JP6285884B2 - ENUM server and unique access determination method - Google Patents

Description

  The present invention is a technical field of ENUM (E.164 Number Mapping) that performs name resolution by associating a telephone number of an IP (Internet Protocol) telephone or the like with a URI (Uniform Resource Identifiers). The present invention relates to an access determination method.

  2. Description of the Related Art Conventionally, in an IP network, an ENUM system has been proposed as a mechanism in which a device (such as a SIP (Session Initiation Protocol) server) in a communication carrier network associates a telephone number with a URI. In this ENUM system, a SIP server installed in a telecommunications carrier's network sends connection destination information (IP address, domain name, etc.) for the telephone number of a terminal (IP phone, etc.) to be connected to the ENUM server. And routing based on the information of the connection destination.

  Also, with the shift from PSTN (Public Switched Telephone Network) to IP network, a number portability mechanism is being considered that allows fixed telephone numbers to be carried freely between telecommunications carriers in the IP network. . An ACQ (ALL CALL QUERY) system has been proposed as a technology that enables number portability in an environment where multiple IP carriers are connected (see Non-Patent Document 1).

  In the ACQ system described in Non-Patent Document 1, a database (“number portability DB” described later) that centrally manages number portability information of each communication carrier is provided in an ENUM server that uses a DNS (Domain Name System) mechanism. The SIP server of each telecommunications carrier accesses the ENUM server to resolve whether each telephone number has been transferred (ported out) to another network, and obtains connection destination information (connection destination information) And communicate.

  FIG. 7 is a diagram for explaining an inquiry about connection destination information to the number portability DB 100 provided in the ENUM server 10A in this ACQ method.

As shown in FIG. 7, first, the terminal 1 (1a: transmission source terminal) in the band 03-3521 (IP telephone or the like) to the terminal 1 (1b: destination terminal) in the band 0422-59 (IP telephone or the like). A connection request message (referred to as “connection request” in FIG. 7; the same applies to other drawings) is transmitted to the SIP server 20 (step S1).
Upon receiving the connection request message, the SIP server 20 inquires of the number portability DB 100 of the ENUM server 10A for connection destination information (such as a URI corresponding to the destination telephone number) for connecting to the destination communication carrier. “Transmission of connection destination information inquiry message”, which will be described later, is described as “connection destination information inquiry” in FIG. 7 (the same applies to other drawings) (step S2).

  When the ENUM server 10A receives the connection destination information inquiry message, the ENUM server 10A refers to the number portability DB 100 stored in itself, extracts the connection destination information corresponding to the terminal of the destination (“destination information” described later), and SIP Response information ("connection destination information inquiry response message" to be described later. In FIG. 7, "connection destination information inquiry response" is described. The same applies to other figures) is transmitted to the server 20 (step S3).

  When the SIP server 20 receives the connection destination information included in the connection destination information inquiry response message, the SIP server 20 determines whether the destination is the local IP network 1000, and manages the subscriber information if the destination IP address is the local IP network 1000. The destination SIP server is resolved by inquiring to the HSS (Home Subscriber Server) 30, and the call is connected to the terminal 1 (1b) in the 0422-59 band as the destination (step S4). On the other hand, when the destination is the IP network 2000 of another communication carrier, the SIP server 20 transfers the SIP signal to the IP network 2000 of the other communication carrier indicated in the connection destination information (not shown).

  Separately from the above processing, the ENUM server 10A also receives a destination terminal (incoming call) managed by itself from another carrier's IP network 2000 (referred to as “other IP network 2000” in FIG. 7). A connection destination information inquiry (connection destination information inquiry message) for the destination information is received (step S5). Then, the ENUM server 10A extracts connection destination information corresponding to the destination terminal (destination information), and sends response information (connection destination information inquiry response) to the IP network 2000 of the other communication carrier that has transmitted the inquiry. Message) is transmitted (step S6).

  In this way, the SIP server 20 of each telecommunications carrier accesses the number portability DB 100 provided in the ENUM server 10A to determine whether each destination telephone number has been transferred (ported out) to another network. The problem is solved by acquiring connection destination information (connection destination information) and communication is performed.

By the way, in the actual operation of the telephone service, it is not intended only for communication between user terminals, but for the purpose of access for the purpose of a telephone number cleaning service, or down of a server called a DOS attack (Denial of Service attack). May be accessed.
Here, the telephone number cleaning service is a service that determines the current usage status (in use, non-use, etc.) of a telephone number without ringing the telephone number of the other party. In this telephone cleaning service, in order to exclude missing numbers in the telephone number list (customer list) used in marketing, sales, election campaigns, etc., a specialized contractor uses the telephone numbers listed in the telephone number list (customer list). A large number of terminals are accessed in a short time to determine the usage status.
Further, the DOS attack refers to sending a large amount of requests to devices constituting a network such as a server and making it impossible to provide a service.
Hereinafter, an access that is not intended for a normal call service, such as a telephone number cleaning service or a DOS attack, is referred to as “single access”.

