KR100641796B1 - P2P overlay network construction method and apparatus - Google Patents

Abstract

The present invention relates to a method and apparatus for constructing a P2P overlay network. The present invention relates to a P2P overlay network in which identification values for a plurality of nodes are obtained using a distributed hash table, and the plurality of nodes are sequentially located based on the identification values. CLAIMS 1. A method of registering a node that wants to participate, the method comprising: (a) sending a join request message from the node that wants to participate to a reference node of the P2P overlay network; (b) As the participation request message is sequentially transmitted between the plurality of nodes, an identification value of a node to which the first node, which has received the participation request message, wants to participate, is the identification value of the first node and the first node. Determining whether the value is between the identification values of the second node next to the node; And (c) registering the node that wants to participate between the first node and the second node when it is determined that the inter-value is determined in the step (b). Therefore, it is possible to search for resources shared by each node more easily and efficiently.

Description

P2P overlay network construction method and apparatus

FIG. 1 is a block diagram illustrating a configuration of a resource information resource locator showing a node and a shared file based on an identification value obtained through a hash function according to the present invention.

2 is a diagram illustrating a method for joining a P2P overlay network in which a node that wants to participate according to the present invention is already configured.

3 is a diagram illustrating a method of checking whether a node and a friend node are operating within two hops according to the present invention.

4 is a diagram illustrating a method of registering a resource information locator of a shared file held by a node on a P2P overlay network according to the present invention.

5 is an example of a method for searching for a shared file stored in another node in one node according to the present invention.

6 is another example of a method for searching for a shared file stored in another node in one node according to the present invention.

7 is an example of a method of solving the problem of duplicated identification values generated when a node having the same identification value attempts to participate using different IP according to the present invention.

FIG. 8 is a diagram illustrating a neighbor node table and a friend node table stored in node 19 in FIG. 3.

The present invention relates to a method and apparatus for constructing a P2P overlay network, and more particularly, to a P2P overlay network construction method for constructing a P2P overlay network in a distributed environment such as the Internet and for easily and efficiently searching for resources shared by each node. And to an apparatus.

IPv6 (Internet Protocol version 6) networks are being built to provide commercial services beyond the test network, but there are not many applications using IPv6. Therefore, in order to activate the IPv6 network, many applications that can operate in a commercial network must be developed. In particular, P2P applications aiming for the end-to-end service, which is the basic concept of the Internet, are considered as one of the most widely used applications in the next-generation Internet. Therefore, the use of IPv6 networks through the development and distribution of P2P applications that operate on IPv6 networks It will be able to contribute a lot to this.

Peer-to-Peer (P2P) technology, which has been studied in the past, is an application level protocol such as HTTP, and is defined as a technology that supports real-time communication, resource distribution and exchange between users. P2P generally includes a hybrid P2P scheme using a server and a pure P2P scheme in which all nodes perform server and client operations. Pure P2P method follows the fundamental concept of peer-to-peer, and it has a problem that it is difficult to search and find resources shared by each node in a large network.

The hybrid P2P method provides a resource sharing function to each node through a server, and is composed of a central server capable of providing a service and P2P nodes having substantial shared resources. The central server maintains network connection sessions from each node and manages and maintains metadata of shared resources so that the P2P nodes can easily search for resources as needed. Each P2P node connects to the server to search for shared resources, searches for nodes with the resources, and exchanges of the actual resources are made through the connection between the two nodes. A representative example of such a structure is Napster, which is well known around the world. However, such a structure lacks scalability and also has a problem in that it is vulnerable to increase in cost and stability due to centralization.

Pure P2P method is widely used by Gnutella and Freenet. In the case of Gnutella, each node connects itself in an application level, and this node can obtain information about the node having the file by flooding the search message to a certain range to search for the file. However, it has a big problem with scalability because it periodically polls all Gnutella networks.

On the other hand, the P2P overlay network, which uses a hash table to construct a network by combining a real value with a key obtained through a hash function, provides scalability and stability. Representative methods include Chord, Pastry, and CAN using a Distributed Hash Table (DHT).

Chord uses the circular m-bit virtual identifier space to place the identification values obtained through the hash function of the node and the shared file, respectively. In addition, to retrieve resources, each node maintains a routing table called a finger table to facilitate the search.

