义业务通知方法 技术领域 本发明涉及通信领域， 更具体地， 涉及下一代网络（NGN ) 中的一种 会议业务通 P方法。 背景技术 在以 IP多媒体子系统 （IMS ) 为核心的下一代网络 ( NGN ) 中， 采用 初始会话协议 ( SIP )作为业务控制协议， 各项通信业务可由用户的智能终端 与网络中的由运营商设置的应用服务器 （AS ) 配合完成。 图 1是示出了下一代网络中的一种典型业务的实现架构框图， 其中， 应 用服务器 （AS ) (可能存在多个， 分别用于不同的业务） 通过接口与用户归 属网络的服务 -呼叫会话控制功能 （S-CSCF )相连， 用户终端 A与用户终端 B之间的 SIP业务控制消息（用虚线标识）会流经各自的拜访网络中的代理- 呼叫会话控制功能 （P-CSCF ) 以及归属网络中的服务 -呼叫会话控制功能 ( S-CSCF )与应用服务器（根据用户业务的种类， 可能经过不同的应用服务 器），应用服务器可通过对业务控制消息的各种处理以实现丰富的业务。用户 终端 A与用户终端 B利用业务消息交换并协商双方所支持的媒体参数，在两 者之间建立 IP媒体流连接 (用实线标识）， IP媒体流用于传送通话话音包等 数据。 如果应用服务器配备媒体处理功能， 则用户终端与应用服务器之间也 可建立媒体流连接， 实现人机对话业务， 例如 4艮行的自动语音服务。 下一代网络需要考虑与传统 PSTN (公共交换电话网络） /ISDN (综合 业务数字网络） 的互通， 包括 NGN中的 IMS智能终端与 PSTN/ISDN网络 中的终端互通， 并且 PSTN/ISDN网络中的终端能使用 NGN所提供的业务， NGN终端能使用 PSTN/ISDN网络所提供的业务。 图 2是示出了 NGN与 PSTN/ISDN网络互通的实现架构框图， 其中， 在 NGN网络与 PSTN/ISDN网络之间增加了两个功能实体：媒体网关（ MGW ) 负责将 NGN中的 IP媒体流转换为 PSTN/ISDN网络中的语音流， 以及反向 转换； 媒体网关控制功能（ MGCF )则负责将 NGN中的 SIP业务消息转换为 PSTN/ISDN网络中的 TUP (电话用户部分） /ISUP (综合业务用户部分） 业
务消息， 以及反向转换， 并对 MGW进行控制。 一些主要的 SIP 业务消息与 TUP/ISUP 业务消息存在对应关系， 诸如 SIP中的 INVITE (邀请）消息可对应 TUP/ISUP中的 IAM (初始地址消息）、 SIP中的 BYE (挂机） 消息可对应 TUP/ISUP中的 REL (释放消息）， 另夕卜， SIP中的 200 OK (应答响应） 消息 （根据其所对应的请求消息的不同）可对 应 TUP/ISUP中的 ANM (应答消息） 和 RLC (释放完成消息）。 图 3是示出了 NGN的 IMS终端与 PSTN/ISDN终端建立通话并释放过 程的示意流图， 其中， 为简化起见， 将 NGN用户的 P-CSCF、 S-CSCF与 AS 合为一体， 将 MGCF与 MGW合为一体， 并且未标出 PSTN/ISDN终端， 但 是这不影响对本发明的阐述。 如图 3所示， 包括以下步骤： 步骤 S301 ~ S302, NGN用户 A向 PSTN/ISDN用户 B发出 INVITE邀 请请求； 步骤 S303 , MGCF将上述请求转换为 PSTN/ISDN中的 IAM消息， 发 送给用户 B所在的 PSTN/ISDN交换机； 步骤 S304 ,用户 B 4离机接听后， PSTN/ISDN交换机向 MGCF返回 ANM 消息； 步骤 S305 ~ S306, MGCF将其转换为 SIP中的 200 OK (应答响应）消 息， 发送给用户 A; 以及 步骤 S307 ~ S308, 用户 A向 MGCF发送 ACK (邀请应答确认 ) 消息， 其无需转换为 PSTN/ISDN中的消息。 通过以上消息的交互， 在用户终端 A与！ VIGW之间建立了 IP媒体流， 在 MGW与 PSTN/ISDN交换机之间建立了语音流， 通过 MGW的转换， 用 户 A与用户 B可进行通话。在用户终端 A要挂机的情况下，其向 PSTN/ISDN 交换机发出挂机请求， 然后 PSTN/ISDN 交换机再将挂机应答响应返回给用 户终端 A (步骤 S309 - S314 )。 图 4是示出了典型的 NGN IMS终端与 PSTN/ISDN终端共同参加的会 议业务过程的示意流图。 为简化起见， 图中省略了 P-CSCF、 S-CSCF等网络 设备， 将 MGCF与 MGW合为一体， 未标出 PSTN/ISDN终端， 这不影响对 本发明的阐述。 在图 4中， 会议业务月良务器位于 NGN中， 用于为所有用户