  Conventionally, various techniques have been developed to protect a server from this DOS attack. For example, in Patent Document 1, in order to protect a SIP server subjected to a denial of service attack such as a DOS attack, access from a malicious user to the SIP server or a load balancer arranged in the preceding stage is determined. A technique for suppressing an increase in the load on the SIP server by providing a function (malicious access determination function) and a delay generation function is disclosed.

“Recommendation ITU-T E.164-Supplement 2: Number Portability”, International Telecommunication Union, 11/2009

JP 2006-331015 A

  However, the technique described in Patent Document 1 is intended to protect the SIP server, and is not supposed to protect the number portability DB of the newly introduced ENUM server. In other words, since the number portability DB accepts not only access from the own IP network but also access from the IP network of other carriers, even if the load on the SIP server of the own network is reduced, other communication businesses It is not possible to prevent an increase in load due to mass access from the user's IP network.

In addition, the specific access such as the telephone number cleaning service causes an overload to the entire IP network including the ENUM server including the number portability DB and the apparatus providing the telephone service such as the SIP server, and also provides the user of the telephone service with On the other hand, there is a risk of connection delay or connection failure. That is, as shown in FIG. 8, a large number of messages are received from a terminal in the own IP network (in FIG. 8, terminal 1 (1c: a terminal of a specific access source) or from the IP network 2000 of another communication carrier. If issued, the load on the ENUM server 10A and the SIP server 20 will increase.
In the conventional telephone system, the above-mentioned problems existed. However, when the number portability DB is arranged in each carrier's IP network due to the introduction of the number portability system in the IP network, all inquiries are number portability. Concentrating on the DB is a concern for further expansion of the impact.

  The present invention has been made in view of such a background, and the present invention can reduce the load caused by unique access to a number portability DB newly introduced in the IP network, and the unique access determination. It is an object to provide a method.

  In order to solve the above-described problem, the invention according to claim 1 is a request for requesting connection destination information indicating a connection destination corresponding to the telephone number of the destination terminal attached to the connection request transmitted by the source terminal. A storage unit for storing a number portability DB for storing the connection destination information corresponding to the destination information including the telephone number of the destination terminal, the ENUM server receiving from the SIP server of the own IP network and the other IP network; Each time the request is received, the destination information attached to the received request is stored in the storage unit as specific access monitoring information, and the specific access monitoring information stored within a predetermined time is used. Each of the destination information shown is referred to, it is determined whether the telephone number of the destination terminal has a predetermined regularity, If it is determined that the request is specific access, the request is output to the specific access countermeasure processing unit, and if it is not determined that the request has the predetermined regularity, the connection destination information search unit determines that the request is not the specific access. The unique access determination unit that outputs to the request, the request that is said to be the unique access, the response information to the request as a response information to the specific access countermeasure processing unit that returns a rejection response, and the request that is not the unique access The connection destination information search unit that receives the connection destination information by referring to the number portability DB based on the destination information received and attached to the request, and inquiry response information including the acquired connection destination information And a connection destination information inquiry response unit that returns a response to the transmission source of the request, and It was ENUM server, characterized in that obtaining.

  According to a fourth aspect of the present invention, there is provided a request for requesting connection destination information indicating a connection destination corresponding to a telephone number of a destination terminal attached to a connection request transmitted by a transmission source terminal. A unique access determination method for an ENUM server received from a server and another IP network, wherein the ENUM server stores a number portability DB for storing the connection destination information corresponding to the destination information including the telephone number of the destination terminal Each time the request is received, the destination information attached to the received request is stored in the storage unit as specific access monitoring information and stored within a predetermined time. In addition, referring to each of the destination information indicated by the specific access monitoring information, whether or not the telephone number of the destination terminal has a predetermined regularity When it is determined that the request has the predetermined regularity, the request is specific access, and when it is not determined that the predetermined regularity is determined, the request is not the specific access. Based on the access determination step, the response information for the request that is said to be the specific access, the specific access countermeasure step of returning a rejection response, and the destination information attached to the request that is not the specific access, A connection destination information search step of acquiring the connection destination information with reference to a number portability DB, an inquiry response step of generating inquiry response information including the acquired connection destination information, and returning the inquiry response information to the transmission source of the request; The unique access determination method is characterized in that

In this way, when the ENUM server receives a request for requesting connection destination information from a SIP server of its own IP network or from another IP network, the destination information (phone of the destination terminal) attached to the request is received. Number) as unique access monitoring information. Then, the ENUM server refers to the specific access management information, determines that the request is specific access when the telephone number of the destination terminal has a predetermined regularity, and rejects it as response information for the request. A response can be sent back.
Therefore, it is possible to eliminate an inquiry by specific access to the number portability DB and reduce the load on the number portability DB. Further, since connection destination information is not responded, a connection request from a request source is not transferred to a SIP server or the like in the network, and the load on the entire network can be reduced.

