CN101009575A - Method for multiple early media services in one call process - Google Patents

The disclosed method for multiple early media business during one calling based on IP multimedia system comprises: expanding the head field of SIP information in RFC 3959 file of IETF by adding a type configuration parameter for different media type; dividing the SDP in SIP information entity into the dialogue SDP and early-media SDP; the early-media platform in IP multimedia system differentiates early-media SDP according to received type configuration parameter in SIP information entity to provide business for the calling and called. This invention is simple and convenient, changes a little to network device, expands business field, and brings both-win for the provider and user.

在一次呼叫过程中实现多个早期媒体类业务的方法Method for realizing multiple early media services in one call

技术领域technical field

本发明涉及一种在一次呼叫过程中实现多个早期媒体类业务的方法，确切地说，涉及一种基于IP多媒体系统在一次呼叫过程中实现多个早期媒体类业务的方法，属于移动通信技术中基于IMS的电信增值业务技术领域。The present invention relates to a method for realizing multiple early media services in one call process, to be precise, relates to a method for realizing multiple early media services in one call process based on an IP multimedia system, which belongs to mobile communication technology In the technical field of IMS-based telecom value-added services.

背景技术Background technique

随着电信网络的发展和人们生活水平的提高，个性化、差异化服务代表了电信增值业务的一个发展趋势。彩铃(CRBT，Color Ring Back Tone)业务是主叫用户拨打被叫用户时，在通话之前主叫用户所收到的由被叫用户定制的多媒体信息；彩像业务则是主叫用户拨打被叫用户时，在通话之前被叫用户所收到的由主叫用户定制的多媒体信息。彩铃业务属于被叫定制、主叫享用的业务，而彩像业务属于主叫定制、被叫享用的业务。彩铃和彩像业务都属于早期媒体(Early Media)类业务，近年来，这类业务获得了用户的欢迎和追捧，为电信运营商创造了极高的收益。With the development of telecommunication networks and the improvement of people's living standards, personalized and differentiated services represent a development trend of telecommunication value-added services. The color ring back tone (CRBT, Color Ring Back Tone) service is the multimedia information customized by the called user received by the calling user before the call when the calling user dials the called user; When the user is a user, the multimedia information customized by the calling user received by the called user before the call. The CRBT service is customized by the called party and enjoyed by the calling party, while the CRBT service is customized by the calling party and enjoyed by the called party. Color ring tones and color video services are both early media services. In recent years, this type of service has been welcomed and sought after by users, and has created extremely high profits for telecom operators.

IETF的RFC3959文件引入了早期媒体的概念，并研究了基于扩展的SIP协议的早期媒体提供方式。IETF的RFC3959文件在SIP的消息头字段内容配置(Content-Disposition)中引入了早期媒体的配置类型(early-session)，以便能够在SIP消息体中区分不同的会话描述协议SDP(Session DescriptionProtocol)部分，这个规范为基于SIP的早期媒体类业务的提供给出了协议级别的支持。IETF的RFC 3960文件还通过网关模式和应用服务器模式扩展了SIP环境中回铃音(Ringing Tone)的提供方式。The RFC3959 document of IETF introduces the concept of early media, and studies the early media provision method based on the extended SIP protocol. IETF's RFC3959 document introduces the early media configuration type (early-session) in the SIP message header field content configuration (Content-Disposition), so that different Session Description Protocol SDP (Session Description Protocol) parts can be distinguished in the SIP message body , this specification provides protocol-level support for the provision of early SIP-based media services. The RFC 3960 document of IETF also expands the provision method of ringback tone (Ringing Tone) in the SIP environment through the gateway mode and the application server mode.

但是，上述这些对于早期媒体的工作和规定都是针对在一次呼叫过程中实现某个单独的早期媒体类业务而进行的，如果在某一次呼叫中要实现两个或两个以上的早期媒体类业务，比如在一次呼叫过程中实现彩铃和彩像业务，则上述这些现有的标准文件或规范都是无能为力的；因此如何对现有技术在一次呼叫过程中只能实现某个单独的早期媒体类业务的局限进行改进和突破，就成为业内技术人员关注和研究的焦点。However, the above-mentioned work and regulations for early media are all aimed at realizing a separate early media service during a call. If two or more early media services are to be implemented in a call services, such as the implementation of CRBT and CRTV services during a call, the above-mentioned existing standard documents or specifications are powerless; therefore, how to implement only a single early media in a call with the existing technology To improve and break through the limitations of similar services has become the focus of attention and research by technical personnel in the industry.

