CN101448046A - Call-establishing method for realizing single-conversation color ring back tone service - Google Patents

Abstract

The invention discloses a call-establishing method for realizing single-conversation coloring ring back tone service. The method comprises the steps as follows: a calling party initiates a call, and a coloring ring back tone application server (AS) plays media information to the calling party in a single-conversation way; a called party answers the call, and after receiving the response information of the called party and before transmitting the response information, the coloring ring back tone AS requests the called party to send an SDP request; the coloring ring back tone AS sends the SDP request to the calling party after receiving the SDP request sent by the called party; and the calling party, the coloring ring back tone AS and the called party realize the call establishment by a standard process. The technical proposal improves the processing after the called party responds, reduces the interactive steps after the response and adjusts the time for starting charging, thereby simplifying the process between responding and starting the call greatly, improving the experience of a user and avoiding charging by mistake.

Description

A kind of call-establishing method of realizing the single session Ring Back Tone service

Technical field

The present invention relates to the communications field, relate more specifically to a kind of call-establishing method of realizing the single session Ring Back Tone service in the IP Multimedia System.

Background technology

IP (network interconnection agreement, Internet Protocol, be called for short IP) IP multimedia subsystem, IMS (IPMultimedia Core Network Subsystem, be called for short IMS) be by third generation partner program (3rd Generation Partnership Project, abbreviation 3GPP) a kind of IP-based network framework that proposes, made up one opening and service environment flexibly, supporting multimedia application can provide abundant multimedia service for the user.

In the IMS business system, key-course separates with operation layer, and key-course does not provide concrete business, and functions such as necessary triggering, route, charging only are provided to operation layer.Professional triggering and controlled function are CSCF (Call Session Control Function in the key-course, be called for short CSCF) finish, CSCF is divided into and acts on behalf of Proxy (P-CSCF), inquiry Interrogating (I-CSCF) and serve Serving (S-CSCF) three types, that wherein take the main responsibility is Serving, and the Interrogating type is optional.Operation layer is to be made up of a series of application servers (Application Server is called for short AS), and concrete business service can be provided.Key-course (S-CSCF) calls the business on the AS according to user's professional triggering of CAMEL-Subscription-Information control, realizes business function.End-to-end equipment in the session is called user equipment (UE) (User Equipment), is responsible for mutual with the user.These functional entitys use SIP (Session Initiation Protocol, session initiation protocol) agreement communication.In the business that needs play multimedia information, can need Multimedia Resource Function (Media Resource Function, be called for short MRF, be divided into control section MRFC and medium processing section MRFP) participation, be also referred to as media server, its control section is responsible for the translation of the SIP signaling of SE and is interpreted as instruction to MRFP, otherwise perhaps with the response translation of MRFP be interpreted as the SIP signaling that sends to SE, and the transmission and the reception of Media Stream are responsible in the processing section.

Session Initiation Protocol can be used as Session Description Protocol (Session Description Protocol, abbreviation SDP) bearing bed, SDP is responsible for carrying out the negotiation of media resource information, comprises information such as medium type, medium link address, medium connectivity port, bandwidth requirement.The SDP protocol contents is divided into request and responds two kinds, and each request must have a response.

Be a kind of business among the IMS simultaneously in the call establishment to the business of playing multimedia information for calling, this business also can be described as Ring Back Tone service, permission is in calling procedure, play by the good multimedia messages of callee's customization in advance to the calling party, and the multimedia messages that stops not stop as yet after the callee replys is play.The single session CRBT is a kind of implementation of Ring Back Tone service, promptly finishes business realizing in a SIP dialog, and does not need to introduce new dialogue.

In order to simplify description, in the diagram CRBT AS and S-CSCF have been drawn as an entity, theirs between the two be the flow process of standard alternately.

