JP2014211758A - Cache server device, cache control method, and cache control program - Google Patents

Abstract

An object is to reduce access to an authoritative server. When an ENUM cache server receives a query request, the ENUM cache server counts the number of times the query request corresponding to each record has been received for each telephone number stored in an ENUM data storage unit. When there is a record whose counted number exceeds the predetermined number, the ENUM cache server 10 extends the period for storing the record and stores it in the ENUM data storage unit 13a. [Selection] Figure 3

Description

  The present invention relates to a cache server device, a cache control method, and a cache control program.

  In recent years, standardization work of ENUM (Enum: Telephone Number Mapping), which performs name resolution using a telephone number of an IP phone or the like as a domain name while utilizing a DNS operation mode, has been promoted. ENUM is a typical telephone number mapping standard that integrates the telephone number system of the public switched telephone network with the IP address system of the Internet.

  In such an ENUM field, in response to a name resolution request (hereinafter referred to as an “ENUM query”) from a communication control device (for example, a call control server), an inquiry response to an ENUM authority server made in the past ( Hereinafter, an ENUM cache server that responds using cache data in which "ENUM answer" is stored is known. For example, the ENUM cache server stores a conversion table in which a telephone number and a corresponding accommodating network are associated as cache data.

  When receiving the ENUM query from the call control server, the ENUM cache server determines whether answer data corresponding to the received ENUM query exists in the cache as cache data. As a result, when the answer data exists in the cache, the ENUM cache server performs name resolution processing using the cache data.

  When the ENUM cache server determines that the answer data does not exist in the cache, the ENUM cache server transmits an ENUM query to the authoritative server, and then receives an ENUM answer from the authoritative server. Then, the ENUM cache server caches the response data included in the ENUM answer received from the authority server, and also sets TTL (Time To Live) included in the ENUM answer as response data. For example, if the ENUM cache server sets 60 seconds as the TTL of the ENUM data, the ENUM data is deleted 60 seconds after the ENUM data is cached.

RFC 6116 (Chapter 7.2): ENUM Protocol Specification (obsoletes RFC 3761) RFC 2915 (Chapter 2): The Naming Authority Pointer (NAPTR) DNS Resource Record Masato Tamita, Yasuhiro Morishita, Tomoya Sakaguchi, “Practical DNS”, Japan Registry Service (JPRS), P177-178, P181-184, P260

  However, in the conventional cache server, since the set TTL does not change, there is a problem that access to the authority server is concentrated and the processing load of the authority server may increase. That is, for example, even in a situation where calls to the same telephone number are concentrated, the cache server deletes ENUM data corresponding to the telephone number according to the TTL. Is received again, the ENUM authority server is accessed again, so the authority server is frequently accessed, and the processing load on the authority server increases.

  Therefore, an object of the present invention is to prevent concentration of access to the authoritative server and reduce access to the authoritative server.

  In order to solve the above-described problems and achieve the object, the cache server device stores a record corresponding to the query request from the communication control device as cache data, and stores a period for storing the record for each record. A reception unit that receives a query request from the communication control device, a determination unit that determines whether a record corresponding to the query request received by the reception unit is stored in the storage unit, and the record by the determination unit Is determined to be stored in the storage unit, the record is used to return a response to the query request to the communication control device using the record, and the record is stored in the storage unit by the determination unit. If it is determined that the query request is not stored, the query request is transferred to the authoritative server, and the transferred query request is When an answer is received from the authoritative server, each transfer record that forwards the answer to the communication control device and each record stored in the storage unit when receiving a query request by the receiving unit, A counting unit that counts the number of times a query request corresponding to a record has been received, and if there is a record that exceeds the predetermined number in the storage unit, the record is stored. And a control unit that extends the period and stores it in the storage unit.

  The cache control method is a cache control method executed by a cache server device, and the cache server device stores a record corresponding to a query request from a communication control device as cache data, and A storage step for storing a period for storing records; a reception step for receiving a query request from the communication control device; and determining whether a record corresponding to the query request received by the reception step is stored in the storage unit A determination step; and a return step for returning a response to a query request to the communication control device using the record when the determination step determines that the record is stored in the storage unit; and the determination If it is determined by the process that the record is not stored in the storage unit The query request is forwarded to the authoritative server, and when a reply to the forwarded query request is received from the authoritative server, the reply request is forwarded to the communication control device, and the query request is sent by the receiving step. For each record stored in the storage unit, a counting step for counting the number of times the query request corresponding to each record has been received, and the number of times counted by the counting step in the storage unit are predetermined. A control step of extending the period for storing the record and storing it in the storage unit when there is a record exceeding the number of times.

  In addition, the cache control program receives a query request from the communication control device, and a record corresponding to the query request received by the receiving step stores a record corresponding to the query request as cache data and for each record. If it is determined that the record is stored in the storage unit storing the period for storing the record, and the determination step determines that the record is stored in the storage unit, the record is used, A reply step of returning a response to the query request to the communication control device, and when the determination step determines that the record is not stored in the storage unit, the query request is transferred to the authoritative server and transferred. When an answer to a query request is received from the authoritative server , A transfer step of transferring the answer to the communication control device, and a number of times of receiving a query request corresponding to each record for each record stored in the storage unit when a query request is received by the receiving step. When there is a counting step for counting and a record in which the number of times counted in the counting step exceeds a predetermined number in the storage unit, the period for storing the record is extended and stored in the storage unit And causing the computer to execute control steps.