发明内容Contents of the invention

有鉴于此，本发明的目的是提供一种能够克服现有技术的局限、基于IMS在一次呼叫过程中实现多个早期媒体类业务的方法，本发明方法的实现过程简单、明晰、方便，对网络设备的改动少，拓宽了增值业务的领域，提高了业务服务质量，能够为运营商和用户带来双赢。In view of this, the purpose of the present invention is to provide a method that can overcome the limitations of the prior art and realize multiple early media services in a call process based on IMS. The implementation process of the method of the present invention is simple, clear, and convenient. There are few changes to network equipment, which broadens the field of value-added services, improves service quality, and can bring a win-win situation for operators and users.

为了达到上述目的，本发明提供了一种基于IP多媒体系统在一次呼叫过程中实现多个早期媒体类业务的方法，其特征在于：先对互联网工程任务组IETF的RFC3959文件中的会话初始化协议SIP消息的头字段进行扩展：增设一个类型配置参数(disposition-parm)，用于区分不同的早期媒体的配置类型(early-session)；再把SIP消息体中会话描述协议部分SDP(Session DescriptionProtocol)根据其信令功能分为两类：通话SDP和早期媒体SDP；然后IP多媒体系统中的各个早期媒体类业务平台根据其所接收到的SIP信息体中的类型配置参数，区分不同的早期媒体SDP，分别为主、被叫用户提供相应的早期媒体类业务，从而在一次呼叫过程中实现多个早期媒体类业务的流程。In order to achieve the above-mentioned purpose, the present invention provides a kind of method based on IP multimedia system to realize a plurality of early stage media business in a calling process, it is characterized in that: the session initialization protocol SIP in the RFC3959 file of Internet Engineering Task Force IETF The header field of the message is extended: a type configuration parameter (disposition-parm) is added to distinguish different early media configuration types (early-session); and then the session description protocol part SDP (Session Description Protocol) in the SIP message body is Its signaling function is divided into two categories: call SDP and early media SDP; then each early media service platform in the IP multimedia system configures parameters according to the type in the SIP message body it receives to distinguish different early media SDPs, Corresponding early media services are provided for the calling user and the called user respectively, so as to realize the flow of multiple early media services in one call.

所述增设的类型配置参数包括两部分：参数名和参数值，其中参数名为设定的字符串，用以标识该增设的类型配置参数字段，参数值设定为表征早期媒体类业务的字符串，且参数值将随着早期媒体类业务种类的增加而动态扩展和定义。The added type configuration parameter includes two parts: a parameter name and a parameter value, wherein the parameter name is a set character string used to identify the added type configuration parameter field, and the parameter value is set as a character string representing early media services , and the parameter value will be dynamically expanded and defined as the types of early media services increase.

所述增设的类型配置参数的安放位置在原来SIP消息的头字段中早期媒体的配置类型参数的后面，即扩展后的SIP消息的头字段为：Content-Disposition：early-session：参数名＝“参数值”。The placement position of the added type configuration parameter is behind the early media configuration type parameter in the header field of the original SIP message, that is, the header field of the expanded SIP message is: Content-Disposition: early-session: parameter name=" parameter value".

参数名设定为type，参数值设定为：彩像业务为mrt，彩铃业务为mrbt，扩展后的SIP消息的头字段为：Content-Disposition：early-session：type＝“mrt”|“mrbt”。The parameter name is set to type, and the parameter value is set to: mrt for color video service, mrbt for color ring service, and the header field of the extended SIP message is: Content-Disposition: early-session: type="mrt"|"mrbt ".

所述通话SDP是主被叫之间为了通话而进行媒体协商时所使用的SDP，早期媒体SDP则是主被叫之间为了建立早期媒体而进行媒体协商时所使用的SDP。The call SDP is the SDP used for media negotiation between the calling party and the called party for calling, and the early media SDP is the SDP used for media negotiation between the calling party and the called party for establishing early media.

