WO2007052894A1

WO2007052894A1 - Distributed hss (home subscriber server) architecture

Info

Publication number: WO2007052894A1
Application number: PCT/KR2006/003657
Authority: WO
Inventors: Hoe Rim Choi; Joon Seok Noh; Woon Yeong Lee
Original assignee: Kt Corporation; Samsung Electronics Co., Ltd.
Priority date: 2005-09-14
Filing date: 2006-09-14
Publication date: 2007-05-10
Also published as: KR20070031155A

Abstract

The present invention relates to a distributed-home subscriber server including a first server for transmitting, receiving and managing subscriber registration and location information management messages in conjunction with an Interrogating-Call Session Control Function I-CSCF; a second server for transmitting, receiving and managing messages performing downloading and updating of the subscriber registration, the location information and profiles, and subscriber authentication in conjunction with an Serving-Call Session Control Function S-CSCF; a third server for transmitting, receiving and managing the subscriber data messages in conjunction with an application server of an IP Multimedia Subsystem IMS network; and a central information management server for storing and managing subscriber information in the IMS network and providing the subscriber information for performance of operations of the first, second and third servers.

Description

DISTRIBUTED HSS (HOME SUBSCRIBER SERVER) ARCHITECTURE

BACKGROUND OF THE INVENTION Field of the Invention The invention relates generally to a distributed-home subscriber server and, more particularly, to a distributed-home subscriber server, which includes sub-servers independently operating for the messages processed in the distributed-home subscriber server.

Description of the Background Art Currently, 3rd Generation Partnership Project 3GPP has been proposed as a new standard for producing, delivering and reproducing multimedia through a high-speed wireless network. An IP Multimedia Subsystem IMS suggested in 3GPP is a system for providing next generation IP-based multimedia services.

An IMS service refers to a service for simultaneously providing various types of packet-based services, which are based on an EP transmission protocol, to mobile subscribers, which enable subscribers to simultaneously use not only a conventional realtime service, such as conventional voice call or image transmission, but also a non-real time service, such as the transmission of files, e-mails and short messages, and, furthermore, allows a new service applying the services. As the important functional elements of a sub-system in the core network of IMS for providing the IMS service, there are a Call Session Control Function hereinafter referred to as a CSCF and a Home Subscriber Server HSS.

The home subscriber server acts as the master database of subscribers, and is a kind of database into which the function of a Home Location Register HLR and the function for the mobility management and authentication of IP multimedia subscribers are integrated.

The CSCF is a device for performing registration using a Session Initiation Protocol SIP and multimedia call processing, and is divided into a Proxy-CSCF Hereinafter referred to as a P-CSCF, an Interrogating-CSCF Hereinafter referred to as an I-CSCF and a Serving-CSCF Hereinafter referred to as an S-CSCF.

The P-CSCF is a point at which subscribers initially access a network, functions to deliver SP registration request messages from the subscribers to the I-CSCF with reference to the home domain of the subscriber, and maintains a security relationship with the subscribers.

The I-CSCF acquires the address of the S-CSCF which actually the SIP registration of subscribers from the home subscriber server and performs assignment of the S-CSCF which performs the actual registration of the subscribers. The S-CSCF downloads and stores a subscription information of subscribers from the home subscriber server and provides a corresponding service to the subscribers.

In the above-described procedure, accesses of the I-CSCF and the S-CSCF to the home subscriber server occur, but two pieces of information requested by the accesses are different.

However, since the home subscriber server has all information necessary for the I- CSCF and the S-CSCF for management of the subscription information of subscribers, accesses to the home subscriber server by the I-CSCF and the S-CSCF frequently occur.

As a result, there is a problem in that the home subscriber server can be in an overload state even when equipment, such as the I-CSCF, or S-CSCF is not in an overload state.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a system having a disbributed-structure, which divides a home subscriber server into several parts for messages used in respective devices interworking therewith, and independently operates the several parts, thereby distributing traffics and process loads in the home subscriber server.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to the following drawings in which like numerals refer to like elements. The accompany drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a diagram illustrating the configuration of a home subscriber server having a distributed-structure according to the present invention. FIG. 2 is a diagram illustrating the configuration of the HSS-I of FIG. 1 in detail. FIG. 3 is a diagram illustrating the configuration of the HSS-S of FIG. 1 in detail. FIG. 4 is a diagram illustrating the configuration of the HSS-AS of FIG. 1 in detail.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described in a more detailed manner with reference to the drawings.

FIG. 1 is a diagram illustrating the configuration of a distributed-home subscriber server according to the present invention. The distributed-home subscriber server includes an HSS distribution system 100, an I-CSCF 200, an S-CSCF 300 and an AS 100.

The HSS distribution system 100 is a system for storing and managing basic information related to subscribers, which is implemented by logically dividing the home subscriber server HSS. The HSS distribution system 100 is a system for storing and managing subscriber information including subscriber identifiers, the security information of subscribers, the location information of the subscribers, and the service profiles of the subscribers. In this case, the subscriber identifiers are numbers(Private Identity) and address information(Public Identity), which identify subscribers. The security information of subscribers is network access control information for authentication and the verification of authority. The location information of subscribers includes registration and mobility information in the level of an inter-system.

