JP2010198319A - Context search method and system - Google Patents

Abstract

The present invention provides a context search method and system capable of efficiently and dynamically reducing the number of search request messages transferred and the number of search response messages transferred.
A hop number limit value setting unit 104 sets first and second limit values for suppressing the number of search request message transfers by limiting the number of hops of a search request message. The first limit value E1 is an absolute limit value of the number of hops, and the search request message is not transferred beyond the first limit value E1. The second limit value E2 is set to a value smaller than the first limit value E1, but is initialized when the search target peers Pdi and Ptj that have received the search request message satisfy the context condition. The search request generation unit 106 describes the first limit value E1 as the first allowable hop number e1, the second limit value E2 as the second allowable hop number e2, and the second limit value E2 and the context search condition. Generate the described search request message.
[Selection] Figure 2

Description

  The present invention relates to a context search method and system, and more particularly to a context search method and system in which an allowable hop count is set in a context search message.

  A search source peer node that performs a context search on a peer-to-peer network transmits a search request message in which a context search condition is described by broadcasting with restrictions such as the allowable number of hops, and the context of the peer node that has received the search request message is A non-patent document 1 discloses a context search method for returning a search response message to a search source peer node when a search condition is satisfied.

Y. Chawathe, S. Ratnasamy, L. Breslau, and S. Shenker, "Making Gnutella-like P2P Systems Scalable", ACM SIGCOMM 2003.

The above prior art has the following technical problems.
(1) Since the context search request message is broadcast-transmitted within the range of the allowable hop count, the transfer count of the search request message increases.
(2) Since peers that satisfy the context search condition individually return search response messages in response to search request messages, the number of search response message transfers increases.

  An object of the present invention is to provide a context search method and system capable of solving the above-described problems of the prior art and efficiently and dynamically reducing the number of search request messages transferred and the number of search response messages transferred thereto. is there.

  In order to achieve the above object, according to the present invention, a search source peer of a context search transmits a search request message, and each peer to be searched relays the received search request message to other peers under a predetermined restriction. In addition, the peer-to-peer type context search system that returns a search response message if it satisfies the search conditions is characterized by the following measures.

  (1) means for the search source peer to set first and second limit values for limiting the number of hops of the search request message so that the first limit value is larger than the second limit value; Means for generating a search request message in which a limit value is described as a first allowable hop number, the second limit value is described as a second allowable hop number, and the second limit value and a context search condition are described; Means for transmitting a search request message to a peer to be searched,

  A means for each search target peer to receive a search request message, a means to determine whether or not its peer satisfies the context search condition described in the received search request message, and a search request that does not satisfy the search condition Based on the first and second allowable hop numbers described in the message, means for determining whether or not to relay the search request message, and discarding the search request message that is determined not to be relayed and does not satisfy the search condition A means for decrementing, a means for decrementing the first and second allowable hop counts of the search request message that does not satisfy the search condition, which are determined to be relayed, and a search response message in response to the search request message that satisfies the search condition Means for initializing a second allowable hop number of a search request message satisfying the search condition to a second limit value; Based on the first allowable hop number of a search request message that satisfies the above-mentioned criteria, a means for determining whether or not to relay the search request message, and a search request message that satisfies the search condition that is determined not to be relayed are discarded. Means for decrementing a first allowable hop number of a search request message satisfying a search condition determined to be relayed, and a search in which the first allowable hop number is decremented and a second allowable hop number is initialized. Means for relaying the request message,

  The search source peer further includes means for receiving a search response message returned from each search target peer.

  (2) The search source peer further describes a timer value corresponding to the reception period of the search response message in the search request message, and counts the timer value in response to transmission of the search request message in which the timer value is described. And means for initiating

  When the search target peer further relays a search request message that satisfies the search condition, a means for shortening the timer value, and in response to relaying the search request message that satisfies the search condition and the timer value is shortened The means for starting the time measurement of the shortened timer value, the search response message received until the timer time measurement is completed, and the own search response message are aggregated and returned as a single search response message. Means,

  The search source peer may continue to receive a search response message until the timer value is measured.

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

  (1) Since the number of allowable hops set in the search request message is more relaxed in peers that satisfy the context search condition and in the neighboring peers than in other peers and neighboring peers, peers with matching contexts If the network topology is close to each other, the number of message hops that are likely to reach peers that satisfy the context search condition is less than the number of message hops that are less likely to reach peers that satisfy the context search condition. Can be long.

