JP6449646B2 - Communication system and address resolution method - Google Patents

Description

The present invention relates to a communication system and a destination resolution method.

  IMS (IP Multimedia Subsystem) is defined as a 3GPP (3rd Generation Partnership Project) international standard for the purpose of providing IP (Internet Protocol) -based multimedia communication services (see, for example, Non-Patent Document 1). The IMS is a core network that communicates with an IP that does not depend on an access network. Each access network is called an IP-CAN (IP Connectivity Access Network). IMS makes it possible to seamlessly accommodate multiple IP-CANs. Since IMS does not depend on an access network, it makes it possible to provide a common multimedia communication service (for example, IP phone, video phone, IM (Instant Message), etc.) in different access networks.

  The IMS mainly includes a session control function (CSCF) and an application service control function (AS). The IMS also includes a user information storage function (HSS). The CSCF is a function that performs session control, which is the core of control of the service control network, and sets and releases a communication session between terminals. In addition, the CSCF selects an AS according to the service condition and transfers an SIP (Session Initiation Protocol) signal that is a session control protocol and an SDP (Session Description Protocol) signal that is a session description protocol. The CSCF includes three functional elements: P-CSCF (Proxy-CSCF), S-CSCF (Serving-CSCF), and I-CSCF (Interrogating-CSCF).

  The IMS can be connected to a different IP network (such as another IMS or NGN (Next Generation Network)). A UE (User Equipment: terminal) registered and subscribed to the home network (Home network) connects to the home network and an external visited network (Visited network) that can be roamed, and provides Internet services via the visited network. Can be used. The UE can initiate service usage registration with the IMS in the home network via the visited network. At this time, the P-CSCF provided in the visited network is used, while the S-CSCF and HSS provided in the home network are used. This makes it possible to provide the service requested by the UE in accordance with the policy of the home network operator. In addition, SIP signals and SDP signals transmitted when providing services such as voice calls are processed by the S-CSCF of the home network, and connection processing to the transmission destination is performed.

  When establishing communication with a communication partner of a telephone number belonging to the home network or a telephone number in the area to which the home network belongs, in a service in which the UE that roams to the visiting network specifies a communication partner such as a voice call by telephone number, The UE adds an international telephone number to the beginning of the telephone number. It is necessary to transmit using the 164 format. In this case, the INVITE (session start request) message transmitted from the UE is received by the S-CSCF of the home network via the P-CSCF of the visited network. The S-CSCF of the home network converts the domain name of the INVITE message into a domain name of “e164.arpa”, and checks the network domain to which the telephone number of the communication partner belongs by ENUM (E.164 NUmber Mapping). Using the domain as the network domain of the INVITE message destination, the communication path to the destination network of the INVITE message is routed, and the INVITE message is transferred.

  On the other hand, in a service in which a UE roaming to a visiting network designates a communication partner such as a voice call by telephone number, communication with a communication partner of a telephone number belonging to the visiting network or a telephone number in the area to which the visiting network belongs is established. In this case, if the UE makes a call using a telephone number (hereinafter referred to as a local number) that does not give an international telephone number at the beginning of the telephone number, communication with the communication partner cannot be established. This is because after the INVITE message transmitted from the UE is received by the S-CSCF of the home network via the P-CSCF of the visited network, the S-CSCF of the home network sets the local number in the INVITE message to E.E. This is because it cannot be converted into the 164 format and the network domain of the destination of the INVITE message cannot be checked.

  In response to this problem, in the “RAVEL (Roaming Architecture for Voice over IMS with Local Breakout)” technique described in Non-Patent Document 2, there is an INVITE message transmitted from the visited network to the home network on the visited network side. The INVITE message is transferred to the S-CSCF of the home network with the server address and voice data path information added. Then, the S-CSCF of the home network confirms that there is a service usage registration of the UE, and transfers the INVITE message to the visited network based on the information added to the INVITE message. In this case, the local number in the INVITE message is set to E.E. Since the process of converting to the 164 format is executed in the visited network to which the local number belongs, the conversion is successful. As a result, the network domain of the destination of the INVITE message can be checked, so that the known network domain is used as the network domain of the destination of the INVITE message, the communication path to the destination network of the INVITE message is routed, and the INVITE message is transferred. Thus, communication with the communication partner can be established.

