JP2012253575A - Number solution system, number solution method, and carrier enum server - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify a carrier at a destination and select POI connected to the carrier, with no extension of an ENUM protocol, in an environment in which both a mutual connection using ISUP and an IP mutual connection using SIP are present.SOLUTION: A carrier ENUM server 10, when receives an inquiry about URI from an SIP server 20 of an originating carrier, attaches NRN to SIP-URI to generate a response information in a case where an arrival carrier holds both IP-POI and STM-POI, and then transmits it to the SIP server 20. A POI selection part 213 of the SIP server 20 specifies an arrival carrier by a domain part of URI or NRN. Further, the POI selection part 213 determines that the arrival carrier holds both IP-POI and STM-POI based on a format of URI, and select any one of POI based on a contract information.

Description

  The present invention manages E.164 numbers (up to 15 digits of international public telecommunication numbers including country codes as defined in the ITU-T E.164 recommendation. For example, “+ 81-3-3333-4444”) The present invention relates to a number resolution system, a number resolution method, and a carrier ENUM (Telephone Number Mapping) server in interconnection of a plurality of carrier networks (networks of communication carriers). In particular, as a call control protocol used for interconnection between individual carrier networks, an interconnection form using ISUP (Integrated Services Digital Network User Part) conventionally used in PSTN (Public Switched Telephone Networks), and IP The present invention relates to a number resolution system, a number resolution method, and a carrier ENUM server in an environment where an interconnection form using SIP (Session Initiation Protocol) used in an (Internet Protocol) network coexists.

  The ENUM protocol used for communication with an ENUM server that associates a telephone number and URI (Uniform Resource Identifiers) by a device (such as a SIP server) in a carrier network uses a DNS (Domain Name System) protocol mechanism. The SIP server or the like makes an inquiry to the ENUM server in a format in which the E.164 number is domain-converted. The SIP server obtains the address and service information of the server to which the E.164 number as the destination is given by the response from the ENUM server, and is defined in IETF (Internet Engineering Task Force) RFC 3761. (See Non-Patent Document 1).

FIG. 9 is a sequence diagram showing a flow of processing of an inquiry from the SIP server to the ENUM server.
As shown in FIG. 9, first, the SIP server receives a SIP signal (INVITE) with a destination telephone number (for example, 0422-59-1111) attached from a VoIP (Voice over Internet Protocol) terminal (S1). .

  Then, the SIP server inquires of the ENUM server about the destination telephone number in the ENUM protocol domain format (S2). Specifically, the SIP server reverses the destination telephone number (0422-59-1111 E.164 number) included in the INVITE, separates them with dots, and adds e164.arpa to the ENUM server. Send.

The ENUM server searches for a resource record in which the destination number is associated with the URI, and notifies the SIP-URI corresponding to the destination telephone number (S3).
By doing so, the SIP server can acquire the SIP-URI corresponding to the destination telephone number from the ENUM server.

  The conventional ENUM that has been studied by the IETF as described above is accessible from the user terminal, and is called “user ENUM”. On the other hand, as an ENUM in a carrier network for the purpose of ensuring security, etc., it relates to an ENUM (hereinafter referred to as “carrier ENUM”) that cannot be accessed from a general user terminal and is used only for devices in the carrier network. The specification is defined by GSMA IR.67 (see Non-Patent Document 2).

“The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM),” IETF, RFC 3761, April 2004 “DNS / ENUM Guidelines for Service Providers & GRX / IPX Providers,” GSM Association IR.67, March 2010

  In recent years, carriers that have telephone networks that manage E.164 numbers have rapidly moved from conventional PSTN accommodation to IP telephone network accommodation as a form of user terminal accommodation. There are still many interconnections using ISUP, which is a call control protocol used in the conventional PSTN. However, in the future, for the purpose of reducing the operation cost of the carrier and expanding the service, it is easily assumed that the interconnection between the carrier telephone networks will also shift to the IP connection.

  In the transition period until all carriers in Japan are completely transferred to IP interconnection using SIP as a call control protocol, a complicated form in which interconnection using existing ISUP and IP interconnection using SIP is mixed It becomes. In this transition period, as a type of point of interface (POI), a carrier possessing only an existing point of connection using ISUP (hereinafter referred to as “STM (Synchronous Transfer Mode) -POI”), SIP Are classified into three types: carriers possessing only interconnection points (hereinafter referred to as “IP-POI”) and carriers possessing both.

  Therefore, even when connecting to the same telephone number (same carrier), a certain carrier is connected via IP-POI, but another carrier is connected via STM-POI. Different types occur. Therefore, it is necessary to have a mechanism for acquiring information for appropriately selecting the POI type by the originating carrier or designating the connection destination POI. In GSMA IR.67, which is a representative example of the carrier ENUM, No POI type notification or a mechanism for specifying a POI is defined.

  In Japan, E.164 numbers are assigned to carriers by number band units such as area codes from the Ministry of Internal Affairs and Communications, so it has been easy to identify the destination carrier by number band. . However, due to the introduction of number portability that changes the carrier without changing the telephone number, it may not be possible to simply identify the destination carrier from the number band. Therefore, a mechanism for efficiently specifying the destination carrier from the telephone number is required.

  The present invention has been made in view of such a background. In the present invention, in the environment where the interconnection using the ISUP and the IP interconnection using the SIP are mixed, the destination is called without extending the ENUM protocol. It is an object of the present invention to provide a number resolution system, a number resolution method, and a carrier ENUM server that can identify a carrier and select a POI connected to the carrier.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the originating carrier and the terminating carrier for transmitting / receiving a call control signal comprise an IP network and a PSTN, and the SIP server of the originating carrier in the IP network A number resolution system comprising a carrier ENUM (Telephone Number Mapping) server that retrieves the URI of the called carrier corresponding to the destination telephone number in response to a request from the SIP server and transmits it as response information to the SIP server, The carrier ENUM server stores a resource record for storing a URI of the called carrier corresponding to the destination telephone number included in the call control signal, and the destination telephone number from the SIP server. The attached request is received, the resource record is searched, and the destination carrier is set to IP-POI and STM. Synchronous Transfer Mode) When generating both of the POI and interconnecting with the originating carrier, a SIP-URI format URI including an NRN (Network Routing Number) for identifying the incoming carrier is generated, A URI notification unit that transmits the response information to the SIP server, and the SIP server can connect the originating carrier and the incoming carrier with both the IP-POI and the STM-POI. A request is made to the carrier ENUM server for the URI of the called carrier, with the storage unit storing contract information indicating which POI is used and the destination telephone number included in the call control signal. Based on the response information from the URI request unit and the carrier ENUM server, a URI in SIP-URI format including the NRN is acquired, and the U The incoming carrier is identified from the domain part of the RI or the NRN, and the format of the URI is a SIP-URI format including the NRN, so that the incoming carrier is the IP-POI and the STM-POI. A number resolution system characterized by comprising a POI selection unit that determines that both are owned and selects either the IP-POI or the STM-POI with reference to the contract information.

