CN101166295A - A method, system and device for establishing carrier - Google Patents

Abstract

The invention in use for solving issue that in current technique, CSI service control function entity (SCFE) is unable to interact with CSI for CSI service information so as not to use CS being as load in IMS session. The method includes steps: (1) when receiving session request related to CSI terminal, CSI SCFE determines whether CSI service is needed to use; (2) using expansion information of session message to CSI terminal, CSI SCFE transfers the information for indicating whether this session is needed to use CSI service; (3) based on the indication information to establish CS load correspondingly. The invention realizes that CS is utilized as a load in IMS session.

Description

Method, system and device for establishing load bearing

Technical Field

The present invention relates to the field of communications, and in particular, to a method, system, and apparatus for establishing a bearer.

Background

The IMS is an IP multimedia subsystem in a WCDMA network defined by the 3GPP R5/R6 standard, and is a target network for a 3G mobile network to implement packet voice and packet data, and provide unified multimedia services and applications. The IMS uses the IP packet domain as a bearer channel for its control signaling and media transmission, and uses the SIP protocol as a call control signaling. In the IMS, user subscription data of the IMS is centrally managed in an HSS, services are uniformly provided by an application server AS, session control is completed by an S-CSCF, the two are completely separated on a network structure, the services are triggered to the AS for processing through the S-CSCF, and a plurality of ASs can cooperatively work. The user accesses IMS through the agent node P-CSCF of the current location, the session and service control are completed by the home domain service node of the registered location, therefore, the user can always obtain the same service at different access points, and the separation of the service management, the session control and the bearing access and the service provision irrelevant to the access and the location are realized.

CSI is a subject of research in the current 3GPP standards. The subject is concerned with how to combine CS domain services of 3G with IMS domain services. The study of this topic is divided into two phases, namely CSI phase1 and CSI phase 2.

The main concern of CSI phase 2 is how IMS uses the circuit bearer of CS domain as the bearer of its voice session in its session, i.e. the problem of the interworking between CSI and VoIP terminals.

In the prior art, an architecture model of a network control scheme using a circuit of a CS domain as its real-time media bearer in an IMS session is solved, which is shown in fig. 1.

Under the network control model, the CSI service logic control entity is located in the as (aswith cbcf) of the IMS domain. The IMS session request initiated by the CSI capable terminal is routed to the CBCF. The CBCF judges that a CS load needs to be established, and then establishes a CS call with the CSI terminal through the MGCF/MGW by using an interworking mechanism of the CS and the IMS.

According to the different directions of the CBCF establishing and the CSI terminal CS calling, the network control mode can be divided into a network-to-client direction and a client-to-network direction. The network-to-client direction means that the establishment of the CS call is initiated from the CBCF to the CSI capable terminal. The client-to-network direction means that the CS call is established in such a way that the CBCF indicates the CSI terminal through IMS signaling, and the CSI terminal initiates the CS call of the CBCF after receiving the indication message.

The existing network control mode is an architecture for solving the CSI phase 2 problem, and in the architecture, how the CBCF and the CSI terminal perform information transfer is not indicated. For example, when the CSI capable terminal is called, the CBCF notifies the CSI capable terminal how to trigger the CSI capable service (i.e., using CS as the bearer of the IMS real-time media), and when the CSI capable terminal is called, the CBCF notifies the CSI capable terminal how to desire to use the CSI capable service (i.e., using CS as the bearer of the IMS real-time media).

Further, in the architecture scheme, there are some detail problems to be considered and solved:

1) optimization problem of CS bearer establishment: how to solve the CS bearer optimization problem between the visited and home locations when the CSI terminal roams to a roaming network?

2) How to avoid the problem of adverse effect of supplementary service of the CS domain on the establishment process during the CS bearer establishment?

3) How does the CBCF handle the session change request?

Disclosure of Invention

The invention provides a method, a system and a device for establishing a bearer, which are used for solving the problem that a CSI service control function entity in the prior art cannot interact CSI service information with a CSI terminal, so that a CS (circuit switched) can not be used as the bearer in an IMS (IP multimedia subsystem) session.

Further, the CS bearing optimization problem between the visited place and the home place when the CSI terminal roams is solved.

Further, the problem that the CS bearing establishing process is influenced by the CS domain supplementary service is solved.

Further, the problem that the prior art does not provide a processing method for the session change request is solved.

The method comprises the following steps:

A. when receiving a session request related to a CSI terminal, a CSI service control functional entity judges whether a CSI service is required to be used; B. the CSI service control function entity uses the extension information of the session message between the CSI terminal and the CSI service control function entity to transmit the indication information whether the session needs to use the CSI service or not; C. and correspondingly establishing the CS load according to the indication information.

Further, in step a, the information required by the CSI service control function entity to determine whether to use the CSI service at least includes: capability information of the CSI terminal, attribute information of the session call, and capability information of the CS access network. The information required by the CSI control function entity to determine whether to use the CSI service further includes: and the capability information of the IP access network where the CSI terminal is located.

Still further, the CSI service control function entity uses the following logic to determine whether to use the CSI service according to the information: the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is the DTM capability information of the CS network supporting the dual transfer mode at the CSI terminal side, and the terminal supports the CSI capability, and the CSI service control function entity determines that the CSI service needs to be used. Or the CSI service control function entity uses the following logic to judge whether the CSI service needs to be used or not according to the information: the attribute information of the session call is IMS real-time media information, the capability information of a CS access network is the DTM capability information supported by the CS network at the CSI terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI terminal is located is a bearer which can not provide real-time service, so that the CSI service control function entity judges that the CSI service needs to be used; or, the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is DTM capability information supported by the CS network at the CSI capable terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI capable terminal is located is a bearer capable of providing a real-time service, and then the CSI service control function entity determines that the CSI service needs to be used.

In summary, when the CSI capable terminal is called, the CSI capable terminal uses the extension header field or the extension message body in the SIP INVITE message with the CSI service control function entity to transmit the willingness information that the current session wants to use the CSI service.

Further, in step B, the CSI service control function entity uses the extended header field or the extended message body of the session message to transmit the indication information whether the session needs to use the CSI service.

Further, in step C, if the indication information indicates that the CSI service needs to be used and the CS bearer establishment direction is the terminal-to-network direction, the CSI terminal initiates a CS bearer from the CS portion of the local terminal to the CSI service control function entity; and if the indication information indicates that the CSI service is required to be used and the CS bearing establishing direction is the direction from the network to the terminal, the CSI service control function entity initiates the CS bearing of the CSI terminal.