3GPP TS 23.228, `` IP Multimedia Subsystem (IMS); Stage 2 '' 3GPP TR 23.850, `` Study on roaming architecture for voice over IP Multimedia Subsystem (IMS) with local breakout ''

  However, in the above-described conventional RAVEL technology, since the SIP signal is transferred from the visited network via the home network to the visited network, the number of communication nodes that relay the SIP signal increases, and unnecessary communication paths are created. There is a possibility that the communication cost and the risk of communication disconnection may increase due to the communication via the network and the transfer processing occurring in many terminals.

The present invention has been made in consideration of such circumstances, and a UE (terminal) connected to a visited network uses a telephone number (local number) that does not give an international telephone number at the beginning of the telephone number. A communication system and destination solution method capable of establishing communication with a communication partner, preventing an increase in communication cost for transferring a SIP signal, and improving a connection rate by simplifying a connection procedure The issue is to provide.

(1) One aspect of the present invention is a communication system of a home network in which a terminal is registered, and a session start request transmitted from a visited network roamed with the home network and received by the home network A location information acquisition unit that acquires location information for specifying a region where the terminal exists, when the telephone number of the terminal included in the message is a local number that does not belong to the home network; Using the local number that is the destination telephone number of the terminal, the processing of resolving the destination network domain that transmits the session start request message having the local number that is the destination telephone number of the terminal is executed a destination settlement part for a telephone number of the destination of the said positional information terminal wherein Using the Karu number, a communication system and a telephone number resolution unit for executing a query of the destination network domain to the telephone number resolution unit area specified by the position information.

( 2 ) One aspect of the present invention is a method for resolving a destination in a communication system of a home network in which a terminal is registered, and the location information acquisition unit is transmitted from a visited network roamed with the home network. When the destination telephone number of the terminal included in the session start request message received on the home network is a local number that does not belong to the home network, location information specifying an area where the terminal exists is acquired. A session having the local number that is the destination telephone number of the terminal, using the location information and the local number that is the destination telephone number of the terminal, using the location information acquisition step and the destination resolution unit Destination resolution process that performs the process of resolving the destination network domain to which the start request message is sent And-up, the telephone number resolution section, using said local number above is position information and telephone number of the destination of the terminal, the destination to the telephone number resolution unit area specified by the position information Performing a network domain query .

  According to the present invention, when a UE (terminal) connected to a visited network makes a call using a telephone number (local number) that does not give an international telephone number at the beginning of the telephone number, communication with a communication partner is established. be able to. In addition, it is possible to prevent the increase in communication cost for transferring the SIP signal and to improve the connection rate by simplifying the connection procedure.

It is a block diagram which shows the radio | wireless communications system which concerns on one Embodiment of this invention. It is a sequence chart which shows Example 1 of the destination resolution method which concerns on one Embodiment of this invention. It is a sequence chart which shows the example 2 of the destination resolution method which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a wireless communication system will be described as an example of the communication system.
FIG. 1 is a configuration diagram showing a wireless communication system according to an embodiment of the present invention. In FIG. 1, a wireless communication system as a home network 10 in which UE (terminal) _30 is registered includes AS_11, S-CSCF_12, H-ENUM_13, and HSS_14. AS_11 includes a position information acquisition unit 110. The S-CSCF_12 includes a destination resolution unit 120. H-ENUM_13 includes a telephone number resolution unit 130.

  The UE_30 is connected to an external visited network 20 capable of roaming connection with the home network 10. The wireless communication system as the visited network 20 includes a P-CSCF_21, an EPC (Evolved Packet Core) _22, an LTE (Long Term Evolution) _23, an MME (Mobility Management Entity) _24, and a V-ENUM_25. V-ENUM — 25 includes a telephone number resolution unit 250. UE_30 is connected to LTE_23 as a radio access network.