Fig. 1 is the basic messae flow process figure of existing single session Ring Back Tone service, described that the calling subscriber calls out the called subscriber in the prior art, CRBT AS in calling procedure to calling subscriber's coloring ring back tone playing, behind called subscriber answer, color ring server is initiated the situation of media re-negotiation, and its process is as follows:

The SDP request is carried in step 101, the calling subscriber UE-A request of making a call, and such as sending INVITE (invitation) message, carries the SDP request in message body, and the forwarding of message travels P-CSCF and S-CSCF arrives CRBT AS;

Step 102, CRBT AS transmit this call request and give called subscriber UE-B, message travels S-CSCF;

Step 103, called subscriber UE-B ring are responded ALERTING message and are given the calling party, and such as sending " 180Ringing " message, this ALERTING message arrives CRBT AS by way of S-CSCF;

Step 104, CRBT AS call out the CRBT media server, carry the SDP request in the step 101, message travels S-CSCF;

Step 105, CRBT media server answering call are given CRBT AS such as sending " 200OK " message, carry the SDP response of CRBT session, message travels S-CSCF.The medium type that uses by this response of standard-required must all be contained in the SDP request, but can lack than the medium type in the SDP request;

Step 106, CRBT AS send the SDP response of CRBT session to the calling party, such as carrying by receiveing the response of message related to calls temporarily, receiveing the response can be the message that " 183 Session Progress " message or " 180 Ringing " message etc. are taken the lead with " 1 " temporarily, carry the SDP response of CRBT session in the message body, message travels S-CSCF and P-CSCF arrive UE-A;

Step 107, simultaneously, CRBT AS sends to the CRBT media server and confirms response message, such as sending ACK (affirmation) message, message travels S-CSCF;

Step 106 and 107 can not have sequencing.

Step 108, CRBT media server are received the affirmation response message that CRBT AS sends, to the UE-A coloring ring back tone playing;

Before step 104 to 108 can occur in after the step 101 109 whenever.

Press standard-required, between the step 106 to 108, caller may be also can with called further negotiation media resource information, and follow-up negotiation all is based on the negotiation result of front, because caller is actually with the CRBT media server and consults medium, then the medium type in the medium type of CRBT medium is asked than the SDP in the step 101 after a little while, called the conversation of being ready to carry out less medium type thought in the caller meeting, calledly can think also that caller has reduced and be ready the medium type that uses that this makes calling and called all only prepare the resource of less medium type before conversation.

Step 109, called subscriber UE-B answering call send response message to the calling party, such as sending " 200OK " message, carry called subscriber's SDP response, and this response message arrives CRBT AS by way of S-CSCF;

After the SDP response in step 110, the CRBT AS deletion response message, be transmitted to the calling party, message travels S-CSCF and P-CSCF;

Step 111, P-CSCF receive response message, and the indication billing function begins to charge;

Step 112, simultaneously, P-CSCF transmits response message and gives UE-A;

Step 111 and 112 can not have sequencing.

Step 113, UE-A receive response message, send to confirm response message to the callee, and such as sending ACK message, message travels P-CSCF and S-CSCF arrive CRBT AS;

Step 114, CRBT AS transmit and confirm that response message is to UE-B, message travels S-CSCF;

Step 115, simultaneously, CRBT AS inquires the SDP information that it is using to the callee, such as sending not re-INVITE with any SDP information (recall) message, message travels S-CSCF arrives UE-B;

Step 114 and 115 can not have sequencing.

Step 116, UE-B receive that recall is message, return the SDP information that UE-B is using, and carry message and mail to the calling party by responding recall with the form of SDP request, responding recall can be " 200OK " message message, the SDP request is carried by message body, and message travels S-CSCF arrives CRBT AS;

By aforementioned analysis as can be known, the medium type of the SDP of this moment request use may lack than the medium type that the request of the SDP in the step 101 is used.

Step 117, CRBT AS send recall message to the calling party after receiving callee's SDP request, carry the callee's who is received SDP request in the message body, and message travels S-CSCF and P-CSCF arrive UE-A;

Step 118, UE-A receive recall message, send it back to answer recall to give the callee message, such as sending " 200 OK " message, carry the SDP response in the message body, and message travels P-CSCF and S-CSCF arrive CRBT AS;

Step 119, CRBT AS send to the callee and confirm to receive the response, and such as sending ACK message, carry the calling party's who is received SDP response in the message body, and message travels S-CSCF arrives UE-B;

Step 120, so far, UE-A has set up medium with UE-B and has been connected, and begins conversation.

