Ims network system and data restore method

(54) Title: NETWORK SYSTEM TO RESTORE SUBSCRIBER DATA AND METHOD TO RESTORE SUBSCRIBER DATA IN A NETWORK SYSTEM (30) Unionist Priority: 02/04/2007 jp 2007-096810 (73) Holder (s): nec Corporation (72) Inventor (s): tamaki ishii (74) Attorney (s): Antonio Maurício Pedras Arnaud (86) International Application: pct JP2008056624 of 03/27/2008 (87) International Publication: W0 2008 / i23562de 10/16 / 2008 (57) Summary: network system for restoring SUBSCRIBER data and METHOD FOR RESTORING SUBSCRIBER DATA ON A NETWORK SYSTEM. When it is detected that subscriber data has been lost for any reason, such as node restart, the S-CSCF transmits a SIP RESET signal to notify the neighboring P-CSCF of the loss of subscriber data. When P-CSCF receives the SIP RESET signal, it searches for subscribers registered with the SCSCF who transmitted the SIP RESET signal. If any, P-CSCF performs FLAG control with respect to P-CSCF 'registration information to identify that subscriber data has been lost on S-CSCF, and transmits the SIP REGISTER signal to S-CSCF'. Upon receiving the SIP REGISTER signal, the S-CSCF restores lost subscriber data from the HSS subscriber database, performing registration processing according to existing procedures.

S101

<img file="BRPI0804477A2_D0001.tif" />

S102

RECONFIGURE SIGN (NOTIFICATION OF LOST SUBSCRIBER DATA)

S104 REGISTRATION CONTROL FOR EACH SUBSCRIBER 'S103

SEARCH RELEVANT SUBSCRIBER, AND LOSE FLAG CONTROL

ΡΙ0804477-5

NETWORK SYSTEM TO RESTORE SUBSCRIBER DATA AND METHOD TO RESTORE SUBSCRIBER DATA ON A NETWORK SYSTEM.

Field of the Invention

The present invention relates to an IMS network system (Multimedia IP Sub-System), and particularly to an IMS network system, characterized by the method of restoring subscriber data, when (Section Initiation Protocol) subscriber to perform a control of service, lose subscriber data for any reason, such as node restart.

History of the Invention of

SIP of a server having data

Studies have been carried out to build and standardize IMS (IP Multimedia Sub-systems) networks over 3 GPP (Third Generation Partnership Project) to flexibly provide voice, video, and other multimedia applications in packet communication networks based on IP technologies (Internet Protocol) and various related technologies, described in Patent Documents 1 to 3 and Non-Patent Document 1, for example.

Figure 9 is a conceptual diagram showing an IMS network configuration. A SIP 1 (Section Initiation Protocol) terminal is a subscriber terminal on the IMS network. A P-CSCF 2 is a SIP server with a section control function for direct proxy call access from the SIP 1 terminal. The S-CSCF 3 is a SIP server called S-CSCF (Service-CSCF) in an area service provider that the SIP 1 terminal directly subscribes to. An AS 4 is an application server that controls a common enabler connected to S-CSCF 3 to be shared by multiple services or to control each service. An HSS 5 is a home subscriber server that stores user subscription information.

The location of the SIP 1 terminal is recorded using registration procedures (user registration procedures) by Gm-I / F using the SIP protocol, whereby the SIP 1 terminal is enabled to enjoy IMS services including transmission / reception services via IMS network, using VoIP (Voice over Internet).

When receiving a SIP REGISTER signal from the SIP 1 terminal, the P-CSCF 2 acquires information on the S-CSCF 3 that provides IMS service, from the HSS 5 subscriber database via Dx I / F, using the Diameter protocol and transmitting the SIP REGISTER signal for S-CSCF 3 by Mw I / F using the SIP protocol. In addition, upon completion of the registration procedures, P-CSCF 2 records the

<td>information</td><td>in</td><td>record,</td><td>such</td><td>as</td><td>IP adress,</td><td>of</td>

<td>SIP terminal</td><td>1 and</td><td>the address</td><td>IP of</td><td colspan="3">S-CSCF 3 to perform</td>

<td>a control</td><td>in</td><td>relay of</td><td>signals</td><td>SIP</td><td>in services</td><td>IMS</td>

subsequent

When receiving a SIP REGISTER signal from a P-CSCF 2, SCSCF 3 acquires subscriber data from HSS 5 over Cx I / F using the Diameter protocol and records it, so that subsequent reception transmission services are performed accordingly. with subscriber data. In addition, S-CSCF 3 transmits the SIP REGISTER signal to AS 4 by ISC I / F using the SIP protocol according to iFC (Initial Filter Criterion) information contained in the subscriber data from HSS 5. Upon completion of the registration procedures, the S-CSCF 3 records registration information, such as the IP address of the PCSCF 2, in order to route to the P-CSCF 2 during the reception service.