  According to a fourth aspect of the present invention, the originating carrier and the terminating carrier for transmitting / receiving a call control signal include an IP network and a PSTN, the SIP server in the IP network of the originating carrier, and the SIP server A number resolution method of a number resolution system comprising: a carrier ENUM server that retrieves a URI of the called carrier corresponding to a destination telephone number according to a request and transmits it as response information to the SIP server, wherein the SIP server A step of requesting the carrier ENUM server for the URI of the called carrier by attaching the destination telephone number included in the control signal is executed, and the carrier ENUM server includes the destination telephone included in the call control signal. A storage unit storing a resource record for storing the URI of the called carrier corresponding to the number; Accepts a request with the destination telephone number from the SIP server, retrieves the resource record, and the called carrier has both IP-POI and STM-POI and interconnects with the originating carrier A SIP-URI-format URI including an NRN for identifying the called carrier is generated and transmitted to the SIP server as the response information, and the SIP server executes the calling carrier and the called carrier. When the carrier can be connected by both the IP-POI and the STM-POI, the carrier ENUM server includes a storage unit that stores contract information indicating which POI is used. A URI in SIP-URI format including the NRN is obtained from the response information from When the received carrier has both the IP-POI and the STM-POI by specifying the received carrier from the NRN and the URI format is a SIP-URI format including the NRN. And determining and selecting either the IP-POI or the STM-POI with reference to the contract information.

As described above, the URI notification unit of the carrier ENUM server transmits the URI in the SIP-URI format including the NRN to the SIP server as response information when the incoming carrier has both the IP-POI and the STM-POI. Then, the SIP server specifies the incoming carrier from the domain part of the URI of the SIP-URI format including the NRN or the NRN, and when the URI format is the SIP-URI including the NRN, the incoming carrier becomes the IP-POI. And STM-POI are determined to be possessed, and one of the POIs is selected with reference to the contract information.
Therefore, the SIP server can identify the incoming carrier of the received call control signal based on the URI attached to the response information from the carrier ENUM server, and can select the POI type of the POI possessed by the incoming carrier.

  According to the second aspect of the present invention, when the URI notification unit of the carrier ENUM server searches for the resource record and the destination carrier has only the IP-POI and interconnects with the originating carrier, A SIP-URI format URI that does not include the NRN is generated and transmitted to the SIP server as the response information, and the POI selection unit of the SIP server includes the NRN according to the response information from the carrier ENUM server. A URI of a non-SIP-URI format is identified, the received carrier is identified from the domain portion of the URI, and the URI format is a SIP-URI format not including the NRN, so that the received carrier is The number resolution system according to claim 1, wherein it is determined that only the IP-POI is owned.

  Further, in the invention according to claim 5, when the carrier ENUM server searches for the resource record and the called carrier has only the IP-POI and interconnects with the originating carrier, the NRN A SIP-URI-format URI that does not include the SIP server, and transmits the response information to the SIP server as the response information. The SIP server uses the response information from the carrier ENUM server to include the SIP that does not include the NRN. Obtaining a URI in URI format, identifying the received carrier from the domain part of the URI, and the URI format being a SIP-URI format not including the NRN, whereby The step of determining that only the IP-POI is owned is performed. It was the number Resolution.

In this way, the URI notification unit of the carrier ENUM server transmits a URI in SIP-URI format not including the NRN to the SIP server as response information when the incoming carrier has only the IP-POI. Then, the SIP server identifies the incoming carrier from the domain part of the URI of the SIP-URI format that does not include the NRN, and the URI type is the SIP-URI that does not include the NRN, so that the incoming carrier is the IP-POI. It is determined that only possession.
Therefore, the SIP server can identify the incoming carrier of the received call control signal based on the URI attached to the response information from the carrier ENUM server, and can select the POI type of the incoming carrier as IP-POI.

  In the invention according to claim 3, when the URI notification unit of the carrier ENUM server searches for the resource record, and the called carrier has only the STM-POI and interconnects with the originating carrier, A TEL-URI format URI including the NRN is generated and transmitted to the SIP server as the response information, and the POI selection unit of the SIP server includes the NRN according to the response information from the carrier ENUM server. -Obtaining a URI in URI format, specifying the received carrier from the NRN, and determining that the received carrier possesses only the STM-POI when the URI format is the TEL-URI format The number resolution system according to claim 2 is provided.

  Further, the invention according to claim 6, wherein the carrier ENUM server searches for the resource record, and when the called carrier has only the STM-POI and interconnects with the originating carrier, the NRN The TEL-URI format including the NRN is generated and transmitted to the SIP server as the response information, and the SIP server includes the TEL-URI including the NRN according to the response information from the carrier ENUM server. Obtaining a URI of the format, identifying the received carrier from the NRN, and determining that the received carrier possesses only the STM-POI by the URI format being the TEL-URI format 6. The number resolution method according to claim 5, wherein the step is executed.

As described above, the URI notification unit of the carrier ENUM server transmits a TEL-URI-format URI including NRN to the SIP server as response information when the incoming carrier has only the STM-POI. Then, the SIP server specifies the incoming carrier from the NRN of the URI in the TEL-URI format including the NRN, and determines that the incoming carrier has only the STM-POI because the URI format is the TEL-URI. .
Therefore, the SIP server can identify the incoming carrier of the received call control signal based on the URI attached to the response information from the carrier ENUM server, and can select the POI type of the incoming carrier as STM-POI.