  The cache server device, the cache control method, and the cache control program disclosed in the present application can prevent concentration of access to the authoritative server and reduce access to the authoritative server.

FIG. 1 is a diagram illustrating an example of a configuration of a system according to the first embodiment. FIG. 2 is a diagram for explaining load distribution processing in the system according to the first embodiment. FIG. 3 is a block diagram illustrating the configuration of the ENUM cache server according to the first embodiment. FIG. 4 is a diagram illustrating an example of information stored in the ENUM data storage unit. FIG. 5 is a diagram illustrating an example of information stored in the ENUM query data storage unit. FIG. 6 is a diagram for explaining processing for changing the TTL for each telephone number in accordance with the status of the ENUM query. FIG. 7 is a diagram for explaining an example of TTL transition in the ENUM cache server. FIG. 8 is a flowchart for explaining the flow of cache control processing by the ENUM cache server according to the first embodiment. FIG. 9 is a diagram for explaining a case where accesses are concentrated on a specific station number in the system according to the first embodiment. FIG. 10 is a diagram illustrating an example of information stored in the ENUM query data storage unit. FIG. 11 is a diagram illustrating a process of changing the TTL for each area code according to the status of the ENUM query. FIG. 12 is a flowchart for explaining the flow of cache control processing by the ENUM cache server according to the second embodiment. FIG. 13 is a diagram illustrating an example of information stored in the ENUM query data storage unit. FIG. 14 is a diagram for explaining processing for changing the TTL for each area code and city code according to the status of the ENUM query. FIG. 15 is a diagram illustrating a computer that executes a cache control program.

  Exemplary embodiments of a cache server device, a cache control method, and a cache control program according to the present invention will be explained below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

[First embodiment]
In the following embodiments, the configuration of the system according to the first embodiment, the configuration of the ENUM cache server, and the flow of processing by the ENUM cache server will be described in order, and finally the effects of the first embodiment will be described.

[System configuration]
First, an example of the configuration of a system 100 to which the ENUM cache server 10 according to the first embodiment is applied will be described. FIG. 1 is a diagram illustrating an example of a configuration of a system 100 according to the first embodiment. As shown in FIG. 1, a system 100 to which the ENUM cache server 10 according to the first embodiment is applied includes an ENUM cache server 10, an ENUM authority server 20, a call control server 30, and a client device 40. The ENUM authority server 20 and the client device 40 are configured via the ENUM cache server 10 and the call control server 30. In the example of the system of FIG. 1, one device is provided for each device 10, 20, 30, 40, but this is not a limitation, and a plurality of devices are provided for each device 10, 20, 30, 40. It may be provided.

  The ENUM cache server 10 has a cache memory in which a conversion table (hereinafter referred to as ENUM data) in which telephone numbers and accommodation networks are associated is cached. When receiving the query request from the call control server 30, the ENUM cache server 10 determines whether or not ENUM data corresponding to the query request is cached. As a result, when the ENUM data corresponding to the query request is cached, the ENUM cache server 10 returns the cached ENUM data to the call control server 30 as a query response. Further, the ENUM cache server 10 transmits a query request to the ENUM authority server 20 when the ENUM data corresponding to the query request is not cached.

  The ENUM authority server 20 is a server that manages all ENUM data in which telephone numbers and accommodation networks are associated with each other. When the ENUM authority server 20 receives a query request from the cache server 10, the ENUM authority server 20 retrieves a corresponding resource record from the ENUM data, and uses the resource record as a search result as a query response to perform call control via the ENUM cache server 10. It returns to the server 30.

  The call control server 30 is a communication control device that controls communication between client devices. For example, when a SIP signal such as “REGISTER” or “INVITE” is received from the client device 40, an ENUM query requesting information on the accommodation network corresponding to the telephone number is transmitted to the ENUM cache server 10. Then, the call control server 30 receives an ENUM answer from the ENUM cache server 10 as an answer to the transmitted ENUM query. When the call control server 30 is connected to a plurality of ENUM cache servers, the call control server 30 determines an ENUM cache server to which an ENUM query is distributed from the plurality of ENUM cache servers, and determines the determined ENUM cache server. To send an ENUM query. Further, the client device 40 transmits a SIP signal to the call control server 30.

  Here, the load distribution processing in the system according to the first embodiment will be described with reference to FIG. FIG. 2 is a diagram for explaining load distribution processing in the system according to the first embodiment. In the example of FIG. 2, a call to the telephone number “0422-59-6981” occurs, and an ENUM query is sent from the call control server 30 to the ENUM cache as an inquiry of the accommodation network corresponding to the telephone number “0422-59-6981”. It is assumed that it has been transmitted to the server 10.

