CN101047718B - System, method and server for realizing media negotiation - Google Patents

Abstract

This invention discloses a method for realizing media negotiation including: a server obtains at least two negotiated SDP message bodies, each of which carries a medium message negotiating on a same network entity, and the server combines said two SDP message bodies to negotiate with the same network entity to get a negotiated SDP message body, which carries the medium message about negotiation on the same network entity. This invention also discloses a method for realizing medium negotiations and a system and servers corresponding to the two methods.

Description

System, method and server for realizing media negotiation

technical field

The invention relates to the communication field, in particular to two systems, methods and servers for realizing media negotiation.

Background technique

Before establishing a media channel between network entities for media exchange, it is often necessary to conduct media negotiation between network entities in advance, that is, to negotiate the service quality and reserved resources required for media exchange according to their respective media capability information. For example, the Session Initiation Protocol (SIP, SessionInitiation Protocol) network is a network that uses SIP messages to initiate, manage and terminate various types of multimedia services. The multimedia services are services such as IP telephony and video sessions. In other words, the SIP network is A network that applies SIP messages to create, modify and terminate multimedia sessions between one or more SIP entities. The entities in the SIP network, also known as SIP entities, carry the Session Description Protocol (SDP, Session Description Protocol) message body in the SIP message to describe the media capability information of each SIP entity, and use the provision/response of the SDP protocol The (OFFER/ANSWER) mechanism implements media negotiation between SIP entities. Here, the SDP protocol is an application layer protocol used to describe multimedia sessions.

Only take the ring back tone service as an example below to specifically illustrate the method for realizing media negotiation at present. Fig. 1 is a flow chart of a method for realizing the media negotiation of the ring back tone service in the prior art, wherein the ring back tone application server is used to manage and implement The ring back tone service function, and the user terminal a (UE a, UserEquipment a) that is used for calling, the UE b that is used for being called and the media resource server (MRS) that is used for controlling and processing the media resource of the ring back tone service , Media Resource Server) is a network entity that needs to perform media negotiation. As shown in Figure 1, UE a first performs media negotiation between the ring-back tone application server and the MRS to realize the media exchange between the MRS and UEa, that is, to realize the function of the MRS playing the ring-back tone to the calling party; then, When UE b answers the call, UE b conducts another media negotiation with UE a through the ringback tone application server to realize media exchange between UE b and UE a, that is, a normal call can be carried out. Media negotiation is implemented by carrying the message body of the SDP protocol in the SIP message. Specific steps are as follows:

Step 101-step 111 is the process of realizing media negotiation between MRS and UE a.

Step 101: UE a sends an INVITE message to the RBT application server.

In this step, UE a sends the INVITE message in the SIP request message to the ring-back tone application server as the calling party, so as to invite the called UE b to talk through the ring-back tone application server, where the ring-back tone application server is UE b The assigned ringback tone application server. The INVITE message carries the SDP1 message body describing UE a, and the ringback tone application server obtains the SDP1 message body through this step.

SIP has two types of messages, the request message from the client to the server and the response message from the server to the client. Among them, commonly used request messages include: INVITE, response acknowledgment (ACK), provisional response acknowledgment (PRACK), update (UPDATE) and other messages. The response message includes a digital response code, including provisional response and final response. The provisional response is 1XX, such as 183, and the final response is 2XX, 3XX, such as 200OK. Each SIP message is composed of a start line, a SIP header and a message body, wherein the message body can be used to describe the initiated session. In this step, the SIP message carries the SDP message body.

Step 102: The ring-back tone application server forwards the INVITE message to UE b.

Step 103: UE b sends a 183 response message to the RBT application server.

In this step, the SDP2 message body describing the called UE b is carried in the message body of the 183 response message. The ring back tone application server obtains the SDP2 message body. Here, 183 is a reliable provisional response.

Step 104: The ring-back tone application server sends a PRACK message to UE b.

In this step, after receiving the 183 response message, the ring-back tone application server sends a PRACK message to the called UE b to confirm that the 183 response message sent by the called UE b has been received.

Step 105: UE b sends a 200 OK response message to the RBT application server.

UE b sends the 200 OK response message of the PRACK message in step 104 to the RBT application server.

Step 106: The RBT application server sends an INVITE message to the MRS.

In this step, the RBT application server creates a new INVITE message and sends it to the MRS, wherein the INVITE message carries the SDP1 message body in step 101 .

Step 107: The MRS sends a 200 OK response message to the RBT application server.

The MRS sends a 200 OK response to the INVITE in step 106 to the RBT application server. The 200 OK message carries the SDP3 message body describing the MRS, and the ring-back tone application server obtains the SDP3 message body through this step.

Step 108: The RBT application server sends an ACK response message to the MRS.

The RBT application server sends an ACK response message corresponding to the 200 OK message in step 106 to the MRS.

Step 109: The ring-back tone application server forwards the 183 response message to UE a.

The ring back tone application server forwards the 183 response message in step 103 to the calling UE a. And, replace the SDP2 message body carried in the 183 response message in step 103 with the SDP3 message body describing the MRS in step 107 .

Step 110: UE a sends a PRACK message to the RBT application server.

After receiving the 183 response in step 109, UE a sends a PRACK message to the ring-back tone application server to confirm that it has received the 183 response sent by the ring-back tone application server, and the message includes the negotiated SDP4 message body.

Step 111: the ring back tone application server sends a 200 OK response message to UE a.

Step 112: UE b sends a 180 response message to the RBT application server.

The 180 response message indicates ringing.

Step 113: the ring-back tone application server sends a PRACK message to UE b.

If 180 in the step 112 is a reliable provisional response, after the ring-back tone application server receives the 180 response message in the step 112, it must send a PRACK message to the 180 response message to UE b.

Step 114: UE b sends a 200 OK response message to the RBT application server.

Step 115: The ring-back tone application server forwards a 180 response message to UE a.

Step 116: UE a sends a PRACK message to the RBT application server.

If the 180 response message in the step 115 is a reliable provisional response, after UE a receives the 180 in the step 115, it must send a PRACK to the ring-back tone application server for the 180.

Step 117: The ring back tone application server sends a 200 OK response message to UE a.

