JP2011198033A - P2p distribution system, and method and system for calculating network distance between peer nodes in the same - Google Patents

Abstract

An object of the present invention is to accurately measure a network distance between peer nodes without imposing a large load on a network or peer nodes.
Each peer node transmits a measurement request packet to each reference server, and measures a network distance index value between the own node and each reference server based on a measurement response packet returned in response thereto. This is notified to the network distance management server 4. The network distance management server 4 calculates a network distance index value between the peer nodes based on the network distance index value notified from each peer node 1. When the distribution control server 2 receives the peer list request from the requesting peer 1a, the distribution control server 2 requests and acquires the network distance index value between the requesting peer 1a and each peer candidate from the network distance management server 4 and obtains the peer peer with a short network distance Create a peer list with higher priority.
[Selection] Figure 1

Description

  The present invention calculates a network distance between peer nodes distributed on a network, and selects a peer peer of P2P distribution based on the network distance between peer nodes, and a network distance calculation method and system between the peer nodes About.

  In a P2P network, a peer node (requesting peer) that wants to receive a content file distribution service or the like obtains a peer candidate possessing a piece of content, for example, a peer list acquired from a distribution control server or a node acquired from another peer node Based on information, etc., P2P communication is performed by selecting the most appropriate peer from the information.

  In Patent Document 1, in order to select an optimum partner peer from among a plurality of partner peer candidates, the requesting peer has one or more of physical network distance information, processing capability, line bandwidth information, etc. between peer nodes. A technique is disclosed in which priority is set for a peer candidate based on a combination, and a peer peer candidate with a high priority is selected as a peer peer. At this time, the physical network distance between the peer nodes is evaluated as the number of hops or the response delay when the requesting peer broadcasts a measurement packet.

JP 2004-258747 A

  The prior art has the following problems.

  (1) In order to measure the distance between peer nodes, a measurement packet is transmitted by broadcast from a requesting peer, so that a load is imposed on the network due to traffic of the measurement packet.

  (2) Since the measurement packet is transmitted to each peer node, the content distribution process may be hindered by the load required for the measurement packet process at the peer node during the distribution process.

  (3) In the measurement method in which the measurement packet is transmitted by broadcast, the measurement result can be obtained only with a one-to-one response time, so the measurement result is easily affected by the network status and sufficient accuracy cannot be obtained. There is.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and to provide a P2P distribution system capable of accurately measuring a network distance between peer nodes without applying a large load to the network or peer node, and a network distance calculation method and system between the peer nodes. Is to provide.

  In order to achieve the above object, the present invention is characterized in that it has the following configuration.

  (1) The network distance calculation system of the present invention includes a plurality of reference servers that return measurement response packets in response to measurement request packets received from each peer node, and a network that serves as an index of the network distance between each peer node and each reference server. A network distance management server that calculates a network distance index value between each peer node based on, for example, a response delay time of the measurement response message with respect to a measurement request message as a distance index value, and each peer node includes a plurality of reference servers Means for transmitting a measurement request message to the device, means for measuring a network distance index value with each reference server based on a measurement response message returned to the measurement request message, and a network distance index value with each reference server. Means for notifying the network distance management server; Equipped.

  (2) The P2P distribution system of the present invention includes a plurality of reference servers that return measurement response packets in response to measurement request packets received from each peer node, and a network distance that serves as an index of the network distance between each peer node and each reference server. A network distance management server for calculating a network distance index value between each peer node based on the index value, each peer node sending a measurement request message to a plurality of reference servers, and a reply to the measurement request message Means for measuring the network distance index value with each reference server based on the measurement response message, means for notifying the network distance index value with each reference server to the network distance management server, and possessing a desired content piece Means for acquiring the address information of the other peer candidate, Beauty peer distance request address information is described for each peer with candidate and means for transmitting to the network distance management server.

  Further, in response to the inter-peer distance request, the network distance management server calculates a network distance index value between each peer node based on the notified network distance index value between each peer node and each reference server, And a means for returning a distance response between peers in which network distance index values between the requesting peer and each peer candidate are described.

