JP2011172036A - Method for changing sip server connecting by terminal under registration, server, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, or the like, of changing to the other SIP server, even if the terminal is already under registration to a SIP server in an IMS network, without extending a technical specification of the terminal. <P>SOLUTION: A first SIP sever receives REGISTER from a terminal and processes position registration of the terminal. Thereafter, the first SIP server shifts to a waiting state for Re-REGISTER from the terminal, when the position registration destination of the terminal is changed to a second SIP server; and further, when the first SIP server is in the waiting state and receives the Re-REGISTER from the terminal, the first SIP server sends back a redirection message for redirection to the second SIP server. As a result, the second SIP server receives the Re-REGISTER, depending on the redirection. The SIP server is a call session control function CSCF, and a first CSCF receives an arrangement change notification for changing the position registration destination of the terminal, to a second CSCF from a subscriber information server HSS. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for changing a SIP (Session Initiation Protocol) server to which a terminal being registered connects.

  SIP is a call control protocol in IP (Internet Protocol), which negotiates an IP address, a port number, and encoding necessary for communication between terminals, and controls outgoing and incoming calls. In order to perform necessary network resource allocation and gate control using SIP, there is an IMS (IP Multimedia Subsystem) as an IP subsystem network. IMS is a service control standard specification standardized to provide multimedia applications (voice, video and data) over IP networks. This is a core technology that realizes the next generation mobile phone network or NGN (Next Generation Network). As a result, the fixed network and the mobile network are integrated, and all-IP communication is realized in which all terminals communicate on an IP basis.

  FIG. 1 is a system configuration diagram of an IMS in the prior art.

  According to the system of FIG. 1, an access network and the Internet are connected to the IMS network 7. The two networks are connected via a gateway. The access network is, for example, a mobile phone network or a wireless / wired broadband access network. The SIP client compatible terminal 6 can be connected to the IMS network 7 via an access network. When the access network is a mobile phone network, the terminal 6 is, for example, a mobile phone.

  The IMS network 7 has a control network 71 separately from the transport network. The control network 71 has S-CSCF (Serving-CSCF) 1, P-CSCF (Proxy-CSCF) 2, and I-CSCF (Interrogating-CSCF) as a call session control function (CSCF). 3. In addition, it has a subscriber information server (HSS (Home Subscriber Server)) that manages subscriber profile information (for example, authentication information) for each terminal. The plurality of terminals 6 corresponding to the SIP client establish a call session with the counterpart terminal by connecting to the CSCF via the access network.

  The P-CSCF 2 is directly accessed from the terminal 6 via the access network. Then, the P-CSCF 2 extracts media information for each session, and instructs gate control and resource control for the gateway when the session is established. The P-CSCF 2 is determined before connection to the IMS, such as when the terminal 6 is connected to the access network, and establishes a secure IPsec tunnel with the terminal 6 and also performs message filtering. The SIP message received from the terminal 6 is transferred to the S-CSCF 1.

  The S-CSCF 1 is a central SIP server for service execution and call session control. The S-CSCF 1 has a domain managed by itself, and manages the SIP-URI (SIP-Uniform Resource Identifier) of the terminals within the domain. Further, the S-CSCF 1 performs user authentication by communicating with the HSS 4. Furthermore, the S-CSCF 1 can provide various services to the terminal 6 by communicating with an application server (AS).

  The I-CSCF 3 has a function of controlling the route of the SIP message within the control network 71. For example, the function of resolving the destination of the SIP message addressed to the S-CSCF transmitted from the P-CSCF 2 and transferring it to the corresponding S-CSCF or the name of the transfer destination belonging to another domain and transferring it to the corresponding destination Perform the function.

3GPP TS 23.228, “IP Multimedia Subsystem (IMS)”

  The terminal sends a SIP message to the IMS network via the access network. The SIP message is forwarded to any one P-CSCF. The P-CSCF transfers the SIP message to any one of the S-CSCFs, and executes an authentication process and a registration process. Thereafter, the P-CSCF and the S-CSCF will manage the terminal. Therefore, the terminal is basically fixedly managed with respect to the P-CSCF and S-CSCF registered once. That is, the P-CSCF and the S-CSCF are basically not changed unless the network environment changes due to, for example, the terminal moving to a different network.

