of the hard disk drive when it is performed (making the user feel a quiet node). In addition, it is possible to prevent the user from feeling uncomfortable (especially at night) due to operation sounds.

  In addition, for the stable operation of the distributed content storage system S, it is possible to continue the message transmission / reception function and stop only the server function while it is determined that there is a person around. This is particularly effective in the case where data can be transmitted and received between the nodes Nn even after the power-off instruction is given by the user (that is, it is very annoying and uncomfortable for the user to make an operation sound after the power-off instruction) ).

  Also, if the surrounding sound is louder than the specified value, the user may not be concerned about the operation sound, so the server function should be continued even while it is determined that there is a person around. With this configuration, it is possible to respond to requests from other nodes Nn.

  In addition, although the content distributed storage system S in the said embodiment was demonstrated on the assumption that it was formed by the algorithm using DHT, this invention is not limited to this.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distributed storage system which concerns on this embodiment. It is a figure which shows an example of the routing table using DHT which node N2 hold | maintains. It is a conceptual diagram which shows an example of ID space of DHT. It is the conceptual diagram which showed an example of the flow of the content location inquiry (search) message sent from the user node in ID space of DHT. It is a figure which shows the example of an outline structure of the node Nn. It is a flowchart which shows the main process in the control part 11 of the node Nn. (A) is a flowchart showing a normal operation, and (B) is a flowchart showing a silent operation. It is a flowchart which shows the detail of a content data acquisition process. It is a flowchart which shows the detail of the message reception process in normal operation | movement. It is a flowchart which shows the detail of the message reception process in silent operation | movement.

Explanation of symbols

8 Network 9 Overlay Network 11 Control Unit 12 Storage Unit 13 Buffer Memory 14 Decoder Unit 15 Video Processing Unit 16 Display Unit 17 Audio Processing Unit 18 Speaker 20 Communication Unit 21 Input Unit 22 Human Sensor 23 Sound Sensor 24 Bus Nn Node S Content Distribution Preservation system

Claims (9)

A plurality of node devices that can communicate with each other via a network, and the plurality of content data are distributed and stored in the plurality of node devices.
Server function that operates for other node devices,
Presence determination means for determining whether or not a person exists in the surroundings;
Control means for stopping the server function while it is determined that a person exists in the surroundings;
A node device comprising: The node device according to claim 1,
The presence determination means acquires information from a human sensor that senses a person existing in the surroundings, and determines whether or not a person exists in the surroundings based on the information . The node device according to claim 1 or 2,
Sound determination means for acquiring information from a sound sensor for detecting ambient sound and determining whether the ambient sound is equal to or higher than a specified value based on the information;
The node device according to claim 1, wherein when the ambient sound is equal to or higher than a predetermined value, the server function is continued even while it is determined that a person exists in the surrounding area. In the node apparatus as described in any one of Claims 1 thru | or 3,
A power-off instruction receiving means for receiving a power-off instruction;
The node device according to claim 1, wherein the presence determination unit determines whether or not a person exists in the surrounding area after the power-off instruction is received. In the node apparatus as described in any one of Claims 1 thru | or 4,
When the control unit receives provision request information indicating a content data provision request from another node apparatus via the network while the server function is stopped, the control unit cannot provide the content data related to the provision request. A node device that transmits information indicating that to the other node device. In the node apparatus as described in any one of Claims 1 thru | or 5,
When the server function receives provision request information indicating a content data provision request from another node apparatus via the network, the server function transmits the content data related to the provision request to the other node apparatus. A node device including a function.   A node processing program for causing a computer to function as the node device according to any one of claims 1 to 6. A content distributed storage system comprising a plurality of node devices that can communicate with each other via a network, wherein a plurality of content data is distributed and stored in the plurality of node devices,
The node device is
A server function for transmitting content data related to the provision request to the other node device when receiving provision request information indicating a content data provision request from the other node device via the network;
Presence determination means for determining whether or not a person exists in the surroundings;
Control means for stopping the server function while it is determined that a person exists in the surroundings;
A content distributed storage system comprising: A server function control method of the node device in a content distributed storage system comprising a plurality of node devices that can communicate with each other via a network, and a plurality of content data distributed and stored in the plurality of node devices,
The node having a server function of transmitting content data related to a provision request to the other node device when receiving provision request information indicating a content data provision request from the other node device via the network The device
Determining whether there is a person in the surroundings;
Stopping the server function while it is determined that a person is present in the surroundings;
A server function control method comprising:

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