  Further, each peer node receives, from the network distance management server, a peer distance response in which a network distance index value between the node and each peer candidate is described, and based on the peer distance response, Means for setting a higher priority for the peer peer candidate with a shorter network distance, and means for establishing a connection by selecting the peer peer from the peer peer candidates based on the priority.

  According to the present invention, the following effects are achieved.

  (1) Since the distance measurement packet is transmitted from the requesting peer to the reference server, each peer node is released from the load for processing the distance measurement packet.

  (2) Since the distance measurement packet is transmitted from the requesting peer to each reference server as a destination instead of broadcasting, an excessive load is not applied to the network due to the traffic of the measurement packet.

  (3) Network distance between peer nodes is calculated based on multiple response delays between each peer node and each reference server, not the response delay of measurement packets sent and received between the peer nodes. Highly accurate measurement results can be obtained.

  (4) Other peer nodes whose peers with the same prefix are already registered in the network distance management server are exempt from distance measurement between the local node and each reference server, so the traffic of the measurement request packet and its response packet is reduced. become able to.

1 is a block diagram of a P2P distribution system according to a first embodiment of the present invention. It is the flowchart which showed the operation | movement of the peer node in 1st Embodiment. It is the flowchart which showed operation | movement of the network distance management server in 1st Embodiment. It is the flowchart which showed operation | movement of the delivery control server in 1st Embodiment. It is a sequence flow of a 1st embodiment. It is the figure which showed an example of the response time management table. It is the figure which showed the calculation method of delay time. It is the figure which showed an example of the network distance management table. It is a functional block diagram of a 1st embodiment. It is a block diagram of the P2P delivery system concerning a 2nd embodiment of the present invention. It is a sequence flow of a 2nd embodiment. It is a functional block diagram of a 2nd embodiment. It is a sequence flow of 3rd Embodiment of this invention. It is a functional block diagram of a 3rd embodiment. It is the flowchart which showed the operation | movement of 4th Embodiment. It is the figure which showed an example of the prefix classification | category table.

[Embodiment 1]
FIG. 1 is a block diagram showing a network configuration of the P2P distribution system according to the first embodiment of the present invention, and a plurality of peer nodes 1 (requesting peer 1a and counterpart peer 1b, which transmit and receive content (files) in pieces. 1c), a P2P distribution control server 2 that grasps the peer node (partner peer candidate) possessing each piece of content and creates a peer list, and receives a measurement request packet related to the network distance from each peer node 1 and receives a measurement response The network distance between the reference server 3 (3a, 3b, 3c) that returns the packet and the peer node 1 and each reference server 3 notified from each peer node 1 (or information that is an index of the network distance or the network distance) Based on the following information: And a network distance management server 4 to calculate the network distance index value between the nodes.

  In such a network configuration, each peer node 1 transmits a measurement request packet to each reference server 3, and the network distance index value between the own node and each reference server 3 based on the measurement response packet returned from each reference server 3. And the network distance management server 4 is notified of the calculation result. Here, the description is continued assuming that the response delay time from the transmission of the measurement request packet to the return of the measurement response packet at each peer node 1 is the network distance index value. The network distance management server 4 calculates a network distance index value between each peer node based on the network distance index value with each reference server 3 notified from each peer node 1.

  When the distribution control server 2 receives the peer list request from the requesting peer 1a, the distribution control server 2 selects a peer candidate having the piece of content requested to be distributed with reference to its own database, for example, and selects the requesting peer 1a and each of the requesting peers 1a and The inter-peer distance request in which the address information of the partner peer candidate is described is transmitted to the network distance management server 4. In response to the inter-peer distance request, the network distance management server 4 returns an inter-peer distance response in which the network distance index values between the requesting peer 1a and each peer candidate are described.

  Further, based on the returned inter-peer distance response, the distribution control server 2 creates a peer list in which the higher priority is set for the peer candidate with a shorter network distance and notifies the requesting peer 1a. The requesting peer 1a acquires a content piece by establishing a connection preferentially from a peer candidate with a higher priority.

  Next, the operation of this embodiment will be described. 2, 3 and 4 are flowcharts showing operations of the peer node 1, the network distance management server 4 and the distribution control server 2, respectively, and FIG. 5 is a sequence flow thereof.