The deficiencies in the prior art part is: chargeing begins too early, after the beginning of chargeing, still has many signaling contacts could really begin conversation, makes charge information and actual conditions have greater difference, and can cause user's impression very bad like this; And behind the called party answer, still have the contact of many signalings could begin conversation, and these signalings contacts are some times of cost obviously, and it is extremely odd that the user can feel, even may feel the problem that taken place and kill-call.In addition, the medium type of appointment when the medium type that Ring Back Tone service scheme of the prior art can be used is subject to calling, and when the medium type of Ring Back Tone service includes only audio frequency, when even caller and called users is ready to carry out video calling for possessing the terminal of video call function and caller, after replying, also may can only adopt voice-frequency telephony, limitation is relatively arranged.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of call-establishing method of realizing the single session Ring Back Tone service, can simplify the process behind the called party answer, improves user experience, and makes the time started of chargeing comparatively reasonable.

In order to address the above problem, the invention provides a kind of call-establishing method of realizing the single session Ring Back Tone service, comprising:

A, calling party make a call, and the CRBT application server AS adopts the single session mode to described calling party's playing media information;

B, callee's answering call, described CRBT AS ask described callee to send the SDP request after receiving callee's response message and before transmitting described response message;

C, CRBT AS issue described calling party with it after receiving the SDP request that the callee sends;

D, described calling party, CRBT AS and callee realize conversation foundation by standard procedure.

Further, in the steps A, described calling party makes a call and specifically comprises: described calling party sends the call request message that carries the SDP request to described CRBT AS;

In the steps A, described CRBT AS is transmitted to described callee after receiving described call request message, and described callee returns receives the response, and wherein carries the SDP response;

Further, in the steps A, after described CRBT AS receives calling party's message or callee's message,, transmit the SDP request or the response of CRBT session to the calling party with the CRBT media apparatus interaction.

Further, in the steps A: the SDP request of the CRBT session that sends to the calling party is carried by UPDATE message.

Further, in the steps A: comprise all medium types in calling party's SDP request or callee's the SDP response to the SDP information of the CRBT session that the calling party sends.

Further, in the steps A: the direction indication of the part or all of medium type of CRBT AS in the SDP information of the CRBT session that the calling party sends is set to only send sendonly.

Further, in the steps A: CRBT AS increases the P-Early-Media header field in the session initiation protocol sip message of the SDP information that sends the CRBT session, and the value of this header field is made as sendonly.

Further, in the steps A: CRBT AS is after sending CRBT session SDP information, if receive the SDP request that the calling party is new, then wherein the direction direction indication that is designated as the medium type that receives only recvonly is revised as both to send and also receives sendrecv.

Further, in the steps A, CRBT AS receives after the calling party carries the call request message of SDP request and issues the callee, and increase the zero bandwidth sign in SDP information.

Further, among the step C, CRBT AS carries the SDP request of callee's transmission so that it is issued the calling party by using renewal UPDATE message or response message.

Further, among the step B:

CRBT AS does not use and asks the callee to send the SDP request with the re-INVITE message of any SDP information, and the callee sends the SDP request by the receiveing the response of " 2 " beginning of re-INVITE.

The processing of technical scheme of the present invention after to called party answer improves, reduced the interactive step after replying, and adjusted the time that begins to charge, the process of replying between the conversation beginning is greatly simplified, improve user's experience, avoided wrong deducting fees; Prioritization scheme of the present invention has overcome the limitation of prior art, makes Ring Back Tone service can realize the broadcast of any medium type and combination thereof; Another prioritization scheme can make medium type that the session of final foundation uses can be because of the medium type of Ring Back Tone service few the minimizing; Also have a prioritization scheme can prevent that the callee from data transfer error taking place.

Description of drawings

Fig. 1 is the basic messae flow process figure of existing single session Ring Back Tone service;

Fig. 2 is the concrete implementing procedure figure of the call-establishing method of realization single session Ring Back Tone service provided by the invention;

Fig. 3 is the basic messae flow process figure of application example one of the present invention;

Fig. 4 is the basic messae flow process figure of application example two of the present invention;

Fig. 5 is the basic messae flow process figure of application example three of the present invention.

Embodiment

Below in conjunction with drawings and Examples technical scheme of the present invention is described in detail.