The HSS distribution system 100 includes an HSS central database 110, an HSS-I 120, an HSS-S 130 and an HSS-AS 140 for efficiency of the operation thereof.

The HSS central database 110 functions to collectively store and manage subscriber information subscriber profile information, location information, registration, profile updating, subscriber authentication, etc., and deliver updated information at the time of changing information.

The HSS-I 120 is a server interworking with an I-CSCF 200, which stores and manages information necessary for the I-CSCF 200. In particular, the HSS-I 120 is updated with information about private IDs, public IDs, server names, server capabilities, network IDs, IMS subscriber state information IMSUserState and un-registered service flag Unreg_Service_flag from the HSS central database 1 10. The information updated from the HSS central database 110 is described below in detail. In an IMS environment, a subscriber has a private ID and a public ED. The private ID is an ID mainly used for authentication when the subscriber initially performs registration through a terminal, whereas the public ID is an address-type ID used for call routing between actual subscribers.

Furthermore, the server name represents the name of an S-CSCF in which a subscriber actually registers, and which downloads the service profile of a corresponding subscriber and serves the corresponding subscriber.

The server capability is a value determined by services in which a subscriber registers, and a parameter guiding the subscriber to register in which S-CSCF the subscriber will register in upon initial registration. The network ID enables a provider operating an IMS environment to identify which specific network a roaming subscriber registers in. For example, when one subscriber tries to perform registration, the HSS identifies the roaming location of the subscriber and then checks whether the location information is included in the network ID. As a result of the determination, when the location information is included in the network ID, the registration of the subscriber at the corresponding location is accepted. Otherwise, the registration is denied.

The IMS subscriber state information IMSUserState is a parameter representing the current registration state of an IMS subscriber. The IMS subscriber state information IMSUserState is divided into a registered state, an unregistered state and a not-registered state where registration cannot be allowed. In particular, a subscriber which is in the unregistered state is substantially in the not-registered state, but, if the subscriber, subscribes to any service with which the subscriber can be provided even in the not registered state, is managed as the unregistered state, rather than the not-registered state. An unregistered service flag Unreg_Service_flag indicates whether a subscriber subscribes to any one service in which the subscriber is managed as the unregistered state.

Furthermore, HSS-I 120 transmits and receives a User Authorization

Request/Answer UAR/UAA message and a Location Information Request/Answer

LIR/LIA message to and from the I-CSCF 200 using a path connected therebetween. The UAR/UAA message is a message used for subscriber authentication and registration to the S-CSCF 300, and the LIR/LIA message is a message used to check out the location of the S-CSCF 300 server, which currently provides services to the subscriber. Furthermore, HSS-I 120 updates HSS central database 110 with information about the IMS subscriber state internally changed.

For this, as illustrated in FIG. 2, the HSS-I 120 includes an UARAJAA process module 121, a LIR/LIA process module 122, and a local database DB 123. The UARAJAA process module 121 transmits and receives the UARAJAA messages and processes them. That is, the UARAJAA messages are used to check the S-CSCF information server-name or server-capabilities of a corresponding subscriber when the subscriber initially tries to perform registration. The I-CSCF 200, having received the S-

CSCF information through the UARAJAA message, determines which S-CSCF the subscriber registers in.

Meanwhile, the LIR/LIA process module 122 transmits and receives the LIR/LIA messages and processes them. The local DB 123 stores and manages information updated by the HSS central database 110, so that it is possible to inquire about and use the updated information stored in the local DB 123 without inquiry about information to the HSS central database 110 when the updated information is needed.

The HSS-S 130 is a server inter-working with the S-CSCF 300, which stores and manages information necessary for the S-CSCF 300. For this, the HSS-S 130 transmits and SAR/SAA Server Assignment Request/Answer, MAR/MAA Multimedia

Authentication Request/Answer, RTR/RTA Registration Termination Request/Answer, PPR/PPA Push Profile Request/ Answer messages to and from the S-CSCF 300.

In this case, the SAR/SAA messages are messages used for the storage of the name of a server which currently provides services to a subscriber, and are used to perform downloading and updating of the subscriber registration, the location information and profiles information, and subscriber authentication. The RTRA3.TA messages are messages for termination of subscriber registration, and the subscriber registration is terminated by force at the time of being abnormal. The MAR/MAA messages are used for transmission of security information and performance of subscriber authentication. The PPR/PPA messages are messages for updating of the subscription information of multimedia subscribers when change of subscription data constituting data, used in client equipment, occurs.

For this purpose, as illustrated in FIG. 3, the HSS-S 130 includes a SAR/SAA process module 131, a MAR/MAA process module 132, a PPR/PPA process module 133 and a RTR/RTA module 134. The SAR/SAA process module 131 transmits and receives SAR/SAA messages to process them. The MAR/MAA process module 132 transmits and receives MAR/MAA messages to process them. The PPR/PPA process module 133 transmits and receives PPR/PPA messages to process them. The RTR/RTA process module 134 transmits and receives RTR/RTA messages to process them.