  As shown in FIG. 2, when receiving the ENUM query from the call control server 30, the ENUM cache server 10 determines whether or not ENUM data corresponding to the ENUM query is cached. In this example, the ENUM cache server 10 assumes that ENUM data corresponding to the ENUM query is not cached, and transfers the ENUM query to the ENUM authority server 20.

  When the ENUM authority server 20 receives the ENUM query from the ENUM cache server 10, the ENUM authority server 20 searches for a corresponding record from the ENUM data, and returns a record as a search result to the ENUM cache server 10 as an ENUM answer. In the example of FIG. 2, the ENUM authority server 20 searches for a record corresponding to the telephone number “0422-59-6981”, and the accommodation network “east.example.jp” corresponding to the telephone number “0422-59-6981”. And an ENUM answer including TTL “60” is returned to the ENUM cache server 10. Here, TTL “60” indicates that the record is stored for 60 seconds. Here, the following description will be made on the assumption that the TTL designated by the ENUM authority server 20 is uniformly “60” seconds.

  Then, the ENUM cache server 10 transfers the ENUM answer received from the ENUM authority server 20 to the call control server 30. Further, the ENUM cache server 10 extracts information included in the ENUM answer and stores the record in the cache memory. For example, as illustrated in FIG. 2, the ENUM cache server 10 caches a record in which the telephone number “0422-59-6981”, the accommodation network “east.example.jp”, and the TTL “60” are associated with each other. To do.

[Configuration of ENUM cache server]
Next, the configuration of the ENUM cache server 10 will be described with reference to FIG. FIG. 3 is a diagram for explaining the configuration of the ENUM cache server 10 according to the first embodiment. As illustrated in FIG. 3, the ENUM cache server 10 includes a communication processing unit 11, a control unit 12, and a storage unit 13.

  The communication processing unit 11 controls communication related to various information exchanged between the ENUM authority server 20 and the call control server 30 to be connected. For example, the communication processing unit 11 transmits and receives an ENUM query or an ENUM answer between the ENUM authority server 20 and the call control server 30.

  As shown in FIG. 3, the storage unit 13 includes an ENUM data storage unit 13a and an ENUM query data storage unit 13b. The storage unit 13 is, for example, a semiconductor memory device such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk.

  The ENUM data storage unit 13a corresponds to a cache memory, stores a record corresponding to a query request from the call control server 30 as cache data, and stores the record for each record.

  Here, an example of data stored in the ENUM data storage unit 13a will be described with reference to FIG. For example, as illustrated in FIG. 4, the ENUM data storage unit 13 a indicates “telephone number”, “accommodating network” that is information on the accommodating network that accommodates the telephone number, and a period for storing records. “TTL” is stored in association with each other. 4, for example, the ENUM data storage unit 13a associates the telephone number “03-aaa-2345”, the accommodation network “east.example.jp”, and the TTL “60”. Remember.

  The ENUM query data storage unit 13b stores the ENUM query reception count for each telephone number counted by the counting unit 12b described later. For example, as illustrated in FIG. 5, the ENUM query data storage unit 13 b includes the “telephone number” included in the record stored in the ENUM data storage unit 13 a and the number of ENUM query receptions counted by the counting unit 12 e. The “number of queries” is stored in association with each other. Referring to the specific example of FIG. 5, for example, the ENUM query data storage unit 13b stores the telephone number “03-aaa-2345” and the query count “55” in association with each other.

  Returning to the description of FIG. 1, the control unit 12 includes a reception unit 12a, a determination unit 12b, a reply unit 12c, a transfer unit 12d, a counting unit 12e, a control unit 12f, and a deletion unit 12g. Here, the control unit 12 is an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), or an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

  The receiving unit 12a receives the ENUM query from the call control server 30. Specifically, when receiving the ENUM query, the receiving unit 12a notifies the determining unit 12c of the ENUM query and notifies the counting unit 12e that the ENUM query has been received.

  The determination unit 12b determines whether a record corresponding to the ENUM query received by the reception unit 12a is stored in the ENUM data storage unit 13a. For example, when receiving the ENUM query from the receiving unit 12a, the determining unit 12b determines whether a record corresponding to the telephone number included in the ENUM query is stored in the ENUM data storage unit 13a. Then, the determination unit 12b notifies the determination result to the reply unit 12c or the transfer unit 12d.

  When the determination unit 12b determines that the record is stored in the ENUM data storage unit 13a, the reply unit 12c returns a response to the query request to the call control server 30 using the record. For example, when the determination result received from the determination unit 12b is the determination result that the record corresponding to the received ENUM query is stored in the ENUM data storage unit 13a, the reply unit 12c returns to the ENUM data storage unit 13a. The record is read out from the telephone number, and the address information of the storage network corresponding to the telephone number, that is, the storage network storing the telephone number is transmitted to the call control server 30 as an ENUM answer.

  When the determination unit 12b determines that the record is not stored in the ENUM data storage unit 13a, the transfer unit 12d transfers the query request to the ENUM authority server 20, and sends an answer to the transferred query request to the ENUM authority server. When received from 20, the response is transferred to the call control server 30.