  (2) A peer that satisfies the context search condition aggregates and relays the search response messages that are replied to the search request message relayed by the peer and relayed by the peer together with the search response message of the peer. The number of search response messages transferred can be reduced.

It is the figure which showed an example of the peer to peer network to which this invention is applied. It is the functional block diagram which showed the structure of the search origin peer which concerns on 1st Embodiment. It is the functional block diagram which showed the structure of the search object peer which concerns on 1st Embodiment. It is the flowchart which showed the operation | movement of the search origin peer in 1st Embodiment. It is the flowchart which showed operation | movement of each search object peer in 1st Embodiment. It is the functional block diagram which showed the structure of the search origin peer which concerns on 2nd Embodiment. It is the functional block diagram which showed the structure of the search object peer which concerns on 2nd Embodiment. It is the flowchart which showed the operation | movement of the search origin peer in 2nd Embodiment. It is the flowchart which showed operation | movement of each search object peer in 2nd Embodiment.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a peer-to-peer network to which the present invention is applied. A black circle represents a search source peer Ps that transmits a search request message in which a context search condition is described and executes a context search. ing. The hatched circle represents a peer Pdi that satisfies the search condition, and the white circle represents a peer Ptj that does not satisfy the search condition.

  FIG. 2 is a functional block diagram showing the configuration of the main part of the search source peer Ps. Here, the configuration unnecessary for the description of the present invention is omitted.

  The hop number limit value setting unit 104 sets first and second limit values for suppressing the number of search request message transfers by limiting the number of hops of the search request message. The first limit value E1 is an absolute limit value of the number of hops. In the present embodiment, the search request message is not transferred beyond the first limit value E1. The second limit value E2 is set to a value smaller than the first limit value E1, but is initialized when the search target peer that has received the search request message satisfies the context condition. The functions of the first and second limit values E1 and E2 will be described in detail later.

  The search condition setting unit 105 sets a context search condition X for searching for a target peer from among a large number of search target peers. The search request generation unit 106 describes the first limit value E1 as the first allowable hop number e1, the second limit value E2 as the second allowable hop number e2, and the second limit value E2 and the context. A search request message in which the search condition X is described is generated. The search request message is broadcast from the search request transmission unit 102 to each search target peer via the communication interface 101.

  The search response receiving unit 103 receives, via the communication interface 101, a search response message returned from the peer Pdi that satisfies the context condition among the search target peers that have received the search request message. The search response processing unit 107 identifies a peer that satisfies the context search condition based on the received search response message.

  FIG. 3 is a functional block diagram showing the configuration of the main part of the search target peers Pdi and Ptj. Here, the configuration unnecessary for the description of the present invention is also omitted.

  The search request receiving unit 202 receives a search request message transmitted from the search source peer Ps or relayed by another search target peer via the communication interface 201. The search condition determining unit 206 compares and collates the context search condition X described in the received search request message with the context registered in the context database 210 of the own peer, and the own peer satisfies the context search condition. It is determined whether or not.

  The relay determination unit 207 determines whether the received search request message is further relayed to other peers based on whether the first and second allowable hop numbers e1 and e2 described in the search request message and the own peer are search conditions. It is determined based on whether or not the above is satisfied. The message discard unit 208 discards the search request message determined not to be relayed

  The message update unit 209 includes an update unit 209a that updates (decrements) the first allowable hop number e1 of the search request message to be relayed, an update unit 209b that updates (decrements) the second allowable hop number e2, and a second allowable hop number. An initialization unit 209c that initializes e2 and returns it to the second limit value E1 is included. The updated search request message is relayed from the search request relay unit 204 to another peer via the communication interface 201. The search response relay unit 203 relays a search response message returned in response to the relayed search request message. The search response reply unit 205 returns a search response message when the peer satisfies the context search condition.

  Next, the operation of the first embodiment of the present invention will be described in detail with reference to the flowchart. FIG. 4 is a flowchart showing the operation of the search source peer Ps, and FIG. 5 is a flowchart showing the operation of each search target peer.

  In the search source peer Ps, the first limit value E1 and the second limit value E2 for limiting the hop number of the search request message are set by the hop number limit value setting unit 104 in step S101 of FIG. In the present embodiment, the description will be continued assuming that “5” is set as the first limit value E1 and “2” is set as the second limit value E2. In step S102, the search condition setting unit 105 sets a context search condition X.