  However, depending on the usage situation, such as optimization and maintenance of the functional configuration in the IMS network, there are cases where it is desired to change the CSCF in which the terminal is being registered to another CSCF. In some cases, it may be desired to distribute processing loads for CSCFs with a high operation rate or to consolidate processing loads by stopping CSCFs with a low operation rate, depending on the usage status of terminals to the IMS network.

  In order to change a CSCF being registered by a terminal to another CSCF, first, location registration information of the terminal in the CSCF being registered needs to be transferred to the other CSCF. The terminal must then reconnect to the IMS network. Also, the HSS needs to update the information of the CSCF that manages the terminal.

  As described above, in the existing IMS network, the P-CSCF and the S-CSCF are fixedly assigned to the terminal, and are difficult to change after location registration. Further, the location registration of the terminal is required to be updated within a certain time for Keep-Alive. When a subscriber profile in a terminal that has already been registered is changed, there may be a contradiction with cache information in the CSCF in the middle.

  On the other hand, there is a technique in which the CSCF is changed by actively transmitting a re-registration notification from the IMS network side to the terminal, and the terminal again transmitting a location registration request. However, it is necessary to extend the technical specifications of the SIP client installed in the terminal. It is actually extremely difficult to install such a function in all terminals.

  Therefore, the present invention provides a method, a server, and a method capable of changing a terminal already registered in a SIP server to another SIP server in the IMS network without extending the technical specifications of the terminal. The purpose is to provide a program.

According to the present invention, for a plurality of SIP (Session Initiation Protocol) servers connected to an IP subsystem network, a method for changing a SIP server to which a terminal connects,
A first SIP server receiving a location registration request from a terminal and processing the location registration of the terminal;
When the first SIP server changes the location registration destination of the terminal to the second SIP server, the second step of shifting to a waiting state for a location registration request from the terminal;
And a third step of returning a redirect message to redirect to the second SIP server when the first SIP server is in a waiting state and receives a location registration request from the terminal. The SIP server receives a location registration request corresponding to the redirect.

According to another embodiment of the SIP server changing method of the present invention,
The IP subsystem network is an IMS (IP Multimedia Subsystem) network,
The SIP server is a call session control function (CSCF),
For the second step, the first CSCF receives a location change notification to change the location registration destination of the terminal to the second CSCF from a subscriber information server (HSS: Home Subscriber Server) connected to the IMS network. It is also preferable to do.

According to another embodiment of the SIP server changing method of the present invention,
The call session control function is preferably an S-CSCF (Serving-CSCF) and / or a P-CSCF (Proxy-CSCSF).

According to another embodiment of the SIP server changing method of the present invention,
For the second step,
The location change notification received by the first CSCF from the HSS includes the SIP-URI of the terminal, the SIP-URI of the second CSCF to be changed, and a waiting time in the waiting state.
The first CSCF maintains a waiting state for the waiting time,
When the first CSCF times out without receiving the location registration request, it is also preferable to transmit information to that effect to the HSS.

According to another embodiment of the SIP server changing method of the present invention,
The second SIP server to be changed is
When the location registration request is received from the terminal, the authentication information of the terminal is acquired from the HSS using the Diameter,
Determining whether the authentication information of the terminal included in the location registration request matches the authentication information of the terminal acquired from the HSS;
If both authentication information does not match, return an authentication failure notification to the terminal and execute the authentication process again.
When both authentication information matches, it is also preferable to return a location registration response including a time interval value at which the terminal transmits a location registration request next to the terminal.

According to the present invention, the SIP server is connected to the IP subsystem network and changes the location registration connected from the terminal to the other SIP server,
Registration request receiving means for receiving a location registration request from a terminal;
Registration processing means for processing location registration of the terminal in response to the location registration request;
Waiting state holding means for shifting to a waiting state for a location registration request from the terminal when the location registration destination of the terminal is changed to the other SIP server;
Redirect reply means for returning a redirect message to redirect to the other SIP server when receiving a location registration request from the terminal in a waiting state, and responding to the redirect by the other SIP server A location registration request is received.

