JP2006221457A - Servant for replication control in pure p2p communication, replication control method for the same, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To speed up and streamline the acquisition of target information in pure P2P communication in a simpler procedure. <P>SOLUTION: For the execution of replication, a history information generation part 6a generates history information associating filenames and IP addresses of destination servants, a publication processing part 6b transmits the history information to other servants specified in a predetermined procedure, and a history information storage processing part 6c, when receiving such history information from other servants, stores the history information in a memory 5. For the transmission of a file search request packet, if a history information reference part 6d finds a search request target file by reference to the history information stored in the memory 5, a packet generation/transmission processing part 6e transmits a download request packet to the servant of the associated IP address. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a Pure-type P2P (Peer-to-Peer) communication technology constructed on an IP (Internet Protocol) network, and more particularly to a technology suitable for improving the retrieval efficiency of a replicated file. is there.

  In recent years, on the Internet, which is an IP network, the use of content search / transfer services by P2P communication is increasing. In P2P communication, file sharing applications such as “Napster” and “Gnutella” are installed in each computer terminal such as a personal computer connected via a network, and each terminal has functions of both a server and a client. Called Peer or Servant.

  P2P type communication can be broadly classified into two types: Hybrid type typified by “Napster” and Pure type typified by “Gnutella”. The Hybrid type is a type in which a dedicated server that collectively manages the location of the objective information (file) exists, and the Pure type is a type in which the location of the objective information is inquired one after another by a message game method.

  In the Hybrid type, search request packets from each servant are concentrated on a dedicated server, and the server is likely to be a bottleneck.

  Also, in the Pure type, each servant inquires the adjacent servant for the existence of target information (file) one after another up to the range of the hop count of the value set in the packet TTL (Time to Live). I do. That is, between each servant, a branch is made by an amount corresponding to the “number of arms (degree)” extended to each adjacent servant, and an inquiry by a packet is executed.

  In a normal procedure related to a file download request in such Pure-type P2P communication, an arbitrary servant that requests a certain file is first (i) a “Query packet (a search request packet including a search character string, Is transmitted to the surrounding servant (servant specified by the “PING packet” and “PONG” packet). (Ii) If a “QueryHit packet (response packet from a servant holding a file that matches the request for the Query packet)” is returned, that is, if it “hits”, the file is held from that information. Know what servant is doing. Then, a target file is obtained through a procedure of (iii) issuing a download request (such as “PUSH”) to the servant holding the file and (iv) executing the download.

  In the conventional Pure type P2P communication, a servant that has made a request to download a file has to perform the above procedure for searching which servant holds the file from the beginning each time. Therefore, when the “hit” rate is low, that is, when there is no target file in the nearby servant, the packet information search packet (Query packet) is transmitted in parallel from many servants, and the packet in the network The number increases explosively and congestion over a wide area in the network occurs.

  As a conventional technique for dealing with such a problem, for example, there are replication techniques described in Non-Patent Documents 1 to 3. In this replication technology, when performing P2P communication in an IP network, a copy (replica) of the content is sent to another servant in order to improve the hit rate for the content (file). Yes, servant load and line usage rate increase can be suppressed.

  In other words, when replication is executed by this technique, the file that was originally held only by the source servant is also held by some other servants. Therefore, the average distance from any servant that requests the file is shortened, it is easy to find from the requesting servant, and the download time is also shortened on average.

  However, also in this case, the requesting servant cannot obtain the target file unless the normal procedures (i) to (iv) described above are executed.

  In a situation where replication is frequently performed in the P2P network, it is desired that the target file can be obtained quickly and efficiently by a simpler procedure without executing the normal procedure.

Q. LV, P. Cao, E .; Cohen, K. Li, and S. Shenker, “Search and replication in unstructured peer-to-peer networks,” proceedings of 16th ACM International Conference on Supercomputing (ICS’02), June 2002. Goto, Ata, Murata: “Replication placement method for improving service stability in P2P networks” IEICE Tech. Bulletin NS2002-152, Oct. 2002. Nogami, Uchida: “File Search and Replication in Pure P2P”, Shingaku Sodai 2004 (announced in March 2004).