Further, the step C further includes: if the session request received by the CSI service control function entity points to the CSI terminal, the CSI service control function entity takes the CS domain roaming number of the CSI terminal from the HLR when initiating the CS bearing establishment of the CSI terminal, and initiates the session request to the roaming number. If the CS bearing establishing direction is a terminal-to-network direction, the CSI terminal uses the E.164 number which can be routed to the MGCF of the roaming place to initiate a CS call to the CSI service control function entity, so that the call is routed to the CSI service control function entity through the MGCF of the roaming place.

Further, in step C, when the CSI service control function entity or the CSI terminal establishes the CS bearer, the CS domain service information in the session message is identified, and corresponding processing is performed according to the identified CS domain service, so as to avoid adverse effects of the CS domain service.

Further, after the session in step C is successfully established, if the CSI service control function entity receives the session change request, the change type indicated by the session change request is identified, and corresponding processing is performed according to the change type.

The system of the present invention comprises:

the CSI service control function entity is used for judging whether the CSI service is required to be used or not when receiving a session request related to the CSI terminal, and transmitting indication information whether the CSI service is required to be used or not in the session by using extension information of a session message between the CSI terminal and the CSI terminal; and establishing a CS bearer between the CSI terminal and the CS bearer in a matching manner; and the CSI terminal is used for establishing a CS (circuit switched) load between the CSI terminal and the CSI control function entity in a matching way according to the indication information issued by the CSI service control function entity.

The CSI service control function entity of the invention comprises the following units:

the system comprises a judging unit and a judging unit, wherein the judging unit is used for judging whether a CSI service is required to be used or not when receiving a session request related to a CSI terminal;

the first transmission unit transmits the judgment result made by the judgment unit to the CSI terminal by using the extension information of the session message between the first transmission unit and the CSI terminal;

and the first CS bearing establishing unit is used for establishing CS bearing between the first CS bearing establishing unit and the CSI terminal in a matching manner.

Further, the entity further comprises: and the first CS bearing initiating unit is used for initiating a CS bearing establishment request to the CSI terminal and triggering the first CS bearing establishment unit when the CS bearing direction is the network-to-terminal direction and the judging unit judges that the CSI service is required to be used.

The CSI terminal comprises the following units:

the indication identification unit is used for identifying the indication information whether the session needs to use the CSI service or not from the session message sent by the CSI service control function entity;

and the second CS bearing establishing unit is used for establishing CS bearing between the CSI control function entity and the CS bearing after knowing whether the CSI service is used or not.

Further, the terminal further includes: and the second CS bearing initiating unit is used for initiating a CS bearing establishing request to the CSI service control function entity and triggering the second CS bearing establishing unit when the CS bearing establishing direction is the terminal-to-network direction and the indication identifying unit determines that the CSI service needs to be used.

The invention has the following beneficial effects:

in the method, when a CSI service control function entity receives a session request related to a CSI terminal, whether the CSI service is required to be used is judged, and indication information of whether the CSI service is required to be used in the current session is transmitted by using extension information of a session message between the CSI terminal and the CSI service control function entity. Then, if the direction of the bearer establishment is the direction from the terminal to the network, the CSI terminal initiates a CS bearer of the CSI service control functional entity according to the indication information, and the CSI service control functional entity establishes the CS bearer in a matching way; if the direction of establishing the load bearing is the direction from the network to the terminal, the CSI terminal acquires that the CSI service is required to be used from the indication information, waits for the CSI service control functional entity to initiate the CS load bearing, and initiates the load bearing of the CSI terminal according to the indication information and establishes the CS load bearing by the cooperation of the CSI terminal.

Therefore, the CSI service control function entity and the CSI terminal can interact CSI service information, and CS is used as a load in the IMS session.

Further, based on the interactive CSI service information and the bearer establishment flow, the invention respectively provides a CS bearer optimization scheme between a visited place and an attribution place when the CSI terminal roams aiming at various specific services; respectively providing a scheme for avoiding the CS bearing establishing process from being influenced by the CS domain supplementary service; a method of processing a session change request is provided.

In order to support the method of the invention, the invention also provides a system for establishing the bearing, a CSI service control functional entity and a CSI terminal.

Drawings

Fig. 1 is a diagram of a network architecture for solving a real-time media bearer in an IMS session by using a circuit of a CS domain;

FIG. 2 is a flow chart of the method steps of the present invention;

FIG. 3 is a signaling flow diagram of an example method;

FIG. 4 is a signaling flow diagram of an example method two;

FIG. 5 is a signaling flow diagram of a method example three;

FIG. 6 is a four signaling flow diagram of an example method;

FIG. 7 is a five signaling flow diagram of an example method;

FIG. 8 is a six signaling flow diagram of an example method;

FIG. 9 is a schematic diagram of the system of the present invention;

fig. 10 is a schematic structural diagram of a CSI service control function entity according to the present invention;

fig. 11 is a schematic diagram of a CSI terminal according to the present invention.

Detailed Description

In order to enable the CSI service control function entity and the CSI terminal to interact CSI service information, the CS is used as a bearer in the IMS session, so as to better implement the interworking between the CS and the IMS. The invention provides a method for establishing a bearer, which comprises the following main steps as shown in figure 2:

and S1, the CSI service control function entity receives the session request related to the CSI terminal.

The session request related to the CSI terminal comprises: an IMS session initial request or a session change request pointing to a CSI terminal; and an IMS session initiation request or a session change request initiated by the CSI capable terminal.

When the CSI terminal is used as a calling party, the CSI terminal can also use an extended header field or an extended message body in an SIP INVITE message between the CSI service control function entity to convey willingness information that the session wants to use the CSI service.

And S2, the CSI service control function entity judges whether the CSI service is needed to be used.

● obtain the required information.

The information required by the CSI service control function entity for judging whether the CSI service needs to be used at least comprises the following information: the capability information of the CSI terminal, the attribute information of the session call and the capability information of the CS access network; further, the method can also comprise the following steps: and the capability information of the IP access network where the CSI terminal is located.