According to another embodiment of the SIP server of the present invention,
The IP subsystem network is an IMS network,
The SIP server is a call session control function (CSCF),
It is also preferable to further include an arrangement change notification receiving means for receiving an arrangement change notice to change the location registration destination of the terminal to the second CSCF from a subscriber information server (HSS) connected to the IMS network.

According to another embodiment of the SIP server of the present invention,
The call session control function of the SIP server is also preferably an S-CSCF and / or a P-CSCF.

According to another embodiment of the SIP server of the present invention,
The location change notification received from the HSS includes the SIP-URI of the terminal, the SIP-URI of the CSCF to be changed, and a waiting time in the waiting state.
Preferably, the waiting state holding unit maintains the waiting state for the waiting time, and when time-out occurs without receiving the location registration request, it is preferable to transmit information to that effect to the HSS.

According to another embodiment of the SIP server of the present invention,
When receiving a location registration request from a terminal, authentication information acquisition means for acquiring authentication information of the terminal from the HSS using a Diameter;
Authentication information determination means for determining whether or not the authentication information of the terminal included in the location registration request matches the authentication information of the terminal acquired from the HSS;
If both authentication information does not match, the authentication failure notification is returned to the terminal and the authentication process is executed again. If both authentication information matches, the time interval value at which the terminal next sends a location registration request is included. It is also preferable to have a registration response transmission means for returning a location registration response to the terminal.

According to the present invention, there is provided a program for causing a computer mounted on a SIP server connected to an IP subsystem network to change the location registration connected from the terminal to the other SIP server,
Registration request receiving means for receiving a location registration request from a terminal;
Registration processing means for processing location registration of the terminal in response to the location registration request;
Waiting state holding means for shifting to a waiting state for a location registration request from the terminal when the location registration destination of the terminal is changed to the other SIP server;
When a location registration request is received from a terminal in a waiting state, the computer functions as a redirect reply means for returning a redirect message to redirect to the other SIP server, and the other SIP server redirects to the redirect. A corresponding location registration request is received.

  The SIP server changing method, server, and program according to the present invention change a terminal that is already registered to a SIP server within the IMS network to another SIP server without extending the technical specifications of the terminal. be able to.

It is a system configuration | structure figure of IMS in a prior art. It is a system configuration diagram of IMS in the present invention. It is a sequence diagram showing change of S-CSCF in this invention. It is a sequence diagram showing change of P-CSCF in this invention. It is a sequence diagram showing change of S-CSCF and P-CSCF in this invention. It is a functional block diagram of CSCF and a subscriber information server in the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a system configuration diagram of the IMS according to the present invention.

  The system of FIG. 2 has a plurality of S-CSCFs and P-CSCFs arranged in an IMS network (IP subsystem network) 7 as compared to FIG. Further, an arrangement change control node 5 is further connected to the IMS network 7. The placement change control node 5 transmits a CSCF placement change notification for each terminal to the HSS (subscriber information server) 4. And HSS4 transmits the arrangement | positioning change notification for every terminal with respect to CSCF, and updates the information of CSCF corresponding to the said terminal.

  FIG. 2 shows a case where the first S-CSCF 11 being registered by the terminal is changed to the second S-CSCF 12 as compared with FIG. 1. Further, the case where the first P-CSCF 21 being registered by the terminal is changed to the second P-CSCF 22 is also shown.

  FIG. 3 is a sequence diagram showing the change of the S-CSCF in the present invention.

(S301) The terminal # 1 transmits a location registration request REGISTER to the IMS network, and the location registration has been completed by the P-CSCF # 1 and the S-CSCF # 1. The HSS stores P-CSCF # 1 being registered and S-CSCF # 1 being registered corresponding to the terminal # 1.