所述各个早期媒体类业务平台根据其所接收到的SIP信息体中的类型配置参数，区分不同的早期媒体SDP，分别为主、被叫用户提供相应的早期媒体类业务的操作包括下列具体步骤：Described each early media class service platform according to the type configuration parameter in the SIP information body that it receives, distinguishes different early media SDP, the operation that provides corresponding early media class business respectively for master and called user comprises the following specific steps :

(1)主叫用户呼叫被叫，主叫发出的呼叫请求INVITE消息中包含通话SDP，该呼叫请求INVITE消息经过主叫归属域的代理呼叫会话控制功能的服务器P-CSCF到达主叫归属域的服务呼叫会话控制功能的服务器S-CSCF；(1) The calling user calls the called party, and the call request INVITE message sent by the calling party includes the conversation SDP, and the call request INVITE message reaches the server P-CSCF of the calling party's home domain through the server P-CSCF of the calling party's home domain The server S-CSCF serving the call session control function;

(2)主叫归属域的S-CSCF从主叫的归属用户服务器HSS上获取业务过滤准则，并根据业务过滤准则进行业务路由：如果存在一个或多个早期媒体类主叫业务，则该S-CSCF根据过滤准则的优先权的不同，按业务优先权的高低依次将呼叫触发到各个对应的早期媒体类主叫业务的业务平台；当所有的早期媒体类主叫业务完成各自相应的业务处理后，该S-CSCF通过SIP的INVITE消息将呼叫路由到被叫归属域的S-CSCF，在该INVITE消息体中包含一个通话SDP、一个或多个早期媒体SDP，各个早期媒体SDP通过扩展的类型配置参数进行区分；(2) The S-CSCF in the calling home domain obtains the service filtering criteria from the calling home subscriber server HSS, and performs service routing according to the service filtering criteria: if there are one or more early media calling services, the S -CSCF triggers the call to the service platform of each corresponding early media calling service according to the priority of the service according to the priority of the filtering criteria; when all the early media calling services complete their corresponding service processing Afterwards, the S-CSCF routes the call to the S-CSCF in the called home domain through the SIP INVITE message. The INVITE message body contains a call SDP, one or more early media SDPs, and each early media SDP is passed through the extended Type configuration parameters are distinguished;

(3)被叫归属域的S-CSCF根据从被叫归属的HSS中获取的过滤准则，对早期媒体类被叫业务进行触发，即将呼叫触发到各个对应的早期媒体类被叫业务的业务平台；当所有的早期媒体类被叫业务各自完成业务处理后，被叫归属域的S-CSCF通过被叫归属域的P-CSCF把INVITE消息路由到被叫；(3) The S-CSCF in the called home domain triggers the early media called service according to the filtering criteria obtained from the called called HSS, that is, the call is triggered to the service platform of each corresponding early media called service ; After all the early media called services complete their service processing, the S-CSCF of the called home domain routes the INVITE message to the called party through the P-CSCF of the called home domain;

(4)被叫终端进行呼叫处理，并按照呼叫路由原则返回INVITE消息的确认消息：183消息，在该183消息体中包含早期媒体类主/被叫业务的早期媒体SDP和被叫终端提供的早期媒体SDP，并通过扩展的类型配置参数区分各个早期媒体SDP；各个早期媒体业务平台根据自己业务的需求，对183消息中的早期媒体SDP进行相应的处理，并完成相应的媒体协商；(4) The called terminal performs call processing, and returns the confirmation message of the INVITE message according to the call routing principle: 183 message, which includes the early media SDP of the early media master/called service and the early media SDP provided by the called terminal in the 183 message body Early media SDP, and distinguish each early media SDP through extended type configuration parameters; each early media service platform performs corresponding processing on the early media SDP in the 183 message according to its own business needs, and completes the corresponding media negotiation;

(5)携带早期媒体SDP的183消息到达主叫终端，与主叫终端进行早期媒体协商，并按照呼叫路由原则通过PRACK/200OK消息对183消息进行应答，并在应答过程中，完成各个早期媒体类业务与用户终端的媒体协商；(5) The 183 message carrying the early media SDP arrives at the calling terminal, conducts early media negotiation with the calling terminal, and responds to the 183 message through the PRACK/200OK message according to the call routing principle, and completes each early media during the response process. media negotiation between such services and user terminals;