  When the receiving unit 12a receives the ENUM query, the counting unit 12e counts the number of times the ENUM query corresponding to each record is received for each record stored in the ENUM data storage unit 13a. Specifically, the measuring unit 12e counts the number of times the query request is received within a predetermined time for each telephone number of the record stored in the ENUM data storage unit 13a.

  For example, every time the receiving unit 12a receives an ENUM query, the counting unit 12e adds 1 to the number of queries corresponding to the telephone number included in the ENUM query in the ENUM query data storage unit 13b. The counting unit 12e updates the number of queries stored in the ENUM query data storage unit 13b to “0” every time 1 second elapses. Note that the present invention is not limited to the case where the number of ENUM query receptions per “second” is counted, and the number of ENUM query receptions during an arbitrarily set period may be counted.

  When there is a record in which the number of times counted by the counting unit exceeds a predetermined number, the control unit 12f controls to extend the period for storing the record. Specifically, when there is a record in which the number of times within a predetermined time counted by the counter 12e exceeds a predetermined number, the control unit 12f extends the period for storing the record. For example, the control unit 12f refers to the ENUM query data storage unit 13b, and if there is a telephone number in which the number of receptions of the ENUM query per second exceeds 100, the corresponding phone in the ENUM data storage unit 13a Add “3600” seconds to the TTL of the number.

  In addition, the control unit 12f performs the process of adding “3600” seconds to the TTL of the corresponding telephone number only once. After the addition process is performed once, the number of times of receiving the ENUM query per second is again determined. Even when the number of times exceeds 100, the process of adding “3600” seconds to the TTL of the corresponding telephone number is not performed. In the above description, a case has been described in which “3600 seconds” is added to TTL when there is a phone number in which the number of ENUM query receptions per “one second” exceeds “100 times”. Each value such as “,” “100 times”, “3600 seconds” can be arbitrarily set in advance.

  Here, a process for changing the TTL for each telephone number according to the status of the ENUM query will be described with reference to FIG. FIG. 6 is a diagram for explaining processing for changing the TTL for each telephone number in accordance with the status of the ENUM query. As shown in FIG. 6, the ENUM cache server 10 normally sets “60” seconds as the TTL designated by the ENUM authority server 20.

  Thereafter, the ENUM cache server 10 sets TTL “3660”, which is obtained by adding “3600” to TTL “60” in a changing state, that is, in a state where calls to a specific telephone number are concentrated.

  In this way, the ENUM cache server 10 changes the TTL received from the ENUM authority server 20 on the ENUM cache server 10 side according to the status of the number of ENUM queries, that is, the call concentration level, so that the ENUM authority server 20 The number of accesses to can be reduced.

  For example, in particular, when calls to a specific telephone number such as a telephone number of a ticket sales destination or a telephone number of a donation are concentrated, in the conventional case, an ENUM query is issued every 60 seconds. Since it reaches the server 20, the load on the ENUM authority server 20 is continuously applied. On the other hand, in the system according to the first embodiment, when the number of ENUM queries per second for the ENUM cache server 10 exceeds a predetermined threshold, the ENUM cache server 10 uses the ENUM authority server 20 to The acquired TTL is ignored and the TTL is changed. For example, by extending the TTL time of the ENUM data of the ENUM cache server 10 for 3600 seconds, the number of ENUM queries to the ENUM authority server 20 can be suppressed, and the load on the ENUM authority server 20 can be reduced.

Further, the control unit 12f controls the TTL to be shortened when the number of times counted by the counting unit 12e is equal to or less than a predetermined number for the record whose period is extended. For example, the control unit 12f refers to the ENUM query data storage unit 13b, and for a record with an extended period, whether there is a telephone number in which the number of receptions of the ENUM query per second is 100 times or less, 1 Judge every second. Then, when there is a telephone number in which the number of receptions of the ENUM query per second is 100 times or less, the control unit 12f
“3600” seconds are subtracted from the TTL of the corresponding telephone number in the ENUM data storage unit 13a.

  Here, an example of TTL transition in the ENUM cache server 10 will be described with reference to FIG. FIG. 7 is a diagram for explaining an example of TTL transition in the ENUM cache server. First, as shown in (1) of FIG. 7, the ENUM cache server 10 immediately after acquiring the ENUM data from the ENUM authority server 20, the TTL set by the ENUM authority server 20 (in the example of FIG. Is set as the TTL of the ENUM data cached in the ENUM cache server 10 (denoted as “cache TTL” in the example of FIG. 7).

  Subsequently, as shown in (2) of FIG. 7, the ENUM cache server 10 sequentially decreases the TTL value as time passes. In this way, when the cache TTL is configured with “only authoritative TTL” (in the normal state), the decrease starts from the authoritative TTL. In the example of (2) in FIG. 7, the decreasing TTL is described as “decreasing authority TTL” and “decreasing cache TTL”.