  Referring to FIG. 2, each peer node 1 calculates a network distance index value between itself and each reference server 3 at an appropriate timing, for example, when participating in a P2P network. In the present embodiment, for example, an ICMP Echo packet or the like is transmitted as a fixed length measurement request packet to each reference server 3 in step S1. When, for example, an ICMP Reply packet or the like is received as a measurement response packet from each reference server 3 in step S2, a response delay time of the corresponding packet is calculated in step S3, and this is calculated between the own node and each reference server 3. Network distance index value between. The transmission / reception of the measurement request packet and the measurement response packet is not limited to one time, and the average value of each response delay time may be used as the network distance index value by repeating a plurality of times.

  In step S4, the network distance index value is notified to the network distance management server 4. A similar procedure is performed asynchronously in all peer nodes 1 without distinguishing between the requesting peer 1a and the counterpart peers 1b and 1c, and the network distance index value between each other reference node 3 and the other peer nodes is the network distance. The management server 4 is notified.

  Referring to FIG. 3, when the network distance management server 4 receives a network distance index value from each peer node 1 to each reference server 3 in step S11, the received index value is response time management in step S12. Recorded in the table 41. FIG. 6 is a diagram illustrating an example of the response time management table 41. Each peer node 1x (1a, 1b...) Has a network distance index value (with each reference server #y (# 1, # 2... #N)). Here, the response delay time txy) is recorded. In step S13, based on the response time management table 41, the network distance index value d between the peer nodes is calculated for each peer node pair by the delay time calculation method as shown in FIG.

  In this embodiment, the network distance index values (response delay times) between the peer node pairs 1a, 1b for distance calculation and the reference servers # 1, # 2,... #N are respectively ta1, ta2 ... tan and tb1, tb2,. where tbn is the delay time difference between each peer node 1a, 1b and each reference server # 1, # 2... #n, D1, D2... Dn, the network distance index value dab between the peer nodes 1a, 1b is Calculated in 1).

  In step S14, based on the network distance index values d of all the peer node pairs, a network distance management table 42 for managing the network distance index values between all the peer nodes as shown in FIG. 8 is generated. Steps S15 to S17 will be described later.

  Referring to FIG. 4, in distribution control server 2, the peer list request transmitted from request peer 1a requesting content distribution is received in step S31. In this peer list request, content identification information requested by the requesting peer 1a and attribute information of the requesting peer 1a are described. In step S32, based on the identification information of the distribution request content described in the peer list request, a peer node possessing the piece is selected as a partner peer candidate. In step S33, the inter-peer distance request in which the IP address of the requesting peer 1a and the IP addresses of the respective peer candidates are described is transmitted to the network distance management server 4.

  Returning to FIG. 3, when the network distance management server 4 receives the inter-peer distance request in step S15, the process proceeds to step S16. In step S16, the network distance management table 42 is referred to based on the IP address of the requesting peer 1a and the IP address of each partner peer candidate, and the network distance index value d between the requesting peer 1a and each partner peer candidate is extracted. . In step S17, the inter-peer distance response in which the extracted network distance index value d is described is returned to the distribution control server 2.

  Returning to FIG. 4, when the inter-peer distance response is received in step S34, the distribution control server 2 proceeds to step S35, and based on the network distance index value between the requesting peer 1a and each partner peer candidate, A peer list in which the priority is set higher as the peer peer candidate whose network distance to 1a is closer is created. In step S36, the peer list is notified to the requesting peer 1a.

  FIG. 9 is a functional block diagram of the present embodiment, and illustrations of components unnecessary for the description of the present embodiment are omitted here.

  The peer node 1 transmits a measurement request packet to each reference server 3, and measures a network distance index value between the own node and each reference server 3 based on a measurement response packet returned thereto. A distance notification unit 12 for notifying the network distance management server 4 of the measurement result of the network distance index value, and a peer list requesting unit 13 for transmitting a peer list request to the distribution control server 2 as a content distribution requesting peer 1a. .