Pastry is a method proposed by Microsoft that makes an IP address or public key a random 128-bit node identifier that is not duplicated through a cryptographic hash and is distributed across the namespace. The data also has a 128-bit key and is stored in the node with the key closest to the key inferred from the data to facilitate retrieval.

Finally, CAN obtains a vector P (p = hash (key)) corresponding to a point in the d dimension through a hash function, and each node stores data corresponding to the range of the zone where the virtual space is divided.

Hybrid P2P method is weak in terms of cost increase, scalability and stability due to central server, and P2P overlay network using Gutella's representative flooding among pure P2P methods also has scalability due to increased traffic due to frequent message flooding. I have a problem with

As such, systems such as Chord, Pastry, and CAN provide scalability, stability, and ease of use, but the above algorithms offer complex methods to implement in practice, as well as DHT's Due to the disadvantages, the actual search success probability is not high. It also has the problem that it is only suitable for certain P2P applications such as storage in a distributed environment.

The present invention provides a method for arranging nodes and shared resources so as to be suitable for a distributed environment using DHT, and each node stores only location information of neighbor nodes and friend nodes, thereby establishing a P2P overlay network through message routing.

In addition, the present invention provides a method for maintaining a character of P2P and enabling file retrieval by using a friend node interworking with an instant messenger to construct a P2P overlay network.

The P2P overlay network construction method of the present invention for solving the above technical problem, obtains identification values for a plurality of nodes using a distributed hash table, and the plurality of nodes are sequentially located based on the identification value P2P A method of registering a node to join an overlay network, the method comprising: (a) sending a join request message from a node to join to a reference node of the P2P overlay network; (b) As the participation request message is sequentially transmitted between the plurality of nodes, an identification value of a node to which the first node, which has received the participation request message, wants to participate, is the identification value of the first node and the first node. Determining whether the value is between the identification values of the second node next to the node; And (c) registering the node, which is desired to participate, between the first node and the second node when it is determined that the inter-value is determined in the step (b).

In addition, the P2P overlay network construction method of the present invention for solving the technical problem, by using a distributed hash table to obtain the identification value for a plurality of nodes and the plurality of nodes are sequentially located based on the identification value A method of registering a node that wants to participate in a P2P overlay network, the method comprising the steps of: (a) transmitting a join request message from a node that wants to participate to a reference node of the P2P overlay network; (b) Whether the participation request message is sequentially transmitted between the plurality of nodes, and whether the identification value of the node that wants to participate in the first node that has received the participation request message matches the identification value of the first node; Determining; (c) if it is determined in step (b) that the first node transmits a password request message to the node that wants to participate; (d) the first node receiving a password from the node that wants to participate; And (e) comparing the password received in the step (d) with the password input when registering the first node and replacing the node with the desired node if the first node matches. Have as characteristic.

In the shared file resource information locator registration method of the present invention for solving the technical problem, obtaining identification values for a plurality of nodes by using a distributed hash table and the plurality of nodes are sequentially located based on the identification values A method of registering a resource information locator for a shared file in a node storing a shared file in a P2P overlay network, the method comprising: (a) a file identification value using a hash through the distributed hash table for the shared file Calculating; (b) a file registration message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file registration message has the file identification value and the identification value of the first node. Determining whether the value is between the identification values of the second node next to the first node; And (c) registering the resource information locator for the file when it is determined that the inter-value is determined in the step (b).

In the shared file retrieval method of the present invention for solving the above technical problem, a P2P overlay in which identification values for a plurality of nodes are obtained using a distributed hash table, and the plurality of nodes are sequentially located based on the identification values. A method of searching for a shared file in a node that wants to search for a shared file in a network, the method comprising: (a) calculating a file identification value using a hash through the distributed hash table for the shared file name to be searched; (b) a file search message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file search message has previously stored the file identification value in the first node. Determining whether it exists in the shared file list; (c) if it is determined in step (b) that the first node transmits the file search message to a node that previously sent a list of shared files matching the file identification value; (d) the node transmitting the shared file list transmitting a search confirmation message including a resource information locator for the file identification value to a node that wants to search the file; And (e) searching for the file by connecting to the node that wants to search for the shared file to the node having the actual file through the resource information locator.

