A method and system to subscription of events using SIP protocol

Event subscription method and system using SIP protocol

Technical field

The present invention relates to a communication system, in particular to event subscription in the communication system.

Background technique

Currently, various communication systems are used to enable communication between two or more entities such as user equipment and/or other nodes related to the system.

Communication systems that provide wireless communication for user terminals or other nodes are known. An example of a wireless system is the public land mobile network (PLMN). A PLMN is usually a cellular network in which a base transceiver station (BTS) or similar access entity serves user equipment (UE) such as a mobile station (MS) through a wireless interface. The operation of the devices required for communication is usually controlled by one or more control entities, which may themselves be interconnected. One or more gateway nodes are used to connect the PLMN to other networks. Examples of other such networks are another cellular network-the public switched telephone network (PSTN) and packet switched data networks such as IP (Internet Protocol) based networks. The communication between the user equipment and the other components of the communication system is based on an appropriate communication protocol, which defines the "rules" for handling communication in the system.

In the current third-generation (3G) wireless system, various servers are defined for handling different communication services of mobile users. This includes a server that provides a call status control function called CSCF. Control functions can also be provided by entities such as a local subscriber server (HSS), and applications are provided by various application servers. HSS is usually used to permanently store the user's profile and is used during authentication. For example, in the version 5 architecture of 3G, as specified by the 3rd Generation Partnership Project (3GPP), these entities can be found in the IP Multimedia Subsystem (IMS).

The IMS network can be located at the center of the 3G architecture, supporting an IP-based network that handles traditional voice telephony and multimedia services. 3GPP has selected Session Initiation Protocol (SIP) as the core session signaling protocol for 3G networks. SIP has been developed by the Internet Engineering Task Force (IETF). Those who are interested can download from http://www.3gpp.org/ftp/Specs/Latest-drafts/24229-201.zip titled "IP Multimedia Call Control Protocol based on SIP and SDP (IP based on SIP and SDP) The 3GPP specification 24.229 that describes the basic operation of the IMS network is found in the SIP Outlook of "Multimedia Call Control Protocol". SIP is a request/response protocol. In the sense that each message sent from the source has an acknowledgement from the destination to receive a related response to the sent message, SIP is a request/response protocol.

For example, in a 3G network, when a user connects to his mobile terminal for the first time, he must register his user ID or address with the network before allowing the terminal to be fully connected. This is done by sending a SIP "REGISTER" message from the terminal to the IMS, which includes the details of the user's address. IMS uses the Serving Call State Control Function (S-CSCF) to receive and process this information. In this article, S-CSCF refers to "registration." The registration information may include the user's status, such as the user's address, location, terminal capabilities, and terminal availability. IMS sends an appropriate confirmation message (such as a 200 OK message) according to SIP to confirm the registration. Whenever the previous registration is terminated or when the user status changes, the subsequent registration takes place (re-"REGISTER"). When a user wants to establish a session with another user, such as a voice call or text message sending, the session negotiation will also be carried out under SIP.

The application server (AS) can provide services through IMS such as instant messaging, local service flow reports, and meeting tools. The AS can be located in or outside of the IMS network. When the supported service is provided by a third party, the AS is usually external. For example, an AS that provides local service flow reports may need recent information about the status of any users subscribed to this service. As noted above, the status information can be updated using SIP re-registration messages. The AS server that needs this status information therefore uses the SIP SUBSCRIBE message to subscribe to the REGISTER message, which is sent by the user who has subscribed to the instant messaging service provided by the AS. IMS records these SUBSCRIBE messages, and whenever it receives a related REGISTER message, it sends a NOTIFY message to the AS. The AS can then use this information to implement its service flow reporting service. More information about the SUBSCRIBE/NOTIFY mechanism can be found in the IETF Internet Draft entitled "SIP-Specific Event Notification", which can be found at http://www.ietf.org/internet- Found on drafts/draft-ietf-sip-events-05.txt.