The CSI service control function entity acquires the information in the following way:

-the CSI service control function entity obtains the capability information of the terminal in the extension information of the registration message of the terminal; and

the CSI service control function entity inquires and acquires the position information of the CSI terminal in the CS domain through an ATI interface, and inquires data configuration according to the position information to acquire the capability information of the CS access network where the CSI terminal is currently located; and

the CSI service control function entity obtains the type of the access network of the IMS where the CSI terminal is currently located through the position field information carried in the IMS message, and obtains the IP access network capability information according to the query data configuration; or, the CSI service control function entity inquires and acquires the position information of the CSI terminal in the IMS domain through the ATI interface, and inquires data configuration according to the position information so as to acquire the capability information of the IP access network where the CSI terminal is currently located; and

-the CSI service control function entity adds to the session path between the peer terminal and the CSI terminal to obtain the attribute information of the current session call.

●, it is determined whether the CSI service needs to be used.

And the CSI service control functional entity judges whether the CSI service needs to be used or not by using the following logic according to the obtained information: the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is the DTM capability information of the CS network supporting the dual transfer mode at the CSI terminal side, and the terminal supports the CSI capability, and the CSI service control function entity determines that the CSI service needs to be used.

Further, if the obtained information includes capability information of an IP access network in which the CSI capable terminal is located, the CSI service control function entity may further use the following logic to determine whether to use the CSI service according to the information: the attribute information of the session call is IMS real-time media information, the capability information of a CS access network is the DTM capability information supported by the CS network at the CSI terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI terminal is located is a bearer which can not provide real-time service, so that the CSI service control function entity judges that the CSI service needs to be used; or, the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is DTM capability information supported by the CS network at the CSI capable terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI capable terminal is located is a bearer capable of providing a real-time service, and then the CSI service control function entity determines that the CSI service needs to be used.

And S3, the CSI service control function entity uses the extension information of the session message between the CSI terminal and the CSI service control function entity to transmit the indication information whether the session needs to use the CSI service.

In the invention, the CSI service control function entity uses the extended header field or the extended message body of the session message to transmit the indication information whether the session needs to use the CSI service.

Further, in a specific implementation, when the CSI capable terminal is used as a calling party, the CSI service control function entity uses an extension header field or an extension message body in an SIP 1xx message between the CSI capable terminal and the CSI capable terminal to transmit an indication message indicating whether the current session needs to use the CSI service;

when the CSI terminal is called, the CSI service control function entity uses an extended header field or an extended message body in a SIP INVITE message between the CSI terminal and the CSI service control function entity to transmit the indication information whether the session needs to use the CSI service or not.

And S4, establishing the CS bearing correspondingly according to the indication information.

●, if the indication information indicates that the CSI service is needed to be used and the CS bearing establishment direction is terminal-to-network direction, the CSI terminal receiving the indication information initiates a CS bearing from the local terminal CS part to the CSI service control function entity by using the CS domain number of the CSI service control function entity as the called number; and then the CSI service control function entity is matched with the CSI terminal to complete the establishment of the CS bearing.

●, if the indication information indicates that the CSI service needs to be used and the CS bearer establishment direction is a network-to-terminal direction (network-to-client), the CSI terminal receiving the indication information waits for the CSI service control function entity to initiate the CS bearer after knowing from the indication information that the CSI service needs to be used; meanwhile, the CSI service control function entity acquires a CS number associated with the IMS of the CSI terminal as a called number and initiates a CS load to the CSI terminal; and then the CSI terminal cooperates with a CSI service control functional entity to complete the establishment of the CS load.

Further, the method for the CSI service control function entity to obtain the CS number associated with the IMS number of the CSI capable terminal includes one of the following:

-the CSI terminal carries the association relationship between the CS number and the IMS number in the extended header field or the extended message body of the registration message, so that the CSI control function entity obtains the information;

-using a fixed numbering rule to enable the CSI service control function entity to obtain, according to one number (IMS number) of the CSI terminal, another number (CS number) of the CSI terminal;

-the CSI service control function entity obtains the CS number of the CSI terminal associated with the CSI terminal IMS number from a local configuration data query.

Based on the process from S1 to S4, in the CS bearer establishment process, the present invention further provides a CS bearer optimization scheme between the visited location and the home location when the CSI capable terminal roams, which includes the following main contents: if the session request received by the CSI service control function entity points to the CSI terminal, whether the CSI terminal roams in a CS domain or not can be judged according to the circuit domain position information (such as a cell number and a position area number) of the CSI terminal in the HSS; if roaming occurs, the CSI service control function entity starts to fetch the CS domain roaming number of the CSI terminal from the HLR when the CS bearing of the CSI terminal is established, and starts a session request to the roaming number. The CS bearer establishment direction is the terminal-to-network direction, and the CSI terminal initiates a CS call to the CSI service control function entity using the e.164 number that can be routed to the MGCF of the roaming destination, so that the call is routed to the CSI service control function entity through the MGCF of the roaming destination. The mode for acquiring the E.164 number by the CSI terminal comprises one of the following modes: the CSI service control functional entity dynamically distributes number information according to the roaming place where the CSI terminal is located and informs the CSI terminal; the CSI terminal senses the roaming place and adds related number prefix information according to the roaming place information.

Based on the flows described in S1 to S4, in the CS bearer establishment process, the present invention further provides a scheme for avoiding the CS bearer establishment process being affected by the CS domain supplementary service, including the following main contents: and when the CSI service control function entity or the CSI terminal establishes the CS load, the CS domain service information in the session message is identified, and corresponding processing is carried out according to the identified CS domain service so as to avoid the adverse effect of the CS domain service.

For various specific services, specific schemes for avoiding the CS bearer establishment process from being affected by the CS domain supplementary service are provided below.

-if the CS domain service is a number display type service, setting, by the CSI service control function entity, a number display restriction on number information of the CSI service control function entity in a related message sent to the CSI terminal; or after the CSI terminal receives the related message sent by the CSI service control function entity, the number information of the CSI service control function entity is subjected to display limiting processing.

If the CS domain service is a Call Hold, Call Wait, Call deflection CD, display Call transfer ECT, or multi-party session MPTY service of the CS domain, the CSI terminal shields the operation on the service when receiving a service operation request of the user, and informs the user to initiate the service in the IMS domain.

-if the CS domain service is a CS domain operator lockout ODB, a call lockout CB service, or a called intelligent service Camel service, performing an override authority configuration of a number of a CSI service control function entity in the CS domain further if the CS bearer direction is a terminal-to-network direction; and further, if the CS bearing establishing direction is a network-to-terminal direction, the CSI service control function entity obtains the roaming number from the HLR, the HLR acquires that the initiator of the roaming number is the CSI service control function entity, and the roaming number of the CSI terminal is directly returned to the CSI service control function entity.