In addition, the shared file search method of the present invention for solving the technical problem, by using the distributed hash table to obtain the identification value for a plurality of nodes and the plurality of nodes are sequentially located based on the identification value A method of searching for a shared file in a node that wants to search for a shared file in a P2P overlay network, the method comprising: (a) calculating a file identification value using a hash through the distributed hash table for the shared file name to be searched; (b) a file search message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file search message has the file identification value and the identification value of the first node. Determining whether the value is between the identification values of the second node next to the first node; And (c) the first node transmitting a search confirmation message including a resource information locator for the file to the node that wants to search for the file, when it is determined that the inter-value is determined in step (b). and (d) searching for the file by connecting to the node having the actual file through the resource information locator.

According to an aspect of the present invention, there is provided a P2P overlay network construction apparatus for obtaining identification values for a plurality of nodes using a distributed hash table, and the plurality of nodes are sequentially located based on the identification values. In constructing a P2P overlay network, each of the plurality of nodes comprises: a neighbor node table for storing resource information locators for neighboring nodes in two hops in both directions from each node; And a friend node table for storing resource information locators for friend nodes that can be obtained by interworking with an instant messenger.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram illustrating a configuration of a resource information resource locator showing a node and a shared file based on an identification value obtained through a hash function according to the present invention. Referring to FIG. 1, the resource information locator 100 includes an identification value (ID) 110, an IP address 120, and a port number 130.

First, the identification value 110 obtains a node or a shared file through a hash using a distributed hash table (DHT). Here, in the case of a node, an hash value is obtained by hashing an e-mail address through an MD5 hash function, and in the case of a shared file, a file name is hashed through an MD5 hash function to obtain an identification value. Acquire. The identification value thus obtained is located counterclockwise in the circular virtual space.

The resource information locator 100 includes an IP address 120 of a node and a port number 130 for providing a current application service, together with an identification value 110 of a node and a shared file located in a counterclockwise direction. Here, IP address 120 is the Internet Protocol version 6 (IPv6) of the real node.

Here, the obtained identification value has been described as being located counterclockwise in the circular virtual space, but in another embodiment of the present invention, it may be positioned clockwise in the circular virtual space.

The present invention also relates to a new P2P overlay network operating on IPv6, unlike the conventional P2P overlay protocol.

2 is a diagram illustrating a method for joining a P2P overlay network in which a node that wants to participate according to the present invention is already configured. Referring to FIG. 2, a process of joining a P2P overlay network in which node 17 (ie, a node that wants to join) having an identification value of 17 is already configured is illustrated.

First, node 17 transmits a PING message for checking whether node 0 is currently operating through information of node 0 (ie, a reference node) while starting an application (S200).

Here, the key node is assumed to be a special node that is always accessible and all nodes know its address from the beginning, and the information of the reference node is loaded together when the P2P application is started to acquire the information. Or obtain specific IP addresses through the Domain Name System (DNS). In the P2P overlay network of FIG. 2, node 0 having an identification value of 0 is a reference node.

Next, if node 0 received the PING message is in operation, transmits a PONG message to node 17 (S210).

Next, node 17 transmits a join request message (JOIN message) to node 0 (S220). As such, all nodes send a join request message to node 0 (contributing node) to join the P2P overlay network for the first time.

Next, node 0 transmits a participation request message to the corresponding position in the clockwise direction to configure the virtual circular space where node 17 is located (S230) (S240) (S250). In FIG. 2, since the node on which node 17 is to be located is the left side of node 22, a join request message is transmitted to node 22.

Next, node 22, which has received the participation request message, transmits a participation confirmation message (JACK) indicating that the node 17 has been successfully located in the P2P overlay network (S260).

Next, because one node must have information about neighboring nodes within two hops, node 22 is a node 17 node to node 2, node 10, node 22 and 51, which are neighbors of node 17. Transmit an update message including the resource information locator of S271, S272, S273, S274, receive the resource information locator from nodes 2, 10, 22, and 51 and register it; do. In Figure 2, transmitting the resource information locator to node 2 (S271), transmitting the resource information locator to node 10 (S272), transmitting the resource information locator to node 22 (S273) and 51 And transmitting the resource information locator to the node (S274).