  The problem to be solved is that, in the conventional technology, even in the case of performing replication in Pure type P2P communication, in order for the servant that requested the file (content / data) to obtain the target file, “ The point is that the above-described normal procedures (i) to (iv) must be executed, including the procedure of sending the “Query packet” to surrounding servants.

  An object of the present invention is to solve these problems of the prior art and to obtain a target file in a P2P network quickly and efficiently by a simpler procedure.

  In order to achieve the above object, according to the present invention, in Pure-type P2P communication, when performing replication of a file (content), each servant performs when the replication is performed, for which servant, and which file. History information consisting of information such as whether or not it has been executed is generated and notified to a servant identified as valid on the P2P network. Upon receiving the notification, the servant stores the notified history information in the storage device, and when making a file search request, refers to the stored history information, and if there is history information about the file, replication of the file is performed. The execution destination servant is specified, and a file search request packet is sent to the servant. Also, when a search request packet is received from another servant, the stored history information is referred to. If there is history information about the file, the identification information (IP address) of the servant that is the replication destination of the file is displayed. By notifying the servant that is the source of the search request packet, distribution of subsequent search request packets is suppressed. The history information transmission destination servant is specified by using the number of hops, or by using at least one of the degree (the number of arms extending to the adjacent servant) and the number of hits together with the number of hops. For example, all servants within a predetermined hop number range, or servants within a predetermined hop number range, and either a degree or the number of hits is greater than or equal to a predetermined threshold value. As specified.

  According to the present invention, information such as when and where and what type of file is replicated is made known to a servant that performs P2P type communication. It is no longer necessary to execute the procedure step by step, and it is no longer necessary to execute the subsequent normal procedure when a search request for the file is received. Each servant is quicker (in a short time) with a simpler procedure. This makes it possible to efficiently find and obtain the target file, and to reduce the number of inquiry packets in the network.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a servant that performs replication control according to the present invention, FIG. 2 is an explanatory diagram showing an example of a procedure for specifying a history information notification destination by the servant in FIG. 1, and FIG. It is explanatory drawing which shows the other specific procedure example of the notification destination of the historical information by the servant in FIG.

  In FIG. 1, 1 is a servant having a replication control function in Pure type P2P communication, 2 is an input / output device (console) composed of a keyboard, a CRT, etc., and inputs information (command) from the outside, and the servant 1 is an IP network such as the Internet that connects the servant 1 to another servant (not shown).

  The servant 1 has a computer configuration such as a general PC (personal computer) including a CPU (Central Processing Unit), a main storage device (main memory), a display device, an input device, an external storage device, a peripheral device, and the like. A program or data such as a file sharing application recorded on a storage medium such as a CD-ROM via an optical disk drive as a peripheral device is installed in the external storage device, and then read from the external storage device into the main memory. As a result, the execution function of each processing unit is configured, and the P2P application layer appears as a servant.

  Specifically, the servant 1 includes processing function units such as a memory unit 3, an information management / transfer processing unit 4, a replication execution unit 5, a history information management processing unit 6, a PAD 7, a packet transmission unit 8, and a packet reception unit 9. It has.

  The PAD 7 has a packet assembling / disassembling function and converts various information into IP packets, and conversely, disassembles IP packets into various information. The packet transmission unit 8 has a function of sending IP packets to other servants connected by the IP network 10, and the packet reception unit 9 has a function of receiving arrival packets from other servants in the IP network 10. .

  The memory unit 3 includes a memory control unit 3a that performs memory capacity management, information storage control, deletion control, and the like, various replication information, hit information, information about the held files, and RTT (Round Trip Time) to each servant. : A round-trip delay time) information, a servant's IP address, history information according to the present invention, and the like.

  The RTT information is acquired as follows. First, the Ping packet is skipped from the packet transmission unit 8, the IP address of the counterpart servant is acquired from the Ping packet returned to the packet reception unit 9, and then the measurement packet is skipped from the packet transmission unit 8 to the address. The RTT to the partner servant is measured by measuring the time difference between arrival and departure until returning to the receiving unit 9.

  The replication execution unit 5 has a function of analyzing / determining various types of information related to replication executed in the past, and based on information such as the hit rate and the number of inquiries, to which servant when the information is replicated. Has the ability to decide and execute it.

  In this example, it is assumed that the replication execution unit 5 determines a servant to be replicated using the technique described in Non-Patent Document 3 described above.