(6)当各个早期媒体类业务平台收到被叫终端180振铃消息后，指示媒体资源功能MRF服务器提供相应的早期媒体类业务，使用户享受早期媒体类业务；(6) After receiving the ringing message of the called terminal 180, each early media service platform instructs the media resource function MRF server to provide corresponding early media services, so that users can enjoy early media services;

(7)当各个早期媒体类业务平台收到被叫终端的接听消息：200OK消息后，即停止早期媒体类业务的提供。(7) When each early media service platform receives an answer message: 200 OK message from the called terminal, it stops providing early media services.

本发明是一种基于IP多媒体系统在一次呼叫过程中实现多个早期媒体类业务的方法，它的优点是：在一个呼叫实例中完成多个早期媒体类业务的协作过程的整个技术方案对现有网络设备的影响和改动很小：只须对现有早期媒体类应用服务器进行升级，使其支持本发明扩展的类型配置参数type；而对于其他非早期媒体类应用服务器和IMS网络核心设备，由于它们不会对早期媒体SDP进行处理，故可不进行升级。这样，本发明的实现过程简单、明晰、方便，容易实现，既拓宽了增值业务的服务领域，又能够提高电信业务的服务质量，有很好的社会效益和经济效益，能够为运营商和用户带来双赢。The present invention is a method for realizing a plurality of early media services in a call process based on an IP multimedia system. Its advantage is that the entire technical scheme of completing the cooperation process of a plurality of early media services in one call instance has great impact on the current situation. The impact and changes of network equipment are very small: only the existing early media application server needs to be upgraded to support the extended type configuration parameter type of the present invention; and for other non-early media application servers and IMS network core equipment, Since they do not process early media SDPs, they may not be upgraded. In this way, the realization process of the present invention is simple, clear, convenient, and easy to realize, which not only broadens the service field of value-added services, but also improves the service quality of telecommunication services, has good social and economic benefits, and can serve operators and users Bring win-win.

附图说明Description of drawings

图1是本发明基于IP多媒体系统在一次呼叫过程中实现多个早期媒体类业务的方法流程方框图。FIG. 1 is a flow block diagram of a method for realizing multiple early media services in a call process based on an IP multimedia system in the present invention.

图2是本发明基于IP多媒体系统在一次呼叫过程中实现多个早期媒体类业务的方法的一实施例信令时序图。FIG. 2 is a signaling sequence diagram of an embodiment of a method for implementing multiple early media services in a call process based on an IP multimedia system according to the present invention.

具体实施方式Detailed ways

为使本发明的目的、技术方案和优点更加清楚，下面结合附图对本发明作进一步的详细描述。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 in conjunction with the accompanying drawings.

参见图1，本发明是一种基于IMS在一次呼叫过程中实现多个早期媒体类业务的方法，该方法主要包括下列三个操作步骤：Referring to Fig. 1, the present invention is a kind of method that realizes a plurality of early media class services in a calling process based on IMS, and this method mainly comprises following three operation steps:

A、对IETF的RFC3959文件中的SIP消息的头字段进行扩展：增设一个类型配置参数(disposition-parm)，用于区分不同的早期媒体的配置类型(early-session)。A. Extend the header field of the SIP message in the IETF RFC3959 file: add a type configuration parameter (disposition-parm) to distinguish different early media configuration types (early-session).

该类型配置参数由参数名和参数值两部分组成，参数名可设定为“type”，参数值可设定为表征早期媒体类业务的字符串，例如彩像业务用″mrt ″表示、彩铃业务用″mrbt″表示等，参数值可随着早期媒体类业务种类的增加而动态定义。该新增的类型配置参数的位置是放在早期媒体的配置类型(early-session)参数的后面，即原来的SIP消息的头字段是：Content-Disposition：early-session；本发明的SIP消息的头字段是：Content-Disposition：early-session：type＝“mrt”|“mrbt”。This type of configuration parameter consists of two parts: parameter name and parameter value. The parameter name can be set as "type", and the parameter value can be set as a character string representing early media services. Expressed by "mrbt", etc., the parameter value can be dynamically defined as the types of early media services increase. The position of this newly-increased type configuration parameter is to be placed on the back of the configuration type (early-session) parameter of early media, promptly the header field of original SIP message is: Content-Disposition: early-session; The SIP message of the present invention The header field is: Content-Disposition: early-session: type="mrt"|"mrbt".