As shown in FIG. 2, a node successfully participating in a P2P overlay network acquires information of a neighbor node and receives a shared file list directly from a friend node such as an instant messenger. In addition, the operation confirmation message (HELLO message) is periodically transmitted to maintain the P2P overlay network. In this regard will be described in detail in FIG.

3 is a diagram illustrating a method of checking whether a node and a friend node are operating within two hops according to the present invention. Here, in the P2P overlay network, the message is transmitted in the clockwise direction with respect to the reference node (node 0), and the identification value for the node or file becomes smaller as the clockwise direction is around the reference node.

Referring to FIG. 3, node 19 (identification value 19) successfully participates in a P2P overlay network and sends a round trip time (RTT) to an operation confirmation message (HELLO message) to its neighbor nodes and friend nodes. This is to check whether neighboring nodes are currently operating well.

First, node 19 transmits an operation confirmation message to node 2, the left node of its left (S300). Next, node 19 receives an operation response message (HACK message) that node 2 itself is operating from node 2 receiving the operation confirmation message (S305). Therefore, node 19 confirms that node 2 is currently operating. On the other hand, if node 2 is not operating in step S305, node 19 does not receive the operation response message. Therefore, node 19 confirms that node 2 is not currently operating.

Next, node 19 transmits an operation confirmation message to node 10, which is its left node (S310). Next, node 19 receives an operation response message indicating that node 10 is operating from node 10 receiving the operation confirmation message (S315). Therefore, node 19 confirms that node 10 is currently operating. On the other hand, if node 10 is not operating in step S315, node 19 does not receive an operation response message. Therefore, node 19 confirms that node 10 is not currently operating.

Next, node 19 transmits an operation confirmation message to node 20, which is its right node (S320). Next, node 19 receives an operation response message that node 20 itself is operating from node 20 that has received the operation confirmation message (S325). Therefore, node 19 confirms that node 20 is currently operating. On the other hand, if node 20 is not operating in step S325, node 19 does not receive an operation response message. Therefore, node 19 confirms that node 20 is not currently operating.

Next, node 19 transmits an operation confirmation message to node 22, which is the right node of its right (S330). Next, node 19 receives an operation response message indicating that node 22 is operating from node 22, which has received the operation confirmation message (S335). Therefore, node 19 confirms that node 22 is currently in operation. On the other hand, if node 22 is not operating in step S335, node 19 does not receive the operation response message. Therefore, node 19 confirms that node 22 is not currently operating.

Next, node 19 transmits an operation confirmation message and a list of files shared by node 19 itself to nodes 67, 51, and 40 of its friend nodes (S340) (S350) (S360). . Next, node 19 receives the operation response message from node 67, node 51, and node 40 that receive the operation confirmation message, and node 67, node 51, and node 40 of the shared file. The list is received (S345) (S355) (S365). Therefore, node 19 confirms that it is currently operating through an operation confirmation message transmitted from node 67, node 51, and node 40, respectively. In addition, node 19 receives and stores a list of files owned by node 67, node 51 and node 40, respectively. On the other hand, when nodes 67, 51 and 40 are not operating in steps S345, S355 and S365, node 19 does not receive an operation response message. Therefore, node 19 confirms that node 67, node 51 and node 40 are not currently operating.

In FIG. 3, each step has been described, but in another embodiment of the present invention, such an operation may be performed at the same time or by another predetermined rule.

4 is a diagram illustrating a method of registering a resource information locator of a shared file held by a node on a P2P overlay network according to the present invention. Here, in the P2P overlay network, the message is transmitted in the clockwise direction with respect to the reference node (node 0), and the identification value for the node or file becomes smaller as the clockwise direction is around the reference node.

Referring to FIG. 4, a process of registering each resource information locator with a P2P overlay network based on identification values of shared files stored in node 10 (identification value 10) is described. Node 10 first locates the identification value of the file using the information of the neighbor nodes in the corresponding node on the P2P overlay network which is a circular space by considering the identification value of the node.

First, node 10 should check the resource information locator of file 8 (identification value 8) of its neighbor nodes, and file 10 should be located at node 10 and node 2 for file 8 Stored to the node itself (S400).