(S302) At this time, the arrangement change control node transmits an arrangement change notification for changing the location registration destination of the terminal # 1 from S-CSCF # 1 to S-CSCF # 2 to the HSS. The placement change control node determines CSCF placement change in accordance with the operator's instruction, the load state of the IMS network, and the like. This arrangement change notification includes the following information, for example.
・ SIP-URI of the terminal
-SIP-URI of the source S-CSCF # 1
-SIP-URI of the destination S-CSCF # 2
・ Standby time

(S303) The HSS receives an arrangement change notification from the arrangement change control node. The HSS stores the SIP-URI of the S-CSCF being registered for each SIP-URI of the terminal. For the terminal # 1, the HSS determines whether the SIP-URI of the change-destination S-CSCF included in the arrangement change notification is different from the SIP-URI of the S-CSCF being registered. Here, since both SIP-URIs are different, the HSS transmits an arrangement change notification to the S-CSCF # 1 during registration. This arrangement change notification includes the following information, for example.
・ SIP-URI of the terminal
-SIP-URI of the destination S-CSCF # 2
・ Standby time

(S304) S-CSCF # 1 receives an arrangement change notification from the HSS. Here, according to the present invention, the S-CSCF # 1 shifts to a waiting state for the location registration request Re-REGISTER message from the terminal # 1.

  Note that when the terminal # 1 has established an active session, the S-CSCF cannot be changed. In that case, even if the S-CSCF # 1 receives the location registration request Re-REGISTER message, it does not proceed to S311. That is, the S-CSCF # 1 maintains a waiting state until the session of the terminal # 1 ends and thereafter receives a location registration request REGISTER message from the terminal # 1.

  If the location registration request Re-REGISTER message is not received from the terminal # 1 even after a predetermined waiting time has elapsed after shifting to the waiting state, the S-CSCF # 1 sends information indicating failure to the HSS. Send.

(S311) Terminal # 1 needs to transmit a location registration request Re-REGISTER message after the location registration and before the specified time elapses. In the SIP profile, “Register timeout value (Timer Register Expires)” is set, and a “Registration resend interval (Timer Register Delta)” seconds before the registration period ends, a location registration request Re-REGISTER message is sent. Send. The P-CSCF # 1 maintains its location registration by receiving the location registration request Re-REGISTER message during “SIP Station Keepalive Interval”.

(S312) Here, the P-CSCF # 1 controls the path by transferring the Re-REGISTER to the I-CSCF. If P-CSCF # 1 holds a cache in S-CSCF # 1, or if Re-REGISTER includes SIP-URI of S-CSCF # 1, P-CSCF # 1 REGISTER may be sent directly to S-CSCF # 1. In this case, the RE-REGISTER moves to S315 without going through the I-CSCF.

(S313) The I-CSCF inquires of the HSS about the S-CSCF in which the terminal is registered using the Diameter protocol. The Diameter protocol is a next-generation AAA (Authentication, Authorization and Accounting) standard protocol that replaces RADIUS (Remote Authentication Dial In User Service). For example, the I-CSCF obtains the SIP-URI of the S-CSCF # 1 by exchanging the following message with the HSS.
UAR (User-Authorization-Request)
UAA (User-Authorization-Answer)
The inquiry from the I-CSCF to the HSS is executed when the first REGISTER is received, but whether or not to execute it when the Re-REGISTER is received depends on the implementation.

(S314) The I-CSCF transfers the Re-REGISTER to the S-CSCF # 1.

(S315) The S-CSCF # 1 that has received the Re-REGSITER returns 301 Moved as a redirect message to the I-CSCF. 301 Moved includes, for example, the following information.
Address of change destination S-CSCF # 2 In addition to 301, 302 Moved may be used as the redirect message.

(S316) The I-CSCF transfers 301 Moved received from the S-CSCF # 1 to the P-CSCF # 1.

(S317) P-CSCF # 1 redirects Re-REGISTER to S-CSCF # 2 according to the received 301 Moved.

(S318) The S-CSCF # 2 performs location registration processing by the received Re-REGISTER. At this time, since the S-CSCF # 2 does not hold the authentication information in the terminal # 1, the S-CSCF # 2 inquires the authentication information to the HSS using the Diameter protocol. The S-CSCF # 2 obtains authentication information of the terminal # 1 by exchanging the following messages with the HSS, for example.
MAR (Multimedia-Auth-Request)
MAA (Multimedia-Auth-Answer)
Here, the S-CSCF # 2 is successfully authenticated when the authentication information of the terminal # 1 acquired from the HSS matches the authentication information included in the Re-REGISTER. If the authentication is successful, the process proceeds to S325.