  A radio communication system as a destination network 40 to which UE_50 that is a communication partner of UE_30 is connected includes S-CSCF_41 and P-CSCF_42. The destination network 40 belongs to the same area as the visited network 20. The area to which the visited network 20 and the destination network 40 belong is different from the home network 10.

  The mnc (mobile network code) of the home network 10 is “111” and the mcc (mobile country code) is “999”. The mnc of the visited network 20 is “222” and the mcc is “888”. These values of mnc and mcc are values for convenience of explanation. The mnc and mcc constitute an identifier (PLMN-ID) of a PLMN (Public Land Mobile Network).

  Next, the operation of the wireless communication system according to the present embodiment will be described with reference to FIGS. FIG. 2 is a sequence chart showing Example 1 of the destination solving method according to the present embodiment. FIG. 3 is a sequence chart showing an example 2 of the destination solving method according to the present embodiment.

  In the following description, the UE_30 connected to the LTE_23 of the visited network 20 has completed use registration with the IMS of the home network 10 via the P-CSCF_21. Further, UE_30 uses a local number that is a telephone number to which the international telephone number is not given at the head of the telephone number as the telephone number of the destination.

[Example of address resolution method 1]
With reference to FIG. 2, the operation of the wireless communication system according to the first example of the destination solving method will be described.

(Step S1) UE_30 performs the transmission which makes UE_50 a communicating party, such as a voice call. As a result, UE_30 transmits an INVITE (session start request) message including the local number, which is the telephone number of UE_50 in destination network 40, as the destination telephone number to P-CSCF_21. An example of the transmitted INVITE message is as follows.
INVITE message: “Request-URI: sip: 12345678; phone-context=ims.mnc111.mcc999.3gppnetwork.org@ims.mnc111.mcc999.3gppnetwork.org; user = phone”
However, the local number of the destination is “12345678”. This destination local number is a number for convenience of explanation. As the network domain described in “phone-context” of the INVITE message, the network domain of the home network 10 included in the IMSI (International Mobile Subscriber Identity) of the UE_30 is used.

(Step S2) P-CSCF_21 transfers the INVITE message received from UE_30 to S-CSCF_12 of home network 10. An example of the transferred INVITE message is as follows.
INVITE message: “Request-URI: sip: 12345678; phone-context=ims.mnc111.mcc999.3gppnetwork.org@ims.mnc111.mcc999.3gppnetwork.org; user = phone P-Visited-Network-ID: ims.mnc222 .mcc888.3gppnetwork.org "
The S-CSCF_12 of the home network 10 is registered in the P-CSCF_21 when the UE_30 is registered for use in the IMS of the home network 10.

(Step S3) The S-CSCF_12 determines whether the “Request-URI” of the INVITE message received from the P-CSCF_21 is in the local number format. As a result of this determination, if “Request-URI” is in the local number format, E.I. The INVITE message received from the P-CSCF_21 is transferred to the AS_11 in order to convert it into “SIP-URI” in the 164 format. In step S3, the S-CSCF_12 does not have to determine whether the area where the UE_30 is located is the home network 10 or the visited network 20.

(Step S4) The AS_11 performs “Number Normalization” processing on the INVITE message received from the S-CSCF_12. In the “Number Normalization” process, the “Request-URI” in the local number format included in the INVITE message is changed to E.E. Convert to “SIP-URI” in 164 format. At this time, if the local number included in “Request-URI” is the local number of the region to which the visited network 20 belongs, the home network 10 sets “Request-URI” to E.E. It cannot be converted to “SIP-URI” in 164 format. This is because the area to which the home network 10 belongs is different from the area to which the visited network 20 belongs, and therefore the home network 10 does not maintain the number format of the visited network 20.

  Here, the local number included in “Request-URI” is the local number “12345678” of the region to which the visited network 20 belongs. Therefore, in the “Number Normalization” process of AS_11, the “Request-URI” of the INVITE message received from the S-CSCF_12 is set to E.E. It cannot be converted to “SIP-URI” in 164 format.

