WO2012013094A1

WO2012013094A1 - Session establishment method and system based on dialog correlation identifier

Info

Publication number: WO2012013094A1
Application number: PCT/CN2011/075595
Authority: WO
Inventors: 高扬
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-07-28
Filing date: 2011-06-10
Publication date: 2012-02-02
Also published as: CN102348291A; CN102348291B

Abstract

A session establishment method based on a dialog correlation identifier is provided by the present invention, in which dialog correlation information for identifying the initiated dialog is set. The method also includes: the dialog correlation information is inserted into the call request initiated by the call request initiator; after receiving the call request, the Application Server (AS) which performs the Back to Back User Agent (B2BUA) behavior generates the call request which will be sent to the receiver of the call request, wherein the call request which will be sent to the receiver of the call request carries the dialog correlation information; after receiving the call request sent by the B2BUA, the receiver of the call request establishes the dialog and stores the dialog correlation information. A session establishment system based on a dialog correlation identifier is provided by the present invention simultaneously. The present invention implements the quickness of the dialog confirmation, is compatible with the prior session establishment flow simultaneously, and ensures the generality of the technical solution.

Description

Method and system for establishing ^^ based on dialogue association identifier

The present invention relates to a conference service establishment technique, and in particular, to a session establishment method and system based on a conversation association identifier. Background technique

The 3rd Generation Partner Project (3GPP) defines the application server (AS, Application Server). When processing Session Initiation Protocol (SIP) messages, the behavior mode can be proxy (proxy), route back to back. User BPDU ( Routing B2BU A, Routing Back to Back User Agent) or Initial Back-to-Back User Agent (Initiating B2BUA) „ When the AS uses the Routing B2BUA or Initiating B2BUA behavior mode, the session IDs (Dialog IDs) on both sides of the AS are modified via AS. The Dialog IDs on both sides of the AS will be different.

Figure 1 is a flow chart of session establishment when there is a B2BUA in the call request path. As shown in Figure 1, the B2BUA is for the call request of the session 1 initiated by the UE-A. The B2BUA-1 will modify the ID of the session due to the B2BUA behavior. That is, after changing to the new conversation 2, the call request is forwarded. The specific session establishment process is as follows:

Step 101: The UE-A sends a call request, where the carried session information is the conversation 1; Step 102, after the service call session control function entity (S-CSCF, Serving Call Session Control Function) receives the call request, according to the user UE -A's signing rule, triggering the call request to B2BUA-1;

Step 103, because the B2BUA-1 performs the function of the B2BUA, when it receives the call request, replaces the dialog 1 information in the call request, for example, replaces the conversation 2, and forwards it to the S-CCSF; Step 104, the S-CSCF may also trigger the call request to other ASs according to the subscription rule of the user, and finally reach the called user UE-B;

Step 105: The dialog information in the call request received by the called user UE-B is the information of the dialog 2, and the UE-B replies with the 200 OK response message;

Step 106: After receiving the 200 OK response, the S-CSCF triggers the response message to B2BUA-1.

Step 107, B2BUA-1 converts the dialog information in the received 200 OK response message into the information of the dialog 1 according to the relationship of the previous dialog information conversion, and forwards the information to the S-CSCF;

Step 108, the S-CSCF forwards the converted 200 OK response message to the UE-A.

It can be seen from the session establishment process shown in FIG. 1 that the dialogue faced by UE-A is conversation 1, and the conversation faced by UE-B is conversation 2, and the association management between conversation 1 and conversation 2 is performed by B2BUA. -1 is responsible.

In the prior art, there are multiple ways to establish a conference. One scenario is to add a user to the conference service through the conference application server. The standard process is shown in FIG. 2, where UE-A and UE-B are A session is established first, and then UE-A establishes another conference service, and it is desired to add UE-B to the established conference service, thereby implementing multi-party communication.

Figure 2 is a flowchart for establishing a conference for adding a user to a conference service through a conference application server. As shown in Figure 2, the following steps are specifically included:

Step 201: UE-A initiates a call request.

Step 202: The call request control function entity (P-CSCF, Proxy Call Session Control Function) sends the call request to the S-CSCF serving the UE-A.

Step 203: The S-CSCF sends the call request to the called user UE-B.