  That is, if the hit rate of the file in the latest T time (that is, T time retroactively from the present time) exceeds a certain threshold at a certain time (Step 1), the replication execution unit 5 is in all routes (intermediate route). Pay attention to each servant i of k hops ahead (Step 2), and if the degree (degree, number of arms) is greater than or equal to a predetermined value m (Deg (i) ≥ m) for that servant i, the probability The target of replication is determined by P (ratio proportional to the number of arms) (Step 3) (where m is a positive number of 0 or more, i is 1 ≦ i ≦ Nj, and Nj is the servant at the j-th k-hop destination. ), The route Mi (Mi = “X * Deg (i)”) in the ratio X of the servant i) (where Mi = “X * Deg (i)” is X * Deg ( Select the largest positive number that does not exceed i) at random and pay attention to servants at k hops away That (Step4). Then, Steps 3 to 4 are executed Nj times (i = 1 to Nj) (Step 5), and Steps 3 to 5 are executed L times (j = 1 to L), thereby determining the replication execution destination servant of the file.

  The replication execution destination based on the number of inquiries is determined as follows. Here, "inquiry" means that when a particular servant is focused on, search packets for various files arrive and pass from any servant. At that time, "Which file was being searched for at what point" Therefore, the “inquiry count” information includes, for example, “the number of arrivals of the Query packet related to the file A is five times” and “the number of arrivals of the Query packet related to the file B are “One time”. Then, a servant whose “inquiry count” is “5 times” or more is determined as a replication execution destination.

  In addition, the control of “when” replication is executed for the servant determined based on “number of hits” and “number of inquiries” is effective for distributing the load. For example, when replication is executed for 50 servants, the 1st to 25th servants (first group) are executed at 10:00 and the 26th to 50th servants ( By executing at 10:10 for the second group), the execution time is shifted, and the load on the execution source servant, the load on the surrounding network, and the like are distributed. As an example of grouping at this time, the order of increasing the number of hits and the number of inquiries is listed.

  The history information management processing unit 6 executes the replication control of the present invention, and includes a history information generation unit 6a, a well-known processing unit 6b, a history information storage processing unit 6c, a history information reference unit 6d, a packet generation / transmission process. And a history information notification processing unit 6f.

  Based on the result of replication executed by the replication execution unit 5, the history information generation unit 6a associates at least the identification information (file name) of the file and the identification information (IP address) of the replication execution servant (history information). Is generated.

  In this example, it is assumed that the execution time of replication is included as history information, and specifically, the following information set related to replication executed by the replication execution unit 5 within the latest time T2 is generated.

  (R1 (S1, Q1, T1), R2 (S2, Q2, R2),..., Rk (Sk, Qk, Tk),...), And Sk = {Ak1, Ak2,.

  Here, “Rk” is k-th replication information retroactive from the present time, “Sk” is a set of servants that have performed k-th replication, and “Qk” is a file that has undergone k-th replication. “Tk” is the time when the k-th replication was executed, and “Aki” is the i-th IP address where the k-th replication was performed.

  The well-known processing unit 6b sends the information management / transfer processing unit 4, the PAD 7, the packet transmission unit 8 and the IP network 10 to other servants specified by the predetermined procedure for the history information generated by the history information generation unit 6a. Send through.

  The history information storage processing unit 6 c stores history information transmitted from other servants via the IP network 10, the packet receiving unit 9, the PAD 7, and the information management / transfer processing unit 4, into the memory 3 b via the memory unit 3. Remember.

  The history information reference unit 6d responds to a search request for an arbitrary file input from the user via the input / output device 2, or the IP network 10, the packet receiving unit 9, the PAD 7, the information management / transfer processing unit 4 The history information stored in the memory 3b of the memory unit 3 is referred to in response to a search request for an arbitrary file from another servant input via the.

  The packet generation / transmission processing unit 6e is a reference result of the history information reference unit 6d corresponding to a search request for an arbitrary file input from the user via the input / output device 2, and the history information stored in the memory 3b. If there is a search request target file name (target file name), the identification information (IP address) associated with the target file name in the history information is read, and the target file is sent to the servant with the IP address. Download request packet (PUSH packet) is generated and transmitted via the information management / transfer processing unit 4, the PAD 7, the packet transmission unit 8, and the IP network 10, and the search request target file name (target file) If there is no name), a normal search request packet is generated and each adjacent servant is assigned the information management / transfer processing unit 4, PAD 7, Transmitted via the Tsu door transmitter unit 8, IP network 10.