  Then, as shown in (3) of FIG. 7, when the number of ENUM queries per second to the ENUM cache server 10 exceeds a predetermined threshold, the ENUM cache server 10 sets the adjustment TTL to the decreasing authority TTL. to add. In FIG. 7 (3), the TTL that has been added and is decreasing is described as “decreasing adjustment TTL”.

  Then, as shown in (4) of FIG. 7, the ENUM cache server 10 sequentially decreases the value of the decrease cache TTL as time elapses. In this way, when the cache TTL is composed of “authoritative TTL and adjustment TTL” (during the change state), the decrease of the authority TTL is stopped (the value of the decrease authority TTL is held), and the decrease starts from the adjustment TTL. (Generation of decrease adjustment TTL). Further, when the decrease adjustment TTL becomes 0, the decrease is restarted from the value of the decrease authority TTL.

  Subsequently, when the number of ENUM queries per second to the ENUM cache server 10 is equal to or less than a predetermined threshold, the ENUM cache server 10 adjusts from the reduced cache TTL as shown in (5) of FIG. Subtract TTL. Thereafter, the TTL value is sequentially decreased with the passage of time from the reduced cache TTL value. When the reduced cache TTL becomes 0, the operation is performed assuming that the reduced authority TTL becomes 0. That is, since the decreasing authority TTL has become 0, the deletion unit 12g described later deletes the corresponding record.

  When the period of the record stored in the ENUM data storage unit 13a has passed, the deletion unit 12g deletes the record from the ENUM data storage unit 13a. For example, the deletion unit 12g refers to the ENUM data storage unit 13a, and when there is a record whose TTL value is 0, deletes the record from the ENUM data storage unit 13a.

[Process by ENUM cache server]
Next, processing of the ENUM cache server 10 according to the first embodiment will be described using FIG. FIG. 8 is a flowchart for explaining the flow of processing in the ENUM cache server 10 according to the first embodiment.

  As shown in FIG. 8, when the receiving unit 12a of the ENUM cache server 10 receives an ENUM query that is a query request from the call control server 30 (Yes in step S101), the counting unit 12e counts the number of times the query request is received for each telephone number. Are counted (step S102). For example, every time the ENUM query is received, the counting unit 12e adds 1 to the number of queries corresponding to the telephone number included in the ENUM query in the ENUM query data storage unit 13b.

  Then, the control unit 12f determines whether or not the number of receptions of the ENUM query exceeds a predetermined threshold (Step S103). For example, the control unit 12f refers to the ENUM query data storage unit 13b and determines whether there is a record of a telephone number that has received 100 times of ENUM queries per second.

  As a result, when it is determined that the number of receptions of the ENUM query has not exceeded the predetermined threshold (No at Step S103), the control unit 12f returns to Step S101. Further, when the control unit 12f determines that the number of receptions of the ENUM query exceeds a predetermined threshold (Yes at Step S103), the control unit 12f determines whether or not the adjustment TTL (for example, 3600 seconds) has already been added. (Step S104). As a result, when it is determined that the adjustment TTL has already been added (Yes at Step S104), the process returns to Step S101. That is, for the record once the adjustment TTL is added, the process of adding the adjustment TTL again is not performed.

  Further, when it is determined that the adjustment TTL has not been added (No at Step S104), the control unit 12f adds the adjustment TTL to the decrease authority TTL of the ENUM data corresponding to the telephone number (Step S105).

  In this way, the ENUM cache server 10 changes the TTL designated by the ENUM authority server 20 in accordance with the number of ENUM queries, so that, for example, the ENUM authority server 20 for a specific destination of ticket sales or donations is sent to the ENUM cache server 10. The ENUM query load can be reduced.

[Effect of the first embodiment]
As described above, the ENUM cache server 10 according to the first embodiment stores a record corresponding to a query request from the call control server 30 as cache data, and stores a period for storing the record for each record. An ENUM data storage unit 13a. The ENUM cache server 10 receives the query request from the call control server 30 and determines whether a record corresponding to the received query request is stored in the ENUM data storage unit 13a. When it is determined that the record is stored in the ENUM data storage unit 13a as a result of the determination, the ENUM cache server 10 returns a response to the query request to the call control server 30 using the record. . When it is determined that the record is not stored in the ENUM data storage unit 13a, the ENUM cache server 10 transfers the query request to the ENUM authority server 20, and sends an answer to the transferred query request to the ENUM authority server. When received from 20, the response is transferred to the call control server 30. Further, when receiving the query request, the ENUM cache server 10 counts the number of times the query request corresponding to each record is received for each record stored in the ENUM data storage unit 13a. When there is a record whose counted number exceeds the predetermined number, the ENUM cache server 10 extends the period for storing the record and stores it in the ENUM data storage unit 13a.

  In this way, the ENUM cache server 10 prevents concentration of access to the authority server by changing the TTL designated from the ENUM authority server 20 according to the status of the number of ENUM queries, thereby preventing access to the authority server. Can be reduced.

  Also, in the ENUM cache server 10 according to the first embodiment, when the number of counted times is less than or equal to a predetermined number for a record with an extended period, the period for storing the record is shortened. And stored in the ENUM data storage unit 13a. For this reason, when the situation where the access to the authority server is concentrated, the extended TTL can be shortened and returned to the normal TTL.