Step 204 to step 206, the UE-B sends a 200 OK response to the UE-A, and the session established between the UE-A and the UE-B may be referred to as the conversation 1;

Step 207, UE-A wants to make a multi-party call, and then initiates a conference establishment request to the conference AS; Step 208 to step 209, the P-CSCF, the S-CSCF sends the conference establishment request to the conference AS;

Step 210 to step 212, the conference AS receives the conference establishment of the UE-A, and returns a 200 OK response to the UE-A. At this time, the conversation established between the UE-A and the conference AS 2;

Step 213 to step 215, at this time, UE-A wants to add UE-B to the newly established conference service, and replaces the conversation between the original UE-A and UE-B, and UE-A sends a handover to the conference AS (REFER). a request, which carries a Replacess header field or parameter whose value is the information of the dialog 1;

Step 216 to step 217, after receiving the transfer request, the conference AS sends a new call request to the called user UE-B, which also carries a Replacess header field or parameter whose value is the information of the conversation 1;

Step 218: After receiving the call request, the UE-B first finds the session 1 information on the UE-B, and determines that the new call is to replace the originally established session 1;

Step 219 to step 220, after the UE-B agrees to the request, sending a 200 OK response to the conference AS;

Step 221 to step 223, at the same time, UE-B sends a request to UE-A to end the original conversation 1; Step 224~Step 226, UE-A sends 200 OK, accepting the end of conversation 1.

At this time, the dialog 1 is replaced by the conference service, but in the above process, there is no case of B2BUA in the process of session establishment, because there are ^^ in the existing IMS network.

The AS will participate in the user's session to serve the user, so it is very common to have B2BU A in the process of session establishment.

Figure 3 is a flowchart of a B2BUA in the process of establishing a conference service. As shown in Figure 3, when a B2BUA occurs during the conference setup process shown in Figure 2, the process is as follows:

Step 301 to step 302, the user initiates a call request, which is the same as steps 201 to 202 shown in FIG. 2; Step 303: The S-CSCF triggers the call request to the B2BUA-1 according to the subscription rule of the user.

Step 304, since the B2BUA-1 functions as a back-to-back user agent, the B2BUA-1 replaces the session 1 information of the call request with the dialog A and then forwards it to the UE-B;

Step 305, the UE-B replies with a 200 OK response, and the session information established on the UE-B is the conversation 2;

Step 306~ Step 308, B2BUA-1 forwards the 200 OK of the UE-B to the UE-A, where the dialog A is converted into the information of the dialog 1, and the session 1 is established on the UE-A;

Step 309 to step 319 are the process of establishing a conference, and the process of establishing the conference is the same as steps 207 to 217 shown in FIG. 2;

Step 320: After receiving the call request sent by the conference AS, the UE-B searches for the dialog 1. Since a B2BUA-1 has passed during the establishment of the previous conversation 1, there is no information of the conversation 1 on the UE-B. ;

Step 321 : Since the information of the conversation 1 is not found, the UE-B rejects the call request sent by the conference AS, so that the adding process fails.

In the application scenario of the non-IP multimedia subsystem (IMS, IP Multimedia Subsystem), the above problem also occurs. If the call passes through one or more B2BUA devices (such as Session Border Controllers (SBCs)), and the B2BUA devices modify the Dialog ID of the call, the subsequent Replaces process cannot be performed. Summary of the invention

In view of this, the main object of the present invention is to provide a session establishment method and system based on a conversation association identifier, which can accurately locate the replaced conversation in the replacement call setup process.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for establishing a session based on a conversation association identifier, and setting session association information for identifying the initiated conversation; the method further includes: Inserting the dialog association information in a call request initiated by a call request originator;

After receiving the call request, the B2BUA generates a call request sent to the call request receiver, where the call request sent to the call request receiver carries the dialog association information; and the call request receiver receives the B2BUA Establishing a conversation after the sent call request, and saving the conversation association information;

When the session party determines to initiate the replacement call, the request with the Replaces header is sent to the B2BUA; wherein the request with the Replaces header carries the session association information.

Preferably, the method further includes:

After receiving the request with the Replaces header, the B2BUA generates a request with a Replaces header sent to the other party of the session; wherein the generated request with the Replaces header carries the dialog association information;

After receiving the request with the Replaces header, the other party of the session releases the associated call according to the conversation associated information.