  In the invention according to claim 2, as the response information for the request that the specific access countermeasure processing unit is the specific access, the request that is the specific access, instead of returning a rejection response, After generating a delay, the data is output to the connection destination information search unit, and the connection destination information search unit receives the request that is the specific access, and adds the destination information attached to the request to the destination information. 2. The ENUM server according to claim 1, wherein the connection destination information is acquired with reference to the number portability DB.

  The invention according to claim 5 relates to the request that is said to be the singular access instead of returning a rejection response as response information to the request that is said to be the singular access in the singular access countermeasure step. 5. The unique access determination method according to claim 4, wherein the connection destination information search step is executed after a delay is generated.

In this way, when the ENUM server determines that the request is a singular access, it generates a delay, refers to the number portability DB, obtains connection destination information, and returns inquiry response information. can do.
Therefore, it is possible to reduce the load caused by specific access to the number portability DB. In addition, since query response information is returned after a delay has occurred, transfer to a SIP server or the like in the network due to a connection request from the request source can be suppressed, thus reducing the load on the entire network. can do.

  According to a third aspect of the present invention, the specific access determination unit includes the telephone number of the source terminal together with the destination information when the telephone number of the source terminal is attached to the request. Stored in the storage unit as the singular access monitoring information and stored as the singular access monitoring information within a predetermined time instead of determining whether the telephone number of the destination terminal has a predetermined regularity. When the number of telephone numbers of the same source terminal exceeds a predetermined threshold, the request with the telephone number of the source terminal is output to the specific access countermeasure processing unit as specific access When the number of telephone numbers of the same source terminal stored as the specific access monitoring information is equal to or less than a predetermined threshold, the request is determined not to be the specific access. It was ENUM server according to claim 1 or claim 2, characterized in that output connection target information retrieval unit.

  In the invention according to claim 6, in the specific access determining step, when the telephone number of the source terminal is attached to the request, the telephone number of the source terminal is set together with the destination information. In addition to storing in the storage unit as the specific access monitoring information, instead of determining whether the telephone number of the destination terminal has a predetermined regularity, as the specific access monitoring information within a predetermined time When the number of stored telephone numbers of the same source terminal exceeds a predetermined threshold, the request to which the telephone number of the source terminal is attached is specific access, and the specific access monitoring information 5. The request is not said specific access when the number of stored telephone numbers of the same source terminal is equal to or less than a predetermined threshold value. Other was specific access determining method according to claim 5.

By doing in this way, when the telephone number of the caller terminal is attached to the request, the ENUM server stores the telephone number of the caller terminal together with the destination information in the storage unit as the specific access monitoring information. . Then, the ENUM server refers to the specific access management information, and can determine that the request is specific access when the number of telephone numbers of the same source terminal exceeds a predetermined threshold.
Therefore, since the ENUM server can execute the countermeasure processing for the specific access for the request to which the telephone number of the transmission source terminal determined to be the specific access is attached, the load on the entire network can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the ENUM server and the specific access determination method which reduce the load by the specific access with respect to the number portability DB newly introduced in an IP network can be provided.

It is a figure which shows the outline | summary of the whole structure and process of a communication system containing the ENUM server which concerns on this embodiment. It is a functional block diagram which shows the structural example of the ENUM server which concerns on this embodiment. It is a figure which shows the data structural example of the specific access monitoring information which concerns on this embodiment. It is a figure which shows the data structural example of the specific access monitoring information which concerns on this embodiment. It is a figure which shows the data structural example of number portability DB which concerns on this embodiment. It is a flowchart which shows the flow of a process of the ENUM server which concerns on this embodiment. It is a figure for demonstrating the inquiry of the connecting point information to number portability DB with which an ENUM server is provided in an ACQ system. It is a figure for demonstrating the subject of a prior art.

  Next, the ENUM server 10 and the specific access determination method in a mode for carrying out the present invention (hereinafter referred to as this embodiment) will be described.

≪Overview≫
First, an overview of the communication system S according to the present embodiment will be described.
FIG. 1 is a diagram illustrating an overall configuration and processing overview of a communication system S including an ENUM server 10 according to the present embodiment.