  The network distance management server 4 receives the index value of the peer node / reference server distance notified from each peer node 1 and registers it in the response time management table 41, and the response time management table 41 A distance calculation unit 44 that calculates a network distance index value between each peer node pair based on the network distance management table 42, and the network distance management table in response to the inter-peer distance request received from the distribution control server 2 42, a distance response unit 45 that provides a network distance index value between the requesting peer and each peer candidate.

  The distribution control server 2 selects a peer candidate in response to the peer list request received from the requesting peer 1a, and requests a peer distance request in which the address information of the requesting peer 1a and the address information of at least one peer candidate are described. A distance request unit 21 that transmits to the network distance management server 4 and a distance acquisition that receives from the network distance management server 4 an inter-peer distance response in which the network distance index values of the requesting peer 1a and each peer candidate are described. Peer list generation unit 23 that generates a peer list in which the priority is set higher as the peer peer candidate with a shorter network distance between unit 22 and request peer 1a, and returns a peer list response including this peer list to request peer 1a And a peer list providing unit 24.

  According to the present embodiment, since the measurement request packet is transmitted from the requesting peer 1a to the reference server 3, each peer node 1 is released from the load for processing the measurement request packet. Moreover, since the measurement request packet is transmitted from the requesting peer 1a not to the broadcast but to each reference server 3 as a destination, an excessive load is not added to the P2P network due to the traffic of the measurement request packet and its response packet. . Further, since the network distance between the peer nodes is calculated based on a plurality of response delays between each peer node 1 and each reference server 3 instead of the response delay of the measurement packet transmitted / received between the peer nodes, Highly accurate measurement results can be obtained without being affected.

[Embodiment 2]
FIG. 10 is a block diagram showing a configuration of a P2P network according to the second embodiment of the present invention, where the same reference numerals as those described above indicate the same or equivalent configurations. FIG. 11 is a sequence flow showing the operation of this embodiment.

  In the first embodiment described above, the request peer 1a requests the distribution control server 2 for a peer list, and the distribution control server 2 inquires the network distance management server 4 about the distance between the request peer 1a and each peer candidate. However, the present embodiment is characterized in that the requesting peer 1a acquires information on the other peer candidate from other than the distribution control server, and inquires the distance to each other peer candidate from the network distance management server 4 itself. .

  Peer nodes participating in the P2P network first collect node information by an appropriate method such as referring to a DHT (distributed hash table). Alternatively, node information is collected from the peer peer that established the connection in response to the connection request. Furthermore, when a connection is established with each peer node, each peer node exchanges a list of content pieces possessed by the node with each other, and each time a piece is acquired, the peer node possesses the connection with the established peer. Since the node information is repeatedly notified, as pieces are collected, a lot of pieces of pieces of information possessed by other peer nodes are accumulated. As a result, the requesting peer 1a can identify the peer candidate possessing the desired content piece by referring to the node information of the own node.

  Therefore, in this embodiment, when the requesting peer 1a can identify the peer candidate for each piece, as shown in FIG. 11, the inter-peer distance request in which the IP address of the node 1a and each peer candidate is described is sent to the network. Direct transmission to the distance management server 4 (step S41). When the requesting peer 1a further receives from the network distance management server 4 the inter-peer distance response in which the network distance index value between each partner peer candidate and the own node is described (step S42), the requesting peer 1a network distance to the own node for each piece Selects a short peer and obtains pieces preferentially from the peer.

  FIG. 12 is a functional block diagram of the present embodiment, and illustrations and descriptions of components unnecessary for the description of the present embodiment are omitted.

  The peer node 1 transmits a measurement request packet to each reference server 3 and measures a network distance index value between the own node and each reference server 3 based on the measurement response packet, and the network distance index value A measurement result notification unit 12 for notifying the network distance management server 4 of the measurement result of the node, a node information acquisition unit 14 for acquiring node information from the DHT or the partner peer, grasping the partner peer candidate based on the node information, and the own node And a distance request unit 15 that transmits an inter-peer distance request in which address information of the partner peer candidate is described to the network distance management server 4, and a network distance index value between the own node and the partner peer candidate from the network distance management server 4. Priority is given to peer nodes that receive the described peer-to-peer distance response and that are close to the network And a mating peer selection unit 16, party peer.