Preferably, the one party or the other party is a user, a user agent or a user equipment. Preferably, the request with a Replaces header includes an INVITE request or a REFER request.

Preferably, the session association information is inserted in a call request initiated by a call request originator, and/or the dialog association information is carried in the request with a Replaces header, specifically:

A session initiation protocol SIP header or SIP header parameter is set for the call request and/or the request with the Replaces header, and the session association information is carried in the SIP header or the SIP header parameter.

Preferably, the session association information is a Session ID.

Preferably, the method further includes: After receiving the call request and/or the request with the Replaces header, the AS acting as a proxy transparently transmits the call request and/or the request with the Replaces header.

Preferably, the method further includes:

The B2BUA or the call request receiver replies with a failure response after the B2BUA or the call request receiver that does not support the SIP header carrying the session association information receives the call request with the SIP header, where The failure response indicates that the B2BUA or the call request receiver does not support the SIP header carrying the conversation association information; the call request initiator reconstructs a call request that does not carry the conversation association information and retransmits.

A session establishing system based on a conversation association identifier, comprising: a setting unit, a first generating unit, a first receiving unit, a second generating unit, a second receiving unit, a dialog establishing unit, a saving unit, and a third generating unit; a receiving unit and the second generating unit are located in the B2BUA, the second receiving unit, the dialog establishing unit and the saving unit are located in the call request receiving party; and the third generating unit is located in a side of the session Medium; among them,

a setting unit, configured to set conversation association information used to identify the initiated conversation;

a first generating unit, configured to generate a call request sent to a call request receiver, where the call request carries the dialog association information;

a first receiving unit, configured to receive the call request;

a second generating unit, configured to: after the first receiving unit receives the call request, generate a call request sent to a call request receiver, where the call request sent to the call request receiver carries the conversation Associated information;

a second receiving unit, located at the call request receiving party, configured to receive a call request sent by the B2BUA;

a dialog establishing unit, configured to establish a dialog after the second receiving unit receives the call request;

a saving unit, configured to save the conversation association information; a third generating unit, configured to generate, when the session party determines to initiate a replacement call

The request of the Replaces header is sent to the B2BUA; wherein the request with the Replaces header carries the dialog association information.

Preferably, the system further includes a release unit, located in the other party of the session; wherein, after the first receiving unit receives the request with the Replaces header, the second generating unit generates and sends the message to the other party of the session. a request with a Replaces header; wherein the generated request with a Replaces header carries the dialog associated information;

And a releasing unit, configured to release the associated call according to the session association information after the other party of the session receives the request with the Replaces header.

Preferably, the one party or the other party is a user, a user agent or a user equipment; the request with a Replaces header includes an INVITE request or a REFER request.

Preferably, the setting unit is further configured to set a SIP header or a SIP header parameter for a call request and a request with a Replaces header, and carry the dialog association in the SIP header or the SIP header parameter information.

Preferably, the system further includes a transparent transmission unit, located in the AS as a proxy behavior, for transparently transmitting the call request and the replacements header after receiving the call request and the request with the Replaces header Ministry's request.

Preferably, the system further comprises:

a first replying unit, located in a B2BUA that does not support the SIP header that carries the session association information, is configured to: after the first receiving unit receives the call request that carries the SIP header, reply to the call request receiver a failure response, where the failure response indicates that the B2BUA does not support the SIP header carrying the conversation association information;

The first generating unit regenerates a call request sent to the call request recipient that does not carry the dialog associated information.

Preferably, the system further comprises: a second reply unit, in a call request receiver that does not support the SIP header that carries the dialog association information, where the second receiving unit receives the SIP header that is forwarded by the B2BUA and carries the dialog association information. After the call request, the call request recipient is replied to the failure response, where the failure response indicates that the call request receiver does not support the SIP header carrying the conversation association information;

In the present invention, by setting the dialog association information identifying the initiated conversation, and inserting the dialog association information when generating the call request and the request with the Replaces header, when the B2BUA receives the call request carrying the conversation associated information, The session association information will not be modified, but will be directly copied and sent to other network elements. After receiving the call request carrying the session association information, the call request receiver saves the session association information. When a session party initiates a request with a Replaces header, the other party of the session receives the request with the Replaces header carrying the session association information, and can directly determine the replacement session according to the session association information, thereby implementing the related conference service. set up. When the B2BUA or the call recipient does not support the extended call request, the call request originator is also notified to regenerate the normal call request that does not carry the session associated information. The invention realizes the quickness of the dialogue confirmation, and is also compatible with the existing session establishment process, thereby ensuring the versatility of the technical solution. DRAWINGS