(S321) If the authentication fails, the S-CSCF # 2 returns 401 Unauthorized to the P-CSCF # 1.
(S322) P-CSCF # 1 further transfers 401 Unauthorized to terminal # 1.
(S323) When the terminal # 1 receives 401 Unauthorized, the terminal # 1 again transmits Re-REIGSTER to which the authentication information is added to the P-CSCF # 1.
(S324) The P-CSCF # 1 transfers the Re-REGISTER to the S-CSCF # 2.

(S331) The S-CSCF # 2 executes the location registration process based on the authentication information acquired from the HSS. If the authentication is successful, the terminal information is updated to the HSS using the Diameter protocol. The S-CSCF # 2 updates the information of the terminal # 1 by exchanging the following messages with the HSS, for example.
SAR (Server-Assignment-Request)
SAA (Server-Assignment-Request)
The HSS confirms that the terminal # 1 has completed registration with the S-CSCF # 2, updates the retained information, and returns S-CSCF # 2 for subsequent inquiries.

(S332) S-CSCF # 2 returns 200OK to P-CSCF # 1. Here, it is also preferable that the time interval value at which the terminal # 1 next transmits Re-REGISTER is included in 200OK. For example, the time interval value is included in the expire of the Contact header at 200 OK.
(S333) The P-CSCF # 1 transfers the received 200OK to the terminal # 1. Terminal # 1 controls the next time to transmit Re-REGISTER according to the time interval value included in 200OK. This makes it possible to adjust the granularity of the arrangement change control interval.

  As described above, the terminal # 1 recognizes the change from S-CSCF # 1 to S-CSCF # 2, and executes the subsequent sequence as usual. Also, the HSS stores that the terminal # 1 has registered its location with the S-CSCF # 2.

  FIG. 4 is a sequence diagram showing the change of the P-CSCF in the present invention.

  FIG. 4 is different from FIG. 3 only in that the P-CSCF is changed. Accordingly, the P-CSCF # 1 transmits a redirect message 301 Moved to the terminal # 1, and the terminal # 1 transmits a redirection Re-REGISTER to the P-CSCF # 2. Since the operation of the S-CSCF in FIG. 3 and the operation of the P-CSCF in FIG. 4 are basically the same, only the differences from FIG. 3 will be briefly described below with reference to FIG. explain.

(S401) The location of terminal # 1 has been registered by P-CSCF # 1 and S-CSCF # 1.
(S402) At this time, the arrangement change control node transmits an arrangement change notification for changing the location registration destination of the terminal # 1 from P-CSCF # 1 to P-CSCF # 2 to the HSS.
(S403) Since the SIP-URI of the change destination P-CSCF included in the arrangement change notification is different from the SIP-URI of the P-CSCF being registered for the terminal # 1, the HSS is registering the P-CSCF # Send a change notification to 1.
(S404) The P-CSCF # 1 shifts to a waiting state for the location registration request Re-REGISTER message from the terminal # 1.

(S411) Terminal # 1 transmits a location registration request Re-REGISTER message after the location registration and before the specified time elapses.
(S412) Receiving Re-REGSITER, P-CSCF # 1 returns 301 Moved as a redirect message to terminal # 1. 301 Moved includes, for example, the following information.
SIP-URI of destination P-CSCF # 2
(S413) Terminal # 1 redirects and transfers Re-REGISTER to P-CSCF # 2 according to the received 301 Moved.
(S414) Here, the P-CSCF # 2 controls the path by transferring the Re-REGISTER to the I-CSCF.
(S415) The I-CSCF inquires of the HSS about the S-CSCF that registers the location of the terminal using the Diameter protocol.
(S416) The I-CSCF transfers the Re-REGISTER to the S-CSCF # 1.
(S417) The S-CSCF # 2 executes location registration processing by the received Re-REGISTER. At this time, the S-CSCF # 2 inquires authentication information to the HSS using the Diameter protocol. The S-CSCF # 2 is successfully authenticated when the authentication information of the terminal # 1 acquired from the HSS matches the authentication information included in the Re-REGISTER.