A specific example of status information is presence information. The user or application server subscribing to the presence service can determine the ability and availability of another user to accept calls. For example, in the PSTN structure arrangement, the concept of existence is extended to be the same as the indication of online (ringing) or offline (busy). However, in systems that support SIP, there are various indications that can be assumed, such as "all calls can be answered in the office", "only private calls at home" and "in a call" (or at least displayed in this way). Therefore, the presence information allows the user to determine the availability of another user before making a call. Like the other status information discussed above, the presence information is passed to the network in the REGISTER message.

At present, there are two key elements in implementing presence services based on SIP: the registrar and the presence server. The registrar receives and processes all REGISTER messages related to the network user. The presence server processes subscriptions from elements such as other users or application servers related to the presence of users in the network. Due to the overlapping nature of the functions provided by the two components, the registrar and the presence server usually share a dedicated location resource such as an LDAP (Lightweight Directory Access Protocol) directory or a location server with which both components interface. Optionally, the registrar and presence server functions can run in a shared process, and both can access registration updates. The effect of these proprietary solutions is the same: the registrar and the presence server co-exist. In the IMS structure arrangement discussed above, the registrar and the presence server are co-located in the S-CSCF. Since the functions provided by the presence server are considerable, the load on the shared resources is increased as a result, and the shared resources will have to deal with registration and a large number of requests for presence information.

The inventor of the present invention found that separating the functions of the registrar and the presence server and enabling them to operate independently has expected benefits. They have developed a solution to achieve this separation, which does not use a dedicated interface, allowing a better integration with the entire network in which they operate.

It should be understood that although the issues discussed above relate to SIP event subscriptions in IP-based third-generation (3G) communication systems, the same shortcomings may also be related to other systems, so this description is not limited to these examples.

Summary of the invention

The embodiments of the present invention aim to overcome one or several of the above-mentioned problems.

According to an aspect of the present invention, there is provided a method in a communication system, the system including a first entity that maintains registration information from a plurality of users and a second entity that maintains information related to the plurality of users, wherein the The second entity information depends on the registration information, and the method includes: sending a subscription message for an event from the second entity to the first entity, where the event is for at least one of the multiple users on the first entity A change in registration information; receiving a registration message from at least one user at the first entity, the message changing the registration information of the at least one user; sending a notification from the first entity to the second entity in response to the registration message, The notification includes information related to the at least one user.

Preferably, an event package is defined, and the event package is related to the event.

Preferably, the first entity is a registrar, and the second entity is a presence server. The change in the registration information may involve presence information.

The system can operate according to the Session Initiation Protocol (SIP), and the subscription message can include a SIP SUBSCRIBE message, and the notification can include a SIP NOTIFY message.

In a preferred embodiment, the third entity sends a subscription message for the information related to the at least one user to the second entity.

The second entity may send a notification to the third entity in response to the notification received on the second entity, wherein the sent notification includes information related to the at least one user. The third entity is the application server.

According to a second aspect of the present invention, there is provided a communication system including a first entity for holding registration information from a plurality of users and a second entity for holding information related to the plurality of users, wherein the second entity Entity information depends on registration information; the second entity may send a subscription message for an event to the first entity and the first entity may receive a registration message from at least one user, and the registration message changes the at least one users Registration information, where the event is related to a change in the registration information of at least one of the multiple users on the first entity; and the first entity may send a notification from the first entity to the second entity in response to the registration message , Wherein the notification includes information related to the at least one user.

According to a third aspect of the present invention, there is provided a network component including means for maintaining registration information from multiple users; means for receiving subscription messages from a first entity for an event, wherein the event is related to the Related to a change in the registration information of at least one of the multiple users on the network component; a device for receiving a registration message from at least one user, the registration message changing the registration information of the at least one user; and A device in which the first entity sends a notification in response to the registration message, wherein the notification includes information related to the at least one user.

According to a fourth aspect of the present invention, there is provided a network component including a device for maintaining information related to a plurality of users, wherein the information depends on registration information maintained on a first entity; A device for sending a subscription message for an event, wherein the event is related to a change in registration information of at least one of a plurality of users on the first entity; and a device for receiving a notification from the first entity, wherein the The notification includes information related to the at least one user.