The invention provides a kind of call-establishing method of realizing the single session Ring Back Tone service, as shown in Figure 2, mainly may further comprise the steps:

A, calling party make a call, and CRBT AS adopts the single session mode to calling party's playing media information;

B, callee's answering call, CRBT AS are after receiving callee's response message and before transmitting this response message, and the request callee sends the SDP request;

C, CRBT AS issue the calling party with it after receiving the SDP request that the callee sends;

D, follow-up calling party, CRBT AS and callee realize conversation foundation by standard procedure.

Further, among the step C, CRBT AS asks it is issued the calling party by the SDP that uses UPDATE message or response message to carry callee's transmission.

As seen from the above, if use response message to carry the SDP request that the callee sends, the process of replying back and beginning call office has been greatly simplified.

Further, in the steps A:

The calling party makes a call and is meant that the calling party sends the call request message that carries the SDP request;

Steps A can also comprise:

CRBT AS receives after the calling party carries the request message of SDP request and is transmitted to the callee that the callee returns receives the response, and wherein carries the SDP response.

After CRBT AS receives calling party's message or callee's message,, transmit the SDP request or the response of CRBT session to the calling party with the CRBT media apparatus interaction.This make the beginning of CRBT can be receive call out the back to receive reply before whenever.

Further, among the step B, the SDP request of the CRBT session that sends to the calling party is carried by UPDATE message; The SDP response of the CRBT session that sends to the calling party " 1 " beginning by INVITE receive the response or " 2 " of PRACK message start receives the response and carry.

It is in order to make Ring Back Tone service can use abundanter medium type, to call out the medium type that uses in the SDP request that the calling party sends when beginning and not only be subject to that the SDP request is carried by UPDATE message.

Further, in the steps A, comprise all medium types in calling party's SDP request or callee's the SDP response to the SDP information of the CRBT session that the calling party sends.

Further, in the steps A, the indication of the direction of the part or all of medium type of CRBT AS in the SDP information of the CRBT session that the calling party sends is set to sendonly (only sending).

Further, in the steps A, CRBT AS increases the P-Early-Media header field in the sip message of the SDP information that sends the CRBT session, and the value of this header field is made as sendonly.

Further, in the steps A, CRBT AS is after sending CRBT session SDP information, if receive the SDP request that the calling party is new, then wherein the direction direction indication that is designated as the medium type of recvonly (receiving only) is revised as sendrecv (both sent also and received).

Above prioritization scheme can guarantee few minimizing of medium type that medium type that final session of setting up uses can not use because of Ring Back Tone service, and the user is conversed by medium early replying before, also can not make can only set up one-way traffic after replying.

Further, steps A also comprises:

CRBT AS receives after the calling party carries the message of SDP request and issues the callee, and increases in SDP information that the zero bandwidth sign---the bandwidth requirement that is about to all medium is made as 0.Be in order to prevent that the callee from data transfer error taking place like this.

Further, among the step B, CRBT AS does not use and asks the callee to send the SDP request with the re-INVITE message of any SDP information, and the callee sends the SDP request by the receiveing the response of " 2 " beginning of re-INVITE.

Further, step D specifically comprises: the calling party returns the SDP response, and after CRBT AS was transmitted to the callee with it, the calling and called both sides set up conversation.

Further specify the present invention with three application examples below.

Fig. 3 is an application example one of the present invention, has described the calling subscriber and has called out the called subscriber, and to calling subscriber's coloring ring back tone playing, behind called subscriber answer, color ring server is initiated the situation of media re-negotiation to color ring server in calling procedure, and its process is as follows:

The SDP request is carried in step 301, the calling subscriber UE-A request of making a call, and such as sending INVITE (invitation) message, carries the SDP request in message body, and the forwarding of message travels P-CSCF and S-CSCF arrives CRBT AS;

Step 302, CRBT AS transmit this message related to calls and give called subscriber UE-B, for preventing UE-B data transfer error take place, and CRBT AS can increase zero bandwidth sign, message travels S-CSCF in SDP information;

Step 303, called UE-B return temporarily receives the response, give the calling party, such as sending the message with " 1 " beginning such as " 180 Ringing " or " 183 Session Progress " message, the SDP of portability UE-B response in the message body, this is receiveed the response temporarily and arrives CRBT AS by way of S-CSCF;

Step 304～305, identical with step 104～105 of Fig. 1;