Step 118: The RBT application server sends an announcement (INFO) message to the MRS.

The RBT application server sends an INFO message to the MRS, instructing the MRS to start playing the RBT. The INFO information carries the specific information of the ring back tone played.

Step 119: The MRS sends a 200 OK response message to the RBT application server.

After receiving the INFO message in step 118, the MRS starts to play the ring back tone, and sends a 200 OK response to the INFO message to the ring back tone application server.

Step 120-step 126 is the process of realizing media negotiation between UE b and UE a.

Step 120: UE b sends a 200 OK response message to the RBT application server.

UE b answers the call, and sends a 200 OK response to the INVITE message in step 102 to the ringback tone application server.

Step 121: The ring-back tone application server sends an UPDATE message to UE a.

After the ring-back tone application server receives the 200OK response message in step 119, it sends an UPDATE message to UE a, which includes the SDP2 message body describing UE b carried in the 183 response message in step 103.

Step 122: UE a sends a 200 OK response message to the RBT application server.

After receiving the UPDATE message described in step 121, UE a sends a 200 OK response message to the ring-back tone application server. The message includes the negotiated SDP5 message body.

Step 123: The RBT application server sends a BYE message to the MRS.

The RBT application server sends a BYE message to the MRS to end the session with the MRS, and the MRS stops playing the RBT.

Step 124: The ring-back tone application server forwards a 200 OK response message to UE a.

The ring back tone application server forwards the 200 OK response message in step 120 to UE a.

Step 125: The MRS sends a 200 OK response message to the RBT application server.

After receiving the BYE message in step 123, the MRS stops playing the ring back tone, and sends a 200 OK response to the ring back tone application server.

Step 126: UE a sends an ACK message to the RBT application server.

UE a sends an ACK message for the 200 OK response message in step 124 to the ring back tone application server.

Step 127: The ring-back tone application server sends an ACK message to UE b.

The ring back tone application server sends an ACK message for the 200 OK response message in step 119 to UE b. After this step, UE a and UE b start talking.

Step 128: UE a sends a BYE message to UE b through the RBT application server.

UE a sends a BYE message to UE b through the ringback tone application server to end the call between UE a and UE b.

Step 129: UE b sends a 200 OK response message to UE a through the RBT application server.

It can be seen that in the process of establishing the ring back tone service, even if UE b and MRS perform media negotiation on the same SIP entity UE a, UE a must send media information for media negotiation to UE b and MRS respectively through the server. That is to say, when multiple network entities negotiate with the same network entity, the multiple network entities can only perform media negotiation with the same network entity through the server respectively.

Similarly, when the same SIP entity performs media negotiation for multiple networks, the same network entity also needs to perform media negotiation with multiple network entities through the server.

Therefore, using the current method for media negotiation, only a single network entity can perform media negotiation, that is, conduct a media negotiation to obtain a media negotiation result between a network entity and a network entity, and it is still not possible to implement one-to-many and multi-party Media consultations on one side.

Contents of the invention

In view of this, the embodiment of the present invention provides a method for realizing media negotiation, which can realize multi-party to one-party media negotiation.

An embodiment of the present invention provides a method for realizing media negotiation, which can realize one-to-many-party media negotiation.

An embodiment of the present invention provides a system for realizing media negotiation, and the system can realize multi-party-to-one media negotiation.

An embodiment of the present invention provides a system for realizing media negotiation, and the system can realize one-to-many-party media negotiation.

An embodiment of the present invention provides a server for realizing media negotiation, and the server can realize multi-party-to-one media negotiation.

An embodiment of the present invention provides a server for realizing media negotiation, and the server can realize one-to-many-party media negotiation.

In order to achieve the above purpose, the technical solutions of the embodiments of the present invention are specifically implemented as follows:

A method for implementing media negotiation, the method comprising:

The server acquires at least two negotiated Session Description Protocol SDP message bodies, each of the negotiated SDP message bodies carries media information negotiated with the same network entity, and the negotiated SDP message bodies consist of a media information description part, timing information The description part and the session information description part are composed;

The server merges the at least two negotiated SDP message bodies, and merging the at least two negotiated SDP message bodies includes: connecting the media information description part of each negotiated SDP message body, generating a timing information description part and a session information description part ; carry out media negotiation with the same network entity through the merged SDP message body, obtain the negotiated SDP message body, and the negotiated SDP message body carries the media information negotiated to the same network entity; according to the merged Decomposing the negotiated SDP message body according to the negotiated manner of the SDP message body; sending the decomposed SDP message body according to the manner of obtaining the negotiated SDP message body.

A method for implementing media negotiation, the method comprising:

The server obtains a negotiated Session Description Protocol SDP message body, the negotiated SDP message body carries media information negotiated for at least two network entities, and the negotiated SDP message body consists of a media information description part, a timing information description part and The session information description part consists of;

The server decomposes the negotiated SDP message body, the decomposing the negotiated SDP message body includes: extracting the media information description part in each decomposed SDP message body from the negotiated SDP message body, and converting the The timing information description part and session information description part in the negotiated SDP message body are used as the timing information description part and session information description part in each decomposed SDP message body;

Perform media negotiation with the at least two network entities through at least two decomposed SDP message bodies to obtain at least two negotiated SDP message bodies, and each of the negotiated SDP message bodies carries information about the at least two networks media information negotiated by one of the network entities;

The server merges the at least two negotiated SDP message bodies according to the manner of decomposing the negotiated SDP message bodies, and sends the merged SDP message bodies according to the manner of obtaining the negotiated SDP message bodies.

A system for realizing media negotiation, the system includes: a server and a first network entity;

The server is configured to obtain at least two negotiated Session Description Protocol SDP message bodies, each of the negotiated SDP message bodies carries media information negotiated with the first network entity, and the negotiated SDP message bodies Consisting of a media information description part, a timing information description part and a session information description part; connecting the media information description part of each negotiated SDP message body; generating a timing information description part and a session information description part to merge the at least two negotiated SDP message body, performing media negotiation with the first network entity through the merged SDP message body to obtain a negotiated SDP message body, where the negotiated SDP message body carries media information negotiated for the first network entity ; Decomposing the negotiated SDP message body according to the method of merging the negotiated SDP message body; sending the decomposed SDP message body according to the method of obtaining the negotiated SDP message body;

The first network entity is configured to perform media negotiation with the server.