Description of the drawings

The embodiments of the present invention are now described by way of example with reference to the accompanying drawings. In these drawings: Figure 1 shows a communication system in which the present invention can be applied; Figure 2 shows a registrar and presence according to the prior art. The structural arrangement of the server; Fig. 3 shows an embodiment of the present invention; Fig. 4 shows the message flow of an embodiment of the present invention.

detailed description

Referring first to FIG. 1, it shows a typical third-generation (3G) wireless telephone communication system operating under the Universal Mobile Telecommunication System (UMTS). The center of the system is the IP Multimedia Subsystem (IMS) 100 network, which routes calls between two or more network users and provides other network functions. Examples of these users are a mobile terminal 111, a laptop computer 112, a personal digital assistant (PDA) 113, a public switched telephone network (PSTN) telephone 131, a computer terminal 123, and an application server 121 and an application server 122. IMS uses IP-based networks to handle these calls, which may include both voice calls and multimedia calls.

The IMS network effectively acts as a gateway between the users 111, 112, 113 and the PSTN 130 and the external IP-based network 120 in the 3G system. The signal transmission between the mobile terminal and other users of the IMS network and within the IMS network is completed under the Session Initiation Protocol (SIP). Unless otherwise stated, all messages mentioned later are SIP messages and will be shown in uppercase.

Fig. 2 shows a schematic diagram of a prior art IMS network 100. IMS includes various components including several call state control functions (CSCF). The CSCF is equivalent to the SIP server in the IETF architecture.

The inquiry CSCF (I-CSCF) 201 is a basic IMS node used to terminate calls in the IMS network and function at the edge of the network. Here, communication with external nodes of the mobile terminal 101, the PDA 113, and the application server (AS) 121 is shown. It should be understood that the connection between the mobile terminal, PDA, and application server to the I-CSCF may not be direct, but through an appropriate intermediate network such as the mobile core network 110 for the mobile terminal and the Internet 120 for the application server, such as As shown in Figure 1.

HSS 202 is a central user database that interfaces with I-CSCF and S-CSCF, and stores information about all users of IMS. The I-CSCF uses the HSS to implement functions such as authorization of new users and retrieval of routing information about the S-CSCF for forwarding messages from external components to the S-CSCF.

S-CSCF 206 is an IMS node responsible for invoking services related to IMS users. In this example, the S-CSCF also performs the registrar function 203 for the IMS user, processes user registration, and provides the presence server function 205. Since these components 203 and 205 have overlapping functions, because they both need to receive information from the user in the REGISTER message, they also share the common resource 204. The public resource here is shown as an LDAP directory, but it can also be a location server. Optionally, the registrar and presence server functions run as shared processes, and both of them can access registration updates.

The reception of a REGISTER message can be classified as an event. The event can be any change of state and is related to an entity such as a user or another node in the communication system. Therefore, a component such as an application server can specifically subscribe to a REGISTER message related to a user or other events such as the reception of INVITE. Other examples of events include user presence information and close friends list, which is an effective collection of users whose subscribers are interested in knowing their presence information. Therefore, the S-CSCF detects the specific event subscribed by the user and sends an appropriate NOTIFY message to respond.

However, in order to subscribe to an event, an event package must be defined, which specifies the attributes of the event. In the event that the event exists, the presence package is used to subscribe to the presence information of any user. The presence package means that any user can send a subscription message for presence information to the presence server, but if such a presence package is not defined, the presence server will not be able to identify what events the user wants to subscribe to. Therefore, it is necessary to define the presence package on the presence server, and then the presence server can receive and recognize the subscription message for the related events of the change in the presence information. The presence server creates a state linked to the presence information, and when there is any change in the presence information, it will trigger a response or notification.

The presence server interfaces with the shared resource 204, and the shared resource 204 stores presence information. The registrar 203 maintains this information by updating it with the information received in the REGISTER message sent by the registered user.

Refer now to FIG. 3, which shows a detailed schematic diagram of the IMS network 100 in an embodiment of the present invention. Among them are I-CSCF 201, HSS 202, registrar 301, and presence server 302. The I-CSCF 201 is shown communicating with external nodes of the mobile terminal 101, the PDA 113, and the application server 121. The registrar includes suitable storage means 302 for storing registration information. Likewise, the presence server has its own storage device 304 for storing presence information. The presence server shown is a specific example of an application server. Other types of application servers include: messaging servers, which handle the sending and receiving of messages between users; content servers, which provide users with general information; and group servers, which maintain information about information that can be used for group distribution lists such as Information about user groups accessed by other applications of the messaging server.