If the CS domain service is a closed user group CUG service of the CS domain, configuring a CS domain number of the CSI capable terminal and a CS domain number of the CSI capable service control function entity as a user group in the CS domain.

Based on the process from S1 to S4, after the CS bearer is established, the present invention further provides a method for processing a session change request, which includes the following main contents: and if the CSI service control function entity receives the session change request, identifying the change type indicated by the session change request, and performing corresponding processing according to the change type.

Specific schemes for processing the session change request are provided below for various specific services.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request from the opposite end to delete a real-time media component, the CSI service control functional entity tears down the CS call to the CSI terminal; or, the CSI service control function entity notifies the CSI terminal (the CSI service control function entity deletes the indication information of the CSI service in the session message sent to the CSI terminal to indicate that the real-time media information is deleted), and the CSI terminal initiates the removal of the CS call.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request from the opposite terminal to delete a non-real-time media component, the CSI service control functional entity initiates an IMS session change request to the CSI terminal to delete the non-real-time media therein; if there is no other media component in the IMS session to the CSI capable terminal, and there is no CS call between the CSI capable service control functional entity and the CSI capable terminal, the CSI capable service control functional entity may tear down the IMS session with the CSI capable terminal.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request from the CSI terminal to delete a non-real-time media component, the CSI service control functional entity sends the session change request to the peer.

If the change type indicated by the session change request received by the CSI service control functional entity is a request from the CSI terminal to delete a real-time media component (the CSI terminal deletes the indication information of the CSI service in the session change request, which indicates that it is a request to delete a real-time media component), the CSI service control functional entity tears down the CS call with the CSI terminal.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request for adding a real-time media component from the opposite end, the CSI service control functional entity establishes a CS call with the CSI terminal.

-if the change type indicated by the session change request received by the CSI service control function entity is a request for adding a non-real-time media component from the opposite end, the CSI service control function entity initiates a session change request to the IMS of the CSI terminal to add a non-real-time media component.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request from the CSI terminal for adding a real-time media component, the CSI service control functional entity establishes a CS call with the CSI terminal.

-if the change type indicated by the session change request received by the CSI service control functional entity is a request from the CSI terminal to add a non-real-time media component, the CSI service control functional entity initiates an IMS session change request to the opposite terminal to add the non-real-time media component.

The process of the present invention is described in detail below by way of six examples, which are summarized so far.

In the first method example, when a CSI terminal (CSI UE) is called, a CSI service Control function entity (CSI-Control) carries an indication that a CSI service needs to be used in an INVITE extension message. Referring to fig. 3, the method comprises the following specific steps:

1. the IMS to which the CSI terminal belongs receives an IMS session request, wherein the request comprises real-time media and non-real-time media information.

2. The CSI service control function entity performs service logic processing according to the related information, and needs to establish a CS bearer from the CSI terminal to the MGW to carry real-time media information.

3. And the CSI service control function entity sends a session request to the CSI terminal. The request message contains non-real-time service and indication information for requiring the CSI terminal to initiate the terminal to the network CS bearing. This indication may be conveyed by extending SIP INVITE the relevant header field of the message.

4. And after receiving the session request message, the CSI terminal initiates a CS call to the CSI service control function entity.

5. And the MGCF receives the CS calling request of the CSI terminal, maps the CS calling request into the INVITE and sends the INVITE to the CSI service control functional entity.

6. And the CSI service control function entity sends a 200OK response message to the MGCF.

7. The MGCF maps the 200OK response message to a connect message of the CS and transmits the connect message to the CSI terminal.

8. The CSI terminal transmits a 200OK response message. The response message only contains the media information of the MSRP.

9. And the CSI service control function entity combines the CS call from the CSI terminal and the IMS session.

10. And the CSI service control function entity sends the combined 200OK response message to the called side.

In the second method example, when the CSI terminal makes a call, the CSI service control function entity carries indication information that the CSI service needs to be used in the 183 message. Referring to fig. 4, the method comprises the following specific steps:

1. the CSI terminal initiates an IMS session request, which contains real-time media and non-real-time media information. The session request is routed to a CSI service control function entity logic function entity of an IMS network to which the CSI terminal belongs to carry out control.

2. The CSI service control function logic function entity forwards the request to the called network.

3. The CSI service control function entity receives 183 corresponding information of the called side, the information carries real-time media information and non-real-time media information of the called side, the CSI service control function entity carries out service logic processing according to related information, and a CS bearer needs to be established in a direction from a terminal to the MGW.

4. And the CSI service control function entity forwards 183 the response message to the CSI terminal. The message contains non-real-time service and indication information requiring the CSI terminal to initiate the terminal to the network CS load. The CSI service control function entity may carry this information through the extended header field of the SIP 183 message.

5. And after receiving the response message, the CSI terminal initiates a CS call to the CSI service control functional entity.

6. And the MGCF receives the CS calling request of the CSI terminal, maps the CS calling request into the INVITE and sends the INVITE to the CSI service control functional entity.

7. And the CSI service control function entity sends a 200OK response message to the MGCF.

8. The MGCF maps the 200OK response message to a connect message of the CS and transmits the connect message to the CSI terminal.

9. And the CSI service control function entity receives a 200OK response message of the called side.

10. And the CSI service control function entity combines the CS call from the CSI terminal and the IMS session.

11. And the CSI service control function entity forwards the 200OK response message to the CSI terminal.

And in the third method example, when the CSI terminal roams, the CSI service control function entity optimizes the CS bearing process. Referring to fig. 5, the method comprises the following specific steps:

1. the CSI service control function entity receives an IMS session request initiated by another terminal, and the request contains real-time media information.

2. And the logic function entity of the CSI service control function entity performs logic control. Here, the CSI service control function entity recognizes that the CS domain of the CSI capable terminal roams. The CSI service control function entity may sense the location information carried in the location update message of the CS domain of the CSI terminal or the location information in the HLR.

3. And the CSI service control functional entity acquires the roaming number information of the CS domain of the CSI terminal from the HLR.

4. And the CSI service control functional entity receives the roaming number information of the CS domain of the CSI terminal returned by the HLR.