提供会议业务功能， 能够与多个用户同时建立话路， 混音后再发送给各个用 户。 如图 4所示， 包括以下步骤： 步骤 S401 ~ S406， NGN用户 A首先向会议业务服务器发送邀请请求 ( INVITE )， 通过正常的会话建立流程在会议业务服务器处创建一个会议资 源 （会议业务服务会分配一个特定的会议资源号码）； 步骤 S407, 在用户 A与会议业务 ¾务器之间建立通话； 步骤 S408 - S409,若 NGN用户 A想邀请 PSTN/ISDN用户 B加入此会 议， 则可向会议业务服务器发送会议邀请请求， 该会议邀请请求采用 SIP协 议中的 REFER (指示） 消息， 其中提供了 PSTN/ISDN用户 B的号码； 步骤 S410 ~ S411 , 会议业务月艮务器返回接受响应， 采用 202 Accepted 响应； 以及 步骤 S412 - S417, 会议业务服务器根据 REFER请求， 向 PSTN/ISDN 用户 B发送邀请请求（ INVITE ), 经过 MGCF/MGW的转换， 最终在会议业 务月 务器与 PSTN/ISDN用户 B之间建立通话， 使得用户 B加入此次^义。 另夕卜， NGN用户 A也可通过各种渠道将 ^义资源号码告知 PSTN/ISDN 用户 C, 由用户 C 自行拨打这个会议资源号码， 即如图 4所示的以下步骤： 步骤 S418, PSTN/ISDN用户 B与会议业务服务器建立通话； 步骤 S419, PSTN/ISDN交换机向 MGCF发送 IAM请求 （被叫号码为 会议资源号码）； 步骤 S420, MGCF将此请求转换为 INVITE请求， 发送给会议业务服 务器； 以及 步骤 S421 - S423 , 会议业务服务器返回应答消息， 表示接受此呼叫请 求， 在会议业务服务器与 PSTN/ISDN用户 C之间也建立通话话路， 使得用 户 C也加入此次会议。 用户在加入会议后，可通过释放与会议业务服务器之间的通话的方式退 出会议。 一个会议可能有很多的用户参与， 当一个用户加入会议后， 可能会 关心后续又有哪些用户加入或退出了此次会议。
在 NGN 中， NGN用户可通过订阅会议事件的方式来获得这些信息。 图 5是 NGN用户订阅会议事件的示意流图。 如图 5所示， 包括以下步骤： 步骤 S501 , NGN用户 A成功加入会议； 步骤 S502 ~ S503 , 向^义业务服务器发送 SUBSCRIBE (订阅） 消息， 其中消息目的地为会议资源号码， Event (事件） 参数为 conference; 步骤 S504 ~ S505， 会议业务服务器返回成功响应 （200 OK ); 步骤 S506 ~ S508, 当有其它用户加入或退出会议时， ^义业务服务器 向用户 A发送一条 NOTIFY (通知） 消息 , 消息体中含有用户号码、 用户动 作 （加入或退出会议） 等信息； 以及 步骤 S509 ~ S510, 用户 A返回确认响应 （200 OK ), 确认收到此通知 消息。 在 PSTN/ISDN网络中， 当有用户加入或退出会议时 , 会议系统会主动 向 PSTN/ISDN用户发送通知消息（在交换机之间采用 ISUP中的 CPG (呼叫 进展） 消息）， 而无需用户事先订阅。 由上可见， NGN与 PSTN/ISDN网络中 ^^义业务的通知机制是不同的， 当 NGN IMS终端与 PSTN/ISDN终端共同参加一个会议时， 就会存在问题。 例如： 当使用 NGN中的会议服务器时， NGN IMS终端可通过订阅^ i义事件 的机制获得通知信息， 而 PSTN/ISDN 终端不会主动订阅会议事件， 则会议 服务器就不会向 PSTN/ISDN终端发送通知消息， 这样， PSTN/ISDN终端就 无法得到其它用户加入或退出会议的通知。 而当使用 PSTN/ISDN 网络中的 会议系统时， 由于会议系统不具备接受用户订阅的能力， NGN IMS终端无法 采用订阅会议事件的机制， 只能被动地接收会议系统发送的所有通知。 因此，急需一种改进方法来解决网络中的用户无法采用订阅机制订阅会 议事件的问题。 发明内容 为了解决上述问题， 本发明提供了一种会议业务通知方法， 其用于跨网 络为 NGN用户或 PSTN/ISDN用户提供会议事件通知功能。
本发明的会议业务通知方法包括以下步骤：在 PSTN/ISDN用户与 NGN 中的会议业务服务器建立通话后， MGCF代表 PSTN/ISDN用户向会议业务 服务器发送会议事件的订阅请求； 以及 MGCF将来自会议业务服务器的会议 事件通知消息转换成 PSTN/ISDN中的呼叫进展消息， 并发送给 PSTN/ISDN 用户。 另夕卜， 该会议业务通知方法还可以包括以下处理： 会议业务服务器收到 订阅请求之后， 向 MGCF返回成功响应。 而 MGCF转换会议事件通知消息 的同时， 向会议业务 ^务器返回确认消息， 以确认收到^ H义事件通知消息。 在本发明中， MGCF通过以下方法判断 PSTN/ISDN用户是否与会议业 务服务器建立通话： MGCF检测 PSTN/ISDN用户与 NGN中的用户的通话建 立过程， 如果发现 NGN 中的用户在会话建立消息中提供的联系地址中包括 预设属性， 则判断 NGN中的用户为会议业务^务器。 其中，预设属性为 "是焦点"（ isfocus )。订阅请求的源地址为 PSTN/ISDN 用户的号码， 订阅请求的目的地地址为会议资源号码， 以及订阅请求的事件 参数为会议。 另夕卜， 会议事件通知消息中包括用户号码以及用户动作信息， 其中用户 动作信息包括用户加入会议动作信息和用户退出会议动作信息。 因而， 通过本发明的方法， 能够跨网络为 NGN用户或 PSTN/ISDN用 户提供会议事件通知功能。 本发明的其它特征和优点将在随后的说明书中阐述， 并且， 部分地从说 明书中变得显而易见， 或者通过实施本发明而了解。 本发明的目的和其他优 点可通过在所写的说明书、 权利要求书、 以及附图中所特别指出的结构来实 现和获得。 附图说明 此处所说明的附图用来提供对本发明的进一步理解，构成本申请的一部 分， 本发明的示意性实施例及其说明用于解释本发明， 并不构成对本发明的 不当限定。 在附图中： 图 1是示出了下一代网络中的一种典型业务的实现架构框图；