B、把SIP消息体中会话描述协议部分SDP根据其信令功能分为两类：通话SDP和早期媒体SDP。B. Divide the SDP part of the session description protocol in the SIP message body into two types according to its signaling function: call SDP and early media SDP.

其中通话SDP是主被叫之间为了通话而进行媒体协商时用到的SDP，此类SDP一般在非1xx(以1开头的消息)系列消息的SIP消息(如INVITE、200OK、ACK)中携带。早期媒体SDP是为建立早期媒体而进行媒体协商时用到的SDP，此类SDP一般在SIP的INVITE、183消息及其应答消息(如PRACK)中携带。Among them, the call SDP is the SDP used for media negotiation between the caller and the called party for the call. This type of SDP is generally carried in SIP messages (such as INVITE, 200OK, ACK) of non-1xx (messages starting with 1) series messages . The early media SDP is the SDP used in media negotiation for the establishment of early media, and this type of SDP is generally carried in the INVITE, 183 messages and their response messages (such as PRACK) of SIP.

C、多媒体系统中的各个早期媒体类业务平台根据其所接收到的SIP信息体中的类型配置参数，区分不同的早期媒体SDP，分别为主、被叫用户提供相应的早期媒体类业务，从而在一次呼叫过程中实现多个早期媒体类业务的流程。该操作步骤可以细分为下列七个操作内容：C, each early media service platform in the multimedia system distinguishes different early media SDPs according to the type configuration parameters in the SIP information body it receives, and provides corresponding early media services for the main and called users respectively, thereby The process of implementing multiple early media services in one call. This operation step can be subdivided into the following seven operation contents:

C1：主叫用户呼叫被叫，主叫发出的呼叫请求INVITE消息中包含通话SDP，呼叫请求INVITE消息经过主叫归属域的P-CSCF到达主叫归属域的S-CSCF；C1: The calling user calls the called party, the call request INVITE message sent by the caller contains the conversation SDP, and the call request INVITE message reaches the S-CSCF of the calling party's home domain through the P-CSCF of the calling party's home domain;

C2：主叫归属域的S-CSCF从主叫归属的HSS上获取业务过滤准则，并根据业务过滤准则进行业务路由：如果存在一个或多个早期媒体类主叫业务，则主叫归属域的S-CSCF根据过滤准则的优先权的不同，按业务优先权的高低依次将呼叫触发到各个对应的早期媒体类主叫业务的业务平台；当所有的早期媒体类主叫业务完成相应的业务处理之后，主叫归属域的S-CSCF通过SIP的INVITE消息将呼叫路由到被叫归属域的S-CSCF，在INVITE消息体中包含一个通话SDP、一个或多个早期媒体SDP，各个早期媒体SDP通过扩展的type参数进行区分；C2: The S-CSCF of the calling home domain obtains the service filtering criterion from the calling home HSS, and performs service routing according to the service filtering criterion: if there are one or more early media calling services, the calling service of the calling home domain The S-CSCF triggers the call to the service platform of each corresponding early media calling service according to the different priorities of the filtering criteria; when all the early media calling services complete the corresponding service processing Afterwards, the S-CSCF in the calling home domain routes the call to the S-CSCF in the called home domain through the SIP INVITE message. The INVITE message body contains a call SDP, one or more early media SDPs, and each early media SDP Distinguished by the extended type parameter;

C3：被叫归属域的S-CSCF根据从被叫归属的HSS中获取的过滤准则，对早期媒体类被叫业务进行触发，即将呼叫触发到各个对应的早期媒体类被叫业务的业务平台；当所有的早期媒体类被叫业务各自完成业务处理后，被叫归属域的S-CSCF通过被叫归属域的P-CSCF把INVITE消息路由到被叫；C3: The S-CSCF of the called home domain triggers the early media called service according to the filter criterion obtained from the called HSS, that is, the call is triggered to each service platform of the corresponding early media called service; After all the called services of the early media class complete the business processing respectively, the S-CSCF of the called home domain routes the INVITE message to the called party through the P-CSCF of the called home domain;