FIG. 1 is a flowchart of establishing a session when a B2BUA exists in a call request path;

2 is a flowchart for establishing a conference by adding a user to a conference service through a conference application server; FIG. 3 is a flowchart of a B2BUA in an existing conference service establishment process;

4 is a flowchart of a session establishment method based on a conversation association identifier according to the present invention;

5 is a flowchart of a B2BUA not supporting a SIP header or a SIP parameter in a conference establishment process according to the present invention; 6 is a flowchart of a receiver not supporting a SIP header or a SIP parameter in a conference establishment process according to the present invention;

7 is a schematic diagram of a first component structure of a session establishment system based on a conversation association identifier according to the present invention;

FIG. 8 is a schematic diagram showing a second composition structure of a session establishment system based on a conversation association identifier according to the present invention. detailed description

The basic idea of the present invention is to insert the dialog association information by setting the dialog association information identifying the initiated conversation and inserting the dialog association information when generating the call request and the request with the Replaces header, so that the B2BUA receives the call request carrying the conversation associated information. The session association information will not be modified, but will be directly copied and sent to other network elements. After the call request receiver receives the call request carrying the session association information, the session association information is saved. When a session party initiates a request with a Replaces header, the other party of the session receives the request with the Replaces header carrying the session association information, and can directly determine the replacement session according to the session association information, thereby implementing the related conference service. set up. When the B2BUA or the call recipient does not support the extended call request, the call request originator is also notified to regenerate the normal call request that does not carry the session associated information.

The present invention will be further described in detail below with reference to the accompanying drawings.

In the present invention, the dialog association information for identifying the initiated conversation is first set; thus, the dialog association information is inserted in the call request initiated by the call request originator; and after the AS performing the B2BUA behavior receives the call request, Generating a call request sent to the call request recipient, where the call request sent to the call request receiver carries the dialog association information; the call request receiver establishes a dialog after receiving the call request sent by the B2BUA, and Save the conversation related information. Specifically, setting a SIP header or SIP parameter for the call request, The SIP header or SIP parameter carries the dialog association information.

When the session party determines to initiate the replacement call, constructs a request with a Replaces header and sends the request to the B2BUA; wherein the request with the Replaces header carries the session association information;

After receiving the request with the Replaces header, the B2BUA generates a request with a Replaces header sent to the other side of the session; wherein the generated request with the Replaces header carries the dialog associated information. A session initiation protocol SIP header is set for the request with the Replaces header, and the SIP header carries the session association information.

In the present invention, the AS acting as a proxy acts to transparently transmit the call request and the request with the Replaces header after receiving the call request and the request with the Replaces header.

When the B2BUA or the call request receiver that does not support the SIP header carrying the session association information receives the call request with the SIP header, the B2BUA or the call request receiver replies with a failure response, where The failure response indicates that the B2BUA or the call request receiver does not support the SIP header carrying the conversation association information; the call request initiator reconstructs a call request that does not carry the conversation association information and retransmits.

The essence of the technical solution of the present invention will be further clarified by specific examples below.

FIG. 4 is a flowchart of a method for establishing a session based on a conversation association identifier according to the present invention. As shown in FIG. 4, the UA is a user agent, which is specifically divided into a client user agent (UAC) and a server user agent (UAS). The session establishment method based on the conversation association identifier of the present invention includes the following steps:

Step 401: The UAC needs to send a call request, and constructs a Dialog Correlation Header while constructing the call request message, and inserts a unique call identifier in the call request message to identify the call (Call or Session);

Step 402: The UAC sends the call request.

Step 403: If a proxy exists in the call path, the proxy needs to transparently transmit the call request. Information, transparent messages include Dialog Correlation Header;

Step 404: The Proxy forwards the transparently transmitted message.