Next, node 10 transmits the resource information locator for file 45 (identification value 45) to node 0 first after checking the information of its neighbor nodes (S410). Next, the node 0 transmits the resource information locator for the file 45 to the node 51 again after checking the information of its neighbor nodes (S415). Here, as a result of considering the information of neighbor nodes, node 51 knows that file 45 should be stored in itself and stores the resource information locator for file 45. That is, since file 45 is located between nodes 51 and 22, node 51 stores the resource information locator for file 45 in itself.

Next, the node 8 transmits the resource information locator for the file 158 (identification value 158) to the node 0 first after checking the information of its neighboring nodes (S420). Here, as a result of considering the information of neighbor nodes, node 0 knows that file 158 should be stored in itself, and stores resource information locator for file 158. That is, file 158 is located between node 0 and node 67, so node 0 stores the resource information locator for file 158.

5 is an example of a method for searching for a shared file stored in another node in one node according to the present invention. Here, in the P2P overlay network, the message is transmitted in the clockwise direction with respect to the reference node (node 0), and the identification value for the node or file becomes smaller as the clockwise direction is around the reference node.

Referring to FIG. 5, first, node 2 (identification value 2) receives a file search message for searching for file 45 (identification value 45) (S500).

Next, the file search message is sequentially transmitted to the node that may store the resource information locator for the file 45 in consideration of the identification value of its neighbor nodes from node 2. In more detail, node 2 stores resource information locators within two hops of nodes 0 and 67, which are its neighbor nodes, in a message transmission direction in a P2P overlay network. The file search message for searching for the resource information locator for the file 45 is transmitted to the node 67 near the file 45 among the nodes (S510). Also, node 67, which received the file transfer message, stores resource information locators for nodes 51 and 22, which are its neighbor nodes, in the message transmission direction in the P2P overlay network. Knowing that it is located in the node 51 that stores the resource information locator for the file number 45 of the node and transmits a file search message to the node 51 (S520).

Next, the node 51 that has received the file search message transmits a search confirmation message including the resource information locator for the file 45 to the node 2 (S530).

Next, node 2 searches for file number 45 by connecting to node number 10 that actually stores file number 45 using the resource information locator (S530).

6 is another example of a method for searching for a shared file stored in another node in one node according to the present invention. Here, in the P2P overlay network, a message is transmitted in a clockwise direction around the reference node (node 0), and the identification value for the node or file is located smaller in the clockwise direction around the reference node.

Referring to FIG. 6, first, node 2 (identification value 2) receives a file search message for searching for file 45 (identification value 45) (S600).

Next, node 2 determines whether there is a node storing the resource information locator for file 45 in consideration of the file list of its friend nodes, and determines whether the node having the file list among the friend nodes is present. The file search message is transmitted (S610). That is, since node 2 has a file information list of its friend nodes in the P2P overlay network, the resource information locator for file 45 is 51 from the file list of file 45 of node 2 It knows that node 1 has it and sends a file search message to node 51.

Next, the node 51 receiving the file search message transmits a search confirmation message including the resource information locator for the file 45 to the node 2 (S620).

Next, node 2 searches for file 45 using the resource information locator in connection with node 10, which actually stores file 45 (S630).

Therefore, using friend node is more efficient because it can simplify the process of file searching. That is, since the friend node is used as a shortcut on the ring forming the P2P overlay network, efficient search is possible.

7 is an example of a method of solving the problem of duplicated identification values generated when a node having the same identification value attempts to participate using different IP according to the present invention. In the present invention, the identification value of the node is obtained through an e-mail address. Therefore, if a user accesses the P2P overlay network with the same email address in different places, that is, different IP addresses, there is a problem in participating in the P2P overlay network due to the same identification value. 7 is to provide a method for solving the problem of duplication of identification values to solve this problem.

Referring to FIG. 7, node 51, which has already participated (identification value 51), is already located on the P2P overlay network, but node 51, which wants to participate with another IP address through the same identification, has node 0. The registration request message (JOIN message) is transmitted to the (reference node) (S700). As such, all nodes send a join request message to node 0 (contributing node) to join the P2P overlay network for the first time.