C4：被叫终端进行呼叫处理，并按照呼叫路由原则返回INVITE消息的确认消息：183消息，在该183消息体中包含早期媒体类主/被叫业务的早期媒体SDP和被叫终端提供的早期媒体类业务的早期媒体SDP，并通过扩展的类型配置参数type区分各个早期媒体SDP；各个早期媒体业务平台根据自己业务的需求，对183消息中的早期媒体SDP进行相应的处理，并完成相应的媒体协商；C4: The called terminal performs call processing, and returns the confirmation message of the INVITE message according to the call routing principle: 183 message, which contains the early media SDP of the early media master/called service and the early media SDP provided by the called terminal in the 183 message body. The early media SDP of the media business, and distinguish each early media SDP through the extended type configuration parameter type; each early media service platform performs corresponding processing on the early media SDP in the 183 message according to its own business needs, and completes the corresponding Media consultation;

C5：携带早期媒体SDP的183消息到达主叫终端，与主叫终端进行早期媒体协商，并按照呼叫路由原则通过PRACK/200OK消息对183消息进行应答，并在应答过程中，完成各个早期媒体类业务与用户终端的媒体协商；C5: The 183 message carrying the early media SDP arrives at the calling terminal, conducts early media negotiation with the calling terminal, and responds to the 183 message through the PRACK/200OK message according to the call routing principle, and completes all early media types during the response process Media negotiation between services and user terminals;

C6：当各个早期媒体类业务平台收到被叫终端180振铃消息后，指示多媒体资源功能MRF服务器提供相应的早期媒体类业务，使用户享受早期媒体类业务；C6: After receiving the ringing message of the called terminal 180, each early media service platform instructs the multimedia resource function MRF server to provide corresponding early media services, so that users can enjoy early media services;

C7：当各个早期媒体类业务平台收到被叫终端的接听消息：200OK消息后，即停止早期媒体类业务的提供。C7: After each early media service platform receives the answering message: 200 OK message from the called terminal, it stops providing early media services.

参见图2，介绍本发明在一次呼叫中实现多个早期媒体类业务的具体操作流程。图2中的IP多媒体系统的主叫归属域包含S-CSCF、多媒体彩像业务平台和媒体资源功能服务器MRF，被叫归属域包含S-CSCF、多媒体彩铃业务平台和媒体资源功能服务器MRF。为了方便描述，图2中省略了P-CSCF，并省略了部分消息，如：180消息的PRACK及其200OK响应。图2中消息后的编号(a、b、c、d、e)是用于区分不同的SIP对话。Referring to FIG. 2 , the specific operation flow of realizing multiple early media services in one call of the present invention is introduced. The calling home domain of the IP multimedia system in Fig. 2 includes the S-CSCF, the multimedia chromatic image service platform and the media resource function server MRF, and the called home domain includes the S-CSCF, the multimedia CRBT service platform and the media resource function server MRF. For convenience of description, the P-CSCF is omitted in FIG. 2 , and some messages are omitted, such as the PRACK of the 180 message and its 200 OK response. The numbers (a, b, c, d, e) after the messages in Fig. 2 are used to distinguish different SIP conversations.

1～2：主叫呼叫被叫，主叫S-CSCF根据过滤准则把呼叫路由到多媒体彩像业务平台，其中INVITE消息中携带主叫用户UE1通话SDP。1-2: The calling party is called, and the calling S-CSCF routes the call to the multimedia chromatic image service platform according to the filtering criteria, wherein the INVITE message carries the call SDP of the calling user UE1.

3～4：为了播放早期媒体(彩像)，多媒体彩像业务平台与MRF进行媒体协商：INVITE中没有SDP，200OK消息中携带了MRF的SDP(sdp-mrt)。3-4: In order to play the early media (color image), the multimedia color image service platform conducts media negotiation with the MRF: there is no SDP in the INVITE, and the SDP (sdp-mrt) of the MRF is carried in the 200OK message.