5. The CSI service control function entity initiates a session request to BGCF1 of the local domain, and the called number information in the request message is the acquired roaming number information.

6. The BGCF1 in this domain selects the BGCF2 of the roaming area where the CSI capable terminal is located as the next hop according to the called number information.

7. The BGCF2 of the roaming domain where the CSI terminal is located selects MGCF2 as the next hop according to the called number information.

8. The MGCF2 transmits a call request of the CS domain to the CSI capable terminal through a routing mechanism of the CS domain.

9. The CSI terminal responds to the CS domain call.

10. MGCF2 sends a 200OK to BGCF 2.

11. BGCF2 sends a 200OK to BGCF 1.

12. The BGCF1 sends 200OK to the CSI service control function entity.

13. And the CSI service control function entity sends 200OK to the calling side. The CSI terminal and the MGW of the visit domain successfully establish a CS bearer, and the MGW and the calling domain successfully establish a VoIP bearer.

And step four, avoiding flow of Incoming CB service. Referring to fig. 6, the method comprises the following specific steps:

1. the CSI service control function entity receives an IMS session request initiated by another terminal, and the request contains real-time media information.

2. And the logic function entity of the CSI service control function entity performs logic control. Here, the entity of the CSI service control function knows the CB service of the called side of the CSI terminal.

3. And the CSI service control functional entity acquires the roaming number information of the CS domain of the CSI terminal from the HLR.

4. And the HLR bypasses the CB service and returns the roaming number information of the CS domain of the CSI terminal to the CSI service control function entity when finding that the CSI service control function entity fetches the roaming number.

5. The CSI service control function entity initiates a session request to the MGCF of the domain, and the called number information in the request message is the acquired roaming number information.

6. MGCF sends the call request of CS domain to CSI terminal through the route mechanism of CS domain.

7. The CSI terminal responds to the CS domain call.

8. MGCF sends 200OK to CSI business control function entity.

9. And the CSI service control function entity sends 200OK to the calling side. The CSI terminal and the MGW of the visit domain successfully establish a CS bearer, and the MGW and the calling domain successfully establish a VoIP bearer.

Fifth, the CSI service control function entity processes a session change process, which is specifically a process of adding real-time media to the IMS terminal. Referring to fig. 7, the method comprises the following specific steps:

1. the CSI terminal and the calling IMS terminal have already established a non-real-time media connection.

2. And the opposite terminal IMS terminal initiates a session change request to add real-time media to the session. The IMS terminal may also request to add non-real time media to an already existing session.

3. And the CSI service control functional entity performs service logic judgment.

4. The CSI service control function entity initiates a session request to MGCF, and if the IMS terminal requests to add non-real-time media, the CSI service control function entity initiates a session change request to the IMS of the CSI terminal.

5. MGCF sends the call request of CS domain to CSI terminal through the route mechanism of CS domain.

6. The CSI terminal responds to the CS domain call. And if the CSI terminal receives the IMS session change request, the CSI terminal replies the IMS session request.

7. MGCF sends 200OK to CSI business control function entity.

8. And the CSI service control function entity sends 200OK to the calling side. The real-time media between the CSI terminal and the calling terminal is increased successfully. If the non-real-time media component is added, the non-real-time media component addition is successful.

In addition: for the CSI terminal initiated add media operation, it can also be done according to a similar procedure.

Sixth, a flow of processing session change by the CSI service control function entity, specifically a flow of processing the CSI terminal to delete the real-time media. Referring to fig. 8, the method comprises the following specific steps:

1. the CSI terminal has established a multimedia connection with the calling IMS terminal.

2. And the CSI terminal initiates a session change request to delete the real-time media. The CSI terminal may also request deletion of non-real time media.

3. And the CSI service control functional entity performs service logic judgment.

4. And the CSI service control function entity initiates a session change request to the opposite terminal.

5. And the CSI service control function entity receives a response message of a session change request of the opposite terminal.

6. The CSI service control function entity initiates a Bye request to the MGCF. And if the CSI terminal initiates a request for deleting the non-real-time media, the CSI service control functional entity directly returns a session change request to the CSI terminal.

7. MGCF sends the call removal request of CS domain to CSI terminal through the route mechanism of CS domain.

8. The CSI terminal responds to the CS domain call tear down.

9. MGCF sends 200OK to CSI business control function entity. And the real-time media between the CSI terminal and the calling terminal is deleted successfully. And if the non-real-time media component is deleted, the deletion of the non-real-time media component is successful.

Note: if the real-time media or the non-real-time media is deleted initiated by the opposite-end IMS terminal, the deletion can be completed by adopting a similar process.

To support the above method, the present invention further provides a system for establishing a bearer, as shown in fig. 9, which includes: and the CSI service control function entity and the CSI terminal are connected with each other.

The CSI service control function entity is used for judging whether the CSI service is required to be used or not when receiving a session request related to the CSI terminal, and transmitting indication information whether the CSI service is required to be used or not in the session by using extension information of a session message between the CSI terminal and the CSI terminal; and the CS load bearing between the CSI terminal and the terminal is established in a matching way.

And the CSI terminal is used for establishing a CS (circuit switched) load with the CSI control function entity in a matching way according to the indication information issued by the CSI service control function entity.

Referring to fig. 10, the CSI service control function entity (i.e., the CSI service control function entity of the present invention) includes: the system comprises a judging unit, a first transmitting unit and a first CS bearing establishing unit which are connected with each other; the system further comprises a first CS bearing initiating unit respectively connected with the judging unit and the first CS bearing establishing unit.

●, the determining unit is configured to determine whether to use the CSI service when receiving a session request related to the CSI capable terminal.

The information required for judging whether the CSI service needs to be used at least comprises the following information: the capability information of the CSI terminal, the attribute information of the session call and the capability information of the CS access network; may further include: and the capability information of the IP access network where the CSI terminal is located.

The judging unit judges whether the CSI service needs to be used or not by using the following logic according to the information: the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is the DTM capability information of the CS network supporting the dual transfer mode at the CSI terminal side, and the terminal supports the CSI capability, and the CSI service control function entity determines that the CSI service needs to be used.

If the information includes capability information of an IP access network where the CSI capable terminal is located, the determining unit may further determine whether to use the CSI service using the following logic according to the information: the attribute information of the session call is IMS real-time media information, the capability information of a CS access network is the DTM capability information supported by the CS network at the CSI terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI terminal is located is a bearer which can not provide real-time service, so that the CSI service control function entity judges that the CSI service needs to be used; or, the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is DTM capability information supported by the CS network at the CSI capable terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI capable terminal is located is a bearer capable of providing a real-time service, and then the CSI service control function entity determines that the CSI service needs to be used.