  According to a seventh aspect of the present invention, an outgoing carrier and an incoming carrier that transmit and receive a call control signal include an IP network and a PSTN, and are connected to a SIP server in the IP network of the outgoing carrier, and from the SIP server A carrier ENUM server that searches the URI of the called carrier corresponding to the destination telephone number in response to the request and transmits it as response information to the SIP server, wherein the destination telephone number corresponding to the destination telephone number included in the call control signal A resource record that stores the URI of a carrier, and a contract that indicates which POI to use when the originating carrier and the destination carrier can be connected by both the IP-POI and the STM-POI A storage unit storing information, a URI notification unit for transmitting the response information to the SIP server, and the POI of the incoming carrier A POI selection unit for selecting, wherein the URI notification unit accepts a request with the destination telephone number from the SIP server, searches for the resource record, and the called carrier has an IP-POI and an STM- When both the POI and the originating carrier are interconnected, a SIP-URI format URI including an NRN for identifying the destination carrier is generated, and a SIP-URI format URI including the generated NRN is generated. The URI is output to the POI selection unit, the request with the destination telephone number is received from the SIP server, the resource record is searched, and the called carrier has only the IP-POI and the calling carrier A SIP-URI-format URI that does not include the NRN, and the SIP server as the response information Transmitting, accepting a request with the destination telephone number from the SIP server, searching the resource record, and when the called carrier interconnects with the originating carrier only having the STM-POI The TEL-URI format URI including the NRN is generated and transmitted as the response information to the SIP server, and the POI selection unit obtains the SIP-URI format URI including the NRN from the URI notification unit. When the URI format is a SIP-URI format including the NRN, it is determined that the incoming carrier has both the IP-POI and the STM-POI, and the IP-POI or the A STM-POI is selected with reference to the contract information, and a URI in SIP-URI format not including the NRN, Other generates the URI of TEL-URI format that includes the NRN, and a carrier ENUM server and transmits to the SIP server as the response information.

Thus, the URI notification unit of the carrier ENUM server outputs the URI in SIP-URI format including NRN to the POI selection unit when the incoming carrier has both IP-POI and STM-POI, and selects POI. Determines that the incoming carrier possesses both IP-POI and STM-POI, and selects one of the POIs by referring to the contract information, as the URI format is SIP-URI including NRN. Then, a URI in the SIP-URI format not including the NRN or a URI in the TEL-URI format including the NRN can be generated and transmitted as response information to the SIP server.
Further, the URI notification unit can transmit a URI in SIP-URI format not including the NRN as response information to the SIP server when the incoming carrier has only the IP-POI.
Furthermore, the URI notification unit can transmit a TEL-URI-format URI including NRN as response information to the SIP server when the incoming carrier has only the STM-POI.
Therefore, the carrier ENUM server can cause the SIP server to identify the incoming carrier of the received call control signal based on the URI attached to the response information, and select the POI type of the POI held by the incoming carrier.

  According to the present invention, in an environment where an interconnection using ISUP and an IP interconnection using SIP are mixed, the destination carrier is specified without expanding the ENUM protocol, and the POI connected to the carrier is specified. A number resolution system, a number resolution method, and a carrier ENUM server can be provided for selection.

It is a figure for demonstrating the form of the interconnection between the carrier networks premised on the number resolution system which concerns on this embodiment. It is a figure for demonstrating the URI format with which the carrier ENUM server which concerns on this embodiment responds. It is a block diagram which illustrates the composition of the number resolution system concerning this embodiment. It is a flowchart which shows the flow of the POI selection process which the POI selection part which concerns on this embodiment performs. It is a figure for demonstrating the number resolution process in the 1st form (interconnection in both IP-POI and STM-POI) of the interconnection between the carriers which concerns on this embodiment. It is a figure for demonstrating the number resolution process in the 1st form (interconnection in both IP-POI and STM-POI) of the interconnection between the carriers which concerns on this embodiment. It is a figure for demonstrating the number resolution process in the 2nd form (interconnection only by IP-POI) of the interconnection between the carriers which concerns on this embodiment. It is a figure for demonstrating the number resolution process in the 3rd form (interconnection only by STM-POI) of the interconnection between the carriers which concerns on this embodiment. It is a sequence diagram which shows the flow of a process of the inquiry from a SIP server to an ENUM server in a prior art.

  Next, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.

(Interconnection form between carrier networks)
First, three forms of interconnection between carrier networks, which are preconditions in this embodiment, will be described with reference to FIG.

  FIG. 1A shows a form in which carrier networks are interconnected by both IP-POI and STM-POI (hereinafter referred to as “first form”). Carrier A and carrier B have IP-POI and STM-POI, and based on discussion between carriers, one of the POIs used for communication is determined and interconnected.

  FIG. 1B shows a form in which carrier networks are interconnected only by IP-POI (hereinafter referred to as “second form”). The carrier C has at least an IP-POI and is interconnected only by the IP-POI based on the discussion between the carriers.

  FIG. 1C shows a form in which carrier networks are interconnected only by STM-POI (hereinafter referred to as “third form”). Carrier D has at least STM-POI and is interconnected only with STM-POI based on discussions between carriers.

(Carrier ENUM server response format)
For example, as shown in FIG. 1A, the flow of processing of the number resolution system 1 according to the present embodiment is that a VoIP terminal becomes a caller and sends a SIP signal (call control signal) to a SIP server in the carrier A (FIG. 1). (Not shown). Then, in the same manner as the inquiry processing flow from the SIP server to the ENUM server shown in FIG. 9, the URI inquiry is performed from the SIP server in the carrier A to the carrier ENUM server based on the destination number.
In the present invention, in the response to the inquiry from the SIP server by the carrier ENUM server, a predetermined rule is set in the URI format that is the response, and the SIP server of the carrier network that has received the response determines the destination address from the URI format. Information on IP-POI and STM-POI, which are types of POI held by the carrier network, is acquired, and the POI can be selected.
A response format for notifying the URI to the SIP server of the calling carrier network, which is performed by the carrier ENUM server, will be described below.

  Due to the specifications of the ENUM protocol, the ENUM server can respond in either TEL-URI or SIP-URI format when it receives an E.164 number query. The URI format to which the carrier ENUM server according to this embodiment responds will be described with reference to FIG.