5～6：多媒体彩像业务平台进行了业务处理后，通过S-CSCF呼叫被叫用户，在该INVITE消息中，携带了两个SDP：通话SDP(sdp-UE1)和早期媒体SDP(sdp-mrt)。其中早期媒体SDP通过“Content-Disposition：early-session；type＝‘mrt’”标识该SDP是一个彩像业务的早期媒体SDP。5-6: After the multimedia chromatic image service platform has processed the service, it calls the called user through the S-CSCF. In the INVITE message, two SDPs are carried: call SDP (sdp-UE1) and early media SDP (sdp-UE1) mrt). The early media SDP identifies the SDP as an early media SDP for color image services through "Content-Disposition: early-session; type='mrt'".

7：INVITE消息到达被叫S-CSCF，被叫S-CSCF根据过滤准则把呼叫路由到多媒体彩铃业务平台。7: The INVITE message arrives at the called S-CSCF, and the called S-CSCF routes the call to the multimedia ring back tone service platform according to the filtering criteria.

8～9：多媒体彩铃业务平台进行业务处理后，把呼叫路由到被叫S-CSCF，被叫S-CSCF呼叫被叫用户。8-9: After the multimedia ring back tone service platform performs service processing, the call is routed to the called S-CSCF, and the called S-CSCF calls the called user.

10～11：被叫用户通过INVITE消息中的early-session标志，获知此次呼叫包含早期媒体类业务，因此通过183消息进行早期媒体(彩像)能力协商，返回对sdp-mrt(SDP Offer)的应答sdp-mrt’(SDP Answer)。10~11: The called user knows that the call contains early media services through the early-session flag in the INVITE message, so the early media (color video) capability negotiation is carried out through the 183 message, and the sdp-mrt (SDP Offer) is returned The answer sdp-mrt'(SDP Answer).

12～15：10～11消息的PRACK应答及PRACK的200OK响应。12-15: PRACK response of messages 10-11 and 200 OK response of PRACK.

16～17：被叫终端振铃，发出180消息到多媒体彩铃业务平台。16-17: The called terminal rings and sends a 180 message to the multimedia CRBT service platform.

18～19：多媒体彩铃业务平台通过180消息得知被叫用户空闲，向MRF发出INVITE消息，进行多媒体彩铃业务的早期媒体协商。MRF在200OK消息中提供多媒体彩铃的早期媒体sdp：sdp-mrbt(SDP Offer)。18-19: The multimedia CRBT service platform learns that the called user is idle through the 180 message, and sends an INVITE message to the MRF for early media negotiation of the multimedia CRBT service. MRF provides the early media sdp of the multimedia ring back tone in the 200OK message: sdp-mrbt (SDP Offer).

20～21：多媒体彩铃平台根据10、19中得到的媒体sdp，向主叫用户发送183消息进行早期媒体协商。从10、19消息中获知：该183消息携带两个早期媒体sdp：sdp-mrbt、sdp-mrt，其Content-Disposition头分别为：Content-Disposition：early-session；type＝‘mrbt’和Content-Disposition：early-session；type＝‘mrt’。20-21: The multimedia CRBT platform sends a 183 message to the calling user for early media negotiation according to the media sdp obtained in 10 and 19. From messages 10 and 19, it is known that the 183 message carries two early media sdp: sdp-mrbt, sdp-mrt, and its Content-Disposition headers are: Content-Disposition: early-session; type='mrbt' and Content- Disposition: early-session; type='mrt'.

22：上述183消息达到多媒体彩像业务平台，多媒体彩像业务平台根据Content-Disposition提取彩像业务sdp，并对4中的200OK进行ACK应答。22: The above 183 message reaches the multimedia chromatic image service platform, and the multimedia chromatic image service platform extracts the chromatic image service sdp according to the Content-Disposition, and responds with ACK to the 200 OK in 4.

23：多媒体彩像业务平台提取彩像sdp后，把183通过S-CSCF转发到主叫用户，此时的183消息中仍携带多媒体彩铃业务的早期媒体sdp：sdp-mrbt(SDP Offer)。23: After the multimedia CRBT service platform extracts the chromatic image sdp, it forwards 183 to the calling user through the S-CSCF. At this time, the 183 message still carries the early media sdp of the multimedia CRBT service: sdp-mrbt (SDP Offer).