In this embodiment of the present invention, only the registration from the user such as the mobile terminal 101 is processed by the registrar, and only the presence query from the component such as the application server 121 is processed by the presence server. The communication between the registrar and the presence server is implemented via SIP messages.

The new SIP event package is defined, executed by the registrar and used by the presence server. The new event package is defined as the aggregation of all REGISTER messages that change the registration details of any user received at the Registrar. For simplicity, this event package will be referred to as the "registration" package, which defines the "registration" event. This "registration" package is used by the presence server to subscribe to the registrar for changes in any user registration status. The registrar creates a description that triggers a notification back to the presence server whenever the registration status of any user changes. In fact, "registration" covers all REGISTER messages sent by any user received by the registrar that has previously received a subscription to the "registration" event. The "registration" event therefore covers all users in the registrar domain with a single event. This domain can be thought of as a group of users handled by a given registrar.

Then, the existence server can use the SUBSCRIBE/NOTIFY mechanism and subscribe to "registration" on the registrar. Whenever a "registration" event occurs, the registrar sends a NOTIFY message with the user's identity and the registration status of the existing server.

The result is that there is now a record 304 where the server saves registration information separate from the registration information used by the registrar 302. Therefore, the presence server can provide presence information to other components independent of the registrar, such as the application server 121, without using any shared resources.

Moreover, the only connection between the registrar and the presence server is through SIP messages and using newly defined events, not a proprietary structure arrangement like the prior art.

The functions of the components in FIG. 3 in one embodiment of the present invention will now be described in detail with reference to the message flow diagram in FIG. 4.

Figure 4 describes the following process: 1. Define a new event package for the "registration" event to be executed by the registrar and used by the presence server.

2. The presence server 303 sends a'SUBSCRIBE subscribed to the "registration" event' message to the registrar 301.

3. The registrar confirms the receipt of the SUBSCRIBE message with the '200 OK' message.

4. The application server (AS) 121 sends the'SUBSCRIBE subscribed to the presence information of the mobile terminal 101 and the PDA 113' message to the presence server.

5. The presence server confirms the receipt of the SUBSCRIBE message from the AS with the '200 OK' message.

6. The mobile terminal 101 sends the REGISTER message to the registrar.

7. The registrar confirms the receipt of the REGISTER message with the '200 OK' message, and updates the registration details on the registrar 302.

8. The REGISTER message sent by the mobile terminal 101 satisfies the "registration" event that the existing server has subscribed to. As a result, the registrar sends the NOTIFY message to the presence server including the registration status details of the user and the mobile terminal. These details are maintained in the storage server 304.

9. The presence server confirms the receipt of the NOTIFY message with the '200 OK' message.

10. When the AS 121 has subscribed to the presence information related to the mobile terminal 101, and the presence information has now changed, the presence server sends a NOTIFY message to the AS using the details of the change in the presence information.

11. The AS confirms the receipt of the NOTIFY message with the '200 OK' message.

12. The PDA 113 sends a REGISTER message to the registrar.

13. The registrar confirms the receipt of the REGISTER message with the '200 OK' message, and updates the registration details on the registrar 302.

14. The registrar also sends a NOTIFY for this REGISTER message to the presence server, because the "registration" event subscribed by the presence server in step 2 covers all registration messages processed by the registrar. The NOTIFY message includes details of the user and registration status of the PDA. These details are maintained on the storage server 304.

15. The presence server confirms receipt of the NOTIFY message with the '200 OK' message.

16. When the AS 121 has subscribed to the presence information related to the PDA, and the presence information has now changed, the presence server sends a NOTIFY message to the AS using the details of the change in the presence information.

17. The AS confirms the receipt of the NOTIFY message with the '200 OK' message.

It should be understood that although the embodiments of the present invention have been described in the context of 3G using SIP, other suitable systems and interface protocols may also be used.

It should be noted here that although the exemplary embodiments of the present invention are described above, various variations and modifications can be made to the disclosed solutions without departing from the scope of the present invention as defined by the appended claims.