Step 306, CRBT AS sends the SDP response of CRBT session to the calling party, such as carrying by receiveing the response of message related to calls temporarily, receiveing the response can be the message that " 183 Session Progress " message or " 180 Ringing " message etc. are taken the lead with " 1 " temporarily, carry the SDP response of CRBT session in the message body, CRBT AS can be revised as the direction indication of the part or all of medium type in this SDP response sendonly (only sending), or in message, add the P-Early-Media header field, and the value of this header field can be made as sendonly, message travels S-CSCF and P-CSCF arrive UE-A;

Step 307～309, identical with step 107～109 of Fig. 1;

Step 310, CRBT AS send the affirmation response message to the callee, and such as sending ACK message, message travels S-CSCF arrives UE-B;

Step 311, simultaneously, CRBT AS request callee sends the SDP request, and such as sending not re-INVITE with any SDP information (recall) message, message travels S-CSCF arrives UE-B;

Step 312, UE-B receive the request message of step 311, send it back to answer recall message, such as sending " 200 OK " message, carry the SDP request in the message body, and message travels S-CSCF arrives CRBT AS;

Following step 313～314th, optional execution in step does not generally need to carry out.

Step 313, CRBT AS send updating message to the calling party after receiving callee's SDP request, such as sending UPDATE message, carry callee's SDP request in the message body, and message travels S-CSCF and P-CSCF arrive UE-A;

Step 314, UE-A receive updating message, send the message of agreeing renewal, such as sending " 200

OK " message etc. receives the response with " 2 " beginning, carries the SDP response in the message body, and message travels P-CSCF and S-CSCF arrive CRBT AS;

Following steps 315,317 and 318 do not have the situation of execution to describe with step 313～314.

Step 315, CRBT AS send response message to the calling party after receiving callee's SDP request, such as sending the message with " 2 " beginning such as " 200 OK " message, carry callee's SDP request in the message body, message travels P-CSCF;

Step 316, P-CSCF receive response message, and the indication billing function begins to charge;

Step 317, simultaneously, P-CSCF transmits response message and gives UE-A;

Step 318, UE-A receive response message, send to confirm response message to the callee, such as sending ACK message, carry calling party's SDP response in the message body, and message travels P-CSCF and S-CSCF arrive CRBT AS;

If carried out step 313～314, then can not carry any SDP information in step 315,317 and 318 the message.

Step 319, CRBT AS transmit and confirm response message to UE-B, wherein carry calling party's SDP response, and response message is by way of S-CSCF;

Whenever step 319 can occur in after the message of receiving the SDP response of carrying the calling party, if in steps 313,314, whenever occur in exactly after the step 314, otherwise be exactly after occurring in step 318.

Step 320, so far, UE-A has set up medium with UE-B and has been connected, and begins conversation.

Fig. 4 is an application example two of the present invention, has described the calling subscriber and has called out the called subscriber, and to calling subscriber's coloring ring back tone playing, behind called subscriber answer, color ring server is initiated the situation of media re-negotiation to color ring server in calling procedure, and its process is as follows:

The SDP request is carried in step 401, the UE-A request of making a call, and such as sending INVITE (invitation) message, carries the SDP request in message body, and the forwarding of message travels P-CSCF and S-CSCF arrives CRBT AS;

Step 402, CRBT AS transmit this message related to calls and give UE-B, message travels S-CSCF;

Step 403, called UE-B send and receive the response to the calling party temporarily, such as receiveing the response such as transmission " 183SessionProgress " message temporarily with " 1 " beginning, carry called SDP response in the message body, this is receiveed the response temporarily and arrives CRBT AS by way of S-CSCF;

Step 404, CRBT AS call out the CRBT media server, carry the SDP request in the step 401, or the SDP request that response generates based on the SDP in the step 403, message travels S-CSCF;

Whenever step 404 can occur in after the step 401 before the step 405.