  The network distance management server 4 receives the network distance index value between the peer node / reference server notified from each peer node 1 and registers it in the response time management table 41, and the response time management table 41. A distance calculation unit 44 that calculates a network distance index value between each peer node pair based on the network distance management table 42 and registers the network distance index value in response to the inter-peer distance request received from the requesting peer 1a. 42, a distance response unit 46 that provides a network distance index value between the requesting peer and the peer candidate.

  According to the present embodiment, even when the requesting peer acquires the peer list not from the distribution control server 2 but from the DHT or the partner peer, the partner peer with a shorter network distance can be selected.

[Embodiment 3]
In the first and second embodiments described above, the request peer 1a or the distribution control server 2 has been described as acquiring the network distance index value between the request peer 1a and each peer candidate from the network distance management server 4. The invention is not limited to this, and both the requesting peer 1a and the distribution control server 2 may acquire the network distance index value from the network distance management server 4.

  FIG. 13 is a sequence flow showing the operation of the present embodiment. Here, each requesting peer first sends a peer list request (S31) to the distribution control server 2 to display a prioritized peer list. Obtain (S36), establish a connection with the peer and obtain a piece. Thereafter, the peer piece information is exchanged with the peer piece with which the connection has been established to identify the peer peer candidate, and each requesting peer 1a directly transmits the inter-peer distance request regarding the peer peer candidate to the network distance management server 4 (S41). Then, an index value of the distance between peers is acquired (S42), and a connection is preferentially established with a peer peer having a short network distance to acquire a piece.

  FIG. 14 is a functional block diagram of the present embodiment, and illustrations of components unnecessary for the description of the present embodiment are omitted here.

  The peer node 1 transmits a measurement request packet to each reference server 3, and measures a network distance index value between the own node and each reference server 3 based on a measurement response packet returned thereto. A distance notification unit 12 for notifying the network distance management server 4 of the measurement result of the network distance index value, and a peer list requesting unit 13 for transmitting a peer list request to the distribution control server 2 as a content distribution requesting peer 1a. .

  The network distance management server 4 receives the index value of the peer node / reference server distance notified from each peer node 1 and registers it in the response time management table 41, and the response time management table 41 Based on the distance calculation unit 44 that calculates the network distance index value between each peer node pair based on the network distance management table 42 and refers to the network distance management table 42 in response to the inter-peer distance request, the requested peer And a distance response unit 45 that provides a network distance index value with each peer candidate.

  The distribution control server 2 selects a peer candidate in response to the peer list request received from the requesting peer 1a, and requests a peer distance request in which the address information of the requesting peer 1a and the address information of at least one peer candidate are described. A distance request unit 21 that transmits to the network distance management server 4 and a distance acquisition that receives from the network distance management server 4 an inter-peer distance response in which the network distance index values of the requesting peer 1a and each peer candidate are described. Peer list generation unit 23 that generates a peer list in which the priority is set higher as the peer peer candidate with a shorter network distance between unit 22 and request peer 1a, and returns a peer list response including this peer list to request peer 1a And a peer list providing unit 24.

  The peer node 1 further identifies a partner peer candidate based on the node information acquisition unit 14 that acquires node information from a partner peer that has established a DHT or connection, and based on the acquired node information. A distance request unit 15 that transmits an inter-peer distance request in which is described to the network distance management server 4, and an inter-peer distance response in which the network distance index value between the node and the peer candidate is described from the network distance management server 4 And a peer peer selection unit 16 that preferentially designates a peer node having a short network distance to the own node as a peer peer.

  The network distance management server 4 further refers to the network distance management table 42 in response to the inter-peer distance request received from the requesting peer 1a, and provides a network distance index value between the requesting peer and the peer candidate. Part 46 is included.

[Embodiment 4]
In each of the above embodiments, all the peer nodes newly participating in the P2P network have been described as measuring the network distance index value with the reference server 3 and notifying the network distance management server 4. In the embodiment, the necessity of network distance measurement is determined for each peer node 1, and a peer node that is determined not to require distance measurement is exempt from distance measurement.