Next, node 0 transmits a join request message to node 67 located in the clockwise direction to construct a virtual circular space in which node 51 wants to participate is located (S710).

Next, node 67 transmits a participation request message to the already participated node 51, which is located in the neighborhood in the clockwise direction, in order to configure a virtual circular space in which node 51 wants to participate is located (S720).

Next, the participation request message is eventually delivered to the already participating node 51, and the already participating node 51 knows that the participation request is received from the same identification value, and requests the password to the node 51 who wants to participate through the password request message. It is made (S730).

Next, node 51 wishing to participate transmits the encrypted password to the participating node 51 by encrypting the password through a hash function (S740).

Next, the already participating node 51 decrypts the encrypted password and checks whether the password matches (S750).

Next, if it is determined that the already participating node 51 has the same password in step S750, the node 51 joins the node 51 that wants to participate, and transmits a participation confirmation message to the node 51 that wants to participate (S760). Thereafter, the newly participating node 51 sends an update message to its neighbor nodes to inform the node of the change.

FIG. 8 is a diagram illustrating a neighbor node table and a friend node table stored in node 19 in FIG. 3. Referring to FIG. 8, a neighbor node table indicating resource information locators for neighbor nodes stored in node 19 and a friend node table indicating resource information locators for friend nodes are configured.

The neighbor node table stores resource information locators for the right side (RR), the right side (R), the left side (L), and the left side (LL) on the left. Specifically, for example, node 19, which is the right (RR) node of the right side, node 20, which is the right (R) node, node 10, which is the left node, and node 2, which is the left (LL) node of FIG. Field, identification, IP address, port number, RTT, and timeout information.

The friend node table stores resource information locators for friend nodes according to an instant messenger. Specifically, for example, in the friend node table of node 19 in FIG. 3, identification values, IP addresses, port numbers, RTTs, and timeouts for nodes 40, 51, and 67, which are their friend nodes, are included in the friend node table. It is storing information.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD_ROM, magnetic tape, floppy disks, and optical data storage, and may also include those implemented in the form of carrier waves (eg, transmission over the Internet). . The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The present invention relates to a method and apparatus for constructing a P2P overlay network. The present invention relates to a P2P overlay network that enables all nodes to act as servers and clients in a pure P2P scheme utilizing the basic characteristics of P2P, and is also suitable for distributed environments such as the Internet. DHT is used to build the network, providing scalability, reliability, maintainability and user convenience.

By maintaining a routing table called a resource locator (Resource Locator), a more efficient resource search is possible, and through the exchange of simply configured messages it is possible to build and maintain a P2P overlay network.

In addition, the P2P overlay network configured through the present invention operates based on IPv6, which is the next generation Internet, and can provide application services that are widely used on the Internet such as instant messenger, VoD service, and resource sharing, and through this, IPv6 based A variety of services can be provided to many users and play a big role in the early adoption of IPv6.

Claims (16)