<System configuration and processing overview>
As shown in FIG. 1, the communication system S according to the present embodiment includes an SIP server 20 that accommodates a plurality of terminals 1 in an IP network (own IP network) 1000 that is a network of a communication carrier, An ENUM server 10 having a number portability DB 100 that stores information that associates connection destination information (telephone number of the terminal 1 of the destination and the E.164 number described later) and connection destination information (URI, etc.) The HSS 30 stores the subscriber information of the terminal 1 accommodated in the SIP server 20.

  The overall configuration of the communication system S according to the present embodiment is the same as the configuration shown in FIG. The message processing flow (steps S1 to S6 in FIG. 1) in the normal telephone service is also the same as the conventional processing flow shown in FIG. 7 (steps S1 to S6 in FIG. 7). However, the ENUM server 10 according to the present embodiment includes a unique access determination unit 121 and a specific access countermeasure processing unit 122 as shown in FIG. 1 in addition to the function of the conventional ENUM server 10A shown in FIG. Different.

The ENUM server 10 according to the present embodiment may be referred to as a connection destination information inquiry message (hereinafter referred to as “request”) from the SIP server 20 in its own IP network 1000 or the IP network 2000 of another communication carrier. )), The unique access determination unit 121 determines whether or not the request is a specific access based on the destination number attached to the request. A method for determining whether or not this unique access will be described later. When the singular access determination unit 121 determines that the access is singular access, the singular access countermeasure processing unit 122 executes a predetermined singular access countermeasure process. The predetermined specific access countermeasure processing is performed by, for example, sending a rejection response to the request instead of the normal connection destination information inquiry response message (steps S3 and S6 in FIG. 1) or connecting destination information inquiry response message. For example, transmission is performed after a delay is generated.
By doing so, it is possible to reduce the load in the network due to unique access to the newly introduced number portability DB 100.

≪Configuration of each device≫
Next, the configuration of each device configuring the communication system S according to the present embodiment will be described.

<SIP server>
When the SIP server 20 (see FIG. 1) according to the present embodiment receives a connection request message from the terminal 1, the SIP server 20 (see FIG. 1) connects to the ENUM server 10 the connection destination corresponding to the destination information (the telephone number of the destination terminal 1) A connection destination information request message for requesting information (such as a URI) is transmitted, and a call connection is established with the terminal 1 serving as a destination based on the connection destination information.

Here, when the SIP server 20 receives the connection request message to which the destination information (the telephone number of the destination terminal 1 or the like) is attached from the terminal 1, the SIP server 20 sends the connection destination information request message including the destination information to the ENUM. Send to server 10. Specifically, the SIP server 20 generates a connection destination information request message including the destination information in the ENUM protocol domain format shown below, and transmits it to the ENUM server 10.
For example, the SIP server 20 receives the E.D. of the destination telephone number (for example, 0422-59-1234) included in the connection request message received from the terminal 1. 164 numbers (+ 81-422-59-1234) in reverse order, separated by dots, and the format (4.3.2.1.9.5.2.2.4.1.8.e164.arpa) with “e164.arpa” attached is called destination information. Is transmitted to the ENUM server 10.

Further, when receiving the connection destination information inquiry response message from the ENUM server 10, the SIP server 20 extracts the connection destination information attached to the connection destination information inquiry response message. Then, the SIP server 20 determines whether or not the extracted connection destination information is the local IP network 1000. If the connection destination information is the local IP network 1000 as a result of the determination, the SIP server 20 obtains the subscriber information related to the terminal 1 indicated in the destination information by inquiring the HSS 30 and is indicated in the subscriber information. Based on the service conditions and the like, a call connection request message is transmitted to the terminal 1 that is the destination, and a call connection is made.
On the other hand, as a result of the determination, if the extracted connection destination information indicates another IP network (for example, the IP network 2000 of another communication carrier) instead of the own IP network 1000, the SIP server 20 A connection request message is transmitted toward the IP network.

<HSS>
HSS30 (refer FIG. 1) is an apparatus implement | achieved by the computer provided with the control part, the memory | storage part, the communication part, etc. FIG. And HSS30 memorize | stores the database of subscriber information, such as service information and authentication information regarding each terminal 1 which the SIP server 20 accommodates. Since the HSS 30 is an existing device in an IMS (IP Multimedia Subsystem) service, detailed description of functions is omitted.

<ENUM server>
Next, the ENUM server 10 will be described.
FIG. 2 is a functional block diagram illustrating a configuration example of the ENUM server 10 according to the present embodiment.
The ENUM server 10 according to the present embodiment includes a number portability DB 100, and receives connection destination information corresponding to destination information received from the SIP server 20 or the IP network 2000 of another communication carrier at the inquiry source. A reply is sent to a certain SIP server 20 or the IP network 2000 of another carrier. Further, when the ENUM server 10 receives the connection destination information inquiry message (request), the ENUM server 10 determines whether or not the request is a specific access. Execute.