(S421 to S424) Same as S321 to S324 in FIG. 3, except that the S-CSCF # 1 executes an authentication sequence with the terminal # 1 via the P-CSCF # 2. Here, since it is necessary to establish an IPSec tunnel between the terminal # 1 and the P-CSCF # 2 regardless of whether the authentication succeeds or fails due to the above-described S417, the authentication processing of S421 to S424 is performed again. Is executed. In the course of this authentication process, an IPSec tunnel is established between terminal # 1 and P-CSCF # 2.

(S431 to S433) Similar to S331 to S333 in FIG. 3, the S-CSCF # 1 updates the terminal information to the HSS, and the S-CSCF # 1 passes through the P-CSCF # 2. The only difference is that 200OK is transmitted to terminal # 1.

  As a result, terminal # 1 recognizes the change from P-CSCF # 1 to P-CSCF # 2 and executes the subsequent sequence as usual. Further, the HSS stores that the terminal # 1 has registered its location with the P-CSCF # 2.

  FIG. 5 is a sequence diagram showing changes of the S-CSCF and the P-CSCF in the present invention.

  According to FIG. 5, the sequences of FIGS. 3 and 4 are combined. Therefore, S3xx is the same as the step of FIG. 3, and S4xx is the same as the step of FIG. In the following, only the steps unique to FIG. 5 will be described briefly.

  According to S502, the location change control node changes the location registration destination of the terminal # 1 from S-CSCF # 1 to S-CSCF # 2, and changes from P-CSCF # 1 to P-CSCF # 2. A notification of change of power allocation is transmitted to the HSS. As a result, the HSS transmits an arrangement change notification to the registering S-CSCF # 1 (S303) and transmits an arrangement change notification to the registering S-CSCF # 2 (S403). During registration, S-CSCF # 1 shifts to a waiting state (S304), and during registration P-CSCF # 1 also shifts to a waiting state (S404).

  According to S411 to S416 in FIG. 5, as in FIG. 4, the Re-REGISTER transmitted from the terminal # 1 to the P-CSCF # 1 is transmitted from the terminal # 1 to the P-CS by the redirect message of the P-CSCF # 1. It is transmitted to CSCF # 2. P-CSCF # 2 transfers the Re-REGISTER to S-CSCF # 1 via I-CSCF.

  Next, according to S315 to S318 in FIG. 5, as in FIG. 3, the Re-REGISTER transmitted from the P-CSCF # 2 to the S-CSCF # 1 is transmitted by the redirect message of the S-CSCF # 1. -Sent from CSCF # 2 to S-CSCF # 2. The S-CSCF # 2 updates the subscriber profile information (for example, the SIP-URI of the CSCF being registered) in the terminal # 1 with respect to the HSS.

  Next, S421 to S424 and S431 to S433 in FIG. 5 are different from FIG. 4 only in that a sequence is executed between S-CSCF # 2 and P-CSCF # 2. Thereby, the terminal # 1 completes the location registration process by the S-CSCF # 2 and the P-CSCF # 2.

  FIG. 6 is a functional configuration diagram of the CSCF in the present invention.

  Here, the CSCF shown in FIG. 6 is an S-CSCF or a P-CSCF. In the case of the S-CSCF, the lower communication partner is the P-CSCF via the IMS. On the other hand, in the case of the P-CSCF, the upper communication partner is the S-CSCF via IMS, and the lower communication partner is a terminal via the IMS and the access network. The HSS can communicate with both the S-CSCF and the P-CSCF.

  According to FIG. 6, the CSCF 1 includes a registration request receiving unit 101, a registration processing unit 102, a waiting state holding unit 103, a redirect reply unit 104, an arrangement change notification receiving unit 105, an authentication information acquiring unit 106, An authentication information determination unit 107 and a registration response transmission unit 108 are included. These functional components are realized by executing a program that causes a computer mounted on the CSCF to function.

  The registration request receiving unit 101 receives a location registration request REGISTER from the terminal 6. When the CSCF is the S-CSCF, the location registration request REGISTER is received from the terminal 6 via the P-CSCF2. The content information included in the location registration request is output to the registration processing unit 102.

  The registration processing unit 102 processes the location registration of the terminal. If the CSCF is a P-CSCF, the location registration request REGISTER is further transferred to the S-CSCF. If the CSCF is an S-CSCF, the location registration information is transmitted to the HSS 4.