When receiving SIP REGISTER signal from S-CSCF 3, AS 4 acquires subscriber data from HSS 5 via Sh I / f, using Diameter protocol, and records the same, so that subsequent transmission / reception services made according to the subscriber data. HSS 5 is a subscriber database for operating service data for all subscribers, and transmits subscriber data in response to a request from S-CSCF 3 or AS 4. In addition, HSS 5 notifies P-CSCF 2 of S-CSCF 3 to perform registration control in registration procedures, and record the address of the S-CSCF 3 from which the notification was made.

As described above, the IMS network downloads subscriber data from the HSS 5 subscriber database required by S-CSCF 3 or AS 4 to perform a receive transmission service, according to the SIP REGISTER signal from the terminal SIP 1 and providing a service according to the subscriber data, when it receives a service request including transmission and reception from the SIP 1 terminal.

Patent Document 1:

<td>Patent Publication Patent Document 2:</td><td>Kokai</td><td>Japanese</td><td>No.</td><td> 2005/064646</td>

<td>Patent Publication Patent Document 3:</td><td>Kokai</td><td>Japanese</td><td>No.</td><td> 2006/109478</td>

<td>Patent Publication Non-Patent Document</td><td>Kokai 1:</td><td>Japanese</td><td>No.</td><td> 2006/517064</td>

Series: IMS Becoming Core of NGN

WBB Forum- http://wbb.f0rum.impressed.jp/serial/list/78 Summary of the Invention

Problems to be solved by the Invention

In an IMS network according to the related technique, SCSCF 3 and AS 4 with subscriber data to perform service control are not provided with means of notification using IP protocol or registration control to activate the IMS node, when subscriber data is lost for any reason, such as node restart. Therefore, when S-CSCF 3 or AS 4 loses subscriber data for any reason, such as node restart, a transmit / receive service cannot be provided until a registration control is performed by the user, and the data subscriptions to be rebuilt.

A description will be made with respect to the transmission / reception control to be performed, when S-CSCF 3 has lost the subscriber data, for reasons such as restarting the node in the IMS network, according to the technique related with reference to the diagram of signal path shown in figure 10.

When a SIP terminal registered on the IMS network transmits a SIP INVITE signal (request to establish a section) as a transmission request to a P-CSCF via the S1001 access network, the P-CSCF transmits when it receives the SIP INVITE signal as a request for transmission, the SIP INVITE signal as a transmission request to an S-CSCF (Serving CSCF) based on the registration information record stored in the P-CSCF S1002. When it receives the SIP INVITE signals as a transmission request, the S-CSCF searches for the subscriber data that originates from the transmission request, and recognizes that the subscriber data no longer exists, since it has been lost.

Since there is no subscriber data, the S-CSCF cannot provide the transmission service, so it transmits a SIP error signal to the P-CSCF S1004. When P-CSCF receives the SIP error signal in response to the transmission request, it transmits the SIP error signal to the SIP S1005 terminal. Due to this processing, the user's transmission request is denied by the IMS network, so the transmission service cannot be provided until the subscriber data is reconstructed (restored).

When the S-CSCF receives an incoming request using SIP INVITE from the originating station S1006, the S-CSCF searches for a user's subscriber data, and recognizes that the subscriber data no longer exists, since the subscriber data have lost S1003. Since the subscriber data no longer exists, the S-CSCF determines which sending user has not performed the registration procedures and transmits a SIP error signal to the originating station S1007. Therefore, the provision of the reception service becomes impossible, even for a user who has performed the registration procedures, and to whom the registration service must be provided.

In view of the problems mentioned above, it is an objective of the present invention to provide an IMS network with means to restore lost subscriber data, when an S-CSCF has lost subscriber data for any reason such as restarting a node or similar without relying on SIP re-registration procedures by a SIP terminal, and quickly enabling the provision of transmission / reception services.

A network system for restoring IMS-type subscriber data according to the present invention comprises a P-CSCF connected to a SIP terminal, as a subscriber terminal via the access network; an S-CSCF located within a service provision area of ​​the provider that the SIP terminal subscribes to; and an HSS that stores user signature information, is characterized by the fact that the S-CSCF has the following functions: to transmit a SIP RESET signal to the neighboring P-CSCF, when the subscriber data acquired by the registration processing is lost; receiving a SIP REGISTER signal transmitted by the P-CSCF in response to the SIP RESET signal; and perform re-registration processing according to the received SIP REGISTER signal to restore lost subscriber data from the HSS.