Note that the ENUM server 10 is managed in a hierarchical structure (Tier0 to Tier2) as in the case of DNS, and when performing name resolution for destination information, the ENUM managing the higher hierarchy Tier0 or Tier1. A query is recursively performed from the server to the ENUM server that manages Tier2. In ENUM, each telecommunications carrier manages an ENUM server belonging to Tier 2, and stores connection destination information corresponding to each terminal 1 in each number band (for example, an area code or a city code). Yes. In the present embodiment, in order to simplify the description, the ENUM server 10 belonging to Tier 2 managed by the communication carrier will be illustrated and described.
The ENUM server 10 includes a communication unit 11, a control unit 12, and a storage unit 13.

  The communication unit 11 includes a communication interface that transmits and receives information to and from the SIP server 20 and the like. When receiving a message or the like from an external device, the communication unit 11 delivers the message or the like to the control unit 12. In addition, the communication unit 11 transmits a message or the like generated in the control unit 12 to an external device.

The storage unit 13 includes a hard disk, a flash memory, a RAM, and the like.
The storage unit 13 stores a number portability DB 100 (described later, see FIG. 5), unique access monitoring information 130 (described later, see FIGS. 3 and 4), and the like.

  The control unit 12 is responsible for the overall processing executed by the ENUM server 10 and includes a singular access determination unit 121, a singular access countermeasure processing unit 122, a connection destination information search unit 123, and a connection destination information inquiry response unit 124. . The control unit 12 is realized by, for example, a CPU (Central Processing Unit) developing and executing a program stored in the storage unit 13 of the ENUM server 10 on a RAM (Random Access Memory).

  The singular access determination unit 121 receives a connection destination information inquiry message (request) from the SIP server 20 or the IP network 2000 of another communication carrier via the communication unit 11, and the connection destination information inquiry message is singular access. It is determined whether or not. When the unique access determination unit 121 determines that the access is specific access, the specific access determination unit 121 outputs the connection destination information inquiry message to the specific access countermeasure processing unit 122. When the unique access determination unit 121 determines that the access is not specific access, the specific access determination unit 121 outputs the connection destination information inquiry message to the connection destination information search unit 123.

The specific access determination unit 121 determines whether or not the connection destination information inquiry message (request) is specific access (hereinafter, referred to as “single access determination processing”).
When receiving the connection destination information inquiry message, the specific access determination unit 121 acquires the destination information included in the connection destination information inquiry message, and the specific access monitoring information 130 (for example, FIGS. 3 and 4) in the storage unit 13. (See below). Then, the singular access determination unit 121 refers to the singular access monitoring information 130 based on a predetermined logic (single access determination method) set in advance, and determines whether or not the received connection destination information inquiry message is singular access. .

(Unique access determination method “1”)
The peculiar access determination unit 121 determines that the peculiar access is a peculiar access when the destination number indicated by the destination information is an inquiry having a predetermined regularity as logic of the peculiar access determination process. This will be described in more detail below.

[Judgment logic (1-1)]
The singular access determination unit 121, as the logic of the singular access determination process, receives the destination number with the end of the subscriber number incremented (increased by 1) within X seconds, and receives the singular access Y times consecutively. Judge as.
FIG. 3A is a diagram illustrating a data configuration example of the specific access monitoring information 130 according to the present embodiment. As shown in FIG. 3A, the specific access monitoring information 130 stores destination information extracted from the connection destination information inquiry message.
Based on this unique access monitoring information 130 (FIG. 3A), the singular access determination unit 121 refers to the last four digits of the subscriber number included in the destination information, and ends the subscriber number. However, when the destination number incremented (incremented by 1) is continuously received Y times within X seconds, it is determined as a specific access.
In the example shown in FIG. 3A, the subscriber number (the last four digits) of the destination number is incremented by 1 as “1231” to “1235”.

  The destination information stored in the singular access monitoring information 130 includes time information (not shown) when the ENUM server 10 receives the connection destination information inquiry message. In the access determination process, it is determined whether or not the access is specific based on the information of the immediately preceding X seconds (predetermined time). The same applies to the following unique access determination processing.

[Judgment logic (1-2)]
When the unique access determination unit 121 receives the connection destination information inquiry message Y times with the same station number (the area code and the local station number are the same) within X seconds as logic of the unique access determination process Then, it is determined as unique access.
As illustrated in FIG. 3B, the specific access determination unit 121 extracts the destination information when receiving the connection destination information inquiry message, and stores the destination information in the specific access monitoring information 130.
Then, the singular access determination unit 121 received the connection destination information inquiry message with the same station number as the destination number Y times based on the destination information of the previous X seconds (predetermined time) during the singular access determination process. In this case, the connection destination information inquiry message to be determined is determined as unique access.