  The arrangement change notification receiving unit 105 receives an arrangement change notification to change the location registration destination of the terminal to another CSCF from the HSS 4. The SIP-URI of the terminal that is the target of the location change notification is output to the waiting state holding unit 103. Further, when the arrangement change notification includes a waiting time, the waiting time is also output to the waiting state holding unit 103.

  The waiting state holding unit 103 shifts to a waiting state for the Re-REGISTER from the terminal that is the target of the location change notification. The fact that it has shifted to the waiting state is output to the redirect reply unit 104. In addition, when it shifts to the waiting state only for the waiting time and times out without receiving the Re-REGISTER at the waiting time, information to that effect is transmitted to the HSS.

When the redirect reply unit 104 is in a waiting state and receives a Re-REGISTER from the terminal, the redirect reply unit 104 returns a redirect message to redirect to the other SIP server. The redirect message includes the SIP-URI of the CSCF to be changed, for example 301
Moved.

  When receiving the Re-REGISER from the terminal, the authentication information acquiring unit 106 acquires the terminal authentication information from the HSS using the Diameter. The acquired authentication information is output to the authentication information determination unit 107.

  The authentication information determination unit 107 determines whether or not the authentication information of the terminal included in the Re-REGISTER matches the authentication information of the terminal acquired from the HSS. The determination result is output to the registration response transmission unit 108.

  The registration response transmission unit 108 returns an authentication failure notification to the terminal when the authentication information does not match, and includes a time interval value at which the terminal transmits a location registration request next when the authentication information matches. A location registration response is returned to the terminal.

  According to FIG. 6, the placement change control node 5 transmits a placement change notification to the HSS 4. The placement change control node 5 determines CSCF change according to the operator's instruction and the situation such as the IMS network load state.

  The HSS 4 stores the SIP-URI of the CSCF being registered for each SIP-URI of the terminal. When the HSS 4 receives the arrangement change notification, the HSS 4 determines whether the SIP-URI of the change-destination CSCF included in the arrangement change notification is different from the SIP-URI of the CSCF being registered for the terminal # 1. If they are different, the HSS 4 transmits an arrangement change notification including the SIP-URI of the change destination CSCF to the CSCF being registered. The HSS 4 stores the SIP-URI of the CSCF being registered in association with the SIP-URI of the terminal. Therefore, not only the S-CSCF being registered but also the SIP-URI of the P-CSCF being registered is stored.

  According to FIGS. 2 to 6, the HSS 4 and the arrangement change control node 5 are each represented as separate devices, but the functions of the arrangement change control node are integrally included in the HSS 4. Also good. In addition, according to FIGS. 2 to 6, the HSS 4 is represented to transmit a placement change notification to the CSCF, but the placement change control node 5 directly sends a placement change notification to the CSCF. You may transmit. However, in this case, the relocation control node 5 needs to store the CSCF being registered in association with the SIP-URI of the terminal.

  As described above in detail, the SIP server changing method, server, and program of the present invention can be a SIP server registered by a terminal in the IMS network without extending the technical specifications of the terminal. Changes can be made to other SIP servers.

  According to the present invention, even a CSCF in which a terminal is being registered can be changed to another CSCF according to the use situation such as optimization and maintenance of a functional configuration in the IMS network. Also, depending on the usage status from the terminal to the IMS network, it is possible to realize the distribution of the processing load for the CSCF having a high operation rate or the concentration of the processing load by stopping the CSCF having a low operation rate.

  In the various embodiments of the present invention described above, various changes, modifications, and omissions in the scope of the technical idea and the viewpoint of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

1, 11, 12 S-CSCF
DESCRIPTION OF SYMBOLS 101 Registration request receiving part 102 Registration processing part 103 Waiting state holding part 104 Redirect reply part 105 Arrangement change notification receiving part 106 Authentication information acquisition part 107 Authentication information determination part 108 Registration response transmission part 2, 21, 22 P-CSCF
3 I-CSCF
4 HSS, subscriber information server 5 relocation control node 6 terminal 7 IMS network 71 control network

Claims (11)