A system for realizing media negotiation, the system includes: a server and at least two network entities;

The server is configured to obtain a Session Description Protocol SDP message body, the SDP message body carries media information for negotiation between at least two network entities, and the negotiated SDP message body is described by a media information description part and timing information part and a session information description part; extract the media information description part in each decomposed SDP message body from the SDP message body of the negotiation, and combine the timing information description part and the session information part in the SDP message body of the negotiation The information description part is used as the timing information description part and the session information description part in each decomposed SDP message body to decompose the SDP message body; perform media negotiation with the at least two network entities through at least two decomposed SDP message bodies , obtaining at least two negotiated SDP message bodies, where the negotiated SDP message bodies carry media information negotiated with one of the at least two network entities; according to decomposing the negotiated SDP message bodies way, merging the at least two negotiated SDP message bodies, and sending the merged SDP message body according to the manner of obtaining the negotiated SDP message bodies;

The at least two network entities are used for media negotiation with the server.

A server for realizing media negotiation, the server includes: an acquisition module, a combination module, a negotiation module and a decomposition module;

The acquiring module is configured to acquire at least two negotiated Session Description Protocol SDP message bodies, each of the SDP message bodies carries media information negotiated with the same network entity, and the negotiated SDP message bodies consist of media information A description part, a timing information description part and a session information description part are composed, and the at least two negotiated SDP message bodies are sent to the merging module;

The merging module is used to connect the media information description part of each negotiated SDP message body, generate a timing information description part and a session information description part to merge at least two negotiated SDP message bodies received, and combine the SDP message body The message body is sent to the negotiation module;

The negotiation module is configured to negotiate with the same network entity through the received merged SDP message body to obtain a negotiated SDP message body, and the negotiated SDP message body carries information about the same network entity. Media information negotiated by the entity;

The decomposing module is configured to decompose the negotiated SDP message body according to the manner of merging the negotiated SDP message bodies, and send the decomposed SDP message body according to the manner of obtaining the negotiated SDP message body.

A server for realizing media negotiation, the server includes: an acquisition module, a decomposition module, a negotiation module and a combination module;

The obtaining module is used to obtain a negotiated Session Description Protocol SDP message body, the negotiated SDP message body carries media information for at least two network entities to be negotiated, and the negotiated SDP message body is described by the media information part, a timing information description part and a session information description part, and send the negotiated SDP message body to the decomposition module;

The decomposing module is used to extract the media information description part in each decomposed SDP message body from the negotiated SDP message body, and combine the timing information description part and session information in the negotiated SDP message body The description part is used as the timing information description part and the session information description part in each decomposed SDP message body to decompose the received SDP message body of the negotiation, and send the decomposed at least two decomposed SDP message bodies to the negotiation module ;

The negotiation module is configured to perform media negotiation with the at least two network entities through the received at least two decomposed SDP message bodies to obtain at least two negotiated SDP message bodies, and each of the negotiated SDP message bodies The SDP message body carries media information negotiated for one of the at least two network entities;

The merging module is configured to merge the at least two negotiated SDP message bodies according to the manner of decomposing the negotiated SDP message bodies, and send the merged SDP according to the manner of obtaining the negotiated SDP message bodies message body.

It can be seen from the above technical solutions that the method system and server for implementing media negotiation provided by the embodiments of the present invention decompose or merge the SDP message body through the server, and use the decomposed or merged SDP message body to perform media negotiation, so that the server can act as a party Negotiate with multiple network entities or perform media negotiation with the same network entity as multiple parties, realizing one-to-many or many-to-one media negotiation.

Description of drawings

FIG. 1 is a flow chart of a method for realizing media negotiation of a ring back tone service in the prior art.

Fig. 2 is a schematic diagram of a system for implementing media negotiation provided in the first embodiment of the present invention.

Fig. 3 is a schematic diagram of a system for realizing media negotiation provided in the second embodiment of the present invention.

Fig. 4 is a schematic diagram of a method for implementing media negotiation provided in a third embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

In the following embodiments of the present invention, the server can negotiate with the same network entity as multiple parties, or can negotiate with multiple network entities as one party.

When the server negotiates with the same network entity as multiple parties, the server obtains at least two negotiated Session Description Protocol SDP message bodies, and each of the negotiated SDP message bodies carries the media information negotiated for the same network entity; the server merges The at least two negotiated SDP message bodies; performing media negotiation with the same network entity through the merged SDP message body to obtain a negotiated SDP message body, the negotiated SDP message body carrying the same Media information negotiated by network entities.

When the server acts as a party to negotiate with multiple network entities, the server obtains a negotiated SDP message body, and the negotiated SDP message body carries media information negotiated with at least two network entities; the server decomposes the negotiated SDP message body; performing media negotiation with the at least two network entities through at least two decomposed SDP message bodies to obtain at least two negotiated SDP message bodies, and each of the negotiated SDP message bodies carries a pair of the at least two Media information negotiated by at least one of the network entities. Give three specific examples below and describe the present invention in detail:

Embodiment one:

Fig. 2 is a schematic diagram of a system for implementing media negotiation provided in the first embodiment of the present invention. The first embodiment of the present invention provides a system for realizing one-to-multi-party media negotiation, and the system includes: a server and a first network entity;

The server obtains at least two negotiated SDP message bodies, each negotiated SDP message body carries media information negotiated with the first network entity, and merges the obtained at least two negotiated SDP message bodies to obtain a merged SDP message body, And carry out media negotiation with the first network entity through the SDP message body of merging, obtain the SDP message body after negotiation, the SDP message body after this negotiation carries the media information after negotiating to the first network entity; And the first network entity then Used for media negotiation with the server.

Referring to Fig. 2, the present embodiment is different from the following embodiments, and the server is represented as the first unit 210 of the server as multiple parties, and in the present embodiment, the network entity as one party is a user agent (UA, UA, User Agent), denoted as UA X230.