Step 405: For the B2BUA device (such as AS, SBC, BGW, etc.), the Dialog Correlation Header needs to be copied, and a call request message forwarded to the call recipient is constructed;

Step 406, the B2BUA sends the constructed call request message with a new Dialog ID; this is the same as the existing call processing flow;

Step 407, after receiving the call request message, the UAS saves the Dialog Correlation Header and the call association identifier therein;

Step 408, the U AS sends a response message, which carries the Dialog Correlation Header. Of course, in the response message sent, it is not necessary to carry the Dialog Correlation Header; Step 409, the B2BUA copies the Dialog Correlation Header, and constructs the Dialog Correlation Header to be sent to the call originator. Respond to the message and send it to the next hop;

Step 410: The Proxy transparently transmits the response message, and the Dialog Correlation Header therein; Step 411, either UAC or UAS, subsequently needs to initiate a call replacement request, and constructs a Replacess header and parameters according to the Dialog Correlation Header; in this example, by UAC Initiating a call replacement request;

Step 412, the UAC (or UAS) sends a call replacement request message, carrying the configured Replacess header and parameters, and the call replacement request message may be any request message carrying a Replacess header, such as an INVITE message or a Refer message;

Step 413, the Proxy transparently transmits the message, and the Replacess header and parameters therein; Step 414, the B2BUA copies the Replacess header and parameters therein, and constructs a request message with a Replaces header sent to the other party of the session;

Step 415, the B2BUA sends the constructed request message with the Replaces header to the new Dialog ID; this is the same as the existing conference establishment processing;

Step 416, UAS (or UAC) receives the message and according to the call in Replaces The association identifier is compared with the recorded call association identifier and replaces the associated call; here, when comparing, the UAS (or UAC) needs to compare the call association identifier in the recorded Dialog Correlation Header, and the original call does not have a Dialog. When the Correlation Header is compared, the recorded Dialog ID is compared.

In the present invention, the UAC can decide to carry the Dialog in the call request initiated this time.

The Correlation Header or the Dialog Correlation Header can also be configured as a selection strategy. For example, when there is no B2BUA device in the networking environment, you can choose not to carry the Dialog Correlation Header.

Considering the interoperability of the device, it is also possible to define a SIP capability representation for the Dialog Correlation Header support (new Require/Supported header option tag), if the flag is set to "DC". When the call request sent by UAC is accompanied by Dialog Correlation Header, in the Require header, the corresponding identifier such as "DC" is set. When there is a network element in the call path, such as B2BUA, or UAS, this header is not supported, and after rejecting the call request, the UAC should re-initiate the call request without the Dialog Correlation Header.

FIG. 5 is a flow chart of the B2BUA not supporting the SIP header or the SIP parameter in the conference establishment process of the present invention. As shown in FIG. 5, the example conference establishment process includes the following steps:

Step 501: The UAC constructs a call request, where the call request carries a SIP header or a SIP parameter, and the SIP header or the SIP parameter carries a Dialog Correlation Header, and the call request may further carry a capability indicating whether the Dialog Correlation Header is supported. Identification, such as DC;

Step 502 to step 504, the intermediate network element (Proxy) transparently transmits the request message, and the intermediate network element (B2BUA) copies the SIP header or the SIP parameter.

Step 505 to step 507, the B2BUA does not support the header, and responds to the corresponding reject message, such as 4xx, indicating rejection, and indicates that the SIP header carrying the Dialog Correlation Header is not supported. Step 508, after receiving the 4xx, the UAC re-initiates the call request. Without Dialog The Correlation Header, which can carry an identifier indicating whether or not the Dialog Correlation Header is supported.

Figure 6 is a flow chart of the SIP header or SIP parameters of the receiver in the conference establishment process of the present invention. As shown in Figure 6, the example conference establishment process includes the following steps:

Step 601: The UAC constructs a call request, where the call request carries a SIP header or a SIP parameter, and the SIP header or the SIP parameter carries a Dialog Correlation Header, and the call request may further carry a capability indicating whether the Dialog Correlation Header is supported. Identification, such as DC;

Step 602 to step 604, the intermediate network element (Proxy) transparently transmits the request message, and the intermediate network element (B2BUA) copies the SIP header or the SIP parameter.