A plurality of SIP (Session Initiation Protocol) servers connected to an IP subsystem network, a method for changing a SIP server to which a terminal is connected,
A first SIP server receiving a location registration request from the terminal and processing location registration of the terminal;
When the first SIP server changes the location registration destination of the terminal to the second SIP server, the second step of shifting to a waiting state for a location registration request from the terminal;
A first step of returning a redirect message to redirect to the second SIP server when the first SIP server is in the waiting state and receives a location registration request from the terminal; The SIP server changing method, wherein the second SIP server receives a location registration request corresponding to the redirect. The IP subsystem network is an IMS (IP Multimedia Subsystem) network,
The SIP server is a call session control function (CSCF).
For the second step, the first CSCF sends a location change notification to change the location registration destination of the terminal to the second CSCF, and a subscriber information server (HSS: Home Subscriber Server) connected to the IMS network. The SIP server changing method according to claim 1, wherein the SIP server changing method is received from the SIP server.   The SIP server changing method according to claim 2, wherein the call session control function is an S-CSCF (Serving-CSCF) and / or a P-CSCF (Proxy-CSCSF). For the second step,
The location change notification received by the first CSCF from the HSS includes the SIP-URI of the terminal, the SIP-URI of the second CSCF to be changed, and a waiting time in a waiting state.
The first CSCF maintains a waiting state for the waiting time,
The SIP server changing method according to claim 2 or 3, wherein when the first CSCF times out without receiving the location registration request, information to that effect is transmitted to the HSS. The second SIP server to be changed is
When the location registration request is received from the terminal, the authentication information of the terminal is acquired from the HSS using a Diameter,
Determining whether the authentication information of the terminal included in the location registration request matches the authentication information of the terminal acquired from the HSS;
If both authentication information does not match, return an authentication failure notification to the terminal,
5. The device according to claim 2, wherein when the authentication information matches, the terminal returns a location registration response including a time interval value at which the terminal transmits a location registration request next to the terminal. The SIP server changing method described. An SIP server connected to the IP subsystem network and changing the location registration connected from the terminal to the other SIP server,
Registration request receiving means for receiving a location registration request from the terminal;
Registration processing means for processing location registration of the terminal in response to the location registration request;
Waiting state holding means for shifting to a waiting state for a location registration request from the terminal when the location registration destination of the terminal is changed to the other SIP server;
Redirect reply means for returning a redirect message to redirect to the other SIP server when receiving the location registration request from the terminal in the waiting state, and by the other SIP server, A SIP server, wherein a location registration request corresponding to a redirect is received. The IP subsystem network is an IMS network;
The SIP server is a call session control function (CSCF),
It further comprises an arrangement change notification receiving means for receiving an arrangement change notice for changing the location registration destination of the terminal to the second CSCF from a subscriber information server (HSS) connected to the IMS network. The SIP server according to claim 6.   The SIP server according to claim 7, wherein the call session control function of the SIP server is an S-CSCF and / or a P-CSCF. The location change notification received from the HSS includes the SIP-URI of the terminal, the SIP-URI of the CSCF to be changed, and a waiting time in a waiting state,
9. The waiting state holding unit maintains a waiting state for the waiting time, and when it times out without receiving the location registration request, transmits information to that effect to the HSS. The described SIP server. Authentication information acquisition means for acquiring authentication information of the terminal from the HSS using Diameter when receiving the location registration request from the terminal;
Authentication information determination means for determining whether or not the authentication information of the terminal included in the location registration request matches the authentication information of the terminal acquired from the HSS;
If both authentication information does not match, an authentication failure notification is returned to the terminal, and if both authentication information matches, the location registration response including a time interval value at which the terminal next transmits a location registration request is The SIP server according to any one of claims 5 to 9, further comprising a registration response transmission unit that replies to the terminal. A program for operating a computer mounted on a SIP server connected to an IP subsystem network and changing the location registration connected from the terminal to the other SIP server,
Registration request receiving means for receiving a location registration request from the terminal;
Registration processing means for processing location registration of the terminal in response to the location registration request;
Waiting state holding means for shifting to a waiting state for a location registration request from the terminal when the location registration destination of the terminal is changed to the other SIP server;
When receiving the location registration request from the terminal in the waiting state, the computer functions as a redirect reply means for returning a redirect message to redirect to the other SIP server, and the other SIP server A program for a SIP server, wherein a location registration request corresponding to the redirect is received.

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