Effects of the Invention

According to the invention, when a node having subscriber data loses the subscriber data, a neighboring node is notified by means of a new SIP RESET signal, whereby the neighboring node is enabled to immediately execute SIP registration procedures for reconstruct (restore) the subscriber data. Therefore, even if the IMS node has lost subscriber data, transmission / reception services can quickly be provided to the SIP terminal, without relying on SIP registration procedures via the SIP terminal.

Brief Description of Drawings

Figure 1 is a schematic diagram showing a first configuration of the present invention;

Figure 2 is an explanatory diagram of the procedures for restoring subscriber data, when an S-CSCF loses subscriber data in the first configuration;

Figure 3 is a schematic diagram showing a second configuration of the present invention;

Figure 4 is an explanatory diagram of the procedures for restoring subscriber data, when an AS has lost subscriber data in the second configuration;

Figure 5, showing a third configuration of the present invention, is an explanatory diagram of the procedures for restoring subscriber data, when an S-CSCF has lost the subscriber data, which procedure is triggered by user transmission;

Figure 6, showing a fourth configuration of the present invention, is an explanatory diagram of procedures for restoring subscriber data, when an AS has lost subscriber data, which procedure is triggered by user transmission;

Figure 7, showing a fifth configuration of the present invention, is an explanatory diagram of procedures for restoring subscriber data, when an AS has lost subscriber data, which procedure is triggered by user reception;

Figure 8, showing a sixth configuration of the present invention, is an explanatory diagram of procedures for restoring subscriber data, when an S-CSCF has lost subscriber data, which procedure is triggered by user reception;

Figure 9 is a conceptual diagram of the IMSI network configuration; and

Figure 10 is a signal trajectory diagram, showing transmission / reception control, when subscriber data is lost on a related technique IMSI network.

Best Way to Execute the Invention

A first configuration of the present invention will be described in connection with figures 1 and 2.

Figure 1 shows a first configuration of the invention and schematically illustrates the procedures for restoring data, when an S-CSCF has lost subscriber data on an IMS network.

In figure 1, when the S-CSCF detects that subscriber data has been lost for any reason, such as restarting node S101, the S-CSCF transmits a SIP signal

RESET to notify a neighboring P-CSCF that subscriber data has been lost S102. When P-CSCF receives the SIP RESET signal, it searches for subscribers registered with the SCSCF that transmitted the SIP RESET signal and, if any, performs FLAG control with respect to P-CSCF registration information to identify that subscriber data were lost on the S-CSCF S103, while transmitting a SIP REGISTER signal to this S-CSCF S104. Upon receiving the SIP REGISTER signal, the S-CSCF performs registration processing according to existing procedures to reconstruct (restore) lost subscriber data from an HSS S105 subscriber database.

Figure 2 shows in more detail the procedures to restore subscriber data, when the S-CSCF has lost subscriber data in a first configuration.

The operation of the first configuration will be described with reference to figures 1 and 2.

In figure 2, a SIP 1 terminal is registered on the IMS network.

The registration shown in figure 9 is made according to a SIP REGISTER signal from the SIP 1 terminal, and subscriber data required for S-CSCF 3 or AS 4 for transmission / reception services, is downloaded from a database. HSS 5 subscriber data, whereby the

S-CSCF 3 or AS 4 are ready to provide the service according to subscriber data, when receiving a service request, such as a reception / transmission request from the SIP 1 terminal.

In this state, S-CSCF 3 detects that subscriber data has been lost for any reason, such as restarting node S201, S-CSCF 3 transmits a SIP RESET signal to neighboring P-CSCF 2 notifying that subscriber data were lost (S202). The SIP RESET signal contains IP address information for the S-CSCF 3 that lost subscriber data.

When it receives the SIP RESET signal, the P-CSCF 2 transmits an OK SIP 200 signal in response to the S-CSCF 3 notifying that it has received the SIP RESET S203 signal. P-CSCF 2 searches the registration information tables in P-CSCF 2 for subscribers registered with the relevant S-CSCF 3 using the S-CSCF information signed in the SIP RESET signal as key S204.