Step 605 to step 607, the UAS does not support the SIP header or the SIP parameter, and responds to the corresponding reject message, such as 4xx, indicating rejection, and indicates that the SIP header or SIP parameter carrying the Dialog Correlation Header is not supported;

Step 608: After receiving the 4xx, the UAC re-initiates the call request without the Dialog Correlation Header, and may carry an identifier indicating whether the Dialog Correlation Header is supported.

As an implementation, the above Dialog Correlation Header can be the header of the Session ID.

FIG. 7 is a schematic diagram of a first component structure of a session establishment system based on a session association identifier according to the present invention. As shown in FIG. 7, the session establishment system based on the session association identifier includes the system including a setting unit 70 and a first generation unit. 71. The first receiving unit 72, the second generating unit 73, the second receiving unit 74, the dialog establishing unit 75, the saving unit 76, and the third generating unit 77. The first generating unit 71 is located in the call request initiator, and the first receiving unit The unit 72 and the second generating unit 73 are located in the B2BUA, the second receiving unit 74, the dialog establishing unit 75 and the saving unit 76 are located in the call request receiving party; the third generating unit 77 is located in one of the sessions; The setting unit 70 is configured to set the dialog association information for identifying the initiated dialog. The first generating unit 71 is configured to generate a call request sent to the call request receiver, where the call request carries the dialog association information;

The first receiving unit 72 is configured to receive the call request.

a second generating unit 73, configured to: after the first receiving unit 71 receives the call request, generate a call request sent to a call request receiver, where the call request sent to the call request receiver carries the dialog Associated information;

The second receiving unit 74 is located at the call request receiving end, and is configured to receive a call request sent by the B2BUA;

The dialog establishing unit 75 is configured to establish a dialog after the second receiving unit 74 receives the call request;

a saving unit 76, configured to save the dialog association information;

The third generating unit 77 is configured to: when the session party determines to initiate the replacement call, generate a request with a Replaces header to send to the B2BUA; where the request with the Replaces header carries the session association information .

FIG. 8 is a schematic diagram of a second component structure of a session establishment system based on a conversation association identifier according to the present invention. As shown in FIG. 8, on the basis of the system shown in FIG. 7, the session establishment system based on the conversation association identifier further includes release. Unit 78, located in the other side of the session; wherein

After the first receiving unit 72 receives the request with the Replaces header, the second generating unit 73 further generates a request with a Replaces header sent to the other party of the session; wherein the generated request with the Replaces header is generated. Carrying the conversation related information;

The releasing unit 78 is configured to release the associated call according to the session association information after the other party of the session receives the request with the Replaces header.

The above-mentioned session party or the other party of the session is a user, a user agent or a user equipment; the request with the Replaces header includes an invitation INVITE request or a transfer REFER request. On the basis of the system shown in FIG. 7 or FIG. 8, the session establishment system based on the session association identifier of the present invention further includes a transparent transmission unit (not shown in FIG. 7 and FIG. 8), which is located in the AS as a proxy behavior, and is used for After receiving the call request and the request with the Replaces header, the call request and the request with the Replaces header are transparently transmitted.

Based on the system shown in FIG. 8, the session establishment system based on the session association identifier of the present invention further includes a first reply unit (not shown in FIG. 8) located in the B2BUA that does not support the SIP header carrying the dialog association information. After receiving the call request carrying the SIP header, the first receiving unit 72 replies to the call request receiver with a failure response, where the failure response indicates that the B2BUA does not support the SIP carrying the session association information. Head

The first generating unit 71 regenerates a call request sent to the call request recipient that does not carry the dialog associated information.

Based on the system shown in FIG. 8, the session establishment system based on the session association identifier of the present invention further includes a second reply unit (not shown in FIG. 8) located in a call that does not support the SIP header carrying the session association information. After receiving the call request of the SIP header carrying the dialog association information forwarded by the B2BUA, the second receiving unit 74 returns a failure response to the call request receiver, where the failure response indicates The call request recipient does not support the SIP header carrying the conversation associated information;

It should be understood by those skilled in the art that the session establishment system based on the session association identifier is designed to implement the foregoing session association method based on the conversation association identifier. The implementation functions of the foregoing processing units may refer to the foregoing method for uplink feedback. Understand the relevant description. The functions of each processing unit can be implemented by a program running on the processor or by a specific logic circuit.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Range of protection.