24：主叫终端根据183消息中的early-session标志，获知此次呼叫包含早期媒体类业务，因此通过PRACK消息进行早期媒体(彩铃)能力协商，返回对sdp-mrbt(SDP Offer)的应答sdp-mrbt’(SDP Answer)。24: According to the early-session flag in the 183 message, the calling terminal knows that the call contains early media services, so it conducts early media (CRBT) capability negotiation through the PRACK message, and returns the response sdp to sdp-mrbt (SDP Offer) -mrbt'(SDP Answer).

25：PRACK的200OK应答。25: 200 OK response to PRACK.

26～27：根据路由原则，把携带sdp-mrbt’的PRACK消息路由到多媒体彩铃业务平台。26-27: According to the routing principle, route the PRACK message carrying sdp-mrbt' to the multimedia ring back tone service platform.

28～29：PRACK消息的200OK应答。28-29: 200 OK response to the PRACK message.

30：根据27中的sdp-mrbt’，对19的200OK进行ACK应答，该ACK消息中携带多媒体彩铃业务的SDP Answer：sdp-mrbt’。30: According to sdp-mrbt' in 27, perform an ACK response to the 200OK of 19, and the ACK message carries the SDP Answer of the multimedia ring back tone service: sdp-mrbt'.

31～34：指示被叫用户空闲的180消息分别达到多媒体彩像业务平台及主叫终端。31-34: The 180 message indicating that the called user is idle reaches the multimedia video service platform and the calling terminal respectively.

35～38：多媒体彩像业务平台指示MRF播放彩像，MRF通过INFO消息上报彩像播放情况。此时被叫用户享受多媒体彩像业务。35-38: The multimedia color image service platform instructs the MRF to play the color image, and the MRF reports the playing status of the color image through the INFO message. At this moment, the called user enjoys the multimedia video service.

39～42：多媒体彩铃业务平台指示MRF播放彩铃，MRF通过INFO消息上报彩像播放情况。此时主叫用户享受多媒体彩铃业务。39-42: The multimedia CRBT service platform instructs the MRF to play the CRBT, and the MRF reports the CRBT playing status through the INFO message. At this time, the calling user enjoys the multimedia ring back tone service.

43～44：表示被叫接听的200OK消息，其中携带了通话SDP的应答(sdp-UE1’)。43-44: Indicates the 200OK message that the called party answers, which carries the call SDP response (sdp-UE1').

45～46：被叫接听，多媒体彩铃业务平台指示(通过BYE消息)MRF停止播放彩铃。45-46: The called party answers the call, and the multimedia CRBT service platform instructs (via BYE message) the MRF to stop playing the CRBT.

47～48：表示被叫接听的200OK消息，其中携带了通话SDP的应答(sdp-UE1’)。47-48: 200OK messages indicating that the called party answered, which carried the call SDP response (sdp-UE1').

49～50：被叫接听，多媒体彩像业务平台指示(通过BYE消息)MRF停止播放彩像。49-50: The called party answers the call, and the multimedia video service platform instructs (via a BYE message) that the MRF stops playing the video.

51～52：表示被叫接听的200OK消息，其中携带了通话SDP的应答(sdp-UE1’)。51-52: 200OK message indicating that the called party answers, which carries the call SDP response (sdp-UE1').

53～58：51～52，47～48，43～44的ACK应答，此时主被叫用户通话建立。53-58: ACK responses of 51-52, 47-48, and 43-44, at this time, the call between the calling and called users is established.

本发明在一个呼叫实例中完成多个早期媒体类业务的实现方法已经在东信北邮公司的IMS实验室进行了实施试验，试验是成功的，完成了性能验证的测试：同一个呼叫实例中包含多媒体彩铃和多媒体彩像业务，实现了发明目的。The implementation method of the present invention to complete multiple early media services in one call instance has been implemented in the IMS laboratory of Dongxin Beiyou Company. The test is successful and the performance verification test has been completed: the same call instance contains multimedia The color ring tones and multimedia color image services realize the purpose of the invention.