If the survey determines that there is a subscriber registered on S-CSCF 3 who has lost subscriber data, processing is performed to establish the relevant subscriber's registration status on P-CSCF 2 as INCOMPLETE S205. After that, the P-CSCF 2 transmits a SIP REGISTER signal to the S-CSCF 3 to reconstruct (restore) the lost subscriber data on the S-CSCF 3 S206.

When receiving the SIP REGISTER signal, the S-CSCF 3 downloads the subscriber data from HSS 5 using the existing registration procedures indicated in S207 to

5210 to reconstruct (restore) the subscriber data, and then transmit an OK SIP 200 signal to the P-CSCF 2 in response to the SIP REGISTER signal.

When P-CSCF 2 receives the SIP 200 OK signal from S-CSCF 3, it recognizes that the lost subscriber data has been reconstructed (restored) and performs a processing to change the registration status of the relevant signed subscriber to COMPLETE (deletion) FLAG) S211. P-CSCF 2 performs a search processing until the entire record information table has been traversed S204, and repeats the procedures from S204 to

5211 for all S-CSCF 3 registered subscribers who have lost S212 subscriber data.

The S-CSCF 3 that lost subscriber data is enabled by the procedures described to perform a registration according to the SIP REGISTER signal initiated by P-CSCF 2, and thus reconstruct (restore) the lost subscriber data without having to receive a signal SIP REGISTER again from the SIP 1 terminal.

A second configuration of the present invention will be described in correction with figures 3 and 4.

Figure 3 shows a second configuration of the present invention, and schematically illustrates the procedures for restoring data, when an AS loses subscriber data on an IMS network.

In figure 3, when the AS detects that the subscriber data has been lost for any reason, such as restarting node S301, the AS receives a SIP RESET signal notifying the neighboring S-CSCF that the subscriber data has been lost S302. Upon receiving the SIP RESET, the S-CSCF searches for subscribers registered with the AS that transmitted the SIP RESET signal, and, if any, performs FLAG control over the S-CSCF subscriber data to identify that subscriber data in the AS S303 were lost, while transmitting a SIP REGISTER signal to the AS S204. Upon receiving the SIP REGISTER signal, the AS performs registration processing according to existing procedures to reconstruct (restore) lost subscriber data from an HSS S205 subscriber database.

Figure 4 shows in more detail the procedures for restoring subscriber data according to a second configuration, when the AS loses subscriber data. The operation of the second configuration will be described with reference to figures 3 and 4. '

When AS 4 detects that the subscriber data acquired through the described registration procedures has been lost for any reason, such as restarting node S401, AS 4 transmits a SIP RESET signal to notify neighboring S-CSCF 3 of the loss of data from S402 subscriber. The SIP RESET signal contains AS 4 IP address information that has lost subscriber data.

When receiving the SIP RESET signal, the S-CSCF 3 transmits a SIP 200 OK signal in response to AS 4 to notify the reception of the SIP RESET S403 signal. S-CSCF 3 searches for a registration information table in S-CSCF 3 with respect to subscribers registered in the relevant AS 4 using the AS information signed in the SIP RESET signal as the S404 key.

If any subscriber registered in AS 4 has lost subscriber data, S-CSCF 3 performs a procedure to sign the relevant subscriber's registration status in INCOMPLETE in S-CSCF 3 (FLAG determination) S405. The S-CSCF 3 then transmits a SIP REGISTER signal to AS 4 to reconstruct (restore) the lost subscriber data on the AS 4 S406. When receiving the SIP REGISTER signal, AS 4 downloads the subscriber data from HSS 5 through existing registration procedures indicated by S407 to S410 to reconstruct (restore) the subscriber data, and then transmits a SIP 200 OK signal to the S- CSCF 3 in response to the SIP REGISTER signal.

When SCSCF 3 receives the SIP 200 OK signal from AS 4, it recognizes that lost subscriber data has been reconstructed (restored), and changes the relevant subscriber's registration status to COMPLETE (cleared FLAG) S411. S-CSCF 3 searches until the entire registration information table has been traversed through S404, and repeats the procedures from S404 to S411 for all subscribers registered in AS 4 who have lost S412 subscriber data.

By the procedures described above, the AS 4 that lost the subscriber data is enabled to register according to the SIP REGISTER signal initiated by P-CSCF 3, and thus reconstruct (restore) the lost subscriber data without having to receive a signal again SIP REGISTER from the SIP 1 terminal.

In the above configuration, P-CSCF or S-CSCF searches for subscribers who require SIP registration procedures when it receives a SIP RESET signal (new) and immediately transmits a SIP REGISTER signal to reconstruct (restore) the subscriber data. However, if the IMS network has a large number of subscribers, a large volume of SIP REGISTER signals is exchanged in a short period of time, probably causing a temporary increase in network load.