  In the ENUM cache server 10 according to the first embodiment, the number of times that a query request is received within a predetermined time is counted for each record, and a record in which the number of times within a predetermined time exceeds the predetermined number is stored in the storage unit. Is stored in the ENUM data storage unit 13a, the period for storing the record is extended. Therefore, for example, it is possible to appropriately determine whether or not the access to the ENUM authority server 20 is concentrated by monitoring query requests for one second.

  The ENUM cache server 10 according to the first embodiment counts the number of times the query request corresponding to each telephone number is received for each telephone number of the record stored in the ENUM data storage unit 13a. When there is a record corresponding to a telephone number whose number of times exceeds a predetermined number, the period for storing the record is extended and stored in the ENUM data storage unit 13a. For this reason, for example, when calls to a specific telephone number such as a telephone number of a ticket sales destination or a telephone number of a donation are concentrated, access concentration to the authority server is prevented, and It is possible to reduce access.

  In the ENUM cache server 10 according to the first embodiment, when the period of the record stored in the ENUM data storage unit 13a has expired, the record is deleted from the ENUM data storage unit 13a. For this reason, it is possible to appropriately delete a record whose TTL is 0.

[Second Embodiment]
In the first embodiment described above, a case has been described in which the number of times that a query request corresponding to each telephone number is received is counted for each telephone number, and the TTL is extended according to the number of times. However, the present invention is limited to this. For example, the number of times a query request corresponding to each telephone number is received may be counted for each station number (city code, city code), and the TTL may be extended according to the number.

  That is, as illustrated in FIG. 9, in the area of a specific station number, when a violence or the like occurs in that area, calls for confirmation of safety from other areas to the area where the violence or the like has occurred are concentrated. For example, in the example of FIG. 9, calls are concentrated on the area code “053”. In such a case, as a result of the ENUM query being concentrated on a specific station number in the system, the ENUM query is concentrated on the ENUM authority server 20, and the processing load on the ENUM authority server 20 is increased.

  Therefore, the ENUM cache server according to the second embodiment counts the number of times a query request corresponding to each telephone number is received for each station number (city code, city code), and extends TTL according to the number. To do. As a result, even when calls to station numbers in a specific area are concentrated, it is possible to prevent concentration of access to the authority server and to reduce access to the authority server.

  Therefore, in the following second embodiment, for each station number (city code, local station number), the number of times the query request corresponding to each station number is received is counted, and the TTL is extended according to the number of times. The processing of the information collection / delivery server in the second embodiment will be described with reference to FIGS. The configuration of the ENUM cache server according to the second embodiment is the same as that of the ENUM cache server according to the first embodiment shown in FIG.

  First, the ENUM query data storage unit 13b of the ENUM cache server according to the second embodiment will be described with reference to FIG. As shown in FIG. 10, the ENUM query data storage unit 13b stores the ENUM query reception count for each area code counted by the counting unit 12e. For example, in the example of FIG. 10, the ENUM query data storage unit 13 b includes the “area code” included in the record stored in the ENUM data storage unit 13 a and the number of ENUM query receptions counted by the counting unit 12 e. “Number of queries” is stored in association with each other. The station number to be measured can be arbitrarily set in advance.

  The counting unit 12e of the ENUM cache server according to the second embodiment counts the number of times the query request corresponding to each area code is received for each same area code in the record stored in the ENUM query data storage unit 13b. To do.

  In addition, the control unit 12f of the ENUM cache server according to the second embodiment stores the record when there is a record corresponding to the area code where the number of times counted by the counting unit 12e exceeds a predetermined number. This period is extended and stored in the ENUM data storage unit 13a.

  For example, as illustrated in FIG. 11, when the ENUM cache server according to the second embodiment determines that the number of ENUM queries for the area code “0053” is 100 or more per second, The TTL of all ENUM data belonging to the external station number 0053 is autonomously extended. For example, in the example of FIG. 11, TTL “3660” is set by adding “3600” to the TTL of all ENUM data belonging to a specific area code 0053.

  In this way, the ENUM cache server according to the second embodiment measures the number of ENUM queries for each area code, and when the number of ENUM queries exceeds a threshold, the ENUM cache server holds TTL values of all ENUM data belonging to station numbers are autonomously extended. Further, when the number of ENUM queries becomes equal to or less than the threshold, the extended TTL is returned to normal. Thereby, it is possible to reduce the number of ENUM queries to the ENUM authoritative server 20 at the time of occurrence of a fierce disaster and to reduce the load on the ENUM authoritative server 20.

  Next, processing of the ENUM cache server according to the second embodiment will be described with reference to FIG. FIG. 12 is a flowchart for explaining the flow of processing in the ENUM cache server according to the second embodiment.

  As shown in FIG. 12, when the receiving unit 12a of the ENUM cache server according to the second embodiment receives an ENUM query that is a query request from the call control server 30 (Yes in step S201), the counting unit 12e The number of times the query request is received is counted (step S202). For example, each time the ENUM query is received, the counting unit 12e adds 1 to the number of queries corresponding to the station number included in the ENUM query in the ENUM query data storage unit 13b.