In this case, the HSS-S 130 does not need an additional local DB because information from the HSS central database 110 is not updated and stored.

Instead, when a data processing request for each message from the S-CSCF 300 occurs, respective process modules 131 to 134 fetch required data from the HSS central database 110 and process it, thereby inter-working with the S-CSCF 300.

The HSS-AS 140 is a server interworking with an Application Server hereinafter referred to as an AS, which stores and manages information necessary for the AS 400. In particular, the HSS-AS 140 and the AS 400 transmit and receive PUR/PUA Profile Update Request/Answer, UDRAJDA User Data Request/ Answer, SNR/SNA Subscribe Notification Request/ Answer, PNR/PNA Profile Update Request/ Answer messages through a path connected therebetween. In this case, the PUR/PUA message is a message for updating of subscriber data in a server, the UDR/UDA messages are messages related to the request of subscriber data, the SNR/SNA messages are messages requesting notification of the change of subscriber data, and PNR/PNA messages are messages announcing the change of subscriber data.

For this, the HSS-AS 140 includes a PUR/PUA process module 141, an UDR/UDA process module 142, an SNR/SNA process module 143, a PNR/PNA process module 144, a repository data DB 145 and a local DB 146 as illustrated in FIG. 4.

The PUR/PUA process module 141 transmits and receives PUR/PUA messages and processes them. The UDR/UDA process module 142 transmits and receives

UDR/UDA messages and processes them. The SNR/SNA process module 143 transmits and receives SNR/SNA messages and processes them. The PNR/PNA process module

144 transmits and receives PNR/PNA messages and processes them.

Furthermore, the repository data DB 145 is an arbitrary database which in an open state, and is corresponding to the management region of the HSS-AS 140 excluding the management region of the HSS central database 1 10, so that the information change of repository data is not updated in the HSS central database 1 10. Therefore, the HSS-AS 140 is interworking with the AS 400 without inquiry about information to the HSS central database 110.

The local DB 146 is updated with public identifications, server names, server capabilities, IMS subscriber state information IMS UserState and profile information and stores and manages them. Since, the public ID, the server name, the server capability and the IMS subscriber state information IMS UserState have been previously described, the detail descriptions are omitted. It should noted that the profile information is a XML type profile having information allowing triggering to an application server providing related services by performing filtering based on the content of SIP messages transmitted and received by an subscriber when the subscriber subscribes to any service.

In this case, the updated information can be changed in the HSS central database 110, rather than in the HSS AS. Therefore, the updating of changed information is performed from the HSS central database 110 to the HSS-AS 140.

I-CSCF 200 is a first point at which subscribers access a home network, the number of which may be several in one network domain. Furthermore, the I-CSCF 200 functions to assign the S-CSCF 300 which actually performs the registration when receiving the address of the S-CSCF 300 which performs the SIP registration of subscribers from the HSS distribution system 100, to route an SIP message received from another network to the S-CSCF 300 and to generate a Charge Data Record thereinafter referred to as a CDR.

The S-CSCF 300 is an equipment for controlling the sessions of subscribers, which functions to acquire subscriber information from the home subscriber server and then store the subscriber information, to manage the session states of registered subscribers, to perform control services, and to acquire the address of the I-CSCF 200 of a called subscriber through the dialed number and of subscribers or SIP URL.

The AS 400 is a local application server, which provides services to a corresponding area, and accesses the home subscriber server on purpose to check whether a service requested by a subscriber is a valid request.

The types of messages described in this specification are disclosed in TS 29.229 and TS 29.329.

As described above, in the distributed home subscriber server of the present invention, according to messages processed in a home subscriber server for storing and managing subscriber profiles in an IMS, the structure of the home subscriber server is implemented using a plurality of structures for processing messages, thereby distributing traffics and process loads, and thus improving the efficiency of the home subscriber server and tolerance to loads. It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A distributed-home subscriber server comprising: a first server for transmitting, receiving and managing subscriber registration and location information management messages in conjunction with an I-CSCF(Interrogating- CaIl Session Control Function); a second server for transmitting, receiving and managing messages performing downloading and updating of the subscriber registration, the location information and profiles, and subscriber authentication in conjunction with an S-CSCF(Serving-Call Session Control Function); a third server for transmitting, receiving and managing the subscriber data messages in conjunction with an application server of an IMS network IP Multimedia Subsystem; and a central information management server for storing and managing subscriber information in the IMS network and providing the subscriber information for performing of operations of the first, second and third servers.

2. The distributed-home subscriber server as set forth in claim 1, wherein the subscriber registration and location information management messages includes information of the subscriber registration and the authentication and server name information of the second server which provides services.

3. The distributed-home subscriber server as set forth in claim 1, wherein the messages performing downloading and updating of the subscriber registration, the location information and profiles, and subscriber authentication includes security information of the subscribers, canceling of registration and principal information changes.

4. The distributed-home subscriber server as set forth in claim 1 , wherein the subscriber data messages includes subscription data of the subscribers, updating information of the subscription data and change information of the subscription data.

5. The distributed-home subscriber server as set forth in claim 1, wherein the first, second and third servers and the central information management server updates the subscriber information in conjunction with each other.