(Step S5) The position information acquisition unit 110 of AS_11 UDR (User Data) that requests “Location Information” of UE_30 that has transmitted an INVITE message (referred to as a request target INVITE message) including “Request-URI” that cannot be converted into “SIP-URI” in 164 format Request) message is sent to HSS_14.

(Step S6) In response to the UDR message received from the AS_11, the HSS_14 sends a UDA (User Data Answer) message including the PLMN-ID [mnc “222”, mcc “888”] of the visited network 20 to which the UE_30 is connected to the AS_11. Reply to The PLMN-ID [mnc “222”, mcc “888”] of the visited network 20 is a ULR (User Location Request) from the MME_24 of the visited network 20 to the HSS_14 of the home network 10 when the UE_30 is connected to the LTE_23 of the visited network 20. Is registered in HSS_14 as the PLMN-ID of LTE_23 to which UE_30 is connected.

(Step S7) The AS_11 uses the PLMN-ID [mnc “222”, mcc “888”] included in the UDA message received from the HSS_14 and uses the home network included in the “phone-context” of the request target INVITE message. The mnc and mcc of 10 are changed to the mnc and mcc of the visited network 20, and the changed request target INVITE message is transferred to the S-CSCF_12. An example of the transferred INVITE message is as follows.
INVITE message: “Request-URI: sip: 12345678; phone-context=ims.mnc222.mcc888.3gppnetwork.orgp@ims.mnc111.mcc999.3gppnetwork.org; user = phone P-Visited-Network-ID: ims.mnc222 .mcc888.3gppnetwork.org "

(Step S8) The S-CSCF_12 determines whether the “Request-URI” of the INVITE message received from the AS_11 is in the local number format. As a result of this determination, if the “Request-URI” is in the local number format, the destination resolution unit 120 executes a process of resolving the destination network domain to which the INVITE message (referred to as a resolution target INVITE message) is transmitted. In this resolution processing, the destination resolution unit 120 includes the local number “12345678” included in the “Request-URI” of the resolution target INVITE message and the PLMN-ID [mnc] included in the “phone-context” of the resolution target INVITE message. "ENUM Query" message is sent to H-ENUM_13 using the query format "8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1" consisting of "222", mcc "888"] To do.

(Step S9) The telephone number resolution unit 130 of the H-ENUM_13 receives the PLMN included in the query format “8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1” of the “ENUM Query” message received from the S-CSCF_12. -"ENUM Query" message in the query format "8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1" to the V-ENUM_25 of the visited network 20 corresponding to the ID [mnc "222", mcc "888"] Forward. The ENUM function operates in the same mechanism as DNS (Domain Name System). As a result, the telephone number resolution unit 130 uses the local number “12345678” based on the query format “8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1” of the “ENUM Query” message received from the S-CSCF_12. "ENUM Query" message of the query format "8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1" is transferred to V-ENUM_25 of the visited network 20 that can resolve "."

(Step S10) In response to the “ENUM Query” message of the query format “8.7.6.5.4.3.2.1.8.8.8.2.2.2.local1” received from H-ENUM_13, the telephone number resolution unit 250 of V-ENUM_25 An “ENUM Answer” message including its own search result for the local number “12345678” is returned to H-ENUM_13. An example of the “ENUM Answer” message returned is as follows.
"ENUM Answer" message: "sip: 12345678; phone-context=ims.mnc222.mcc888.3gppnetwork.org@dest.com; user = phone"

(Step S11) The telephone number resolution unit 130 of the H-ENUM_13 transfers the “ENUM Answer” message received from the V-ENUM_25 to the S-CSCF_12.