  Then, the control unit 12f determines whether or not the number of receptions of the ENUM query exceeds a predetermined threshold (Step S203). For example, the control unit 12f refers to the ENUM query data storage unit 13b and determines whether there is a record with a station number in which the number of receptions of the ENUM query per second exceeds 100 times.

  As a result, when it is determined that the number of receptions of the ENUM query has not exceeded the predetermined threshold (No at Step S203), the control unit 12f returns to Step S201. If the control unit 12f determines that the number of ENUM query receptions exceeds a predetermined threshold (Yes in step S203), the control unit 12f determines whether or not an adjustment TTL (eg, 3600 seconds) has already been added. (Step S204). As a result, when it is determined that the adjustment TTL has already been added (Yes at step S204), the process returns to step S201.

  If it is determined that the adjustment TTL has not been added (No at Step S204), the control unit 12f adds the adjustment TTL to the decrease authority TTL of all ENUM data belonging to the station number (Step S205).

  In addition, the number of ENUM queries may be measured in a unit determined by a combination of the area code and the city code, not only when the number of ENUM queries is measured in the area code unit. In such a case, for example, as illustrated in FIG. 13, the ENUM query data storage unit 13b stores the number of ENUM query receptions for each unit determined by the combination of the area code and the city code counted by the counting unit 12e. To do. For example, in the example of FIG. 13, the ENUM query data storage unit 13b includes the “area code” and “city code” included in the record stored in the ENUM data storage unit 13a, and the ENUM counted by the counting unit 12e. The “number of queries” that is the number of query receptions is stored in association with each other.

  Next, a process of changing the TTL for each area code and city code according to the status of the ENUM query will be described with reference to FIG. FIG. 14 is a diagram for explaining processing for changing the TTL for each area code and city code according to the status of the ENUM query. As illustrated in FIG. 14, the ENUM cache server according to the second embodiment is configured such that the number of ENUM queries for the area code “0053” and the city code “bbbb” is 100 per second. If it is determined that the number is equal to or greater than the number of times, the TTL of all ENUM data whose area code is “0053” and whose city code is “bbbb” is autonomously extended. For example, in the example of FIG. 13, TTL “3660” is set by adding “3600” to the TTL of all corresponding ENUM data.

  As described above, the ENUM cache server according to the second embodiment measures the number of ENUM queries in a unit determined by the combination of the area code and the city code, and if the number of ENUM queries exceeds the threshold, the ENUM By automatically extending the TTL values of all ENUM data belonging to the relevant station number held by the cache server, the number of ENUM queries to the ENUM authority server 20 in the event of a catastrophe or the like is reduced, and the load on the ENUM authority server 20 Can be reduced.

[System configuration, etc.]
Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, the control unit 12f and the deletion unit 12g may be integrated. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  Also, among the processes described in the present embodiment, all or part of the processes described as being performed automatically can be performed manually, or the processes described as being performed manually can be performed. All or a part can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

[program]
It is also possible to create a program in which the processing executed by the ENUM cache server 10 described in the above embodiment is described in a language that can be executed by a computer. For example, it is possible to create a cache control program in which processing executed by the ENUM cache server 10 according to the first embodiment is described in a language that can be executed by a computer. In this case, when the computer executes the cache control program, the same effect as in the above embodiment can be obtained. Further, the cache control program is recorded on a computer-readable recording medium, and the processing similar to that of the first embodiment is realized by recording the cache control program on the recording medium and causing the computer to read and execute the cache control program. May be. Hereinafter, an example of a computer that executes a cache control program that realizes the same function as the ENUM cache server 10 illustrated in FIG. 3 will be described.

  FIG. 15 is a diagram illustrating a computer 1000 that executes a cache control program. As illustrated in FIG. 15, the computer 1000 includes, for example, a memory 1010, a CPU 1020, a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. These units are connected by a bus 1080.

  The memory 1010 includes a ROM (Read Only Memory) 1011 and a RAM 1012 as illustrated in FIG. The ROM 1011 stores a boot program such as BIOS (Basic Input Output System). The hard disk drive interface 1030 is connected to the hard disk drive 1031 as illustrated in FIG. The disk drive interface 1040 is connected to the disk drive 1041 as illustrated in FIG. For example, a removable storage medium such as a magnetic disk or an optical disk is inserted into the disk drive 1041. The serial port interface 1050 is connected to, for example, a mouse 1051 and a keyboard 1052 as illustrated in FIG. The video adapter 1060 is connected to a display 1061, for example, as illustrated in FIG.

  Here, as illustrated in FIG. 15, the hard disk drive 1031 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. That is, the cache control program is stored in, for example, the hard disk drive 1031 as a program module in which a command to be executed by the computer 1000 is described.

  The various data described in the above embodiment is stored as program data, for example, in the memory 1010 or the hard disk drive 1031. Then, the CPU 1020 reads the program module 1093 and the program data 1094 stored in the memory 1010 and the hard disk drive 1031 to the RAM 1012 as necessary, and executes various processing procedures.