Step 405, CRBT media server answering call are given CRBT AS such as sending " 200OK " message etc. with the message of " 2 " beginning, carry the SDP response of CRBT session, message travels S-CSCF;

Step 406, CRBT AS sends the SDP response of carrying in the SDP response of CRBT session or the step 403 to the calling party, such as carrying by receiveing the response of message related to calls temporarily, receiveing the response can be the message with " 1 " beginning such as " 183 Session Progress " message or " 180 Ringing " message temporarily, carry the SDP response in the message body, the SDP response of carrying can be CRBT session SDP response, also can be by standing procedure, part or all of medium type on the basis of CRBT session SDP response in the SDP request of interpolation step 401, or the part or all of medium type in the SDP of step 403 response, it can also be exactly the SDP response in the step 403, to guarantee that the medium type that final session of setting up is used can not reduce because of Ring Back Tone service, CRBT AS also can be revised as the direction indication of the part or all of medium type in the SDP response of carrying sendonly (only sending), or in message, add the P-Early-Media header field, and the value of this header field can be made as sendonly, message travels S-CSCF and P-CSCF arrive UE-A;

Before step 406 can occur in after the step 403 407 whenever, if step 304 does not take place before step 306 as yet, then step 304～305 can not have, what this moment, step 406 sent to the calling party is exactly the SDP response of carrying in the step 403, step 408 is call requests, step 409 is response messages, and step 411 has not just had.

Step 407, UE-A receive temporarily receives the response, and sends pre-acknowledge message to the callee, such as sending PRACK message, carries calling party's new SDP request in the message body, and message travels P-CSCF and S-CSCF arrive CRBT AS;

Step 408, CRBT AS send pre-acknowledge message to the CRBT media server, such as sending PRACK message, carry the SDP request in the step 407 in the message body, message travels S-CSCF;

Step 409, CRBT media server are received the message of step 308, send it back acknowledge message in advance, such as sending the message with " 2 " beginning such as " 200 OK " message, carry the SDP response of new CRBT session, and message travels S-CSCF arrives CRBT AS;

Step 410, CRBT AS send it back in advance acknowledge message and give the calling party, such as sending the message with " 2 " beginning such as " 200 OK " message, carry the SDP response in the step 309 in the message body, and primary school arrives UE-A by way of S-CSCF and P-CSCF;

Step 411, color ring server answering call are given CRBT AS such as sending " 200 OK " message etc. with the message of " 2 " beginning;

Step 411 and step 410 do not have ordinal relation.

After step 412, CRBT AS receive the response message of color ring server, send and confirm response message, such as sending ACK message to color ring server; Message travels S-CSCF;

Step 413, CRBT AS transmit the pre-acknowledge message of step 407 and give the callee, and can in the SDP request in the pre-acknowledge message, increase the zero bandwidth sign, to prevent that UE-B from data transfer error taking place, simultaneously, if CRBT AS has revised the direction indication of medium in the step 406, then can be with the direction indicated value of the medium type in the SDP that the receives request recvonly (receiving only) be revised as sendrecv (promptly send also and receive), message travels S-CSCF arrives UE-B;

Whenever step 413 can occur in after the step 407 before the step 414.

Step 414, UE-B receive pre-acknowledge message, send it back acknowledge message in advance, such as sending the message with " 2 " beginning such as " 200OK " message, carry called new SDP response in the message body, and message travels S-CSCF arrives CRBT AS;

After step 415, CRBT media server are received and are confirmed response message, to calling party's coloring ring back tone playing;

Whenever step 415 can occur in after the step 409 before the step 416.

Step 416～419, identical with step 309～312 among Fig. 3;

Between step 419 and 420, also can insert with Fig. 3 in the identical step in step 313～314, if like this, then can not carry any SDP information in step 420,422 and 423 the message.

Step 420～425 are identical with step 315～320 among Fig. 3.

Fig. 5 is an application example three of the present invention, has described the calling subscriber and has called out the called subscriber, and to calling subscriber's coloring ring back tone playing, behind called subscriber answer, color ring server is initiated the situation of media re-negotiation to color ring server in calling procedure, and its process is as follows:

Step 501～503, identical with step 401～403 among Fig. 4;

Step 504, CRBT AS transmit receives the response to the calling party temporarily, and message travels S-CSCF and P-CSCF arrive UE-A

Step 505, simultaneously, CRBT AS calls out the CRBT media server, such as sending INVITE, does not carry any SDP information, message travels S-CSCF;

Whenever step 505 can occur in after the step 501 before the step 506.