  In step S103, the search request generation unit 106 describes the first limit value E1 as the first allowable hop number e1, the second limit value E2 as the second allowable hop number e2, and the second limit value E2. A search request message in which the limit value E2 and the context search condition X are described is generated. In step S104, the search request transmission unit 102 broadcasts a search request message.

  Proceeding to FIG. 5, each search target peer Pdi, Ptj proceeds to step S202 when the search request message is received by the search request receiving unit 202 in step S201, and has already received the same search request message via another route. It is determined whether or not there is. If it has been received, the process proceeds to step S230, and the message discarding unit 208 discards the search request message.

  On the other hand, if it is the first search request message, the process proceeds to step S203, and the search condition determination unit 206 determines whether or not the own peer satisfies the context search condition described in the search request message. The If it is determined that the peers Pt0, Pt1, and Pt2 in FIG. 1 do not satisfy the search condition, the process proceeds to step S220, and the message update unit 209 decrements the second allowable hop number e2 by “1”. The That is, the second allowable hop number e2 is updated from the initial value “2” to “1”.

  In step S221, whether or not the updated second allowable hop number e2 is “0” is determined by the relay determination unit 207. Here, since it is determined other than “0”, the process proceeds to step S222. In step S222, the message update unit 209 decrements the first allowable hop number e1 by “1”. That is, the first allowable hop number e1 is updated from “5” to “4”.

  In step S223, the relay determination unit 207 determines whether or not the updated first allowable hop number e1 is “0”. Here, since it is determined other than “0”, the process proceeds to step S224. In step S224, the search request message updated to the first allowable hop number e1 = 4 and the second allowable hop number e2 = 1 is relayed by the search request relay unit 204 to another peer.

  In step S225, it is determined whether or not a search response message for the relayed search request message has been received by the search response relay unit 203. When reception is detected, the process proceeds to step S226, and the search response message is relayed. Such a relay process of the search response message is continued until it is determined in step S227 that the predetermined waiting time has timed out.

  Next, a description will be given focusing on the peer Pt3 that does not satisfy the search condition. In step S201, the peer Pt3 receives the search request message relayed by the peer Pt0, and proceeds to step S202. If this is the first search request message, the peer Pt3 proceeds to step S203. In step S203, since the search condition determination unit 206 determines that the search condition is not satisfied, the process proceeds to step S220, and the message update unit 209 decrements the second allowable hop number e2 by “1”. That is, the second allowable hop number e2 is updated from “1” to “0”. In step S221, the updated second allowable hop number e2 is determined to be “0”, so the process proceeds to step S230, and the search request message is discarded.

  Next, description will be made by paying attention to the peer Pd0 that satisfies the search condition. When the peer Pd0 receives the search request message relayed by the peer Pt0 in step S201, the process proceeds to step S202. If this is the first search request message, the process proceeds to step S203. In step S203, since the search condition determination unit 206 determines that the context search condition is satisfied, the process proceeds to step S204, and the message update unit 209 initializes the second allowable hop number e2 and the second restriction. The value is returned to E2 (= 2).

  In step S205, the message update unit 209 decrements the first allowable hop number e1 by “1”. That is, the first allowable hop number e1 is updated from “4” to “3”. In step S206, whether or not the updated first allowable hop number e1 is “0” is determined by the relay determination unit 207. Here, since it is determined that it is other than “0”, the process proceeds to step S207. In step S207, the search request relay unit 204 transmits the search request message updated to the first allowable hop number e1 = 3 and the second allowable hop number e2 = 2.

  In step S208, the search response reply unit 205 generates and returns a search response message of its own peer. In step S209, it is determined whether a search response message for the search request message relayed in step S207 has been received by the search response relay unit 203. When reception is detected, the process proceeds to step S210, and the search response message is relayed. This search response message relay process is continued until it is determined in step S211 that the predetermined waiting time has timed out.

  Next, a description will be given focusing on the peer Pt10 that does not satisfy the search condition. When the peer Pt10 receives the search request message relayed by the peer Pd3 in step S201, the process proceeds to step S202, and if this is the first search request message, the process proceeds to step S203. In step S203, since the search condition determination unit 206 determines that the search condition is not satisfied, the process proceeds to step S220, and the message update unit 209 decrements the second allowable hop number e2 by “1”. That is, the second allowable hop number e2 is updated from “2” to “1”.