●, the first transfer unit transfers the judgment result made by the judgment unit to the CSI terminal by using the extension information of the session message (including the extension header field or the extension message body of the session message) between the CSI terminal and the CSI terminal.

In a specific implementation, when the CSI capable terminal is used as a calling party, the first transmitting unit transmits the determination result made by the determining unit to the CSI capable terminal by using an extended header field or an extended message body in an SIP 1xx message with the CSI capable terminal; when the CSI terminal is called, the first transfer unit transfers the judgment result made by the judgment unit to the CSI terminal by using an extension header field or an extension message body in an SIP INVITE message between the CSI terminal and the CSI terminal.

●, the first CS bearer initiating unit is configured to initiate a CS bearer establishment request to the CSI capable terminal and trigger the first CS bearer establishing unit when the CS bearer direction is a network to terminal direction and the determining unit determines that the CSI service needs to be used.

●, the first CS bearer establishing unit is configured to establish a CS bearer with the CSI capable terminal in a coordinated manner.

Referring to fig. 11, the CSI terminals (i.e., CSI terminals of the present invention) include: an indication identification unit and a second CS bearing establishing unit which are connected with each other; the second CS bearing initiating unit is respectively connected with the indication identification unit and the second CS bearing establishing unit; still further, the method may further comprise: a second transfer unit or a third transfer unit, and a fourth transfer unit.

The indication identification unit is used for identifying the indication information whether the session needs to use the CSI service or not from the session message sent by the CSI service control function entity.

And the second CS bearer initiating unit is configured to initiate a CS bearer establishment request to the CSI service control function entity and trigger the second CS bearer establishing unit when the CS bearer establishing direction is a terminal-to-network direction and the indication identifying unit determines that the CSI service needs to be used.

And the second CS bearing establishing unit is used for establishing CS bearing between the second CS bearing establishing unit and the CSI control function entity in a matching way after knowing whether the CSI service is used or not.

The second transmission unit is configured to transmit willingness information that the current session desires to use the CSI service by using an extension header field or an extension message body in an SIP INVITE message between the CSI service control function entity when the CSI terminal is used as a calling party; and the third transmission unit is used for carrying CSI capability information in an extended header field or an extended message body of a registration message when the CSI terminal is registered.

The fourth transmission unit is configured to carry, in an extended header field or an extended message body of a registration message, an association relationship between a CS number and an IMS number of the CSI capable terminal when the CSI capable terminal is registered, so that the CSI control function entity obtains the information.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (40)

1. A method for establishing a bearer, comprising the steps of:

A. when receiving a session request related to a CSI terminal, a CSI service control functional entity judges whether a CSI service is required to be used;

B. the CSI service control function entity uses the extension information of the session message between the CSI terminal and the CSI service control function entity to transmit the indication information whether the session needs to use the CSI service or not;

C. and correspondingly establishing the CS load according to the indication information.

2. The method of claim 1, wherein in step a, the determining, by the CSI service control function entity, whether the information required for using the CSI service is required at least includes: capability information of the CSI terminal, attribute information of the session call, and capability information of the CS access network.

3. The method of claim 2, wherein the information required by the CSI control function entity to determine whether the CSI service needs to be used further comprises: and the capability information of the IP access network where the CSI terminal is located.

4. The method of claim 2, wherein the CSI service control function entity determines whether the CSI service needs to be used, according to the information, using the following logic:

the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is the DTM capability information of the CS network supporting the dual transfer mode at the CSI terminal side, and the terminal supports the CSI capability, and the CSI service control function entity determines that the CSI service needs to be used.

5. The method of claim 3, wherein the CSI service control function entity uses the following logic to determine whether to use the CSI service according to the information:

the attribute information of the session call is IMS real-time media information, the capability information of a CS access network is the DTM capability information supported by the CS network at the CSI terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI terminal is located is a bearer which can not provide real-time service, so that the CSI service control function entity judges that the CSI service needs to be used; or,

the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is DTM capability information supported by the CS network on the CSI capable terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI capable terminal is located is a bearer capable of providing a real-time service, and then the CSI service control function entity determines that the CSI service needs to be used.

6. The method of claim 3,

the CSI service control function entity acquires the capability information of the terminal from the extended information of the registration message of the terminal; and

the CSI service control function entity inquires and acquires the position information of the CSI terminal in the CS domain through an ATI interface, and inquires data configuration according to the position information so as to acquire the capability information of the CS access network where the CSI terminal is located currently; and

the CSI service control function entity acquires the type of an access network of an IMS where the CSI terminal is currently located through position field information carried in the IMS message, and acquires IP access network capacity information according to the query data configuration; or, the CSI service control function entity inquires and acquires the position information of the CSI terminal in the IMS domain through the ATI interface, and inquires data configuration according to the position information so as to acquire the capability information of the IP access network where the CSI terminal is currently located; and

and the CSI service control function entity is added into a session path between the opposite terminal and the CSI terminal to acquire the attribute information of the session call.

7. The method of any one of claims 2 to 5, wherein when the CSI terminal is used as a calling party, the CSI terminal uses an extended header field or an extended message body in an SIP INVITE message with a CSI service control function entity to convey the willingness information that the session wishes to use the CSI service.

8. The method of claim 1, wherein in step B, the CSI service control function entity uses an extended header field or an extended message body of the session message to transmit indication information whether the CSI service needs to be used for the current session.

9. The method of claim 8,

when the CSI terminal is used as a calling party, after receiving a session request from the CSI terminal, the CSI service control function entity transmits indication information whether the session needs to use the CSI service or not by using an extended header field or an extended message body in an SIP 1xx message between the CSI terminal and the CSI terminal;

when the CSI terminal is called, after receiving a session request directed to the CSI terminal, the CSI service control function entity transmits indication information whether the session needs to use the CSI service or not by using an extended header field or an extended message body in SIP INVITE messages between the CSI terminal and the CSI terminal.

10. The method of claim 1, wherein in step C, if the indication information indicates that the CSI service needs to be used and the CS bearer establishment direction is a terminal-to-network direction, the CSI terminal initiates a CS bearer from a CS part of a home terminal to a CSI service control function entity;

and if the indication information indicates that the CSI service is required to be used and the CS bearing establishing direction is the direction from the network to the terminal, the CSI service control function entity initiates the CS bearing of the CSI terminal.