Step 506, CRBT media server answering call are given CRBT AS such as sending " 200 OK " message etc. with the message of " 2 " beginning, carry the SDP request of CRBT session, message travels S-CSCF;

Step 507, CRBT AS sends the SDP request of CRBT session to the calling party, such as carrying by sending the UPDATE updating message, carry the SDP request of CRBT session in the message body, message travels S-CSCF and P-CSCF arrive UE-A, requirement according to standard, SDP request in this message may be done a little adjustment on the basis of the SDP of step 506 request, CRBT AS also can be revised as the direction indication of the part or all of medium type in the SDP request of carrying sendonly (only sending), or in message, add the P-Early-Media header field, and the value of this header field can be made as sendonly;

Step 508, UE-A receive updating message, send to agree updating message to the callee, such as sending the message with " 2 " beginning such as " 200 OK " message, carry calling party's SDP response in the message body, and message travels P-CSCF and S-CSCF arrive CRBT AS;

After step 509, CRBT AS receive calling party's SDP response, send the affirmation response message to the CRBT media server, such as sending ACK message, carry calling party's SDP response in the message body, message travels S-CSCF, according to the requirement of standard, the SDP response in this message may be done a little adjustment on the basis of the SDP of step 508 response;

After step 510, CRBT media server are received and are confirmed response message, to calling party's coloring ring back tone playing;

Step 511～520, basic identical with step 416～425 among Fig. 4, it is requirement according to standard, SDP request in the step 515 may be done a little adjustment on the basis of the SDP of step 514 request, the SDP response in the step 519 may be done a little adjustment on the basis of the SDP of step 518 response;

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of claim of the present invention.

Claims (11)

1, a kind of call-establishing method of realizing the single session Ring Back Tone service comprises:

A, calling party make a call, and the CRBT application server AS adopts the single session mode to described calling party's playing media information;

B, callee's answering call, described CRBT AS ask described callee to send the SDP request after receiving callee's response message and before transmitting described response message;

C, CRBT AS issue described calling party with it after receiving the SDP request that the callee sends;

D, described calling party, CRBT AS and callee realize conversation foundation by standard procedure.

2, the method for claim 1 is characterized in that,

In the steps A, described calling party makes a call and specifically comprises: described calling party sends the call request message that carries the SDP request to described CRBT AS;

In the steps A, described CRBT AS is transmitted to described callee after receiving described call request message, and described callee returns receives the response, and wherein carries the SDP response;

3, method as claimed in claim 2 is characterized in that,

In the steps A, after described CRBT AS receives calling party's message or callee's message,, transmit the SDP request or the response of CRBT session to the calling party with the CRBT media apparatus interaction.

4, method as claimed in claim 3 is characterized in that, in the steps A:

The SDP request of the CRBT session that sends to the calling party is carried by UPDATE message.

5, method as claimed in claim 3 is characterized in that, in the steps A:

Comprise all medium types in calling party's SDP request or callee's the SDP response to the SDP information of the CRBT session that the calling party sends.

6, method as claimed in claim 5 is characterized in that, in the steps A:

The direction indication of the part or all of medium type of CRBT AS in the SDP information of the CRBT session that the calling party sends is set to only send sendonly.

7, method as claimed in claim 5 is characterized in that, in the steps A:

CRBT AS increases the P-Early-Media header field in the session initiation protocol sip message of the SDP information that sends the CRBT session, and the value of this header field is made as sendonly.

8, method as claimed in claim 5 is characterized in that, in the steps A:

CRBT AS is after sending CRBT session SDP information, if receive the SDP request that the calling party is new, then wherein the direction direction indication that is designated as the medium type that receives only recvonly is revised as both to send and also receives sendrecv.

9, method as claimed in claim 2 is characterized in that,

In the steps A, CRBT AS receives after the calling party carries the call request message of SDP request and issues the callee, and increase the zero bandwidth sign in SDP information.

10, the method for claim 1 is characterized in that:

Among the step C, CRBT AS carries the SDP request of callee's transmission so that it is issued the calling party by using renewal UPDATE message or response message.

11, the method for claim 1 is characterized in that, among the step B:

CRBT AS does not use and asks the callee to send the SDP request with the re-INVITE message of any SDP information, and the callee sends the SDP request by the receiveing the response of " 2 " beginning of re-INVITE.

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