  In step S221, it is determined whether or not the updated second allowable hop number e2 is “0”. Here, since it is determined that the number is not “0”, the process proceeds to step S222. In step S222, the message update unit 209 decrements the first allowable hop number e1 by “1”. Here, the first allowable hop number e1 is updated from “1” to “0”. In step S223, it is determined whether or not the updated first allowable hop number e1 is “0”. Here, since it is determined to be “0”, the process proceeds to step S230, and the search request message is discarded.

  Next, description will be made by paying attention to the peer Pd4 that satisfies the search condition. In step S201, the peer Pd4 receives the search request message relayed by the peer Pt7, and proceeds to step S202. If this is the first search request message, the peer Pd4 proceeds to step S203. In step S203, since the search condition determination unit 206 determines that the search condition is satisfied, the process proceeds to step S204, where the message update unit 209 initializes the second allowable hop number e2 and sets the second limit value. Return to E2 (= 2). The second limit value E2 is described in the search request message.

  In step S205, the message update unit 209 decrements the first allowable hop number e1 by “1”. That is, the first allowable hop number e1 is updated from “1” to “0”. In step S206, it is determined whether or not the updated first allowed hop number e1 is “0”. Here, since it is determined to be “0”, the process proceeds to step S212. In step S212, the search request message is discarded. In step S213, the search response reply unit 205 generates a search response message of its own peer and sends it back.

  Returning to FIG. 4, when the search response message is received by the search response receiving unit 103 in step S105, the search source peer Ps proceeds to step S106, and the identification information of the transmission source peer of the message is captured as a context search result. It is. This search response message reception process is continued until it is determined in step S107 that the predetermined waiting time has timed out.

  In the first embodiment described above, each search target peer has been described as relaying a search response message returned in response to a search request message relayed by itself, every time it is received. Then, a search response message reception period is set for each search target peer node, and each search target peer node aggregates at least one search response message received during the reception period, and relays the search response messages together in one search response message. There is a feature in the point made to do.

  FIG. 6 is a functional block diagram showing the configuration of the main part of the search source peer Ps in the second embodiment of the present invention, and the same reference numerals as those described above represent the same or equivalent parts.

  The reception period setting unit 108 sets a reception period Tm that the search source peer Ps and each search target peer node wait for the reception of the search response message. The search request generation unit 106 describes the first limit value E1 as a first allowable hop number e1, the second limit value E2 as a second allowable hop number e2, and further, the reception period Tm, the first 2. A search request message in which the limit value E2 and the context search condition X are described is generated. The disassembly unit 103a of the search response receiving unit 103 disassembles a message in which a plurality of search response messages are aggregated, and provides each search response message to the search response processing unit 107.

  FIG. 7 is a functional block diagram showing the configuration of the main part of the search target peer in the second embodiment of the present invention. The same reference numerals as those described above represent the same or equivalent parts.

  In the search response relay unit 203, the temporary storage unit 203a temporarily stores all the search response messages received within a predetermined reception period Tm. The aggregating unit 203b aggregates all the search response messages received within the reception period Tm, and compiles them into one message and sends it back to the source peer. The aggregation unit 203b aggregates a plurality of search response messages by, for example, known encapsulation. In the message update unit 209, the reception period update unit 209d updates the reception period Tm described in the search request message to be relayed in the shorter time direction.

  Next, the operation of the second exemplary embodiment of the present invention will be described in detail with reference to the flowchart. FIG. 8 is a flowchart showing the operation of the search source peer Ps, and FIG. 9 is a flowchart showing the operation of each search target peer.

  In the search source peer Ps, the first limit value E1 and the second limit value E2 for limiting the number of hops of the search request message are set by the hop number limit value setting unit 104 in step S101 of FIG. In the present embodiment, the description will be continued assuming that “5” is set as the first limit value E1 and “2” is set as the second limit value E2. In step S101a, the reception period setting unit 108 sets a search response message reception period Tm. In step S102, the search condition setting unit 105 sets a context search condition.

  In step S103, the search request generation unit 106 describes the first limit value E1 as the first allowable hop number e1, the second limit value E2 as the second allowable hop number e2, and the reception period. A search request message in which Tm, the second limit value E2, and the context search condition X are described is generated. In step S104, the search request transmission unit 102 transmits a search request message. In step S104a, a timer for the reception period Tm is started.