图 2是示出了 NGN与 PSTN/ISDN网络互通的实现架构框图； 图 3是示出了 NGN的 IMS终端与 PSTN/ISDN终端建立通话并释放过 程的示意流图； 图 4是示出了典型的 NGN IMS终端与 PSTN/ISDN终端共同参加的会 议业务过程的示意流图； 图 5是现有技术中 NGN用户订阅会议事件的示意流图； 图 6是根据本发明的会议业务通知方法的流程图； 以及 图 7是根据本发明实施例的 NGN会议业务服务器为 PSTN/ISDN用户 提供会议事件通知功能的过程的示意流图。 具体实施方式 以下结合附图对本发明的优选实施例进行说明， 应当理解， 此处所描述 的优选实施例仅用于说明和解释本发明， 并不用于限定本发明。 对于会议业务服务器在 NGN中的情况， 主要问题是在 PSTN/ISDN现 有机制中， PSTN/ISDN终端是不会主动订阅会议事件的， 也没有相应的消息 可用来做这种订阅操作； 而在 NGN会议业务机制中， 用户不订阅， 会议业 务服务器就不会向用户发送通知消息。 在本发明中， 由 MGCF 代表 PSTN/ISDN终端向 ^义业务服务器发送会议事件订阅请求。 图 6是根据本发明的会议业务通知方法的流程图。 如图 6所示， 该方法 包括以下步骤： 步骤 S602 , 在 PSTN/ISDN用户与 NGN中的会议业务服务器建立通话 后， MGCF代表 PSTN/ISDN用户向会议业务服务器发送会议事件的订阅请 求； 以及 步骤 S604 , MGCF将来自会议业务服务器的会议事件通知消息转换成 PSTN/ISDN中的呼叫进展消息， 并发送给 PSTN/ISDN用户。 另外， 该会议业务通知方法还可以包括以下处理： 会议业务 务器收到 订阅请求之后， 向 MGCF返回成功响应。 而 MGCF转换会议事件通知消息 的同时， 向会议业务 务器返回确认消息， 以确认收到会议事件通知消息。
MGCF通过以下方法判断 PSTN/ISDN用户是否与会议业务服务器建立 通话： MGCF检测 PSTN/ISDN用户与 NGN中的用户的通话建立过程， 如果 发现 NGN 中的用户在^舌建立消息中提供的联系地址中包括预设属性， 则 判断 NGN中的用户为会议业务服务器。 其中， 预设属性为 isfocus (是焦点， 以下用英文标注）。 订阅请求的源 地址为 PSTN/ISDN 用户的号码， 订阅请求的目的地地址为会议资源号码， 以及订阅请求的事件参数为会议。 另外 , ^义事件通知消息中包括用户号码以及用户动作信息， 其中用户 动作信息包括用户加入会议动作信息和用户退出会议动作信息。 图 7是根据本发明实施例的 NGN会议业务服务器为 PSTN/ISDN用户 提供会议事件通知功能的过程的示意流图。 如图 7所示， 包括以下步骤： 步骤 S701 , PSTN/ISDN用户与 NGN中的会议业务服务器建立通话； 步骤 S702, MGCF代表此 PSTN/ISDN用户主动向会议业务服务器发送 会议事件的订阅请求， 此 SUBSCRIBE消息的源地址为 PSTN/ISDN用户的 号码， 目的地为会议资源号码， Event (事件） 参数为 conference; 步骤 S703 , 会议业务服务器返回成功响应 （200 OK ); 步骤 S704 ~ S705 , 当有其它用户加入或退出会议时， 会议业务服务器 向 MGCF发送一条 NOTIFY (通知）消息， 消息体中含有用户号码、 用户动 作 （加入或退出会议） 等信息； 步骤 S706, MGCF将此通知消息转换为 ISUP中的 CPG (呼叫 ϋ^ ) 消息， 发送给 PSTN/ISDN交换机； 以及 步骤 S707, 向会议业务服务器返回确认响应（200 OK ), 确认收到此通 知消息。 通过上述方法， PSTN/ISDN 用户在加入会议后， 即可欠到其它用户加 入或退出会议的通知消息。 在图 7中， MGCF必须判断出 PSTN/ISDN用户是与会议业务服务器建 立了通话， 才能向会议业务^^务器发送会议事件订阅消息。 如果 PSTN/ISDN