Here, the landline number in Japan (for example, “0123-45-6789”) is a domestic prefix “0” and a total of 5 digits (“123-45”) of the area code and the city code. , Defined by the subscriber number (“6789”). Thus, E.I. Of the 164 numbers, the same area code (the area code and the city area code are the same) can be obtained by referring to the country code “81” in Japan, up to a total of 5 digits including the area code and the area code. The called number can be specified.
FIG. 3B shows an example in which the area code and the city code are the same “0422-59”, and the connection destination information inquiry message having the same station number is received Y times in X seconds.

(Unique access determination method “2”)
The singular access determination unit 121 receives, as a logic of the singular access determination process, a connection destination information inquiry message with the same telephone number of the connection request information inquiry message exceeding a predetermined threshold within a predetermined time. In this case, it is determined that the access is unique.

As shown in FIG. 4, when the connection destination information inquiry message is received, the singular access determination unit 121 assigns the telephone number of the inquiry request source that has transmitted the connection destination information inquiry message in association with the destination information. Stored in the access monitoring information 130.
Then, the singular access determination unit 121 uses the telephone number of the same inquiry request source on the basis of the telephone number of the inquiry request source corresponding to the destination information of X seconds (predetermined time) immediately before the singular access determination process. When the number exceeds a predetermined threshold value, a connection destination information inquiry message transmitted from the same telephone number as the telephone number of the inquiry request source exceeding the threshold value is determined as a unique access.

  Note that the logic of this unique access determination process is not limited to the above-described specific access determination methods “1” and “2”, and the administrator of the ENUM server 10 responds to the inquiry response of the trader that generates the specific access. Can be set arbitrarily.

  Returning to FIG. 2, the singular access countermeasure processing unit 122 receives the connection destination information inquiry message determined by the singular access determination unit 121 to be singular access, and executes a predetermined singular access countermeasure process described below.

(Unique access countermeasure processing “1”)
The specific access countermeasure processing unit 122 transmits a rejection response as a response to the connection destination information inquiry message determined to be the specific access.
As a result, the telephone number cleaning service provider who has received the rejection response cannot check whether the telephone number actually exists. A telephone number cleaning service provider or the like again transmits a connection destination information inquiry message when the number of receptions of the connection destination information inquiry message in the ENUM server 10 falls below a threshold value after a predetermined time has elapsed. Therefore, it is possible to suppress the load on the entire network and prevent the telephone number cleaning service provider from causing substantial damage.

(Unique access countermeasure processing “2”)
The unique access countermeasure processing unit 122 causes a delay in the response to the connection destination information inquiry message determined to be the unique access. Then, the specific access countermeasure processing unit 122 outputs the connection destination information inquiry message to the connection destination information search unit 123 after the delay occurs (waiting for a predetermined time). Thereby, the connection destination information inquiry response unit 124 transmits a connection destination information inquiry response message after the time corresponding to the generated delay has elapsed.
By doing so, it is possible to delay the transmission of the response information (connection destination information inquiry response message) and suppress the load in the network.

  The connection destination information search unit 123 receives the connection destination information inquiry message via the singular access determination unit 121 or the singular access countermeasure processing unit 122, and extracts the destination information attached to the connection destination information inquiry message. Then, the connection destination information search unit 123 refers to the number portability DB 100 in the storage unit 13 and searches for connection destination information corresponding to the destination information. The connection destination information search unit 123 extracts connection destination information obtained as a result of searching the number portability DB 100, and outputs a processing instruction to the connection destination information inquiry response unit 124.

FIG. 5 is a diagram showing a data configuration example of the number portability DB 100 according to the present embodiment.
As in the example illustrated in FIG. 5, the connection information is stored in the number portability DB 100 in association with the destination information. Specifically, the destination information includes, for example, E.D. based on the telephone number of the destination terminal 1. Information obtained by converting the 164 number into the domain format of the ENUM protocol is stored. In association with the destination information, the connection destination information includes, for example, the E.E. The URI including the 164 number and the domain name (area1.carrier_A) of the connection carrier is stored. Here, the domain indicated by “carrier_A” in the domain name means the connection destination information of the own IP network 1000. In addition, the domain indicated by “carrier_B” and “carrier_C” means the connection destination information of the IP network 2000 of another carrier, and that the destination telephone number has been transferred (ported out) to another network. Show.

  Returning to FIG. 2, the connection destination information inquiry response unit 124 generates a connection destination information inquiry response message (inquiry response information) with the connection destination information extracted by the connection destination information search unit 123. Then, the connection destination information inquiry response unit 124 transmits the generated connection destination information inquiry response message to the SIP server 20 or the IP network 2000 of another communication carrier as the inquiry source.