  The carrier ENUM server according to the present embodiment responds in a URI format based on the following rules.

(Rule A) When a carrier (destination carrier) that accommodates a destination E.164 number has an IP-POI In the case of a carrier that has an IP-POI as a URI format indicating the destination information, the SIP-URI It responds in a form (for example, in the case of a carrier having only IP-POI, refer to “without IP-POI” and “without STM-POI” in FIG. 2). In the case of a carrier that does not have an IP-POI, it responds in a TEL-URI format without a domain part.
(Rule B) When a carrier (destination carrier) that accommodates a destination E.164 number has an STM-POI If a carrier that has an STM-POI is used as a URI method indicating the destination information, NRN (Network Routing Number) is assigned using the npdi and rn parameters specified in IETF RFC 4694. Note that NRN means a routing number (E.164 format) that can identify an incoming carrier and an STM-POI held by the incoming carrier.
According to rule A, when an IP-POI is held, it becomes a SIP-URI. When the IP-POI is held and the carrier having the STM-POI is held, an NRN is assigned to the userinfo part of the SIP-URI (“IP-POI is present” in FIG. 2 and “STM-POI is present”). "reference). In addition, if the SIP-POI is not held but only the STM-POI is held, an NRN is given to the TEL-URI (see “Without IP-POI” in FIG. 2 and “With STM-POI”).

  In this way, the carrier ENUM server has three cases where the destination carrier has both IP-POI and STM-POI, only IP-POI, and only STM-POI. Can be set to the format shown in FIG. 2 to respond to the SIP server. The SIP server can obtain information on the POI format held by the incoming carrier by determining which of the three types the incoming carrier corresponds to from the received URI format.

(Configuration of each device of the number resolution system)
Next, each device constituting the number resolution system 1 according to the present embodiment will be described in detail with reference to FIG.

<Carrier ENUM server>
The carrier ENUM server 10 receives an inquiry from the SIP server 20 and transmits a URI corresponding to the destination telephone number to the SIP server 20 as response information. The carrier ENUM server 10 can be accessed from a device (such as the SIP server 20) in the IP network of each carrier in any of the interconnection forms between the carrier networks shown in FIG. Unlike a server, access from an VoIP terminal or an analog terminal to which an E.164 number is assigned is impossible for ensuring security. In the present embodiment, the carrier ENUM server 10 is described as being deployed as a server shared by a plurality of carriers, but may be deployed in each carrier network.

  As shown in FIG. 3, the carrier ENUM server 10 includes a control unit 11, an input / output unit 12, a memory unit 13, and a storage unit 14.

  The input / output unit 12 inputs / outputs information to / from other devices. For example, the input / output unit 12 receives a URI inquiry corresponding to the destination telephone number from the SIP server 20 in the carrier network, and transmits URI information as a response to the SIP server 20 as response information. . The input / output unit 12 includes a communication interface that transmits and receives information via a communication line, and an input / output interface that performs input / output between an input device such as a keyboard (not shown) and an output device such as a monitor. Is done.

  The control unit 11 controls the carrier ENUM server 10 as a whole, and includes an information reception unit 111, a URI notification unit 112, and an information transmission unit 113. The control unit 11 is realized by, for example, a program stored in the storage unit 14 of the carrier ENUM server 10 being expanded and executed by a CPU (Central Processing Unit) on a RAM (Random Access Memory) that is the memory unit 13. Is done.

  The information receiving unit 111 acquires a URI inquiry corresponding to the destination telephone number from the SIP server or the like in the carrier network via the input / output unit 12 and passes it to the URI notification unit 112.

The URI notification unit 112 searches the resource record 100 in the storage unit 14 based on the acquired destination telephone number, and acquires the URI corresponding to the destination telephone number.
In this resource record 100, the URI corresponding to the destination telephone number is stored in the SIP-URI format when the incoming carrier has only the IP-POI, and when the incoming carrier has only the STM-POI. Is stored in the TEL-URI format. Further, when the incoming carrier has both IP-POI and STM-POI, it is stored in the SIP-URI format including the NRN.

When the URI notification unit 112 searches the resource record 100 based on the acquired destination telephone number, the URI notification unit 112 responds to the SIP server 20 in the URI format shown in FIG. 2 based on the (Rule A) and (Rule B) described above. Send information.
Specifically, the URI notification unit 112 searches the resource record 100, and if the incoming carrier is a carrier having IP-POI and STM-POI, the response is made in SIP-URI format based on (Rule A). Further, based on (Rule B), the NRN is added to the userinfo part of the SIP-URI (see “With IP-POI” and “STM-POI” in FIG. 2), and responds to the SIP server 20 To do.
The URI notification unit 112 searches the resource record 100, and when the incoming carrier is only the IP-POI, it responds to the SIP server 20 in the SIP-URI format based on (Rule A) ("IP-POI" in FIG. 2). “Yes” and “No STM-POI”).
Further, the URI notification unit 112 searches the resource record 100, and when the incoming carrier is only the STM-POI, based on (Rule B), the NRN is given using the npdi and rn parameters in the TEL-URI format. In response to the SIP server 20 (see “Without IP-POI” and “With STM-POI” in FIG. 2).

  The information transmission unit 113 transmits the response information of the URI generated by the URI notification unit 112 to the SIP server 20 via the input / output unit 12.

  Next, the storage unit 14 includes a storage device such as a hard disk or a flash memory, and stores a resource record 100 in which an incoming telephone number is associated with a URI.

  The memory unit 13 includes a primary storage device such as a RAM, and temporarily stores information necessary for data processing by the control unit 11.

<SIP server>
Next, the SIP server 20 in the originating carrier network according to the present embodiment will be described with reference to FIG. The SIP server 20 receives a SIP signal (INVITE) obtained by converting a SIP signal (INVITE) from a VoIP terminal or a connection request signal from an analog terminal via a PSTN network by a gateway device (not shown), The carrier ENUM server 10 is inquired about the URI corresponding to the destination telephone number attached to the SIP signal (call control signal). Then, the SIP server 20 receives the URI as response information from the carrier ENUM server 10, determines the incoming carrier and the POI type held by the incoming carrier, and performs a process of transferring the SIP signal.