In this embodiment, it is assumed that the first server unit 210 obtains the negotiated SDP message body, that is, the SDPx1, SDPx2...SDPxn message body from UA1, UA2...UAm, and the first server unit 210 will obtain The SDPx1, SDPx2...SDPxn message bodies are combined into the SDP X message body, and the SDP X message body is used to negotiate with the same network entity UA X230 to obtain the negotiated SDP message body, that is, the SDP Y message body.

In this embodiment, the first unit 210 of the server can decompose the SDP Y message body into SDPy1, SDPy2...SDPyn according to the method of merging the SDP X message body, and when necessary, obtain the negotiated SDP message body Send any one or all of the decomposed SDPy1, SDPy2...SDPyn to the corresponding network entities UA1, UA2...UAm. As shown in Figure 2, the server first unit 210 includes an acquisition module 211, a combination module 212 and a negotiation module 213;

The obtaining module 211 obtains the negotiated SDP message body, that is, SDPx1, SDPx2...SDPxn message body, each negotiated SDP message body carries the media information negotiated with UA X230, and the acquired SDPx1, SDPx2... ... the SDPxn message body is sent to the merge module;

Merging module 212 merges the SDPx1, SDPx2...SDPxn message body that receives, and the SDP message body of merging, that is, the SDP X message body is sent to the negotiation module 213;

The negotiation module 213 negotiates with the UA X230 using the received merged SDP message body to obtain the negotiated SDP message body, that is, the SDP Y message body, and the SDP Y message body carries the media information negotiated by the UA X230.

The first server unit 210 may also include: a decomposition module 214;

The decomposing module 214 decomposes the negotiated SDPy1, SDPy2...SDPyn message bodies according to the method of merging the message bodies of SDPx1, SDPx2...SDPxn, and obtains SDPx1, SDPx2...SDPxn Any one or all of the decomposed SDP message bodies SDPy1 , SDPy2 . . . SDPyn are sent to the corresponding network entity 220 in a message body manner.

The UA entity in this embodiment may be a network entity such as a terminal, a media resource server, and a proxy server. Of course, m and n in this embodiment may or may not be equal. For example, a network entity with two network functions can send two negotiated SDP message bodies to the server, and m is not equal to n at this time.

It can be seen from the above embodiments that the first unit of the server in the embodiment of the present invention can obtain multiple network The negotiation result between the entity and the same network entity can prevent the same network entity from interacting with the other party's network entity through the server multiple times, which can improve the problem of media loss and improve user experience.

Embodiment two:

Fig. 3 is a schematic diagram of a system for realizing media negotiation provided in the second embodiment of the present invention. The second embodiment of the present invention provides a one-to-many system. Referring to FIG. 3, the system includes: a server and at least two network entities;

The server obtains a negotiated SDP message body, the negotiated SDP message body carries media information for negotiation between at least two network entities, the server decomposes the obtained SDP message body, obtains at least two decomposed SDP message bodies, and uses at least two A decomposed SDP message body performs media negotiation with at least two network entities to obtain at least two negotiated SDP message bodies, and each negotiated SDP message body carries a negotiation for one network entity in the at least two network entities The following media information; at least two network entities are used for media negotiation with the server.

Referring to Fig. 3, in order to distinguish it from the server in the first embodiment in this embodiment, the server is represented as the server second unit 310 as one party, and at least two network entities as multiple parties are m UAs in the SIP network Entities, expressed as UA1320, UA2320...UAm320;

In this embodiment, the SDP message body obtained by the server second unit 310 for negotiation is the SDP U message body from UA X330, which carries the media information negotiated by UA1320, UA2320 ... UAm320 network entities , decompose the SDP U message body into SDPu1, SDPu2...SDPun, use the server to negotiate with UA1320, UA2320...UAm320 using SDPu1, SDPu2...SDPun, and get the negotiated SDPv1, SDPv2...SDPvn.

UAX330 in Fig. 3, after server second unit 310 merges SDPu1, SDPu2...SDPun message body; When necessary, send the merged SDP message body to UA X330. As shown in Figure 3, the second server unit 310 also includes: an acquisition module 311, a decomposition module 312 and a negotiation module 313;

Obtaining module 311 obtains a negotiated SDP message body, that is, SDP U message body, and SDP U message body carries media information negotiated to UA1320, UA2320...UAm320, and SDP U message body is sent to decomposition module 312;

The decomposing module 312 decomposes the received SDPu message body, and the SDPu1, SDPu2...SDPun message body obtained by decomposing is sent to the negotiation module 313;

The negotiation module 313 performs media negotiation with at least two network entities in UA1320, UA2320...UAm320 by using the received SDPu1, SDPu2...SDPun message body, and obtains at least two negotiated SDP Message body, SDPv1, SDPv2...SDPvn message body, each negotiated SDP message body carries media information negotiated for at least one network entity in the UA1320, UA2320...UAm320.

The second server unit 310 may also include: a merging module 314;

The merging module 314 merges the SDPv1, SDPv2...SDPvn message bodies according to the method of decomposing the negotiated SDP message body, and according to the method of obtaining the negotiated SDP message body, the obtained merged SDP message body The SDP V message body is sent to the same network entity UA X330.

The UA entity in this embodiment may be a network entity such as a terminal, a media resource server, and a proxy server. In this embodiment, m and n may also be equal or unequal.

It can be seen from the above embodiments that the second unit of the server in the embodiment of the present invention can avoid multiple SDP messages from the same network entity by decomposing the SDP message body and using the decomposed SDP message body to negotiate with at least one network entity. Interacting with the network entity of the other party through the server for the first time can improve the problem of media loss and improve user experience.

Embodiment three:

Fig. 4 is a schematic diagram of a method for implementing media negotiation provided in a third embodiment of the present invention. The present embodiment takes the ring-back tone service as an example, because the server in the present embodiment both negotiates as a multi-party and also negotiates as a party, so the ring-back tone application server in Fig. 4 includes the server first in the first embodiment. unit and the server second unit in the second embodiment, the specific steps are as follows:

Step 401-step 413 is the process that the server performs media negotiation with UE a as multiple parties.

Step 401: UE a sends an INVITE message to the RBT application server.