  The history information notification processing unit 6f is a reference result of the history information reference unit 6d corresponding to a search request for an arbitrary file from another servant. The history information stored in the memory 3b includes the name of the search request target file ( If there is a target file name), the identification information (IP address) associated with the target file name in the history information is read, and the IP address is sent to the servant that is the source of the search request packet as an information management / transfer processing unit 4, PAD 7, packet transmitter 8, and notification via IP network 10. In this example, the packet sent by the servant 1 is sent in accordance with a routing protocol (for example, OSPF: Open Shortest Path First) used in normal TCP / IP, and the history information notification processing unit 6f Use this routing protocol.

  In the history information referred to by the history information reference unit 6d, when a plurality of servants are registered in association with the search request target file name (target file name), the history information notification processing unit 6f and the packet The generation / transmission processing unit 6e selects one servant according to a predetermined procedure. For example, a process of narrowing down to one servant by selecting at random or in the order of registration is performed.

  Further, in the transmission of the “download request packet (PUSH packet)” in the packet generation / transmission processing unit 6e, for example, a “Gnuttela frame” further embedded in a TCP frame embedded in the IP packet to be transmitted. “PUSH” is selected by specifying a bit in “payload discritor” in “Gnuttela header”, and the transmission (download) of the file is requested. If there is no replica of the file in the requested servant and the time is over, select another servant at random and request the download. If there is no other servant, A search request is made with a Query packet.

  Further, the well-known processing unit 6b uses the number of hops or the degree of hops together with the degree (number of arms) and the number of hits to specify the servant as the transmission destination of the history information. Do. For example, all servants within a predetermined hop number range, or servants within a predetermined hop number range, and a servant whose degree or hit number is greater than a predetermined number are sent to As specified.

  For example, as the target servant for notifying the history information, the servant 1 that has performed replication is within M hops, and (1) the current degree (the number of arms extending to the adjacent servant) is D or more, (2 ) If the condition that the number of hits H (T1) within the most recent time T1 is equal to or greater than H1 is to be satisfied, and if it is widely known, the value of the number of hops M is increased and more limited. When it is desired to make the servant efficiently known, the thresholds D and H1 for the degree and the number of hits are increased.

  For example, (1) in the servant that is the replication execution source, information packets are periodically transmitted between the servants in the M hops to communicate the number of hits and the degree, or (2) ) In the servant that is the replication execution source, a query packet is periodically sent to the servant in the M hop, information in the reply packet is read, and the number of hits and degree are obtained.

  In this example, all the servants in M hops are notified of the history information so that each servant has a hit count H (T1) within the most recent time T1 equal to or greater than a predetermined threshold, or When it is determined that the degree (the number of arms) at that time is a predetermined threshold D or more, the notified history information is stored. Otherwise, the history information is stored. Ignoring it makes the history information known.

  In FIG. 2, when the number of hops from the servant 21 is within M = 3, and further when the degree threshold D = 3 and the hit number threshold H1 = 10, the history information is known. The specific status of the target servant (shaded circle in the figure) is shown. In FIG. 2, the numbers (1 to 4, 6, 7, 9 to 13 and 15) attached to each target servant are the number of hits.

  Further, in FIG. 3, the target servant as a known destination of history information is specified as a servant that is more than the number of hops K from the servant 31 that is the replication execution source. In this case, if the value of TTL (Time To Live) of a packet for transmitting history information is L, all servants that are K + 1 hops or more and L hops or less become target servants as known destinations. Here, an example in which the number of hops K = 3 and TTL = 7 is shown.

  Further, the well-known processing unit 6b notifies each target servant of the history information generated by the history information generating unit 6a at regular intervals (for example, every predetermined T minutes). Only the history information for the latest Q (= n × T: n is an appropriate positive number) is held. In this way, each target servant always holds only the information for the latest Q, and every time history information from the servants 1, 21 and 31 is notified, the history of T minutes before Q minutes. Information is deleted, and history information in each target servant can be periodically refreshed (updated).