  FIG. 15 is a flowchart showing the operation of this embodiment, and shows the operation of the peer node 1 and the network distance management server 4.

  Each peer node 1 makes a distance measurement necessity determination request in which the IP address of its own node is described to the network distance management server 4 at an appropriate timing before measuring the network distance index value with each reference server 3 in step S51. Send.

  When the network distance management server 4 receives the determination request in step S61, the prefix is identified based on the IP address of the peer node 1 in step S62. As shown in FIG. 16, the network distance management server 4 includes a prefix classification table that classifies each registered peer node by its prefix. In step S63, the peer node having the same prefix as the identified prefix It is determined whether 1 is already registered in the prefix classification table. If not registered, the process proceeds to step S64 to determine whether measurement is necessary. If it is already registered, the process proceeds to step S65 and determination of unnecessary measurement is made. In step S66, a distance measurement necessity determination response in which the determination result is described is returned to each peer node 1.

  When each peer node 1 receives the distance measurement necessity determination response in step S52, the process proceeds to step S53, and the determination result described in the determination response is referred to. If it is a measurement necessity determination, the process proceeds to step S54, and the network distance index value measurement and the notification process (steps S1 to S4) described with reference to FIG. 2 are similarly executed. On the other hand, if it is determined that the measurement is unnecessary, the measurement is finished without performing the measurement of the distance index value and the notification process thereof.

  Thereafter, the network distance management server 4 sends the inter-peer distance in which the IP addresses of the requesting peer and the other peer are described from the distribution control server 2 (first and third embodiments) or the requesting peer 1a (second and third embodiments). When the request is received, the position of each peer node is regarded as the same as the position of another peer node having the same prefix, and the network distance index value between the peers is calculated.

  According to the present embodiment, other peer nodes whose peers having the same prefix are already registered in the network distance management server 4 are exempt from distance measurement between the own node and each reference server 3. Response packet traffic can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Peer node 2 ... Distribution control server Distribution control server 3 ... Reference server 4 ... Network distance management server

Claims (10)