Considering the network load, the procedures for restoring subscriber data can be performed so that the transmission of the SIP REGISTER signal is triggered by user transmission / reception. A description of a configuration will be provided, in which the restoration of subscriber data is triggered by user transmission / reception.

A third configuration of the present invention will be described in connection with figure 5.

Figure 5, showing the third configuration of the present invention, is an explanatory diagram of the procedures that must be performed when triggering the restoration of subscriber data by a user transmission, when the S-CSCF has lost the subscriber data. The operation of the third configuration will be described with reference to figure 5.

When S-CSCF 3 detects that subscriber data has been lost for any reason, such as restarting node S501, S-CSCF 3 transmits a SIP RESET signal to a neighboring P-CSCF 2 notifying that subscriber data has been lost S502. The SIP RESET signal contains IP address information for the S-CSCF 3 that lost subscriber data.

When receiving the SIP RESET signal, the P-CSCF 2 transmits a SIP 200 OK signal in response to the S-CSCF 3 notifying the reception of the SIP RESET S503 signal. P-CSCF 2 searches for a registration information table in P-CSCF 2 with respect to registered subscribers to the relevant S-CSCF 3 using the S-CSCF information signed in the SIP RESET signal as key S504.

When there is a subscriber registered on the S-CSCF 3 who lost the subscriber data, the P-CSCF 3 enters the registration status on the P-CSCF 2 in INCOMPLETE (FLAG determination) S505. Search processing is performed until the entire registration information table is traversed through S504, and the S505 procedures are repeated for all subscribers registered on S-CSCF 3 who have lost S506 subscriber data.

When performing S507 transmission operation, SIP terminal 1 issues a transmission request to P-CSCF 2 for a SIP INVITE S508 signal. When P-CSCF 2 receives the SIP INVITE signal, it searches for a registration information table with respect to a relevant subscriber, determines the registration status entered in steps 504 to S505, and recognizes that the registration status is in INCOMPLETE ( FLAG determination) S509.

Recognizing the registration status in INCOMPLETE, the PCSCF 2 transmits a SIP REGISTER signal to the S-CSCF 3 to reconstruct (restore) the lost subscriber data on the S-CSCF 3 S510. Upon receiving the SIP REGISTER signal, the S-CSCF 3 downloads the subscriber data from the HSS 5 through existing registration procedures, and then transmits a SIP 200 OK signal to the P-CSCF 2 in response to the SIP REGISTER S514 signal.

Upon receiving the SIP 200 OK signal from the S-CSCF 3, P-CSCF 2 recognizes that the lost subscriber data has been reconstructed, and performs processing to change the relevant subscriber's registration status to COMPLETE (FLAG determination) S515. When the subscriber's registration status changes to COMPLETE, P-CSCF 2 performs an INVITE transmission processing, according to existing S516 procedures.

According to this configuration, the configuration is made so that each time the P-CSCF 2 receives a SIP INVITE signal, the S-CSCF 3 reconstructs (restores) the subscriber data from the SIP terminal that transmitted the SIP INVITE signal , preventing a large volume of SIP INVITE signals from being exchanged in a short period of time and, therefore, a temporary increase in network load. A fourth configuration of the present invention will be described in connection with figure 6.

Figure 6, showing a fourth configuration of the present invention, is an explanatory diagram of the procedures that must be performed when triggered by user transmission, when the AS has lost subscriber data. The operation of the fourth configuration will be described with reference to figure 6.

When AS 4 detects that subscriber data has been lost for any reason, such as restarting node S601, AS 4 transmits a SIP RESET signal to the neighboring S-CSCF 3 notifying that subscriber data has been lost S602. The SIP RESET signal contains AS 4 IP address information that lost subscriber data. When receiving the SIP RESET signal, the S-CSCF 3 transmits to the AS 4 a SIP 200 OK signal in response notifying the reception of the SIP RESET S603 signal. 0 S-CSCF 3 searches for subscriber data in S-CSCF 3 with respect to subscribers registered in the relevant AS 4, using AS information signed in the SIP RESET signal, as key S604.

If there is a subscriber registered in AS 4 who has lost subscriber data, the S-CSCF 3 procedure for entering the relevant subscriber data in S-CSCF 3 in (FLAG determination) S604. S-CSCF 3 performs an INCOMPLETE registration performs a search procedure until it covers all S604 subscriber data and repeats the S605 procedure for all subscribers registered in AS 4 that lost S606 subscriber data.