Claims

Claim

A method for establishing a session based on a conversation association identifier, characterized in that: setting session association information for identifying a initiated conversation; the method further comprising:

Inserting the dialog association information in a call request initiated by the call request originator; after receiving the call request, the back-to-back user agent B2BUA generates a call request sent to the call request receiver, and the call sent to the call request receiver The conversation associated information is carried in the request;

The call request receiving party establishes a dialog after receiving the call request sent by the B2BUA, and saves the dialog association information;

When the session party determines to initiate the replacement call, the request with the replacement Replaces header is sent to the B2BUA; wherein the request with the Replaces header carries the session association information.

The method according to claim 1, wherein the method further comprises: after receiving the request with the Replaces header, the B2BUA generates a request with a Replaces header sent to the other party of the session; The generated request with a Replaces header carries the dialog association information;

3. The method according to claim 2, wherein the one party or the other party is a user, a user agent or a user equipment.

4. The method of claim 1, wherein the request with a Replaces header comprises an invite INVITE request or a transfer REFER request.

The method according to claim 1, wherein the session association information is inserted in a call request initiated by a call request originator, and/or carried in the request with a Replaces header The conversation related information specifically refers to: A session initiation protocol SIP header or SIP header parameter is set for the call request and/or the request with the Replaces header, and the session association information is carried in the SIP header or the SIP header parameter.

The method according to claim 5, wherein the session association information is a Session ID.

The method according to claim 1, wherein the method further comprises: after receiving the call request and/or the request with the Replaces header, the AS as the proxy behavior transparently transmits the call request and/or Or the request with the Replaces header.

8. The method according to claim 5, wherein the method further comprises: not supporting a B2BUA or a call request receiver of the SIP header carrying the session association information to receive a call with the SIP header After the request, the B2BUA or the call request receiver replies with a failure response, where the failure response indicates that the B2BUA or the call request receiver does not support the SIP header carrying the conversation association information; The requesting initiator reconstructs a call request that does not carry the conversation-related information and resends it.

A session establishment system based on a conversation association identifier, wherein the system includes a setting unit, a first generation unit, a first receiving unit, a second generating unit, a second receiving unit, a dialog establishing unit, and a saving unit. And a third generating unit; the first generating unit is located in a call request originator, the first receiving unit and the second generating unit are located in a B2BUA, the second receiving unit, the dialog establishing unit, and the The saving unit is located in the call request receiving party; the third generating unit is located in one side of the session;

a first receiving unit, configured to receive the call request;

a second generating unit, configured to: after the first receiving unit receives the call request, And the call request sent to the call request receiver, where the call request sent to the call request receiver carries the dialog association information;

a saving unit, configured to save the conversation association information;

And a third generating unit, configured to send a request with a Replaces header to the B2BUA when the session party determines to initiate the replacement call, where the request with the Replaces header carries the session association information.

10. The system according to claim 9, wherein the system further comprises a release unit located in the other party of the session;

After the first receiving unit receives the request with the Replaces header, the second generating unit further generates a request with a Replaces header sent to the other side of the session; wherein the generated Replaces header The request carries the conversation related information;

11. The system according to claim 10, wherein the one party or the other party is a user, a user agent or a user equipment; and the request with a Replaces header includes an INVITE request or a REFER request.

12. The system according to claim 9, wherein the setting unit is further configured to set a SIP header or a SIP header parameter for a call request and a request with a Replaces header, in the SIP header or The dialog related information is carried in the SIP header parameter.

13. The system according to claim 9, wherein the system further comprises a transparent transmission unit located in the AS as a proxy behavior for receiving a call request and with a Replaces After the request of the header, the call request and the request with the Replaces header are transparently transmitted.

The system according to claim 12, wherein the system further comprises: a first reply unit, located in a B2BUA that does not support a SIP header carrying the dialog association information, for the first After receiving the call request that carries the SIP header, the receiving unit sends a failure response to the call request receiver, where the failure response indicates that the B2BUA does not support the SIP header that carries the session association information;

The system according to claim 12, wherein the system further comprises: a second reply unit, located in a call request receiver that does not support a SIP header carrying the dialog association information, in the After receiving the call request of the SIP header that carries the session association information, the receiving unit sends a failure response to the call request receiver, where the failure response indicates that the call request receiver does not support carrying a SIP header of the conversation associated information;