  Proceeding to FIG. 9, each search target peer proceeds to step S202 when the search request message is received by the search request receiving unit 202 in step S201, and whether or not the same search request message has already been received through another route. Is determined. If it has been received, the process proceeds to step S230, and the message discarding unit 208 discards the search request message.

  On the other hand, if it is the first search request message, the process proceeds to step S203, and the search condition determination unit 206 determines whether or not the own node satisfies the context search condition described in the search request message. The For the peers Pt0, Pt1, and Pt2 in FIG. 5, if it is determined that the search condition is not satisfied, the process proceeds to step S220, and the message update unit 209 decrements the second allowable hop number e2 by “1”. The That is, the second allowable hop number e2 is updated from the initial value “2” to “1”.

  In step S221, it is determined whether or not the updated second allowable hop number e2 is “0”. Here, since it is determined that the number is not “0”, the process proceeds to step S222, and the message update unit 209 determines One allowable hop number e1 is decremented by “1”. That is, the first allowable hop number e1 is updated from “5” to “4”. In step S223, it is determined whether or not the updated first allowable hop number e1 is “0”. Here, since it is determined that the number is not “0”, the process proceeds to step S224. In step S224, the search request message updated to the first allowable hop number e1 = 4 and the second allowable hop number e2 = 1 is relayed by the search request relay unit 204.

  In step S225, it is determined whether or not a search response message for the relayed search request message has been received by the search response relay unit 203. When reception is detected, the process proceeds to step S226, and the search response message is relayed. This search response message relay process is continued until it is determined in step S227 that the predetermined waiting time has timed out.

  Next, description will be made by paying attention to the peer Pd0 that satisfies the search condition. When the peer Pd0 receives the search request message relayed by the peer Pt0 in step S201, the process proceeds to step S202. If this is the first search request message, the process proceeds to step S203. In step S203, since the search condition determination unit 206 determines that the search condition is satisfied, the process proceeds to step S204, where the message update unit 209 initializes the second allowable hop number e2 and sets the second limit value. Return to E2 (= 2).

  In step S205, the message update unit 209 decrements the first allowable hop number e1 by “1”. That is, the first allowable hop number e1 is updated from “4” to “3”. In step S206, it is determined whether or not the updated first allowable hop number e1 is “0”. Here, since it is determined other than “0”, the process proceeds to step S206a.

  In step S206a, the message update unit 209 shortens the reception period Tm by a predetermined time Δt. In step S207, the search request relay unit 204 transmits the search request message updated to the first allowable hop number e1 = 3, the second allowable hop number e2 = 2, and the reception period Tm = Tm−Δt. In step S207a, the timer of the updated reception period Tm starts.

  In step S209, it is determined whether a search response message for the search request message relayed in step S207 has been received by the search response relay unit 203. When reception is detected, the process proceeds to step S209a and temporarily held. In step S211, it is determined whether or not the timer has timed out. Until the time is up, the process returns to step S209 to prepare for reception of the next search response message.

  If a timeout is detected in step S211, the process proceeds to step S211a. In step S211a, all search response messages received within the reception period Tm are collected into one search response message. In step S211b, the aggregated search response message is returned.

  Returning to FIG. 8, in step S105, the search source peer Ps receives the aggregated and combined search response message, and proceeds to step S105a, where the search message is disassembled and each search response message is extracted. Is done. In step S106, the identification information of the transmission source peer of each search response message is captured as a context search result. This search response message reception process is continued until it is determined in step S107 that the reception period Tm has timed out.

  DESCRIPTION OF SYMBOLS 101 ... Communication interface, 102 ... Search request transmission part, 103 ... Search response reception part, 104 ... Hop number limit value setting part, 105 ... Search condition setting part, 106 ... Search request generation part, 107 ... Search response process part, 201 ... Communication interface, 202 ... Search request receiving unit, 203 ... Search response relay unit, 204 ... Search request relay unit, 205 ... Search response reply unit, 206 ... Search condition determination unit, 207 ... Relay determination unit, 208 ... Message discard unit 209: Message update unit 210: Context database

Claims (4)