用户是与 NGN中的普通 IMS终端建立了通话， MGCF不能代表 PSTN/ISDN 用户向普通 IMS终端发送会议事件订阅消息。 TECHNICAL FIELD The present invention relates to the field of communications, and more particularly to a conference service P method in a Next Generation Network (NGN). BACKGROUND In a Next Generation Network (NGN) with an IP Multimedia Subsystem (IMS) as the core, an Initial Session Protocol (SIP) is adopted as a service control protocol, and various communication services can be performed by a user's intelligent terminal and an operator in the network. The set application server (AS) is completed. 1 is a block diagram showing an implementation architecture of a typical service in a next generation network, where an application server (AS) (there may be multiple, respectively for different services) service-call through the interface with the user's home network The session control function (S-CSCF) is connected, and the SIP service control message (identified by the dotted line) between the user terminal A and the user terminal B flows through the proxy-call session control function (P-CSCF) in the respective visited network and The service-call session control function (S-CSCF) in the home network and the application server (may pass through different application servers according to the type of user service), and the application server can implement rich services through various processing of service control messages. . The user terminal A and the user terminal B exchange and negotiate the media parameters supported by the two parties, and establish an IP media stream connection (identified by a solid line) between the two, and the IP media stream is used for transmitting data such as a voice packet. If the application server is equipped with a media processing function, a media stream connection can also be established between the user terminal and the application server to implement a human-machine conversation service, such as an automatic voice service of 4 lines. Next-generation networks need to consider interworking with traditional PSTN (Public Switched Telephone Network)/ISDN (Integrated Services Digital Network), including IMS intelligent terminals in NGN and terminals in PSTN/ISDN networks, and terminals in PSTN/ISDN networks. The NGN terminal can use the services provided by the PSTN/ISDN network using the services provided by the NGN. 2 is a block diagram showing an implementation architecture of interworking between