  As illustrated in FIG. 3, the SIP server 20 includes a control unit 21, an input / output unit 22, a memory unit 23, and a storage unit 24.

  The input / output unit 22 inputs / outputs information to / from the VoIP terminal, other devices in the carrier network, the carrier ENUM server 10 and the like. For example, the input / output unit 22 receives a SIP signal (call control signal) from the VoIP terminal, transmits URI inquiry information to the carrier ENUM server 10, and receives response information as a response. The input / output unit 22 includes a communication interface that transmits and receives information via a communication line, and an input / output interface that performs input / output between an input device such as a keyboard (not shown) and an output device such as a monitor. Is done.

  The control unit 21 controls the entire SIP server 20 and includes an information reception unit 211, a URI request unit 212, a POI selection unit 213, a transfer processing unit 214, and an information transmission unit 215. The control unit 21 is realized, for example, when the CPU stores the program stored in the storage unit 24 of the SIP server 20 in the RAM serving as the memory unit 23 and executes the program.

  The information reception unit 211 receives a SIP signal from a VoIP terminal or the like via the input / output unit 22 and passes it to the URI request unit 212. In addition, when receiving the response information with the URI from the carrier ENUM server 10, the information receiving unit 211 delivers it to the POI selection unit 213.

  When receiving the SIP signal (INVITE) from the VoIP terminal or the like, the URI request unit 212 uses the destination telephone number attached to the SIP signal to send the corresponding URI to the carrier ENUM server 10 via the information transmission unit 215. Inquire. The destination telephone number is inquired using, for example, the destination telephone number set in the Request-URI of the SIP signal.

  The POI selection unit 213 acquires response information from the carrier ENUM server 10 via the information reception unit 211, identifies the incoming carrier from the URI attached to the received response information, and also forms the URI of the response information To determine the POI type of the incoming carrier.

  The determination of the POI type by the POI selection unit 213 is performed based on the URI format shown in FIG. When the acquired URI is in the TEL-URI format, the POI selection unit 213 selects the POI type of the incoming carrier as STM-POI. Further, when the acquired URI is in the SIP-URI format, the POI selection unit 213 determines whether or not the NRN is attached. If the NRN is not attached, the POI selection unit 213 sets the POI type of the incoming carrier to the IP-POI. Select. On the other hand, if the SIP-URI format and NRN are attached, it is determined that the POI type of the incoming carrier is both IP-POI and STM-POI. Details will be described later (see FIG. 4).

Further, when the POI selection unit 213 determines that the POI type of the incoming carrier is both IP-POI and STM-POI, the POI selection unit 213 refers to the contract information table (contract information) 200 in the storage unit 24 to make the arrival / departure. Either POI is selected according to the contract between the carriers.
Note that the contract information table 200 stores contents determined in advance based on which POI is used for interconnection when the destination carrier has both IP-POI and STM-POI. .

  The transfer processing unit 214 transmits the SIP signal to the destination carrier via the POI of the destination carrier selected by the POI selection unit 213 based on the URI from the carrier ENUM server 10.

  The information transmitting unit 215 transmits URI inquiry information from the URI requesting unit 212 to the carrier ENUM server 10 via the input / output unit 22. In addition, the information transmission unit 215 transmits the SIP signal to the destination carrier via the POI selected by the POI selection unit 213 by the processing of the transfer processing unit 214.

  Next, the storage unit 24 includes a storage device such as a hard disk or a flash memory, and stores a contract information table (contract information) 200 and the like.

  The memory unit 23 includes a primary storage device such as a RAM, and temporarily stores information necessary for data processing by the control unit 21.

  In the number resolution system 1 according to the present embodiment illustrated in FIG. 3, the configuration has been described in which the SIP server 20 in the calling carrier network includes the POI selection unit 213 and the contract information table 200. However, the present invention is not limited to this configuration, and the carrier ENUM server 10 may include the POI selection unit 213 and the contract information table 200 as described later with reference to FIG. In that case, the transfer processing unit 214 of the SIP server 20 receives either the SIP-URI format URI without the NRN or the TEL-URI format URI from the carrier ENUM server 10 and receives the URI. The SIP signal is transferred via the indicated carrier POI.

(Number resolution system operation)
Next, the number resolution process performed by the number resolution system 1 according to the present embodiment will be described in detail. First, POI selection processing performed by the POI selection unit 213 according to the present embodiment will be described, and then the overall processing flow will be described for each of the three forms of interconnection between the carrier networks shown in FIG.

<POI selection process>
FIG. 4 is a flowchart showing a flow of POI selection processing performed by the POI selection unit 213 according to the present embodiment (see FIG. 2 as appropriate). Here, as shown in FIG. 3, it is assumed that the POI selection unit 213 is provided in the control unit 21 of the SIP server 20, and the contract information table 200 is also stored in the storage unit 24 in the SIP server 20. explain.

  First, the POI selection unit 213 of the SIP server 20 acquires the response information with the URI from the carrier ENUM server 10 via the information reception unit 211 (step S101).

  Next, the POI selection unit 213 determines whether or not the acquired URI is in the SIP-URI format (step S102). Here, if the acquired URI is not in the SIP-URI format, that is, if it is determined to be in the TEL-URI format (step S102 → No), the POI selection unit 213 determines that the incoming carrier has only the STM-POI. Then, STM-POI is selected (step S103).

  On the other hand, when it is determined that the acquired URI is in the SIP-URI format (step S102 → Yes), the POI selection unit 213 next determines whether or not the npdi, rn parameter is included (step S104). .

  When the POI selection unit 213 determines that the npdi and rn parameters are not included (step S104 → No), the POI selection unit 213 determines that the destination carrier has only the IP-POI, and selects the IP-POI (step S105). .

  On the other hand, when the POI selection unit 213 determines that the npdi and rn parameters are included (step S104 → Yes), the POI selection unit 213 determines that the incoming carrier possesses both the IP-POI and the STM-POI (step S106). Then, the POI selection unit 213 refers to the contract information table 200 in the storage unit 24, and when the IP-POI is set by the contract with the destination carrier (step S107 → Yes), IP-POI is selected for connection (step S108). On the other hand, when the IP-POI is not set by the contract with the called carrier, that is, when the STM-POI is set (step S107 → No), the POI selecting unit 213 connects to the called carrier. STM-POI is selected for (Step S109).