(Step S12) The destination resolution unit 120 of the S-CSCF_12 obtains the network domain of the destination to which the resolution target INVITE message is transmitted from the “ENUM Answer” message received from the H-ENUM_13. The S-CSCF_12 performs a routing process based on the network domain acquired from the “ENUM Answer” message, and transmits the solution target INVITE message to the S-CSCF_41 of the destination network 40 that is the destination network. An example of the transmitted INVITE message is as follows.
INVITE message: “Request-URI: sip: 12345678; phone-context=ims.mnc222.mcc888.3gppnetwork.org@dest.com; user = phone”

  Note that the ENUM provided with the telephone number resolution unit preferably retains data in a DNS record in a format in which a PLMN-ID is added to the local number. In addition, when the H-ENUM_13 of the home network 10 cooperates with an ENUM in a network other than the home network 10, it is preferable that the cooperation destination ENUM also has the same structure to perform telephone number resolution.

  Further, as shown in FIG. 1, the telephone number resolution unit may be a part of the ENUM or may be a device separate from the ENUM. Further, the telephone number resolution unit may be provided as a database in which each of the home network 10 and the visited network 20 is associated with a local number and a destination network domain corresponding to the local number.

[Example 2 of address resolution]
The operation of the wireless communication system according to Example 2 of the destination resolution method will be described with reference to FIG. 3, parts corresponding to the respective steps in FIG. 2 described above are denoted by the same reference numerals, and description thereof is omitted.

  Steps S1 to S7 are the same as those in the above-described destination resolution method example 1 (FIG. 2). It progresses to step S21 after step S7.

(Step S21) The S-CSCF_12 determines whether the “Request-URI” of the INVITE message received from the AS_11 is in the local number format. As a result of this determination, if the “Request-URI” is in the local number format, the destination resolution unit 120 executes a process of resolving the destination network domain to which the INVITE message (referred to as a resolution target INVITE message) is transmitted. In this resolution process, the destination resolution unit 120 uses the query format “8.8.8.2.2.2” including the PLMN-ID [mnc “222”, mcc “888”] included in the “phone-context” of the resolution target INVITE message. “ENUM Query” message is transmitted to H-ENUM_13 using “.local2”.

(Step S22) In response to the “ENUM Query” message of the query format “8.8.8.2.2.2.local2” received from the S-CSCF_12, the telephone number resolution unit 130 of the H-ENUM_13 determines the query format “8.8.8.2. The search for the international telephone number corresponding to the PLMN-ID [mnc “222”, mcc “888”] included in “2.2.local2” is executed. The telephone number resolution unit 130 returns an “ENUM Answer” message including the international telephone number “123” as a result of the search to the S-CSCF_12.

(Step S23) The destination resolution unit 120 of the S-CSCF — 12 receives the international telephone number “123” included in the “ENUM Answer” message received from the H-ENUM — 13 and the local number included in the “Request-URI” of the INVITE message to be resolved. Using the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa” composed of the number “12345678” and the domain name “e164.arpa”, to H-ENUM_13, “ Send "ENUM Query" message.

(Step S24) The telephone number resolution unit 130 of the H-ENUM_13 supports the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa” of the “ENUM Query” message received from the S-CSCF_12. The “ENUM Query” message in the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa” is transferred to V-ENUM_25 of the visiting network 20 to be visited. Note that the telephone number resolution unit 130 has the telephone number of the communication partner to which the telephone number of the communication partner belongs by ENUM (E.164 NUmber Mapping) based on the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa”. The “ENUM Query” message in the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa” is transferred to V-ENUM_25 of the visited network 20 by a predetermined procedure for checking the network domain.

(Step S25) The telephone number resolution unit 250 of V-ENUM_25 responds to the “ENUM Query” message in the DNS NAPTR record format “8.7.6.5.4.3.2.1.3.2.1.e164.arpa” received from H-ENUM_13. Then, an “ENUM Answer” message including the search result for the local number “12345678” is returned to H-ENUM_13. An example of the “ENUM Answer” message returned is as follows.
"ENUM Answer" message: "sip: 12345678; phone-context=ims.mnc222.mcc888.3gppnetwork.org@dest.com; user = phone"

(Step S26) The telephone number resolution unit 130 of the H-ENUM_13 transfers the “ENUM Answer” message received from the V-ENUM_25 to the S-CSCF_12. After step S26, the process proceeds to step S12. Step S12 is the same as the above-described destination resolution method example 1 (FIG. 2).