The search source peer of the context search sends a search request message, and each peer to be searched relays the received search request message to other peers under a predetermined limit, and if it satisfies the search condition, the search response In a peer-to-peer context search method that returns a message,
The source peer is
A procedure for setting the first and second limit values for limiting the number of hops in the search request message so that the first limit value is larger than the second limit value;
The first limit value is described as a first allowable hop number, the second limit value is described as a second allowable hop number, and a search request message in which the second limit value and a context search condition are described is generated. Procedure and
Sending the search request message to a peer to be searched,
Each peer to be searched
Receiving a search request message;
A procedure for determining whether or not the peer satisfies the context search condition described in the received search request message;
Determining whether to relay the search request message based on the first and second allowable hop numbers described in the search request message that does not satisfy the search condition;
A procedure for discarding a search request message that is determined not to be relayed and does not satisfy a search condition;
A procedure for decrementing the first and second allowable hop numbers of a search request message that is determined to be relayed and that does not satisfy a search condition;
A procedure for returning a search response message in response to a search request message that satisfies the search conditions;
A procedure for initializing a second allowable hop number of a search request message that satisfies a search condition to a second limit value;
Determining whether to relay the search request message based on the first allowable hop number of the search request message satisfying the search condition;
A procedure for discarding a search request message that is determined not to be relayed and that satisfies a search condition;
A procedure for decrementing the first allowed hop count of a search request message that is determined to be relayed and that satisfies a search condition;
Relaying a search request message in which the first allowable hop number is decremented and the second allowable hop number is initialized, and
The search source peer further includes:
A context search method comprising a procedure of receiving a search response message returned from each of the search target peers. The search source peer further includes:
The procedure for describing the timer value corresponding to the reception period of the search response message in the search request message,
Further comprising a step of starting timing of the timer value in response to transmission of the search request message in which the timer value is described,
The search target peer is further
When relaying a search request message that satisfies the search conditions, a procedure for shortening the timer value,
In response to the relay of the search request message whose timer value is shortened while satisfying the search condition, a procedure for starting timing of the shortened timer value;
A procedure of aggregating the search response message and the search response message received by the time until the time measurement of the timer value is completed, and collectively returning the search response message in one search response message,
The context search method according to claim 1, wherein the search source peer continues to receive a search response message until the timer value is measured. The search source peer of the context search sends a search request message, and each peer to be searched relays the received search request message to other peers under a predetermined limit, and if it satisfies the search condition, the search response In a peer-to-peer context search system that sends back messages,
The source peer is
Means for setting first and second limit values for limiting the number of hops of the search request message so that the first limit value is larger than the second limit value;
The first limit value is described as a first allowable hop number, the second limit value is described as a second allowable hop number, and a search request message in which the second limit value and a context search condition are described is generated. Means,
Means for transmitting the search request message to a peer to be searched,
Each peer to be searched
Means for receiving a search request message;
Means for determining whether or not the peer satisfies the context search condition described in the received search request message;
Means for determining whether to relay the search request message based on the first and second allowable hop numbers described in the search request message not satisfying the search condition;
Means for discarding a search request message that is determined not to be relayed and does not satisfy the search condition;
Means for decrementing the first and second allowable hop numbers of a search request message that is determined to be relayed and that does not satisfy a search condition;
Means for returning a search response message in response to a search request message that satisfies the search conditions;
Means for initializing a second allowable hop number of a search request message that satisfies a search condition to a second limit value;
Means for determining whether to relay the search request message based on the first allowable hop number of the search request message satisfying the search condition;
Means for discarding a search request message that satisfies a search condition, determined not to be relayed;
Means for decrementing the first allowed hop count of a search request message that is determined to be relayed and that satisfies a search condition;
Means for relaying a search request message in which the first allowable hop number is decremented and the second allowable hop number is initialized,
The search source peer further includes:
A context search system comprising means for receiving a search response message returned from each of the search target peers. The search source peer further includes:
Means for describing a timer value corresponding to the reception period of the search response message in the search request message;
Means for starting timing of the timer value in response to transmission of the search request message in which the timer value is described;
The search target peer is further
A means for shortening the timer value when relaying a search request message that satisfies the search condition;
Means for responding to the relay of the search request message in which the search condition is satisfied and the timer value is shortened, and starting timing of the shortened timer value;
Means for aggregating the search response message and the search response message received by the time until the timer value is timed, and collectively returning the search response message in one search response message;
The context search system according to claim 3, wherein the search source peer continues to receive a search response message until the timer value is measured.

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