In a system for calculating a network distance between a plurality of peer nodes distributed on a network,
A plurality of reference servers that return measurement response packets in response to measurement request packets received from each peer node;
A network distance management server that calculates a network distance index value between each peer node based on a network distance index value that is an index of the network distance between each peer node and each reference server;
Each peer node is
Means for sending a measurement request message to a plurality of reference servers;
Means for calculating a network distance index value with each reference server based on a measurement response message returned from each reference server;
A network distance calculation system between peer nodes, comprising means for registering a network distance index value with each reference server in the network distance management server.   The network distance calculation system according to claim 1, wherein the network distance index value is a response delay time of the measurement response message with respect to the measurement request message. In a method for calculating a network distance between a plurality of peer nodes distributed on a network,
Each peer node sends a measurement request message to multiple reference servers;
A procedure in which each peer node calculates a network distance index value serving as an index of the network distance to each reference server based on a measurement response message returned from each reference server;
A procedure in which each peer node registers a network distance index value with each reference server in a network distance management server;
A network distance calculation method between peer nodes, wherein the network distance management server includes a procedure for calculating a network distance index value between each peer node based on a network distance index value between each peer node and each reference server. In a P2P distribution system in which peer nodes distributed on the network send and receive content files via P2P communication,
A plurality of reference servers that return measurement response packets in response to measurement request packets received from each peer node;
A network distance management server that calculates a network distance index value between each peer node based on a network distance index value that is an index of the network distance between each peer node and each reference server;
A P2P distribution control server that responds to a peer list request received from each peer node and returns a peer list in which peer peer candidates are described;
Each peer node is
Means for sending a measurement request message to a plurality of reference servers;
Means for calculating a network distance index value with each reference server based on a measurement response message returned from each reference server;
Means for notifying the network distance management server of the network distance index value with each reference server;
Means for requesting a peer list from the distribution control server,
The delivery control server is
Means for selecting a peer candidate in response to the peer list request;
Means for transmitting an inter-peer distance request in which address information of peers requesting the peer list and each peer candidate is described to the network distance management server;
The network distance management server is
Means for calculating a network distance index value between each peer node based on the notified network distance index value between each peer node and each reference server;
Means for responding to the inter-peer distance request, and returning a inter-peer distance response in which network distance index values between the requesting peer and each peer candidate are described;
The delivery control server further comprises:
Means for receiving a peer-to-peer distance response from the network distance management server;
Means for generating a peer list in which priority is set higher for a peer candidate whose network distance to the requesting peer is closer;
Means for returning a peer list response describing the peer list to the requesting peer;
Each peer node further comprises:
Means for receiving a peer list from the delivery control server;
A P2P distribution system comprising: means for selecting a peer with a higher priority from peer peer candidates based on the peer list and establishing a connection. In a P2P distribution system in which peer nodes distributed on the network send and receive content files via P2P communication,
A plurality of reference servers that return measurement response packets in response to measurement request packets received from each peer node;
A network distance management server that calculates a network distance index value between each peer node based on a network distance index value that is an index of the network distance between each peer node and each reference server;
Each peer node is
Means for sending a measurement request message to a plurality of reference servers;
Means for calculating a network distance index value with each reference server based on a measurement response message returned from each reference server;
Means for notifying the network distance management server of the network distance index value with each reference server;
Means for acquiring address information of the peer candidate who owns the content piece;
Means for transmitting an inter-peer distance request in which address information of its own node and each peer candidate is described to the network distance management server,
The network distance management server is
Means for calculating a network distance index value between each peer node based on the notified network distance index value between each peer node and each reference server;
Means for responding to the inter-peer distance request, and returning a inter-peer distance response in which the network distance index value between the requesting peer and each peer candidate is described;
Each peer node further comprises:
Means for receiving, from the network distance management server, a peer-to-peer distance response in which a network distance index value between the node and each peer candidate is described;
P2P distribution comprising means for preferentially selecting a partner peer candidate having a shorter network distance from the peer node based on the peer distance response and establishing a connection. system. A distribution control server that responds to a peer list request received from each peer node and returns a peer list in which peer peer candidates are described;
Each peer node further comprises:
Means for requesting a peer list from the distribution control server;
The delivery control server is
Means for selecting a peer candidate in response to the peer list request;
Means for transmitting a peer distance request in which address information of peers requesting the peer list and each peer candidate is described to the network distance management server;
Means for receiving from the network distance management server a peer-to-peer distance response in which network distance index values between the requesting peer and each peer candidate are described;
Means for generating a peer list in which priority is set higher for peer candidates whose network distance to the requesting peer is closer;
Means for returning a peer list response describing the peer list to the requesting peer;
Each peer node further comprises:
Means for receiving a peer list from the delivery control server;
6. The P2P distribution system according to claim 5, wherein a connection is established by selecting a partner peer having a higher priority from partner peer candidates based on the received peer list.   The means for acquiring address information of the partner peer candidate in each peer node acquires address information of the partner peer candidate with reference to a DHT (distributed hash table). P2P distribution system.   The means for acquiring address information of the partner peer candidate in each peer node acquires address information of the partner peer candidate from node information exchanged with the partner peer with which the connection has been established. The described P2P distribution system. Each peer node is
Prior to transmission of the measurement request message to the reference server, means for transmitting a distance measurement necessity determination request in which address information of the own node is described to the network distance management server;
Means for receiving a distance measurement necessity determination response returned in response to the distance measurement necessity determination request;
The network distance management server is
Means for determining whether or not the network distance between each reference server has already been registered with respect to another peer node having the same prefix and address of the peer node described in the distance measurement necessity determination request;
And a means for returning a distance measurement necessity determination response in which a determination result indicating that distance measurement is not required is described if registered,
Each peer node does not transmit the measurement request message when it is determined in the distance measurement necessity determination response that measurement of the network distance index value with each reference server is unnecessary,
The P2P distribution system according to any one of claims 4 to 8, wherein the network distance management server calculates a network distance index value between peer nodes assuming that peer nodes having the same prefix have the same position on the network.   The network distance calculation system according to any one of claims 4 to 9, wherein the network distance index value is a response delay time of the measurement response message with respect to the measurement request message.

Images