  Note that the program module 1093 and the program data 1094 related to the cache control program are not limited to being stored in the hard disk drive 1031, but are stored in, for example, a removable storage medium and read out by the CPU 1020 via the disk drive or the like. Also good. Alternatively, the program module 1093 and the program data 1094 related to the cache control program are stored in another computer connected via a network (LAN (Local Area Network), WAN (Wide Area Network), etc.), and the network interface 1070 is stored. Via the CPU 1020.

DESCRIPTION OF SYMBOLS 10 ENUM cache server 11 Communication processing part 12 Control part 12a Reception part 12b Determination part 12c Reply part 12d Transfer part 12e Count part 12f Control part 12g Deletion part 13 Storage part 13a ENUM data storage part 13b ENUM query data storage part 20 ENUM authority server 30 Call control server 40 Client device

Claims (8)

A storage unit that stores a record corresponding to a query request from the communication control device as cache data, and stores a period for storing the record for each record;
A receiving unit for receiving a query request from the communication control device;
A determination unit that determines whether a record corresponding to the query request received by the reception unit is stored in the storage unit;
If the determination unit determines that the record is stored in the storage unit, using the record, a reply unit that returns a response to the query request to the communication control device;
When it is determined by the determination unit that the record is not stored in the storage unit, the query request is transferred to the authority server, and when an answer to the transferred query request is received from the authority server, A transfer unit for transferring the answer to the communication control device;
When receiving a query request by the receiving unit, for each record stored in the storage unit, a counting unit that counts the number of times a query request corresponding to each record is received;
When there is a record in which the number of times counted by the counting unit exceeds a predetermined number in the storage unit, a control unit that extends the period for storing the record and stores the record in the storage unit;
A cache server device comprising:   When the number of times counted by the counting unit is less than or equal to a predetermined number of records with an extended period, the control unit shortens the period for storing the record and stores it in the storage unit The cache server device according to claim 1, wherein: The measurement unit counts the number of times a query request is received within a predetermined time for each record,
When the number of times counted within the predetermined time counted by the counting unit exceeds the predetermined number, the control unit extends the period for storing the record to the storage unit. The cache server device according to claim 1, wherein the cache server device is stored. The storage unit stores a telephone number and a storage network corresponding to the telephone number in association with each other as a record corresponding to the query request from the communication control device,
The counting unit counts the number of times the query request corresponding to each telephone number is received for each telephone number of the record stored in the storage unit,
When there is a record corresponding to a telephone number for which the number counted by the counting unit exceeds a predetermined number, the control unit extends the period for storing the record and stores the record in the storage unit The cache server device according to any one of claims 1 to 3. The storage unit stores a telephone number and a storage network corresponding to the telephone number in association with each other as a record corresponding to the query request from the communication control device,
The counting unit counts the number of times a query request corresponding to each station number is received for each identical station number in the record stored in the storage unit,
When there is a record corresponding to a station number in which the number of times counted by the counting unit exceeds a predetermined number, the control unit extends a period for storing the record and stores the record in the storage unit. The cache server device according to any one of claims 1 to 3, wherein   The cache according to claim 1, further comprising a deletion unit that deletes the record from the storage unit when a period of the record stored in the storage unit has passed. Server device. A cache control method executed by a cache server device,
The cache server device
A record corresponding to the query request from the communication control device is stored as cache data, and a storage unit that stores a period for storing the record for each record is provided.
Receiving a query request from the communication control device;
A determination step of determining whether a record corresponding to the query request received by the reception step is stored in the storage unit;
If it is determined by the determination step that the record is stored in the storage unit, using the record, a reply step of returning a response to the query request to the communication control device;
If it is determined in the determination step that the record is not stored in the storage unit, the query request is transferred to an authority server, and when an answer to the transferred query request is received from the authority server, A transfer step of transferring an answer to the communication control device;
When receiving a query request by the receiving step, for each record stored in the storage unit, a counting step for counting the number of times a query request corresponding to each record is received;
In the storage unit, when there is a record in which the number of times counted by the counting step exceeds a predetermined number, a control step of extending the period for storing the record and storing the record in the storage unit;
A cache control method comprising: A receiving step of receiving a query request from the communication control device;
Determination step of determining whether the record corresponding to the query request received by the reception step is stored in a storage unit that stores a record corresponding to the query request as cache data and stores a period for storing the record for each record When,
If the determination step determines that the record is stored in the storage unit, using the record, a reply step of returning a response to the query request to the communication control device;
If it is determined in the determination step that the record is not stored in the storage unit, the query request is transferred to an authority server, and when an answer to the transferred query request is received from the authority server, A transfer step of transferring an answer to the communication control device;
When receiving a query request by the receiving step, for each record stored in the storage unit, a counting step for counting the number of times the query request corresponding to each record is received;
In the storage unit, when there is a record in which the number of times counted by the counting step exceeds a predetermined number, a control step of extending the period for storing the record and storing the record in the storage unit;
Control program for causing a computer to execute.

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