≪Process of ENUM server≫
Next, processing of the ENUM server 10 according to the present embodiment will be described.
FIG. 6 is a flowchart showing a processing flow of the ENUM server 10 according to the present embodiment.

  First, the ENUM server 10 (unique access determination unit 121) receives a connection destination information inquiry message from the SIP server 20 or the IP network 2000 of another communication carrier (step S10).

Next, the singular access determination unit 121 determines whether or not the received connection destination information inquiry message is singular access (step S11).
Here, the singular access determination unit 121 executes a process of determining whether or not the received connection destination information inquiry message is singular access based on a predetermined logic set in advance. Specifically, for example, the singular access determination unit 121 refers to the singular access monitoring information 130 in the storage unit 13 by using any one of the above-described singular access determination methods “1”, “2”, and the like. Then, it is determined whether or not the received connection destination information inquiry message is unique access.

  If it is determined in step S11 that the received connection destination information inquiry message is not unique access (step S11 → No), the unique access determination unit 121 outputs the connection destination information inquiry message to the connection destination information search unit 123. Then, the process proceeds to step S12.

  In step S12, the connection destination information search unit 123 extracts the destination information from the connection destination information inquiry message, and acquires the connection destination information corresponding to the destination information with reference to the number portability DB 100 (FIG. 5). . Then, the connection destination information inquiry response unit 124 generates a connection destination information inquiry response message with the connection destination information, and transmits the connection destination information inquiry response message to the SIP server 20 or the IP network 2000 of another communication carrier as the inquiry source.

  On the other hand, when it is determined in step S11 that the received connection destination information inquiry message is specific access (step S11 → Yes), the specific access determination unit 121 uses the connection destination information inquiry message as a specific access countermeasure processing unit. It outputs to 122 and progresses to step S13.

In step S <b> 13, the singular access countermeasure processing unit 122 executes a predetermined singular access countermeasure process set in advance.
Here, the singular access countermeasure processing unit 122 executes processing of the connection destination inquiry message determined to be singular access using, for example, any of the aforementioned singular access countermeasure processes “1”, “2”, and the like.

  As described above, according to the ENUM server 10 and the specific access determination method according to the present embodiment, when the ENUM server 10 receives the connection destination information inquiry message (request), is the request a specific access? If it is determined that the access is specific access, for example, a specific access countermeasure process such as sending a rejection response or generating a response delay is executed. Thereby, it is possible to suppress an increase in load in the network due to specific access, which is a concern when the number portability DB 100 is newly introduced in the IP network.

  Note that the present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention.

  The unique access determination unit 121 of the ENUM server 10 determines whether or not the received connection destination information inquiry message is specific access, for example, as follows, in addition to the above-described specific access determination methods “1” and “2”. Judgment can be made.

The ENUM server 10 stores the unique access monitoring information 130 in which the destination information and the telephone number of the inquiry request source are associated with each other as shown in FIG. When the ENUM server 10 receives the connection destination information inquiry message from the IP network 2000 of another communication carrier and refers to the number portability DB 100, the ENUM server 10 acquires the connection destination information to which the own IP network 1000 is the connection destination. Information indicating that the number portability DB 100 has been inquired of the HSS 30 of the local IP network 1000 to which a connection request is to be transferred from the IP network 2000 of another communication carrier (for example, the telephone number of the destination) Be notified. Based on the notification, the HSS 30 actually monitors whether there is a connection request from another carrier's IP network 2000 to the destination telephone number. Is not received, information indicating that is transmitted to the ENUM server 10. The ENUM server 10 uses the inquiry request source (telephone number) of the connection destination information inquiry message that has not been inquired to the HSS 30 of the local IP network 1000 even though the number portability DB 100 has been inquired as the source of unique access. As specified. When the ENUM server 10 receives the connection destination information inquiry message (request) from the specified transmission source after the specification, the ENUM server 10 determines that the request is a unique access.
In the above description, whether or not there is actually a connection request in the own IP network 1000 may be monitored by the SIP server 20 of the own IP network 1000 instead of the HSS 30.

  Further, the unique access countermeasure processing unit 122 of the ENUM server 10 can execute the following unique access countermeasure processing, for example, other than the above-described unique access countermeasure processing “1” and “2”.

  When a telephone number cleaning service provider or the like provides a service for determining whether a certain telephone number has been transferred (ported out) to another network, the specific access countermeasure processing unit 122 of the ENUM server 10 Incorrect information is returned at a predetermined rate (for example, information that is registered in the own network even though it is ported out to another network). This is based on the prediction that a user who has once ported out to another network, that is, a user who has changed the carrier, is likely to change again. This is a measure for unique access sent by a provider providing a service for extracting a telephone number that is being ported out. By including incorrect information, the service provider of the telephone number cleaning service loses the value of the information, so that it is possible to eliminate the incentive to send the specific access. As a result, the service provider sends the specific access. As a result, an increase in the load in the network due to the specific access can be suppressed.