A method for acquiring an identification value for a plurality of nodes using a distributed hash table and registering a node that wants to participate in a P2P overlay network in which the plurality of nodes are sequentially located based on the identification value, (a) sending a join request message from a node wishing to join to a reference node of the P2P overlay network; (b) As the participation request message is sequentially transmitted between the plurality of nodes, an identification value of a node to which the first node, which has received the participation request message, wants to participate, is the identification value of the first node and the first node. Determining whether the value is between the identification values of the second node next to the node; And and (c) registering the node that wants to participate between the first node and the second node when it is determined that the inter-value is found in the step (b). The method of claim 1, (d) the first node transmitting a participation confirmation message indicating that registration is successful to the node that wants to participate. The method of claim 2, And each of the plurality of nodes stores resource information locators for neighboring nodes within two hops in both directions about each node. The method of claim 3, wherein (f) the first node transmitting the resource information locator of the node wishing to participate to a node existing within two hops in both directions with respect to the node wishing to participate. How to build a network. A method for acquiring identification values for a plurality of nodes using a distributed hash table and registering a node that wants to participate in a P2P overlay network in which the plurality of nodes are sequentially located based on the identification values, (a) sending a join request message from a node wishing to join to a reference node of the P2P overlay network; (b) Whether the participation request message is sequentially transmitted between the plurality of nodes, and whether the identification value of the node that wants to participate in the first node that has received the participation request message matches the identification value of the first node; Determining; (c) if it is determined in step (b) that the first node transmits a password request message to the node that wants to participate; (d) the first node receiving a password from the node that wants to participate; And (e) comparing the password received in the step (d) with the password input when registering the first node and replacing the password with the desired node if the first node matches. To build a P2P overlay network. The method of claim 5, And each of the plurality of nodes stores resource information locators for neighboring nodes within two hops in both directions about each node. The method of claim 6, (f) transmitting the resource information locator of the node that wants to participate to the node that wants to participate, which is registered in place of the first node and is located within two hops in both directions with respect to itself; P2P overlay network construction method, characterized in that. A resource for the shared file in a node storing a shared file in a P2P overlay network in which identification values for a plurality of nodes are obtained using a distributed hash table and the plurality of nodes are sequentially located based on the identification values. A method of registering an information locator, calculating a file identification value of the shared file using a hash through the distributed hash table; (b) a file registration message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file registration message has the file identification value and the identification value of the first node. Determining whether the value is between the identification values of the second node next to the first node; And and (c) registering the resource information locator for the file when it is determined that the inter-value is determined in the step (b). The method of claim 8, And each of the plurality of nodes stores resource information locators for neighboring nodes within two hops in both directions with respect to each of the plurality of nodes. A method for acquiring an identification value for a plurality of nodes using a distributed hash table and searching for a shared file in a node that wants to search for a shared file in a P2P overlay network in which the plurality of nodes are sequentially located based on the identification value. To (a) calculating a file identification value using a hash through the distributed hash table of the shared file name to be searched; (b) a file search message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file search message has the file identification value and the identification value of the first node. Determining whether the value is between the identification values of the second node next to the first node; And (c) if it is determined in step (b) that the inter-value is determined, the first node sends a search confirmation message including a resource information locator for the file to a node that wants to search the file; and (d) searching for the file by connecting the node that wants to search the file to the node having the actual file through the resource information locator. A method for acquiring an identification value for a plurality of nodes using a distributed hash table and searching for a shared file in a node that wants to search for a shared file in a P2P overlay network in which the plurality of nodes are sequentially located based on the identification value. To (a) calculating a file identification value using a hash through the distributed hash table of the shared file name to be searched; (b) a file search message including the file identification value is sequentially transmitted between the plurality of nodes, so that the first node receiving the file search message has previously stored the file identification value in the first node. Determining whether it exists in the shared file list; (c) if it is determined in step (b) that the first node transmits the file search message to a node that previously sent a list of shared files matching the file identification value; (d) the node transmitting the shared file list transmitting a search confirmation message including a resource information locator for the file identification value to a node that wants to search the file; And (e) searching for the file by connecting the node that wants to search for the shared file to the node having the actual file through the resource information locator. The method of claim 11, In step (c), if it is determined that the file search message does not exist in step (b), the file search message including the file identification value is sequentially transmitted between the plurality of nodes, and the node receiving the file search message is received. Determines whether the file identification value is a value between an identification value of a node receiving the file search message and an identification value of a node located next to the node receiving the file search message. And transmitting the file search message to a node receiving the file search message. In obtaining an identification value for a plurality of nodes using a distributed hash table and constructing a P2P overlay network in which the plurality of nodes are sequentially located based on the identification value, Each of the plurality of nodes includes: a neighbor node table for storing resource information locators for neighboring nodes within two hops in both directions from its own node; And And a friend node table for storing resource information locators of friend nodes that can be obtained by interworking with an instant messenger. The resource information locator of claim 13, wherein An identification value that is a hash function value obtained by hashing an email address of a corresponding node; An IP address representing the actual location of the corresponding node; And And a port number for providing a current application service in the corresponding node. The method of claim 13, Each of the plurality of nodes periodically transmits an operation status confirmation message to neighboring nodes through the neighbor node table and friend nodes through the friend node table, and measures the RTT value so that the neighboring nodes and the friend nodes are measured. P2P overlay network building apparatus characterized in that it measures whether or not the operation. The method of claim 15, Each of the plurality of nodes transmits a list of shared files that it owns to friend nodes operating among the friend nodes. And a shared file list held by the friend nodes in operation.

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