When the user performs an S607 transmission operation, the SIP terminal 1 issues a transmission request to the P-CSCF 2 via a SIP INVITE S608 signal. When P-CSCF 2 receives the SIP INVITE signal, it transmits the SIP INVITE signal to the S-CSCF 3 according to the S-CSCF 3 address information on the SIP INVITE S609 signal. When receiving the SIP INVITE signal, the S-CSCF 3 searches the subscriber data table with respect to the relevant subscriber, and determines the registration status established in procedures S604 to S605, and recognizes the registration status in INCOMPLETE S610.

Recognizing the registration status in INCOMPLETE, S-CSCF 3 transmits a SIP REGISTER signal to AS 4 to reconstruct (restore) the lost subscriber data on AS 4 S611. When receiving the SIP REGISTER signal, AS 4 downloads the subscriber data from HSS 5 using existing registration procedures indicated in S612 to S615 to reconstruct (restore) the subscriber data, and then transmits a SIP (200) OK signal to the S-CSCF 3, in response to the SIP REGISTER signal.

When SCSCF 3 receives the SIP 200 OK signal from AS 4, it recognizes that the lost subscriber data has been reconstructed, and performs processing to change the relevant subscriber's registration status to COMPLETE (FLAG determination) S616. When the subscriber's registration status changes to COMPLETE, the S-CSCF 3 performs an INVITE transmission processing, according to existing S617 procedures.

According to a fourth configuration, a configuration is provided, so that each time S-CSCF 3 receives a SIP INVITE signal from P-CSCF 2, AS 4 reconstructs (restores) the subscriber data of the terminal SIP that transmitted the SIP INVITE signal, preventing a large volume of SIP INVITE signals from being exchanged in a short period of time and, therefore, a temporary increase in network load.

A fifth configuration of the present invention will be described in connection with figure 7.

Figure 7, showing the fifth configuration of the present invention, is an explanatory diagram of the procedures to restore subscriber data to be performed by triggering user reception, when the AS has lost the subscriber data. The operation of the fifth configuration will be described with reference to figure 7.

When AS 4 detects that subscriber data has been lost for any reason, such as restarting node S710, AS 4 transmits a SIP RESET signal to the neighboring S-CSCF 3 notifying that subscriber data has been lost S702. The SIP RESET signal contains the information of the AS 4 IP address that lost the subscriber data.

When receiving the SIP RESET signal, the S-CSCF 3 transmits to the AS 4 a SIP 200 OK response signal notifying the reception of the SIP RESET S703 signal. In addition, S-CSCF 3 searches for subscriber data in S-CSCF 3 with respect to subscribers registered in AS 4 using the AS information entered as a key in the SIP RESET S704 signal.

If there is a subscriber registered in AS 4 that has lost subscriber data, S-CSCF 3 performs a processing to establish the registration status of the relevant subscriber in S-CSCF 3 in (FLAG determination) S705. The S-CSCF 3 poll processing until all S704 subscriber data is passed, and it repeats the S705 procedure for all subscribers registered in AS 4 who lost S706 subscriber data.

When S-CSCF 3 receives a SIP INVITE reception request from a subscriber whose subscriber data has been lost by AS 4, S-CSCF 3 searches a subscriber data table with respect to the relevant subscriber, and determines the status of signed in procedures S704 to S705, and recognizes the registration status in INCOMPLETE S708.

When receiving the SIP 200 OK signal from AS 4, SCSCF 3 recognizes that lost subscriber data

INCOMPLETE performs the reconstructed (restored) processing to change the relevant subscriber state to COMPLETE and performs a registration (determination of

FLAG) S714. When the subscriber's registration status changes to COMPLETE, the S-CSCF 3 performs an INVITE receive processing according to existing S715 procedures.

According to the fifth configuration, the configuration is such that each time the S-CSCF 3 receives a reception request signal, AS 4 restores the subscriber data from the SIP terminal, from which the reception request was received , preventing a large volume of SIP REGISTER signals from being exchanged in a short period of time, and therefore a temporary increase in network load.

A sixth configuration of the present invention will be described in connection with figure 8.

Figure 8, showing the sixth configuration of the present invention, is an explanatory diagram of the procedures for restoring subscriber data by triggering by user reception, when the S-CSCF has lost the subscriber data.