  In addition, it is possible to cache a destination resolution result by the telephone number resolution unit operating on a DNS basis. Further, the destination resolution unit 120 may use the international telephone number of the destination resolution result stored in its own cache when an inquiry for international telephone number resolution for the same PLMN-ID occurs. In this case, steps S21 and S22 can be omitted.

  According to the above-described embodiment, when the UE_30 connected to the visited network 20 makes a call using a telephone number (local number) that does not give an international telephone number at the beginning of the telephone number, communication with the communication partner is established. be able to. Further, as in the RAVEL technique, since it is not necessary to transfer the SIP signal through a communication path that returns from the visited network to the visited network via the home network, it is possible to prevent an increase in communication cost for transferring the SIP signal.

  Further, according to the present embodiment, the destination network domain corresponding to the local number can be acquired on the home network side. As a result, the SIP signal transfer path can be determined on the home network side. In addition, an IPX (Internetwork Packet eXchange) operator that relays the SIP signal can be designated on the home network side.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  S-CSCF_12 is an example of a communication relay device. The S-CSCF_12 supplies the INVITE message received from the visited network 20 roamed with the home network 10 to which the UE_30 is registered to the location information acquisition unit 110, and the destination of the UE_30 included in the INVITE message When the telephone number is a local number that does not belong to the home network 10, the location information specifying the area where the UE_30 exists is acquired from the location information acquisition unit 110, and the location information received from the location information acquisition unit 110 and the INVITE The local number included in the message is supplied to the destination resolution unit 120, the execution result of the resolution process of the destination network domain that transmits the INVITE message is acquired from the destination resolution unit 120, and the acquired result from the destination resolution unit 120 Network domain of execution results Based on emissions, it may transfer the INVITE message.

  In the above-described embodiment, a wireless communication system has been described as an example of a communication system, but the present invention can be similarly applied to a wired communication system in which terminals are connected via a wired line.

DESCRIPTION OF SYMBOLS 10 ... Home network, 11 ... AS, 12, 41 ... S-CSCF, 13 ... H-ENUM, 14 ... HSS, 20 ... Visit network, 21, 42 ... P-CSCF, 22 ... EPC, 23 ... LTE, 24 ... MME, 25 ... V-ENUM, 30, 50 ... UE, 40 ... destination network, 110 ... location information acquisition unit, 120 ... destination resolution unit, 130 ... phone number resolution unit, 250 ... phone number resolution unit

Claims (2)

A home network communication system in which the terminal is registered,
The destination telephone number of the terminal included in the session start request message transmitted from the visited network roamed with the home network and received by the home network is a local number that does not belong to the home network. A location information acquisition unit that acquires location information that identifies an area where the terminal exists;
Using the location information and the local number that is the destination telephone number of the terminal, the destination network domain that transmits the session start request message having the local number that is the destination telephone number of the terminal A destination resolution unit for executing resolution processing;
Using the location information and the local number that is the destination phone number of the terminal, a phone number resolution is used to query the destination network domain to the phone number resolution unit in the area specified by the location information. And
A communication system comprising: A destination solution method for a communication system of a home network in which a terminal is registered,
A location information acquisition unit transmits a telephone number of a destination of the terminal included in a session start request message transmitted from a visited network roamed to the home network and received by the home network to the home network. If it is a local number that does not belong, a location information acquisition step for acquiring location information specifying the area where the terminal exists;
The destination resolution unit transmits a session start request message having the local number that is the telephone number of the terminal, using the location information and the local number that is the telephone number of the terminal. A destination resolution step for performing a process of resolving the destination network domain;
The telephone number resolution unit uses the location information and the local number that is the destination telephone number of the terminal to query the destination network domain to the local telephone number resolution unit specified by the location information. A step of performing
Destination resolution method including:

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