  When the acquired URI is in the TEL-URL format, the POI selection unit 213 obtains information on the routing number that can identify the incoming carrier and the STM-POI held by the incoming carrier from the NRN (for example, +81111112222). get. In addition, when the acquired URI is in the SIP-URI format, the POI selection unit 213 specifies the incoming carrier based on the domain part (character string after @) of the SIP-URI or the NRN.

  In this way, the POI selection unit 213 selects the incoming carrier and the POI held by the incoming carrier based on the URI attached to the response information acquired from the carrier ENUM server 10, and transmits the SIP signal. be able to.

(Processing of number resolution system in each form)
Next, number resolution processing in the interconnection between the carriers in the first to third modes shown in FIG. 1 will be described with reference to FIGS. 5 and 6 are diagrams for explaining number resolution processing in the first mode (interconnection between both IP-POI and STM-POI). FIG. 7 is a diagram for explaining number resolution processing in the second mode (interconnect only with IP-POI). FIG. 8 is a diagram for explaining number resolution processing in the third mode (interconnect only with STM-POI).

<Number Resolution Processing in First Form>
First, with reference to FIGS. 5 and 6, the number resolution processing in the first embodiment will be described. The difference between FIG. 5 and FIG. 6 is that, in FIG. 5, the POI selection unit 213 and the contract information table 200 are provided in the SIP server 20 in the IP network of the originating carrier, and in FIG. 6, the POI selection unit 213 and the contract information table 200 are The carrier ENUM server 10 is provided.

  First, referring to FIG. 5, when the SIP server 20 includes the POI selection unit 213 and the contract information table 200, between the carriers of the first form (interconnection between both IP-POI and STM-POI) The number resolution process in the interconnection will be described.

  First, when the SIP server 20 of the calling carrier network (carrier A) receives the SIP signal (INVITE) from the VoIP terminal 5, the URI request unit 212 of the SIP server 20 is set in the Request-URI of the SIP signal. The carrier ENUM server 10 is inquired of the destination telephone number in the domain format of the ENUM protocol (step S10). For example, “.e164enum.net” defined by the carrier ENUM of GSMA IR.67 of Non-Patent Document 2 is used as the domain used here.

Next, the carrier ENUM server 10 (URI notification unit 112) searches the resource record 100 for the destination telephone number for which an inquiry has been made. Then, based on the search result, the URI notification unit 112 transmits the URI to the SIP server 20 as response information in the SIP-URI format or TEL-URI format according to (Rule A) and (Rule B) described above. (Step S11).
Here, since the carrier B, which is the incoming carrier, holds both IP-POI and STM-POI as the search result, the URI notification unit 112 uses “sip: +81111111111; npdi; rn = + 81111112222” as the URI. “@carrier_B” is transmitted as response information.

  The POI selection unit 213 of the SIP server 20 acquires the response information from the carrier ENUM server 10, and if the URI format is the SIP-URI format or the TEL-URI format, and the SIP-URI format, the NRN It is determined whether or not (npdi, rn parameter) is included (see POI selection processing in FIG. 4).

  Then, since the URI acquired as the response information is in the SIP-URI format and includes the NRN (npdi, rn parameter) (because of the NRN), the POI selection unit 213 determines that the carrier B as the incoming carrier is IP- It is determined that both POI and STM-POI are held (step S12). The POI selection unit 213 identifies the received carrier as the carrier B from the acquired URI domain part (carrier_B) or the value (+81111112222) of the NRN (npdi, rn parameter).

  Subsequently, the POI selection unit 213 refers to the contract information table 200 in the storage unit 24 and selects to connect using the IP-POI according to the contract between the carrier A and the carrier B (step S13). .

  Next, the transfer processing unit 214 of the SIP server 20 transmits a SIP signal to the destination carrier (carrier B) via the IP-POI that is the POI selected by the POI selection unit 213.

  By doing in this way, the SIP server 20 selects the arrival carrier of the received SIP signal and its POI type based on the URI attached to the response information from the carrier ENUM server 10, and transmits the SIP signal. Can do.

  Next, referring to FIG. 6, the carrier in the first form (interconnection between both IP-POI and STM-POI) in the case where the carrier ENUM server 10 includes the POI selection unit 213 and the contract information table 200 The number resolution process in the interconnection between the two will be described.

  First, when the SIP server 20 of the calling carrier network (carrier A) receives the SIP signal (INVITE) from the VoIP terminal 5, the URI request unit 212 of the SIP server 20 is set in the Request-URI of the SIP signal. The carrier ENUM server 10 is inquired of the destination telephone number in the ENUM protocol domain format (“.e164enum.net”, etc.) (step S20).

  Next, the URI notification unit 112 of the carrier ENUM server 10 searches the resource record 100 for the destination telephone number for which an inquiry has been made (step S21). Then, the URI notification unit 112 converts the URI into the SIP-URI format or the TEL-URI format according to (Rule A) and (Rule B). Here, since the carrier B, which is the incoming carrier, holds both IP-POI and STM-POI as the search result, the URI notification unit 112 uses “sip: +81111111111; npdi; rn = + 81111112222” as the URI. @carrier_B ”is generated and delivered to the POI selection unit 213.

  The POI selection unit 213 determines whether the acquired URI format is SIP-URI format or TEL-URI format, and includes NRN (npdi, rn parameter) in the case of SIP-URI format. (Refer to the POI selection process in FIG. 4).

  Then, since the acquired URI is in the SIP-URI format and there is an NRN (npdi, rn parameter), the POI selection unit 213 has both the IP-POI and the STM-POI as the carrier B. It is determined that it is in progress (step S22).

  Subsequently, the POI selection unit 213 refers to the contract information table 200 in the storage unit 14 and selects connection using the IP-POI according to the contract between the carrier A and the carrier B (step S23). . Then, the URI notification unit 112 changes the URI to “sip: 81111111111 @ carrier_B” based on the POI selection result of the POI selection unit 213 and transmits the response information to the SIP server 20.

  Next, the transfer processing unit 214 of the SIP server 20 acquires the URI included in the response information, and transmits a SIP signal to the destination carrier (carrier B) via the IP-POI based on the URI.