  As described above, according to this example, in the servant that has executed replication, the history information including the information set (S, Q, T) that identifies the replication target file and the execution destination servant is generated, and the specific information is generated. In each servant, the received history information is stored, and when making a search request for a file from its own servant, the history information is referred to. Instead of a normal search request packet (Query packet), a download request packet (PUSH packet) is sent to the servant with the IP address associated with. This eliminates the need for packet transmission in a normal procedure including a search request packet (Query packet), reducing the load on the servant and the network load.

  In particular, the servant near the replication execution servant becomes a known servant by using a procedure similar to the procedure used for specifying the replication servant to identify the servant to which the history information is made known. Increases the efficiency of using replication.

  Also, if the history information does not include the identification information of the servant that is the replication execution source, in this case, file download requests to the replication execution servant are distributed, and the load on the replication execution servant is reduced. Can be reduced.

  In addition, normally, each servant can only recognize the information of each retained file only with respect to the servants adjacent to each other, whereas in this example, history information (information set) is set close to within a small number of hops, for example. By informing each servant of the servant, the servant that has been informed of the history information has the IP address of the servant holding the file to be searched within a relatively small number of hops, that is, nearby. It can be known from the set (S, Q, T).

  In this example, history information is made known to servants whose number of hits or degree is greater than a predetermined value. This is because servants with a large number of hits and degrees are so-called “active servants”. This is because the number of files held is large, and transmission / reception with other servants is large. That is, such an “active servant” performs a P2P communication operation of requesting and downloading a file, and vice versa, and sending a file when requested. By making the history information known to the servant, the opportunity to utilize the known information increases.

  The number of hits means the number of times a search request packet is received for a file held by the servant in each servant. More strictly, each servant receives a search request packet for a file held by the servant. This is the number of times that the requested file and the file held by the local servant match.

  Next, a processing procedure related to the replication control method according to the present invention by the servant 1 will be described with reference to FIGS.

  FIG. 4 is a flowchart showing a first embodiment of the replication control method according to the present invention, and FIG. 5 is a flowchart showing a second embodiment of the replication control method according to the present invention.

  FIG. 4 shows an example of a processing procedure performed by the history information generation unit 6a and the well-known processing unit 6b in the history information management processing unit 6 of the servant 1 of FIG. 1, and first, at each preset time T (step S401). ), It is determined whether or not a new replication is executed by the replication execution unit 5 (step S402). If a new replication is executed, history information is generated by the history information generation unit 6a, and the generated history information is The well-known processing unit 6b transmits to each servant identified by a predetermined procedure (step S403).

  FIG. 5 shows an example of a processing procedure by the history information storage processing unit 6c and the history information reference unit 6d in the history information management processing unit 6 of the servant 1 of FIG. (Step S501) The history information storage processing unit 6c reads each parameter (a pair of the hop number M and the degree D and the hit number H1 or a pair of the hop number K and the TTL value L) in the history information (Step S502). Then, it is determined whether or not the own servant corresponds to the servant specified by the parameter (step S503), and if it corresponds, the received history information is written in the memory 5, and the history information reference unit 6d searches for the target file. Reference is made at the time of request (step S504).

  If the own servant does not correspond to the servant specified by the parameter, it is determined whether or not the TTL value in the history information notification packet is zero (0) (step S505). If the result is not zero, the history information notification packet is transferred to the next servant, and then the process returns to step S501 (step S506).

  As described above with reference to FIGS. 1 to 5, in this example, when replication is executed, information such as the location of the replication, the type of the copied file, and the time are set (S, Q, T) is stored as history information, and is made known to neighboring servants, thereby making it easier for each servant to find a file that the servant seeks. “S” is a set of servants that have replicated {A1, A2,..., Ai,..., “Q” is a file name that has been replicated, and “T” is a time at which replication is performed. “Ai” is the IP address of the i-th servant that performed replication.

  More specifically, as an information set related to the replication performed by itself within the latest time T2, (R1 (S1, Q1, T1), R2 (S2, Q2, T2), ..., Rk (Sk, Qk, Tk) ),...) And Sk = {Ak1, Ak2,..., Aki,.

  Here, Rk is the k-th replication information retroactive from the present time, Sk is the set of servants that have been replicated k-th from the current time, and Qk is the k-th replication from the current time. The performed file name, Tk, is the time when the k-th replication was performed retroactively from the current time, and Aki is the IP address of the i-th servant that performed the k-th replication from the current time.