11. The method of claim 10, wherein if the CS bearer establishment direction is a terminal-to-network direction, the CSI terminal initiates a CS bearer establishment procedure with a CS domain number of the CSI service control function entity as a called number;

if the CS bearing establishing direction is the direction from the terminal to the network, the CSI service control function entity acquires a CS number associated with the IMS of the CSI terminal as a called number to initiate the CS bearing establishing process.

12. The method of claim 11, wherein a manner for the CSI service control function entity to acquire the CS number associated with the IMS number of the CSI terminal comprises one of:

the CSI terminal carries the incidence relation of the CS number and the IMS number in an extended header domain or an extended message body of the registration message so that a CSI control function entity acquires the information;

a fixed numbering rule is adopted to enable a CSI service control function entity to obtain another number of the CSI terminal according to one number of the CSI terminal;

and the CSI service control function entity acquires the CS number of the CSI terminal associated with the IMS number of the CSI terminal from the local configuration data query.

13. The method of claim 1, wherein step C further comprises:

if the session request received by the CSI service control function entity points to the CSI terminal, the CSI service control function entity takes the CS domain roaming number of the CSI terminal from the HLR when initiating the CS bearing establishment of the CSI terminal, and initiates the session request to the roaming number.

14. The method of claim 1, wherein step C further comprises: the CSI terminal initiates a CS call to the CSI service control function entity using an E.164 number that can be routed to the MGCF at the roaming site, so that the call is routed to the CSI service control function entity through the MGCF at the roaming site.

15. The method of claim 14, wherein the manner in which the CSI capable terminal obtains the e.164 number comprises one of:

the CSI service control functional entity dynamically distributes number information according to the roaming place where the CSI terminal is located and informs the CSI terminal;

the CSI terminal senses the roaming place and adds related number prefix information according to the roaming place information.

16. The method of claim 1, wherein in step C, when the CSI service control function entity or the CSI terminal establishes the CS bearer, the CSI service control function entity identifies CS domain service information in the session message, and performs corresponding processing according to the identified CS domain service, so as to avoid adverse effects of the CS domain service.

17. The method of claim 16, wherein if the CS domain service is a number display type service, a CSI service control function entity sets a number display restriction on number information of the CSI service control function entity in a related message sent to the CSI terminal; or after receiving the relevant message sent by the CSI service control function entity, the CSI terminal carries out display limit processing on the number information of the CSI service control function entity;

if the CS domain service is a Call Hold, Call Wait, Call deflection CD, display Call transfer ECT or multi-party conversation MPTY service of the CS domain, the CSI terminal shields the operation of the service when receiving a service operation request of a user and informs the user to initiate the service in the IMS domain;

if the CS domain service is a CS domain operator locking ODB service, a calling locking CB service or a called intelligent service Camel service, and further if the CS bearing direction is a terminal-to-network direction, performing the exceeding authority configuration of the number of the CSI service control function entity in the CS domain; further, if the CS bearing establishing direction is a network-to-terminal direction, the CSI service control function entity obtains a roaming number from the HLR, the HLR acquires that an initiator of the roaming number is the CSI service control function entity, and the roaming number of the CSI terminal is directly returned to the CSI service control function entity;

and if the CS domain service is a closed user group CUG service of the CS domain, configuring the CS domain number of the CSI terminal and the CS domain number of the CSI service control function entity in the CS domain as a user group.

18. The method of claim 1, wherein after the session is successfully established in step C, if the CSI service control function entity receives the session change request, the change type indicated by the session change request is identified, and corresponding processing is performed according to the change type.

19. The method of claim 18, wherein if the change type indicated by the session change request received by the CSI service control function entity is a request for deleting a real-time media component from an opposite end, the CSI service control function entity tears down the CS call to the CSI terminal; or, the CSI service control function entity informs the CSI terminal, and the CSI terminal initiates the removal of the CS call;

if the change type indicated by the session change request received by the CSI service control functional entity is a request for deleting the non-real-time media component from the opposite terminal, the CSI service control functional entity initiates an IMS session change request of the CSI terminal to delete the non-real-time media therein;

if the change type indicated by the session change request received by the CSI service control functional entity is a request for deleting the non-real-time media component from the CSI terminal, the CSI service control functional entity sends the session change request to the opposite terminal;

if the change type indicated by the session change request received by the CSI service control functional entity is a request from the CSI terminal for deleting the real-time media components, the CSI service control functional entity removes a CS call between the CSI service control functional entity and the CSI terminal;

if the change type indicated by the session change request received by the CSI service control functional entity is a request for adding real-time media components from the opposite terminal, the CSI service control functional entity establishes a CS call with the CSI terminal;

if the change type indicated by the session change request received by the CSI service control functional entity is a request for adding non-real-time media components from the opposite terminal, the CSI service control functional entity initiates the session change request of the IMS of the CSI terminal to add the non-real-time media components;

if the change type indicated by the session change request received by the CSI service control functional entity is a request for adding real-time media components from the CSI terminal, the CSI service control functional entity establishes a CS call with the CSI terminal;

if the change type indicated by the session change request received by the CSI service control function entity is a request for adding non-real-time media components from the CSI terminal, the CSI service control function entity initiates an IMS session change request to the opposite terminal so as to add the non-real-time media components.

20. The method of claim 18, wherein if the change type indicated by the session change request received by the CSI service control function entity is a request from the opposite end to delete the real-time media component, the CSI service control function entity deletes the indication information of the CSI service in the session message sent to the CSI terminal to indicate that the real-time media information is deleted.

21. The method of claim 18, wherein if the change type indicated by the session change request received by the CSI service control function entity is a request from the CSI terminal to delete the real-time media component, the CSI terminal deletes the CSI service indication information in the session change request, indicating that it is a request to delete the real-time media component.

22. A system for establishing a bearer, comprising:

the CSI service control function entity is used for judging whether the CSI service is required to be used or not when receiving a session request related to the CSI terminal, and transmitting indication information whether the CSI service is required to be used or not in the session by using extension information of a session message between the CSI terminal and the CSI terminal; and establishing a CS bearer between the CSI terminal and the CS bearer in a matching manner;

and the CSI terminal is used for establishing a CS (circuit switched) load between the CSI terminal and the CSI control function entity in a matching way according to the indication information issued by the CSI service control function entity.