In this embodiment, UE a sends an INVITE message of the SIP protocol to the ring-back tone application server as the calling party, so that the called UE b is invited to make a call request through the ring-back tone application server, where the ring-back tone application server is provided by UE b The assigned ringback tone application server. The message body of the INVITE message carries the SDP1 message body describing UE a. In this embodiment, the content of SDP1 is as follows:

v=0

o＝APP1.0 10000 10000 IN IP4 10.164.104.58

s=-

c=IN IP4 10.164.104.58

t=00

m=audio 10500 RTP/AVP 97

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1

a=sendrecv

m=video 10510 RTP/AVP 34

b=AS:512

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:34 H263/90000

a＝fmtp:34 QCIF＝1 CIF＝4 MaxBR＝3200

a=sendrecv

In this embodiment, the media information carried in the SDP1 message body includes the media information of the audio media and video media used by UE a for negotiation, and each media information consists of an m line and the following m lines describe all attribute lines a of the media line composition.

Usually, the SDP message body includes three levels of information description parts, namely session information description part, timing information description part and media information description part. Among them, line v to c are the part of the session information description, and the line o belongs to the part of the session information description, indicating the information of the initiator of the SDP negotiation and the identifier of the session, including 6 parameters, which are user name, session ID, and session version in sequence , network type, address type, description information of the session creation address; the t line is the timing information description part, and the following part is the media information description part, wherein the m line belongs to the media information description part, indicating the media description information, including 4 parameters, followed by Expressed as media type, port number, transmission protocol, and description information of specific media formats; line c can appear in session information and media information, indicating connection information, including 3 parameters, followed by network type, address type, and connection address description information . In this embodiment, line c appears in the session information description part.

Step 402: The RBT application server forwards the INVITE message to UE b.

In this embodiment, the ring-back tone application server forwards the INVITE message to UE b, and the message carries the SDP1 message body describing UE a.

Step 403: UE b sends a 183 response message to the RBT application server.

After receiving the INVITE message forwarded by the ring-back tone application server, UE b sends a 183 response message to the ring-back tone application server. Here, 183 is a reliable provisional response. The 183 response message carries the SDP2 message body describing UE b. In this embodiment, the content of SDP2 is as follows:

v=0

o＝APP1.020004 20004 IN IP4 10.164.104.99

s=-

c=IN IP4 10.164.104.99

t=00

m=audio 10600RTP/AVP 97

a＝curr :qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1

a=sendrecv

m=video 10610 RTP/AVP 34

b=AS:512

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:34 H263/90000

a＝fmtp:34 QCIF＝1 CIF＝4 MaxBR＝3200

a=sendrecv

In this embodiment, the media information carried in the SDP2 message body includes the media information of the audio media and video media used by UE b for negotiation, that is, the m line in the SDP2 message body and all attribute line a line information of the corresponding media.

Step 404: The ring-back tone application server forwards the 183 response message to UE a.

In this embodiment, the 183 response message carries the SDP2 message body describing UE b.

Step 405: UE a sends a PRACK message to the RBT application server.

In this embodiment, after UE a receives the 183 response, it sends a PRACK message to the ringback tone application server. This step is used for renegotiation, and in the PRACK message, it carries the SDP3 message body used for negotiation. If no The renegotiation may not carry the SDP3 message body. This embodiment assumes that there is no renegotiation.

Step 406: The ring-back tone application server forwards the PRACK message to UE b.

Step 407: UE b sends a 200 OK response message to the RBT application server.

In this embodiment, after UE b receives the PRACK message, it sends a 200 OK response to the ringback tone application server. If the SDP3 message body for renegotiation is carried in the PRACK message in step 405, then the negotiated SDP4 is correspondingly carried in the 200 OK response in this step. In this embodiment, since there is no re-negotiation, there is no SDP4 message body.

Step 408: The RBT application server forwards the 200 OK response message to UE a.

Step 409: The RBT application server sends an INVITE message to the MRS.

In this embodiment, the RBT application server recreates a new INVITE message, which does not carry SDP information.

Step 410: The MRS sends a 200 OK response message to the RBT application server.

In this embodiment, after the MRS receives the INVITE message in step 409, it sends a 200 OK response to the RBT application server. Carry the SDP5 message body describing oneself in this response, in the present embodiment, the content of SDP5 is as follows:

v=0

o＝-4654229 4654229 IN IP4ims_mpc

s = media server session

c=IN IP4 10.164.71.233

t=00

m=audio 36060 RTP/AVP 97

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1; mode-set=0, 1, 2, 3, 4, 5, 6, 7

a=sendonly

m=video 32840 RTP/AVP 34

b=AS:384

a＝rtpmap:34 H263/90000

a=fmtp:34 CIF=4

a=sendonly

In this embodiment, the media information carried in the SDP5 message body includes the media information of the audio media and video media used by the MRS for negotiation, that is, the m line in the SDP5 message body and the information of all attribute lines a of the corresponding media.

Step 411: The ring-back tone application server sends an UPDATE message to UE a.

After the ring-back tone application server receives the 200OK response in step 410, it sends an UPDATE message to UE a, and the UPDATE message carries the SDP6 message body, and SDP6 is obtained after merging SDP2 in step 403 and SDP5 in step 410, if In step 407, the PRACK message carries the SDP4 message body, and then SDP6 is obtained by combining SDP4 in step 407 and SDP5 in step 410. The merging method is as follows: if the connection information c line appears in the session information description part, then the m lines in each media information description part will use this c line, that is, the c line will be copied to the media information description part, and the c line will be used in this embodiment Copy it to the line below line m, if line m has its own line c, then use its own line c.

In this embodiment, line c appears in the session information description part, and since the SDP2 message body is the second negotiation, and the SDP5 message body is the first negotiation, when merging the SDP2 and SDP5 message bodies, the SDP5 message body needs to be The media information description part in is connected to the end of the media information description part of the SDP2 message body, and the session version number of the SDP2 message body stored at the time of the first negotiation is added. The specific merging method is: put the c line in SDP5 into each m line respectively, and then put the detailed information of each media in the media information description part in SDP5, that is, one m line and all attribute lines describing the media , put it behind the media information description part of the SDP2 message body, and increase the session version number in the o line in the stored SDP2 message body by 1, indicating that it is obtained by modifying the SDP2 message body.