  When searching for a file with its own servant, this information set is referred to. If the target file is included in the information, a download request is sent to the appropriate servant. Note that if the target file is not included in these pieces of information, a normal search procedure is executed.

  In a P2P communication performed by the servant 1, in a situation where replication is performed relatively frequently for a plurality of files, as described above, “to which servant for which file, at which time, It is the efficiency of information transmission on the P2P network that the history information consisting of information such as “executed replication” is actively communicated to the servant that is considered to be important on the P2P network. In this example, in this example, in order to execute such processing in the servant 1, to which servant should be notified of history information, and what kind of contents A function to execute processing such as whether history information should be conveyed, and to retain the history information It is made to have the ability.

  That is, when the replication execution unit 5 executes file replication, the servant 1 uses the history information generation unit 6a to at least identify the file (name) and the identification information (IP History information associated with the address), and the well-known processing unit 6b transmits the history information to another servant specified by a predetermined procedure, and conversely, history information from the other servant is obtained. When received, the history information is stored in the memory 5 by the history information storage processing unit 6c.

  For example, when a search request packet for an arbitrary file is transmitted in response to an instruction input from the input / output device 2, the history information stored in the memory 5 is referred to by the history information reference unit 6d, and the search request target If there is a file, a download request packet for the file is transmitted to the servant with the IP address associated with identification information (file name) in the file, and if there is no file to be searched, a normal procedure is performed. As described above, a search request packet for the file is transferred to each adjacent servant.

  When a search request packet transferred from another servant is received, the history information stored in the memory 5 is referred to by the history information reference unit 6d. If there is a search request target file, the history information is stored. The notification processing unit 6f reads the identification information (IP address) associated with the target file name in the history information, and notifies the IP address to the servant that is the transmission source of the search request packet.

  In the well-known processing unit 6b, when the servant as the transmission destination of the history information is specified, the number of hops, the degree, the number of hits, and the like are used. For example, a servant within a predetermined hop number range is specified as a transmission destination. Alternatively, a servant within a predetermined hop count range and a servant whose degree or hit count is greater than or equal to a predetermined number is specified as a transmission destination.

  As described above, in this example, when performing Pure type P2P type communication, information on when and what type of file replication is performed to each servant in the network, so that The target file can be found in a short time while reducing the number of inquiry packets.

  In addition, this invention is not limited to the example demonstrated using FIGS. 1-5, In the range which does not deviate from the summary, various changes are possible. For example, in this example, the history information is made known to servants (within a predetermined hop count range) near the replication execution servant, but the present invention is not limited to this. It may be made known to the servant. Even in this case, the servant holding the history information can easily identify the servant holding the target file by using the history information about the target file to be downloaded. This eliminates the trouble of searching for the target file using the search request packet.

  In this example, the history information has been described as not including the identification information of the servant that is the replication execution source. However, the history information can include the identification information of the servant that is the replication execution source. . Also in this case, the load on the download request in the replication execution source servant can be distributed to the replication execution destination servant.

  In this example, as a computer configuration example, a keyboard and an optical disk drive device are provided. However, a computer configuration without these devices may be used. In this example, an optical disk is used as a recording medium. However, an FD (Flexible Disk) or the like may be used as a recording medium. As for the program installation, the program may be downloaded and installed via a network via a communication device.

It is a block diagram which shows the structural example of the servant which performs replication control concerning this invention. It is explanatory drawing which shows the example of a specific procedure of the notification destination of the historical information by the servant in FIG. It is explanatory drawing which shows the other specific procedure example of the notification destination of the historical information by the servant in FIG. It is a flowchart which shows the 1st Example of the replication control method concerning this invention. It is a flowchart which shows the 2nd Example of the replication control method concerning this invention.

Explanation of symbols

  1: servant, 2: input / output device (console), 3: memory unit, 3a: memory control unit, 3b: memory, 4: information management / transfer processing unit, 5: replication execution unit, 6: history information management processing unit 6a: history information generation unit, 6b: well-known processing unit, 6c: history information storage processing unit, 6d: history information reference unit, 6e: packet generation / transmission processing unit, 6f: history information notification processing unit, 7: PAD, 8: Packet transmission unit, 9: Packet reception unit, 10: IP network (Internet).