In the procedures to restore subscriber data triggered by an INVITE reception, when the subscriber data was lost in the S-CSCE, the HSS works only with the registered S-CSCF addresses, although it does not work with the P-CSCF address. Therefore, S-CSCF is unable to activate P-CSCF via INVITE reception. Therefore, the procedures for restoring subscriber data described in figures 5, 6, 7, (third, fourth, and fifth configurations) are not sufficient.

The sixth configuration, therefore, has an additional step to transmit the P-CSCF address information acquired by the S-CSCF to the HSS, when the SIP terminal 1 performs the SIP registration (user registration) to register it in the HSS, so that P-CSCF address information is used in the procedures to restore subscriber data on S-CSCF 3. The operation of the sixth configuration will be described in connection with figure 8. When the SIP 1 terminal transmits a SIP REGISTER signal to P-CSCF 2 for the S801 SIP (user registration) register, the P-CSCF 2 receiving this SIP REGISTER signal performs existing procedures S802 to S803 to acquire information from HSS 3 address of the S-CSCF 3 from which the registration was made, and transmits a SIP REGISTER signal to the S-CSCF 2 S804.

When receiving the SIP REGISTER signal from P-CSCF 2, the S-CSCF 3 transmits the Diameter SAR signal to the HSS 5 to request subscriber data, while at the same time signing the PCSCF 2 address information into the Diameter SAR signal, that should be used in the procedures to restore subscriber data on the S-CSCF 3 S805. When it receives the Diameter SAR signal with P-CSCF 2 address information on it, the HSS 5 stores the P-CSCF 2 address information as S806 subscriber data, and transmits the Diameter SAA signal having the subscriber data to the S-CSCF 3 S807.

When receiving the Diameter SAA signal, the S-CSCF 3 stores the received subscriber data and transmits to the P-CSCF 2 a SIP 200 OK signal, indicating that the SIP registration has been successfully made S808. When P-CSCF 2 receives the SIP 200 OK signal, it transmits the SIP 200 OK signal to the SIP 1 terminal S809. The S-CSCF 3 performs existing S810 procedures to build the AS 4 subscriber data. This completes the SIP registration procedures from the SIP 1 terminal.

In this SIP registration state, when S-CSCF 3 receives a SIP INVITE receipt request for a subscriber whose subscriber data has been lost by S-CSCF 3 S815 in a state in which S-CSCF 3 has lost subscriber data by for any reason, such as restarting node S814, S-CSCF 3 searches the subscriber data for the purpose of performing a receive processing for the relevant subscriber, and recognizes that the subscriber's subscriber data no longer exists, since the subscriber data was lost S816.

When it recognizes that the subscriber data no longer exists, the S-CSCF 3 transmits a Diameter SAR signal to the HSS 5 to acquire S817 subscriber data. The Diameter SAR signal in step S817 does not contain address information from P-CSCF 2, since S-CSCF 3 does not store information from P-CSCF 2.

When receiving the Diameter SAR signal that does not contain the address information from the P-CSCF 2, HSS 5 recognizes that the signal is a request to acquire subscriber data by restoring subscriber data, and transmits the SCSCF 3 the Diameter SAA signal containing the P-CSCF 2 address information stored in step S806 signed in the same S818. Upon receiving the Diameter SAA signal, SCSCF 3 completes the data restoration by storing subscriber data and address information from P-CSCF 2 S819. Completing the procedures to restore subscriber data, the S-CSCF 3 performs a reception processing, transmitting to the P-CSCF 3 an INVITE reception signal, according to existing procedures.

According to a sixth configuration, even if the S-CSCF has lost the P-CSCF address to which an INVITE reception is to be transmitted, the S-CSCF is able to download the P-CSCF address from AS 4 or request transmission from the P-CSCF address by broadcasting to AS 4.

This means that the present invention is characterized by the fact that when data is lost by an S-CSCF or AS in an IMS network for any reason, such as node restart, the node that lost the subscriber data notifies a neighboring node of this effect, and the neighboring node when it receives the notification initiates a control to reconstruct (restore) the subscriber data on the node that lost the subscriber data, whereby lost subscriber data is restored without asking the user to perform a re-registration operation by switching it on and off.

More specifically, the present invention provides an IMS network having a P-CSCF connected to a SIP terminal as a subscriber terminal via the access network; an S-CSCF located in a service provision area of ​​the provider that the SIP terminal subscribes to; and an HSS that stores user signature information characterized by the fact that the S-CSCF has a function to transmit a signal

SIP RESET to the neighboring P-CSCF, when it loses the subscriber data acquired by the registration process, a function to receive a SIP REGISTER signal transmitted by the P-CSCF in response to the SIP RESET signal, and a function to restore the lost subscriber data from the HSS, performing a re-registration processing, according to the received SIP REGISTER signal.