At this time, according to the SDP2 and SDP5 message body content in the present embodiment, the content of the SDP6 message body after the merger is obtained as follows:

v=0

o＝APP1.0 20004 20005 IN IP4 10.164.104.99

s=-

t=00

m=audio 10600 RTP/AVP 97

c=IN IP4 10164.104.99

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1

a=sendrecv

m=video 10610 RTP/AVP 34

c=IN IP4 10.164.104.99

b=AS:512

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:34 H263/90000

a＝fmtp:34 QCIF＝1 CIF＝4 MaxBR＝3200

a=sendrecv

m=audio 36060 RTP/AVP 97

c=IN IP4 10.164.71.233

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1; mode-set=0, 1, 2, 3, 4, 5, 6, 7

a=sendonly

m=video 32840 RTP/AVP 34

c=IN IP4 10.164.71.233

b=AS:384

a＝rtpmap:34 H263/90000

a=fmtp:34 CIF=4

a=sendonly

In this embodiment, the media information carried in the SDP6 message body includes the media information of the audio media and video media used by MRS for negotiation and the media information of audio media and video media used by UE b for negotiation, that is, the first two media information Corresponds to the media information used by UE b for negotiation, and the latter two media information corresponds to the media information used by MRS for negotiation.

If the times of negotiation of the SDP2 and SDP5 message bodies in this embodiment are the same, if it is the first negotiation, the SDP2 and SD5 message bodies are connected in any order. If negotiated, the SDP2 and SD5 message bodies are concatenated in the order that was used.

If the SDP4 message body is obtained through re-negotiation in this embodiment, then this step should be changed to merge the SDP4 and SDP5 messages.

Step 412: UE a sends a 200 OK response message to the RBT application server.

In this embodiment, after receiving the UPDATE message in step 411, UE a sends a 200 OK response to the ring-back tone application server, which carries the negotiated SDP7 message body. Specifically, SDP7 is the response made by UE a to SDP6, that is, on the basis of the negotiation result between UE a and UE b, the result of negotiation between UE a and MRS is also added. In this embodiment, the content of SDP7 is as follows :

v=0

o＝APP1.0 10000 10001 IN IP4 10.164.104.58

s=-

c=IN IP4 10.164.104.58

t=00

m=audio 10500 RTP/AVP 97

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1

a=sendrecv

m=video 10510 RTP/AVP 34

b=AS:512

a=curr:qos local none

a=curr:qos remote none

a＝des:qos optional local sendrecv

a＝des:qos optional remote sendrecv

a＝rtpmap:34 H263/90000

a＝fmtp:34 QCIF＝1 CIF＝4 MaxBR＝3200

a=sendrecv

m=audio 10600 RTP/AVP 97

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1; mode-set=0, 1, 2, 3, 4, 5, 6, 7

a=sendonly

m=video 10610 RTP/AVP 34

b=AS:384

a＝rtpmap:34 H263/90000

a=fmtp:34 CIF=4

a=sendonly

In this embodiment, the media information carried in the SDP7 message body includes media information of audio media and video media after negotiation between UE a and UE b and media information of audio media and video media after negotiation between UE a and MRS, that is, the preceding The two media information correspond to the media information negotiated between UE a and UE b, and the latter two media information correspond to the media information negotiated between UE a and MRS.

Step 413: The RBT application server sends an ACK message to the MRS.

In this embodiment, after receiving the 200 OK response in step 412, the ring-back tone application server decomposes the SDP7 carried in the response message. In this embodiment, the ring-back tone application server decomposes the corresponding The media resource information related to SDP5 is extracted as SDP8. And the SDP8 message body is carried in the ACK message sent by the ring back tone application server to the MRS. The ACK message is an acknowledgment message for the 200 OK response message in step 410 . Since the provision of SDP and the response mode are in a one-to-one relationship, SDP8 is the response corresponding to the SDP5 part in SDP7. In this embodiment, the content of SDP8 is as follows:

v=0

o＝APP1.0 10000 10001 IN IP4 10.164.104.58

s=-

c=IN IP4 10.164.104.58

t=00

m=audio 10600 RTP/AVP 97

a＝rtpmap:97 AMR/8000

a=fmtp:97 octet-align=1; mode-set=0, 1, 2, 3, 4, 5, 6, 7

a=sendonly

m=video 10610 RTP/AVP 34

b=AS:384

a＝rtpmap:34 H263/90000

a=fmtp:34 CIF=4

a=sendonly

When necessary, the same method can also be used to extract the negotiated media information corresponding to UE b.

Steps 414 to 420 are the process of resource reservation, which is an optional process. In this process, the server performs media negotiation with UE b and MRS as a party.

Step 414: UE a sends an UPDATE message to the RBT application server.

In this embodiment, UE a sends an UPDATE message including resource reservation success information to the ring back tone application server, and the resource reservation success information is included in the SDP9 message body.

Step 415: The ring-back tone application server sends an UPDATE message to UE b.

In this embodiment, after the ring-back tone application server receives the UPDATE message, the SDP9 message body is decomposed into two parts according to the method of merging, which are respectively: SDP10 describing UE b and SDP11 describing MRS. The ringback tone application server sends an UPDATE message to UE b, and the UPDATE message carries the SDP10 message body. The decomposition method is: extract the media information description part in the SDP10 and SDP11 message body from the SDP9 message body; use the timing information description part and the session information description part in the SDP9 message body as the timing information description in the SDP10 and SDP11 message body section and the session information description section. The extraction method is: extract according to the connection sequence adopted for the media information description part when merging the SDP message body.

Step 416: The RBT application server sends a REINVITE message to the MRS.

In this embodiment, the RBT application server sends a REINVITE message to the MRS, and the REINVITE carries the SDP11 message body in step 415 .

Step 417: The MRS sends a 200 OK response message to the RBT application server.

In this embodiment, after receiving the REINVITE message, the MRS sends a 200 OK response to the RBT application server. Wherein, the message carries the SDP12 message body including the resource reservation information of the MRS.

Step 418: The RBT application server sends an ACK message to the MRS.

In this embodiment, after receiving the 200 OK response message, the RBT application server sends an ACK message to the MRS.