Claims (17)

A servant that performs replication control in Pure type P2P communication,
A first means for generating history information in which identification information of a file that has undergone replication is associated with identification information of a servant that is a replication execution destination;
A second means for transmitting the history information to another servant specified by a predetermined procedure;
Third means for storing the history information received from another servant in a storage device;
A fourth means for referring to the stored history information when transmitting a search request packet for an arbitrary file;
If there is history information related to the file to be searched as a result of the reference by the fourth means, a download request packet for the file is transmitted to the servant associated with the identification information for the file, And a fifth means for transmitting a search request packet for the file to each adjacent servant if there is none. The servant according to claim 1,
The servant characterized in that the second means includes means for specifying a servant within a predetermined hop number range as a transmission destination of the history information. The servant according to claim 1,
The second means is a means for specifying a servant within a predetermined hop number range and having a degree or hit number equal to or greater than a predetermined threshold as a transmission destination of the history information. A servant characterized by comprising: The servant according to claim 1,
The servant characterized in that the second means includes means for specifying a destination servant of the history information using at least one of the degree and the number of hits and the number of hops. The servant according to any one of claims 1 to 4,
Means for transmitting the generated history information to the specified servant at a predetermined time interval T;
Each time the history information is received from another servant, there is provided means for deleting history information received before a predetermined latest Q (= n × T: n is an arbitrary positive number). servant. The servant according to any one of claims 1 to 5,
A servant characterized in that the history information includes a replication execution time. The servant according to any one of claims 1 to 6,
The fifth means selects one servant according to a predetermined procedure if there are a plurality of servants in the history information in which identification information is associated with the file to be searched in the reference result of the fourth means. And transmitting a download request packet of the file. The servant according to any one of claims 1 to 7,
Means for notifying the servant of the search request packet of the identification information of the servant associated with the file if the file requested in the search request packet received from another servant is in the history information;
And a means for transmitting a download request packet for the file to a servant having identification information notified from another servant.   The program for functioning a computer as each means in the servant in any one of Claims 1-8. A replication control method in a servant that performs Pure type P2P communication,
A servant that has performed replication of a file generates history information that associates at least the identification information of the file with the identification information of the servant that is the replication execution destination, and the history information is specified by a predetermined procedure. To send to other servants,
When the servant that has received the history information stores the history information in a storage device and transmits a search request packet for an arbitrary file, the stored history information is referred to and there is history information about the file to be searched. From the procedure of transmitting the download request packet of the file to the servant associated with the identification information in the file, and transmitting the search request packet of the file to each adjacent servant if there is no search target file A replication control method characterized by: The replication control method according to claim 10, comprising:
A replication control method characterized in that, in the procedure for specifying a destination servant of the history information, a servant within a predetermined hop number range is specified as a destination. The replication control method according to claim 10, comprising:
In the procedure for specifying the history information transmission destination servant, a servant within a predetermined number of hops and having a degree or hit count equal to or greater than a predetermined threshold is specified as the transmission destination. A replication control method characterized by the above. The replication control method according to claim 10, comprising:
A replication control method characterized in that, in the procedure for specifying the destination servant of the history information, the destination servant is specified by using at least one of the degree, the hit number, and the hop number. The replication control method according to any one of claims 10 to 13,
A procedure in which the servant of the replication execution source transmits the generated history information to the specified servant at a predetermined time interval T;
Each time the servant that has received the history information receives the history information, the servant has a procedure for deleting the history information received before a predetermined latest Q (= n × T: n is an arbitrary positive number). A replication control method characterized by the above. The replication control method according to any one of claims 10 to 14,
A replication control method, wherein the history information includes a replication execution time. The replication control method according to any one of claims 10 to 15,
If there is a plurality of servants whose identification information is associated with the search target file in the history information, the servant that has received the history information selects one servant by a predetermined procedure and downloads the file. A replication control method characterized by transmitting a packet. The replication control method according to any one of claims 10 to 16, comprising:
If the servant that has received the history information has a file requested in the search request packet received from another servant in the history information, the servant identification information associated with the file is transmitted from the source of the search request packet. To notify the servant,
A replication control method, wherein the transmission source servant transmits a download request packet of the file to the servant of the notified identification information.

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