23. The system of claim 22, wherein the CSI service control function entity comprises the following elements:

the system comprises a judging unit and a judging unit, wherein the judging unit is used for judging whether a CSI service is required to be used or not when receiving a session request related to a CSI terminal;

the first transmission unit transmits the judgment result made by the judgment unit to the CSI terminal by using the extension information of the session message between the first transmission unit and the CSI terminal;

and the first CS bearing establishing unit is used for establishing CS bearing between the first CS bearing establishing unit and the CSI terminal in a matching manner.

24. The system of claim 23, wherein the CSI service control function entity further comprises:

and the first CS bearing initiating unit is used for initiating a CS bearing establishment request to the CSI terminal and triggering the first CS bearing establishment unit when the CS bearing direction is the network-to-terminal direction and the judging unit judges that the CSI service is required to be used.

25. The system according to claim 23 or 24, wherein the information required by the determining unit to determine whether the CSI service needs to be used at least comprises: capability information of the CSI terminal, attribute information of the session call, and capability information of the CS access network.

26. The system of claim 25, wherein the determining unit determines whether information required for using the CSI service is required further comprises: and the capability information of the IP access network where the CSI terminal is located.

27. The system of claim 25, wherein the determining unit determines whether the CSI service needs to be used using the following logic based on the information: the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is the DTM capability information of the CS network supporting the dual transfer mode at the CSI terminal side, and the terminal supports the CSI capability, and the CSI service control function entity determines that the CSI service needs to be used.

28. The system of claim 26, wherein the determining unit determines whether the CSI service needs to be used using the following logic based on the information:

the attribute information of the session call is IMS real-time media information, the capability information of a CS access network is the DTM capability information supported by the CS network at the CSI terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI terminal is located is a bearer which can not provide real-time service, so that the CSI service control function entity judges that the CSI service needs to be used; or,

the attribute information of the session call is IMS real-time media information, the capability information of the CS access network is DTM capability information supported by the CS network on the CSI capable terminal side, the terminal supports CSI capability, and the capability information of the IP access network where the CSI capable terminal is located is a bearer capable of providing a real-time service, and then the CSI service control function entity determines that the CSI service needs to be used.

29. The system of claim 23, wherein the first delivery unit delivers the determination result made by the determination unit to a CSI terminal using an extended header field or an extended message body of the session message.

30. The system of claim 29, wherein when the CSI capable terminal is called, the first forwarding unit forwards the result of the determination made by the determining unit to the CSI capable terminal using an extended header field or an extended message body in an SIP 1xx message with the CSI capable terminal;

when the CSI terminal is called, the first transmission unit transmits the judgment result made by the judgment unit to the CSI terminal by using an extension header field or an extension message body in the SIP INVITE message between the first transmission unit and the CSI terminal.

31. The system of claim 22, wherein the CSI terminal comprises the following elements:

the indication identification unit is used for identifying the indication information whether the session needs to use the CSI service or not from the session message sent by the CSI service control function entity;

and the second CS bearing establishing unit is used for establishing CS bearing between the CSI control function entity and the CS bearing after knowing whether the CSI service is used or not.

32. The system of claim 31, wherein the CSI terminal further comprises:

and the second CS bearing initiating unit is used for initiating a CS bearing establishing request to the CSI service control function entity and triggering the second CS bearing establishing unit when the CS bearing establishing direction is the terminal-to-network direction and the indication identifying unit determines that the CSI service needs to be used.

33. The system of claim 31 or 32, wherein the CSI terminal further comprises:

a second transmission unit, configured to transmit willingness information that the current session desires to use the CSI service by using an extension header or an extension message body in an SIP INVITE message between the CSI service control function entity when the current CSI terminal is used as a calling party;

or further comprising: and the third transmission unit is used for carrying CSI capability information in an extended header field or an extended message body of the registration message when the CSI terminal is registered.

34. The system of claim 31 or 32, wherein the CSI terminal further comprises:

and the fourth transmission unit is used for carrying the association relationship between the CS number and the IMS number of the CSI terminal in an extended header field or an extended message body of a registration message when the CSI terminal is registered so as to enable the CSI control function entity to acquire the information.

35. A CSI service control function entity, comprising the following elements:

the system comprises a judging unit and a judging unit, wherein the judging unit is used for judging whether a CSI service is required to be used or not when receiving a session request related to a CSI terminal;

the first transmission unit transmits the judgment result made by the judgment unit to the CSI terminal by using the extension information of the session message between the first transmission unit and the CSI terminal;

and the first CS bearing establishing unit is used for establishing CS bearing between the first CS bearing establishing unit and the CSI terminal in a matching manner.

36. The entity of claim 35, wherein the entity further comprises:

and the first CS bearing initiating unit is used for initiating a CS bearing establishment request to the CSI terminal and triggering the first CS bearing establishment unit when the CS bearing direction is the network-to-terminal direction and the judging unit judges that the CSI service is required to be used.

37. A CSI terminal, comprising the following elements:

the indication identification unit is used for identifying the indication information whether the session needs to use the CSI service or not from the session message sent by the CSI service control function entity;

and the second CS bearing establishing unit is used for establishing CS bearing between the CSI control function entity and the CS bearing after knowing whether the CSI service is used or not.

38. The CSI terminal of claim 37, wherein said terminal further comprises:

and the second CS bearing initiating unit is used for initiating a CS bearing establishing request to the CSI service control function entity and triggering the second CS bearing establishing unit when the CS bearing establishing direction is the terminal-to-network direction and the indication identifying unit determines that the CSI service needs to be used.

39. The CSI terminal of claim 37 or 38, wherein said terminal further comprises:

a second transmission unit, configured to transmit willingness information that the current session desires to use the CSI service by using an extension header or an extension message body in an SIP INVITE message between the CSI service control function entity when the current CSI terminal is used as a calling party;

or further comprising: and the third transmission unit is used for carrying CSI capability information in an extended header field or an extended message body of the registration message when the CSI terminal is registered.

40. The CSI terminal of claim 37 or 38, wherein said terminal further comprises:

and the fourth transmission unit is used for carrying the association relationship between the CS number and the IMS number of the CSI terminal in an extended header field or an extended message body of a registration message when the CSI terminal is registered so as to enable the CSI control function entity to acquire the information.

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