Step 419: UE b sends a 200 OK response message to the RBT application server.

In this embodiment, after UE b receives the UPDATE message in step 415, it sends a 200 OK response to the ring-back tone application server, wherein the 200 OK response message carries the SDP13 message body containing the resource reservation information of UE b.

Step 420: The ring back tone application server sends a 200 OK response message to UE a.

In this embodiment, the ring-back tone application server merges SDP13 and SDP12 into SDP14 according to the merging method in step 11, and carries resource reservation information in the 200 OK response message to the UPDATE message in step 14 sent to UE a The SDP14 message body.

Step 421-step 439 is the process of media exchange.

Steps 421 to 428 are the same as steps 112 to 119 in the prior art, and will not be repeated here.

Step 429: UE b sends a 200 OK response message to the RBT application server.

In this embodiment, after UE b accepts the session, it sends a 200 OK response to the INVITE message in step 2 to the ringback tone application server.

Step 430: The RBT application server forwards the 200 OK response message to UE a.

Step 431: The RBT application server sends a BYE message to the MRS.

In this embodiment, the ring-back tone application server sends a BYE message to the MRS to end the playback of the ring-back tone.

Step 432: The MRS sends a 200 OK response message to the RBT application server.

Step 433: UE a sends an ACK message to the RBT application server.

Step 434: The ring-back tone application server forwards the ACK message to UE b.

Step 435: The RBT application server sends a REINVITE message to UE a.

In this embodiment, the ring-back tone application server sends a REINVITE message to UE a, and the message carries an SDP15 message body. The function of SDP15 is to close the media connection between UE a and MRS, that is, connect UE a and MRS The ports of the m rows between are set to 0.

Step 436: UE a sends a 200 OK response message to the RBT application server.

In this embodiment, after receiving the REINVITE message, UE a sends a 200 OK response message to the ring-back tone application server, which carries the SDP16 message body. The media port corresponding to the MRS in SDP16 is set to 0.

Step 437: The ring-back tone application server sends an ACK message to UE a.

In this embodiment, after receiving the 200 OK response message in step 436, the ring-back tone application server sends an ACK message to UE a.

Step 438 and step 439 are the same as steps 128-129 in the prior art, and will not be repeated here.

It can be seen from the above-mentioned embodiments that in the embodiment of the present invention, in the process of setting up the ring back tone service, because the media negotiation between UE a, MRS, and UE b is carried out at the same time, it avoids that when UE b answers the call in the prior art, due to UE A and UE b do not establish a media connection, resulting in media loss, which can improve user experience.

The method for merging the SDP message body in the embodiment of the present invention can also be: after describing the partial connection sequence for the media information in each SDP message body, set the corresponding media attribute mark, then when decomposing the SDP message body, according to the set Media attribute tags are extracted from each disassembled SDP message body.

The embodiment of the present invention is applicable to the communication field where the SDP message body is used for negotiation.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. a method that realizes media negotiation is characterized in that, this method comprises:

Server obtains Session Description Protocol SDP message body of at least two negotiations, the SDP message body of each described negotiation is carried the media information that same network entity is held consultation, and the SDP message body of described negotiation is described part, timing information description part and session information description part by media information and formed;

Server merges SDP message body of described at least two negotiations, and the SDP message body that merges described at least two negotiations comprises: the media information that connects the SDP message body of each negotiation is described part, produces timing information description part and session information and describes part; Carry out media negotiation by SDP message body and the described same network entity that merges, SDP message body after obtaining consulting, the SDP message body after the described negotiation is carried the media information after the described same network entity negotiation;

Server is according to the mode of the SDP message body that merges described negotiation, decomposes SDP message body after the described negotiation; According to the mode of the SDP message body of obtaining described negotiation, send SDP message body that decomposes.

2. the method for realization media negotiation according to claim 1 is characterized in that, the media information of the SDP message body of described each negotiation of connection is described part and comprised:

The media information that connects the SDP message body of each negotiation of consulting for the first time with random order is described part, and/or part is described with the media information that the order of connection that once adopted connects the SDP message body of each negotiation with identical negotiation number of times, and/or to consult the descending of number of times, the media information that connects the SDP message body of each negotiation is described part.

3. the method for realization media negotiation according to claim 1, it is characterized in that, described connection media information further comprises before describing part: the link information that the SDP message body session information that will appear at each negotiation is described part copies to the media information of the SDP message body of each negotiation and describes part.

4. according to the method for claim 1,2 or 3 described realization media negotiations, it is characterized in that described generation timing information describes part and session information description part comprises:

Determine that link information occurs in session information description part, if the negotiation number of times difference of the SDP message body of two negotiations, number increase by 1 of session version in the SDP message body that the negotiation number of times of storage is more, and after deleting the link information of session information description part in this SDP message body, part is described as the session information of the SDP message body that merges; If the negotiation number of times of the SDP message body of two negotiations is identical, if all be to consult for the first time, then random order connects SDP message body of two negotiations, if once held consultation, then uses SDP message body of used two negotiations that are linked in sequence once;

Describe part when identical at the timing information of the SDP of two negotiations message body, the timing information that this is identical is described part and is described part as the timing information of the SDP message body that merges.

5. the method for realization media negotiation according to claim 1 is characterized in that, described method of carrying out media negotiation by the SDP message body and the described same network entity of merging comprises:

Server sends SDP message body that merges to described same network entity;

Server obtains SDP message body after the negotiation that described same network entity sends, and the SDP message body after the described negotiation is carried the media information after the negotiation that described same network entity produces according to the SDP message body that merges.

6. the method for realization media negotiation according to claim 1 is characterized in that, the SDP message body after the described negotiation is described part, timing information description part and session information description part by media information and formed;

SDP message body after the described negotiation of described decomposition comprises: when merging the SDP message body of described at least two negotiations, the media information that connects in the SDP message body of each negotiation is described the order of connection that part is adopted, the media information that extracts the SDP message body after described negotiation in the SDP message body of each decomposition is described part, perhaps describe the medium property mark of the part order of connection according to what be provided with at each media information, the media information that extracts in the SDP message body of each decomposition is described part; Timing information in the SDP message body after the described negotiation is described part and session information describe that part is described partly as the timing information in the SDP message body of each decomposition and session information is described part.