In addition, the configuration can be such that the P-CSCF has a function to search registration information in the P-CSCF with respect to subscribers registered in the S-CSCF when it receives the SIP RESET signal, a function to perform a FLAG control on the information of a relevant subscriber's record to identify that subscriber data has been lost in the S-CSCF, a function of transmitting to the S-CSCF a SIP REGISTER signal from the relevant subscriber, and a function to clear FLAG control when receiving a response signal from the S-CSCF in response to the SIP REGISTER signal transmitted to it. Alternatively, P-CSCF may have a function to search P-CSCF registration information with respect to subscribers registered with S-CSCF, when receiving SIP RESET signal, a function to perform FLAG control on a subscriber's registration information relevant to identify that subscriber data has been lost on the S-CSCF, a function of transmitting a SIP INVITE signal from the relevant subscriber to the S-CSCF when it receives a transmission request from the SIP terminal, in which a FLAG control is performed, and a function to clear FLAG control, when it receives a response signal from the S-CSCF in response to the SIP REGISTER signal transmitted to it, and then perform the transmission procedure in response to the request for SIP INVITE transmission.

Furthermore, the invention can be configured so that, in an IMS network comprising a P-CSCF connected to a SIP terminal as a subscriber terminal via the access network, an S-CSCF located in a service provision area of ​​the provider that the SIP terminal signs, and an HSS that stores user signature information, the SCSCF has a function of transmitting a Diameter SAR signal transmitted to the HSS when it executes one that should be processing the registration information, address while signing on the P-CSCF that transmitted a SIP REGISTER signal, a function to transmit to the HSS a Diameter SAR signal that does not contain address information from the P-CSCF, when receiving a SIP INVITE reception request, when data subscribers acquired by registration processing are lost, a function to receive a Diameter SAA signal with address information signed by the HSS to the Diameter SAR signal that does not contain the address information of the P-CSCF, a function for P-CSCF in response information to restore lost subscriber data and P-CSCF address information, performing a re-registration processing, according to the received Diameter SAA signal, and a function for performing reception processing via of a SIP INVITE reception request, according to the restored subscriber data.

In this case, the HSS is configured to have a transmit function, when it receives a Diameter SAR signal that does not contain the P-CSCF address information from the SCSCF, a Diameter SAA signal containing P-CSCF address information stored during the registration processing, to the S-CSCF.

The IMS network according to the present invention can be additionally provided with an AS activated by S-CSCF according to the subscription status of each user to perform the respective application services, the AS has the function of transmitting a SIP RESET signal S-CSCF, when subscriber data acquired during registration processing is lost, a function of receiving a SIP REGISTER signal transmitted by S-CSCF in response to the SIP RESET signal, and a function to restore the lost subscriber data from the HSS, performing a re-registration processing, according to the received SIP REGISTER signal.

A method of restoring subscriber data on an IMS network, in accordance with the present invention, is characterized by the fact that the S-CSCF transmits a SIP RESET signal to the neighboring P-CSCF, when the subscriber data acquired by registration processing are lost, receive a SIP RESET signal transmitted by the P-CSCF in response to the SIP RESET signal, and perform re-registration processing according to the received SIP REGISTER signal to reconstruct (restore) the lost subscriber data from the HSS.

Specifically, according to the present invention, firstly a neighboring node is notified, by means of a SIP RESET signal, that an IMS node (S-CSCF or AS) with subscriber data has lost subscriber data for any reason, such as restarting a node, or similar. This allows the neighboring node to recognize that it is unable to provide a transmit / receive service to a related subscriber. Thus, the neighboring node performs registration procedures for subscribers whose subscriber data has been lost. Thus, the IMS node with subscriber data is enabled to reconstruct (restore) the subscriber data, immediately after detecting that the subscriber data has been lost, and to provide transmission / reception services similar to those provided before the subscriber data had been lost.

Although the present invention has been described based on the above configurations, it is not limited to these configurations. For example, although the method of restoring data according to said configuration is restricted to an IMS network, the method of restoring data of the invention is equally suitable for any network operating similarly to the IMS network. Particular configurations and details of the present invention may be altered in several ways, conceivably to those skilled in the art, without departing from the scope of the claims of the present invention.

This patent application is based on and claims priority benefits from Japanese Patent Application No. 2007-096810, filed on April 2, 07, the description of which is incorporated herein by reference in its entirety.