  In this way, even when the POI selection unit 213 and the contract information table 200 are held on the carrier ENUM server 10 side, the SIP server 20 acquires the received carrier of the received SIP signal and its POI type, and A signal can be transmitted.

<Number Resolution Processing in Second Mode>
Next, with reference to FIG. 7, the number resolution processing in the second mode (interconnect only with IP-POI) shown in FIG. 1 will be described. The POI selection unit 213 and the contract information table 200 are provided in the SIP server 20.

  First, when the SIP server 20 of the calling carrier network (carrier A) receives the SIP signal (INVITE) from the VoIP terminal 5, the URI request unit 212 of the SIP server 20 is set in the Request-URI of the SIP signal. The carrier ENUM server 10 is inquired of the destination telephone number in the ENUM protocol domain format (“.e164enum.net”, etc.) (step S30).

Next, the carrier ENUM server 10 (URI notification unit 112) searches the resource record 100 for the destination telephone number for which an inquiry has been made. Then, based on the search result, the URI notification unit 112 transmits the URI to the SIP server 20 as response information in the SIP-URI format or TEL-URI format according to (Rule A) and (Rule B) described above. (Step S31).
Here, it is assumed that the URI notification unit 112 transmits “sip: + 81111111111 @ carrier_C” as response information as the URI because carrier C, which is the incoming carrier, has only IP-POI as a search result. .

  The POI selection unit 213 of the SIP server 20 acquires the response information from the carrier ENUM server 10, and if the URI format is the SIP-URI format or the TEL-URI format, and the SIP-URI format, the NRN It is determined whether or not (npdi, rn parameter) is included (see POI selection processing in FIG. 4).

  Then, since the URI acquired as the response information is in the SIP-URI format and there is no NRN (npdi, rn parameter), the POI selection unit 213 has only the IP-POI as the carrier C as the incoming carrier. (Step S32). The POI selection unit 213 identifies the received carrier as the carrier C from the domain portion (carrier_C) of the acquired URI.

  Subsequently, the transfer processing unit 214 of the SIP server 20 transmits a SIP signal to the destination carrier (carrier C) via the IP-POI that is the POI selected by the POI selection unit 213.

  In this way, the SIP server 20 acquires the received carrier (carrier C) of the received SIP signal and its POI type (IP-POI) based on the URI attached to the response information from the carrier ENUM server 10. Thus, the SIP signal can be transmitted.

<Number Resolution Processing in Third Mode>
Next, with reference to FIG. 8, the number resolution processing in the third mode (interconnect only with STM-POI) shown in FIG. 1 will be described.

  First, when the SIP server 20 of the calling carrier network (carrier A) receives the SIP signal (INVITE) from the VoIP terminal 5, the URI request unit 212 of the SIP server 20 is set in the Request-URI of the SIP signal. The carrier ENUM server 10 is inquired about the destination telephone number in the ENUM protocol domain format (".e164enum.net", etc.) (step S40).

Next, the carrier ENUM server 10 (URI notification unit 112) searches the resource record 100 for the destination telephone number for which an inquiry has been made. Then, based on the search result, the URI notification unit 112 transmits the URI to the SIP server 20 as response information in the SIP-URI format or TEL-URI format according to (Rule A) and (Rule B) described above. (Step S41).
Here, since the carrier D, which is the incoming carrier, has only the STM-POI as the search result, the URI notification unit 112 uses “tel: +81333333333; npdi; rn = + 81333331111” as response information as the URI. Suppose that it was sent.

  The POI selection unit 213 of the SIP server 20 acquires the response information from the carrier ENUM server 10, and if the URI format is the SIP-URI format or the TEL-URI format, and the SIP-URI format, the NRN It is determined whether or not (npdi, rn parameter) is included (see POI selection processing in FIG. 4).

  Then, the POI selection unit 213 identifies the carrier D from the value “+81333331111” of the NRN (npdi, rn parameter), and the URI acquired as the response information is in the TEL-URI format, and the carrier D is the STM-POI. It is determined that only the possession is held (step S42).

  Subsequently, the transfer processing unit 214 of the SIP server 20 transmits a SIP signal to the destination carrier (carrier D) via the STM-POI that is the POI selected by the POI selection unit 213.

  In this way, the SIP server 20 acquires the received carrier (carrier D) of the received SIP signal and its POI type (STM-POI) based on the URI attached to the response information from the carrier ENUM server 10. Thus, the SIP signal can be transmitted through the PSTN network.

As described above, according to the number resolution system 1, the number resolution method, and the carrier ENUM server 10 according to the present embodiment, in an environment where the interconnection using the existing ISUP and the IP interconnection by the SIP are mixed, The carrier ENUM server 10 can be used to simultaneously notify the originating carrier network of the POI type information related to the destination carrier and the carrier information, and to route the SIP signal.
In addition, by providing a rule for the URI in the response from the carrier ENUM server 10 and providing a POI selection unit 213 that selects a POI type based on the rule, the ENUM protocol can be extended even in the transitional period of IP interconnection. Without the operation, the carrier ENUM server 10 is operated, and a smooth transition to the IP connection becomes possible.

1 Number Resolution System 5 VoIP Terminal 10 Carrier ENUM Server 11, 21 Control Unit 12, 22 Input / Output Unit 13, 23 Memory Unit 14, 24 Storage Unit 20 SIP Server 100 Resource Record 111, 211 Information Reception Unit 112 URI Notification Unit 113, 215 Information transmission unit 200 Contract information table (contract information)
212 URI request unit 213 POI selection unit 214 transfer processing unit

Claims (7)