1 Terminal 10 ENUM Server 11 Communication Unit 12 Control Unit 13 Storage Unit 20 SIP Server 30 HSS
100 number portability DB
121 Singular Access Determination Unit 122 Singular Access Countermeasure Processing Unit 123 Connection Destination Information Search Unit 124 Connection Destination Information Query Response Unit 130 Singular Access Monitoring Information 1000 IP Network (Own IP Network)
2000 Other carrier's IP network (other IP network)
S communication system

Claims (6)

An ENUM server that accepts a request for connection destination information indicating the connection destination corresponding to the telephone number of the destination terminal attached to the connection request transmitted by the transmission source terminal from the SIP server of the own IP network and the other IP network. And
A storage unit for storing a number portability DB for storing the connection destination information corresponding to the destination information including the telephone number of the destination terminal;
Each time the request is received, the destination information attached to the received request is stored in the storage unit as specific access monitoring information and indicated by the specific access monitoring information stored within a predetermined time. Each of the destination information is determined to determine whether or not the telephone number of the destination terminal has a predetermined regularity. If it is determined that the request is not the singular access, the singular access determination unit that outputs to the singular access countermeasure processing unit as being, and that the request is not the singular access,
The specific access countermeasure processing unit that receives the request that is the specific access and returns a rejection response as response information to the request;
The connection destination information search unit that receives the request that is not the specific access and acquires the connection destination information with reference to the number portability DB based on the destination information attached to the request;
A connection destination information inquiry response unit that generates inquiry response information including the acquired connection destination information and returns the inquiry response information to the transmission source of the request;
An ENUM server comprising: The specific access countermeasure processing unit
Instead of returning a rejection response as response information to the request that is said to be the unique access, the request that is assumed to be the unique access is output to the connection destination information search unit after causing a delay. ,
The connection destination information search unit
2. The connection destination information is acquired based on the destination information attached to the request by referring to the number portability DB based on the destination information attached to the request. The ENUM server described. The singular access determination unit
When the telephone number of the caller terminal is attached to the request, together with the callee information, the phone number of the caller terminal is included in the storage unit as the specific access monitoring information, and the callee Instead of determining whether or not the terminal telephone number has a predetermined regularity, the number of telephone numbers of the same source terminal stored as the specific access monitoring information within a predetermined time When the threshold value is exceeded, the request with the telephone number of the source terminal is output as specific access, and the same source stored in the specific access monitoring information is output to the specific access countermeasure processing unit. 2. The request is output to the connection destination information search unit as the request is not the unique access when the number of telephone numbers of the terminal is equal to or less than a predetermined threshold. Alternatively, the ENUM server according to claim 2. Specificity of an ENUM server that accepts a request for connection destination information indicating a connection destination corresponding to a telephone number of a destination terminal attached to a connection request transmitted by a transmission source terminal from the SIP server of the own IP network and another IP network An access determination method,
The ENUM server is
A storage unit for storing a number portability DB for storing the connection destination information corresponding to the destination information including the telephone number of the destination terminal;
Each time the request is received, the destination information attached to the received request is stored in the storage unit as specific access monitoring information and indicated by the specific access monitoring information stored within a predetermined time. Each of the destination information is determined to determine whether or not the telephone number of the destination terminal has a predetermined regularity. A specific access determination step that determines that the request is not the specific access when it is determined that the request does not have the predetermined regularity;
Specific response countermeasure step for returning a rejection response as response information to the request that is the specific access,
A connection destination information search step for obtaining the connection destination information with reference to the number portability DB based on the destination information attached to the request that is not the specific access;
An inquiry response step for generating inquiry response information including the acquired connection destination information and returning the inquiry response information to the transmission source of the request;
A singular access determination method comprising: In the specific access countermeasure step, instead of returning a rejection response as response information to the request that is said to be the specific access, a delay is generated for the request that is the specific access, and then the connection is made. The specific access determination method according to claim 4, wherein a destination information search step is executed. In the specific access determination step,
When the telephone number of the caller terminal is attached to the request, together with the callee information, the phone number of the caller terminal is included in the storage unit as the specific access monitoring information, and the callee Instead of determining whether or not the terminal telephone number has a predetermined regularity, the number of telephone numbers of the same source terminal stored as the specific access monitoring information within a predetermined time When the threshold is exceeded, the request with the telephone number of the source terminal is assumed to be unique access, and the number of the same source terminal telephone number stored as the specific access monitoring information is a predetermined number The specific access determination method according to claim 4, wherein the request is not the specific access when the value is equal to or less than a threshold value.

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