7. a method that realizes media negotiation is characterized in that, this method comprises:

Server obtains Session Description Protocol SDP message body of a negotiation, the SDP message body of described negotiation is carried the media information that at least two network entities are held consultation, and the SDP message body of described negotiation is described part, timing information description part and session information description part by media information and formed;

Server decomposes SDP message body of described negotiation, the SDP message body of the described negotiation of described decomposition comprises: the media information that extracts from the SDP message body of described negotiation in the SDP message body of each decomposition is described part, the timing information in the SDP message body of described negotiation is described part and session information describe that part is described partly as the timing information in the SDP message body of each decomposition and session information is described part;

SDP message body and described at least two network entities by at least two decomposition carry out media negotiation, obtain SDP message body after at least two negotiations, the media information after the SDP message body after each described negotiation is carried a network entity in described at least two network entities consulted;

Server is according to the mode of the SDP message body of decomposing described negotiation, merges SDP message body after described at least two negotiations, according to the mode of the SDP message body of obtaining described negotiation, sends SDP message body after the merging.

8. the method for realization media negotiation according to claim 7, it is characterized in that, the described media information that extracts is described part and is comprised: when producing the SDP message body of consulting, each media information is described the order of connection that part is adopted, perhaps describe the medium property mark of the part order of connection according to what be provided with at each media information, the media information that extracts in the SDP message body of each decomposition is described part.

9. the method for realization media negotiation according to claim 7 is characterized in that, described method of carrying out media negotiation by SDP message body and described at least two network entities of at least two decomposition comprises:

Server sends SDP message body of at least two decomposition at least to described two network entities;

Server obtains SDP message body after at least two negotiations that described at least two network entities send, and the SDP message body after each described negotiation is carried the media information after the negotiation that a network entity in described at least two network entities produces according to the SDP message body of decomposing.

10. a system that realizes media negotiation is characterized in that, this system comprises: the server and first network entity;

Described server, be used to obtain Session Description Protocol SDP message body of at least two negotiations, the SDP message body of each described negotiation is carried the media information that described first network entity is held consultation, and the SDP message body of described negotiation is described part, timing information description part and session information description part by media information and formed; The media information that connects the SDP message body of each negotiation is described part; Produce timing information description part and session information and describe part to merge SDP message body of described at least two negotiations, carry out media negotiation by SDP message body and described first network entity that merges, SDP message body after obtaining consulting, the SDP message body after the described negotiation is carried the media information after described first network entity negotiation; According to the mode of the SDP message body that merges described negotiation, decompose SDP message body after the described negotiation; According to the mode of the SDP message body of obtaining described negotiation, send SDP message body that decomposes;

Described first network entity is used for carrying out media negotiation with server.

11. a system that realizes media negotiation is characterized in that, this system comprises: server and at least two network entities;

Described server, be used to obtain Session Description Protocol SDP message body, described SDP message body is carried the media information that at least two network entities are held consultation, and the SDP message body of described negotiation is described part, timing information description part and session information description part by media information and formed; The media information that extracts from the SDP message body of described negotiation in the SDP message body of each decomposition is described part, the timing information in the SDP message body of described negotiation is described part and session information describe part and describe part and session information description partly to decompose described SDP message body as the timing information in the SDP message body of each decomposition; SDP message body and described at least two network entities by at least two decomposition carry out media negotiation, obtain SDP message body after at least two negotiations, the SDP message body after the described negotiation carry with described at least two network entities in the media information of a network entity after consulting; According to the mode of the SDP message body of decomposing described negotiation, merges SDP message body after described at least two negotiations, according to the mode of the SDP message body of obtaining described negotiation, send SDP message body after the merging;

Described at least two network entities are used for carrying out media negotiation with server.

12. a server of realizing media negotiation is characterized in that, this server comprises: acquisition module, merging module, negotiation module and decomposing module;

Described acquisition module, be used to obtain Session Description Protocol SDP message body of at least two negotiations, each described SDP message body is carried the media information that same network entity is held consultation, the SDP message body of described negotiation is described part, timing information by media information and is described part and session information and describe part and form, and the SDP message body of described at least two negotiations is sent to the merging module;

Described merging module, the media information that is used to connect the SDP message body of each negotiation is described part, produce timing information and describe SDP message body that part and session information are described at least two negotiations that part receives with merging, the SDP message body of merging is sent to negotiation module;

Described negotiation module, be used for holding consultation by the SDP message body and the described same network entity of the merging that receives, SDP message body after obtaining consulting, the SDP message body after the described negotiation is carried the media information after the described same network entity negotiation;

Described decomposing module is used for the mode according to the SDP message body that merges described negotiation, decomposes SDP message body after the described negotiation, according to the mode of the SDP message body of obtaining described negotiation, sends SDP message body that decomposes.

13. a server of realizing media negotiation is characterized in that, this server comprises: acquisition module, decomposing module, negotiation module and merging module;

Described acquisition module, be used to obtain Session Description Protocol SDP message body of a negotiation, the SDP message body of described negotiation is carried the media information that at least two network entities are held consultation, the SDP message body of described negotiation is described part, timing information by media information and is described part and session information and describe part and form, and the SDP message body of described negotiation is sent to decomposing module;

Described decomposing module, be used for describing part from the media information that the SDP message body of described negotiation extracts the SDP message body of each decomposition, timing information in the SDP message body of described negotiation is described part and session information describe part and describe SDP message body of the described negotiation that part and session information description partly receive with decomposition as the timing information in the SDP message body of each decomposition, the SDP message body of at least two decomposition that decomposition is obtained sends to negotiation module;

Described negotiation module, be used for carrying out media negotiation by SDP message body and described at least two network entities of at least two decomposition receiving, obtain SDP message body after at least two negotiations, the media information after the SDP message body after each described negotiation is carried a network entity in described at least two network entities consulted;

Described merging module is used for the mode according to the SDP message body of decomposing described negotiation, merges SDP message body after described at least two negotiations, according to the mode of the SDP message body of obtaining described negotiation, sends SDP message body after the merging.

Images