The originating carrier and the terminating carrier for transmitting / receiving a call control signal include an IP network and a PSTN, and the SIP server in the IP network of the originating carrier and the destination telephone number corresponding to the destination telephone number according to a request from the SIP server. A number resolution system comprising a carrier ENUM (Telephone Number Mapping) server that searches for a carrier URI and transmits it as response information to the SIP server,
The carrier ENUM server is
A storage unit storing a resource record for storing a URI of the called carrier corresponding to the destination telephone number included in the call control signal;
The request with the destination telephone number is received from the SIP server, the resource record is searched, and the called carrier has both IP-POI and STM (Synchronous Transfer Mode) -POI. A URI notification unit configured to generate a URI in SIP-URI format including an NRN (Network Routing Number) for specifying the destination carrier and to transmit the response information to the SIP server when interconnecting with a carrier ,
The SIP server
A storage unit that stores contract information indicating which POI to use when the originating carrier and the incoming carrier can be connected to both the IP-POI and the STM-POI;
A URI requesting unit that requests the carrier ENUM server for the URI of the called carrier with the destination telephone number included in the call control signal;
According to the response information from the carrier ENUM server, a URI in SIP-URI format including the NRN is acquired, and the destination carrier is identified from the domain part of the URI or the NRN.
When the URI format is the SIP-URI format including the NRN, it is determined that the incoming carrier has both the IP-POI and the STM-POI, and the IP-POI or the STM- A POI selection unit that selects any of the POIs with reference to the contract information;
A number resolution system comprising: The URI notification part of the carrier ENUM server is
The resource record is searched, and when the destination carrier has only the IP-POI and interconnects with the originating carrier, it generates a URI in SIP-URI format not including the NRN, and as the response information Sent to the SIP server,
The POI selection unit of the SIP server is
From the response information from the carrier ENUM server, obtain a URI in SIP-URI format that does not include the NRN, identify the incoming carrier from the domain part of the URI,
2. The number resolution system according to claim 1, wherein the URI is determined to have only the IP-POI by determining that the URI is a SIP-URI format that does not include the NRN. The URI notification part of the carrier ENUM server is
The resource record is searched, and when the called carrier has only the STM-POI and interconnects with the originating carrier, a TEL-URI-format URI including the NRN is generated, and the response information includes the response record information. Send to the SIP server,
The POI selection unit of the SIP server is
Based on the response information from the carrier ENUM server, obtain a URI in TEL-URI format including the NRN, and identify the incoming carrier from the NRN.
3. The number resolution system according to claim 2, wherein, when the URI format is the TEL-URI format, it is determined that the incoming carrier has only the STM-POI. The originating carrier and the terminating carrier for transmitting / receiving a call control signal include an IP network and a PSTN, and the SIP server in the IP network of the originating carrier and the destination telephone number corresponding to the destination telephone number according to a request from the SIP server. A number resolution method for a number resolution system, comprising: a carrier ENUM server that retrieves a carrier URI and transmits it as response information to the SIP server,
The SIP server
Performing the step of requesting the carrier ENUM server the URI of the called carrier with the destination telephone number included in the call control signal;
The carrier ENUM server is
A storage unit storing a resource record that stores a URI of the called carrier corresponding to the destination telephone number included in the call control signal;
Accepts a request with the destination telephone number from the SIP server, retrieves the resource record, and the called carrier has both IP-POI and STM-POI and interconnects with the originating carrier A SIP-URI-format URI including an NRN for identifying the called carrier is generated and transmitted to the SIP server as the response information;
The SIP server
A storage unit storing contract information indicating which POI is used when the originating carrier and the incoming carrier can be connected by both the IP-POI and the STM-POI; And
Obtaining a URI in SIP-URI format including the NRN from the response information from the carrier ENUM server, and identifying the incoming carrier from the domain part of the URI or the NRN;
When the URI format is the SIP-URI format including the NRN, it is determined that the incoming carrier has both the IP-POI and the STM-POI, and the IP-POI or the STM- And selecting one of the POIs with reference to the contract information. The carrier ENUM server is
The resource record is searched, and when the destination carrier has only the IP-POI and interconnects with the originating carrier, it generates a URI in SIP-URI format not including the NRN, and as the response information Performing the step of transmitting to the SIP server;
The SIP server
Obtaining a URI in SIP-URI format not including the NRN from the response information from the carrier ENUM server, and identifying the incoming carrier from the domain part of the URI;
5. The step of determining that the destination carrier possesses only the IP-POI by performing the URI format in a SIP-URI format that does not include the NRN is performed. The number resolution method described. The carrier ENUM server is
The resource record is searched, and when the called carrier has only the STM-POI and interconnects with the originating carrier, a TEL-URI-format URI including the NRN is generated, and the response information includes the response record information. Performing the step of sending to the SIP server;
The SIP server
Obtaining a TEL-URI-format URI including the NRN from the response information from the carrier ENUM server, and identifying the destination carrier from the NRN;
The number resolution according to claim 5, further comprising: determining that the incoming carrier has only the STM-POI when the URI format is the TEL-URI format. Method. The originating carrier and the terminating carrier for transmitting / receiving a call control signal include an IP network and a PSTN, are connected to a SIP server in the IP network of the originating carrier, and correspond to a destination telephone number according to a request from the SIP server A carrier ENUM server that retrieves the URI of the called carrier and transmits it as response information to the SIP server,
A resource record that stores a URI of the called carrier corresponding to the destination telephone number included in the call control signal, and the calling carrier and the called carrier are both the IP-POI and the STM-POI. When a connection is possible, a storage unit storing contract information indicating which POI is used, a URI notification unit that transmits the response information to the SIP server, and a POI of the called carrier are selected. A POI selection unit,
The URI notification unit
Accepts a request with the destination telephone number from the SIP server, retrieves the resource record, and the called carrier has both IP-POI and STM-POI and interconnects with the originating carrier A SIP-URI-format URI including an NRN for identifying the called carrier is generated, and the SIP-URI-format URI including the generated NRN is output to the POI selection unit,
The NRN receives the request with the destination telephone number from the SIP server, searches the resource record, and the incoming carrier has only the IP-POI and interconnects with the outgoing carrier. A URI in SIP-URI format that does not include the URL, and transmits it as the response information to the SIP server,
The NRN receives the request with the destination telephone number from the SIP server, searches the resource record, and the incoming carrier has only the STM-POI and interconnects with the outgoing carrier. A TEL-URI format URI including the response information and sending it to the SIP server as the response information,
The POI selection unit
A URI in SIP-URI format including the NRN is obtained from the URI notification unit, and the URI format is a SIP-URI format including the NRN. It is determined that both the STM-POI and the IP-POI or the STM-POI are selected with reference to the contract information, and the URI of the SIP-URI format not including the NRN, or A carrier ENUM server, wherein a URI in TEL-URI format including the NRN is generated and transmitted to the SIP server as the response information.

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