NGN and PSTN/ISDN networks, wherein two functional entities are added between the NGN network and the PSTN/ISDN network: the Media Gateway (MGW) is responsible for IP media streams in the NGN. Converted to voice stream in PSTN/ISDN network, and reverse conversion; Media Gateway Control Function (MGCF) is responsible for converting SIP service messages in NGN into TUP (Telephone User Part) / ISUP in PSTN/ISDN network (integrated Business user part) Messages, as well as reverse conversion, and control the MGW. Some major SIP service messages are associated with TUP/ISUP service messages. For example, the INVITE message in SIP can correspond to IAM (initial address message) in TUP/ISUP, and BYE (on-hook) message in SIP can correspond to TUP. REL (release message) in /ISUP, in addition, the 200 OK (response response) message in SIP (depending on the request message corresponding to it) can correspond to ANM (answer message) and RLC (in TUP/ISUP) Release the completion message). 3 is a schematic flow diagram showing a process of establishing a call and releasing a IMS terminal of an NGN with a PSTN/ISDN terminal. For the sake of simplicity, the P-CSCF, the S-CSCF of the NGN user are integrated with the AS, and the MGCF is integrated. It is integrated with the MGW and the PSTN/ISDN terminal is not labeled, but this does not affect the description of the present invention. As shown in FIG. 3, the method includes the following steps: Steps S301 to S302, the NGN user A sends an INVITE invitation request to the PSTN/ISDN user B. Step S303, the MGCF converts the request into an IAM message in the PSTN/ISDN, and sends the request to the user B. The PSTN/ISDN switch is located; Step S304, after the user B 4 picks up the call, the PSTN/ISDN switch returns an ANM message to the MGCF; Steps S305 ~ S306, the MGCF converts it into a 200 OK (Response Response) message in the SIP, and sends To user A; and steps S307 ~ S308, user A sends an ACK (Invite Response Acknowledgement) message to the MGCF, which does not need to be converted to a message in the PSTN/ISDN. Through the interaction of the above messages, in the user terminal A and! An IP media stream is established between the VIGWs, and a voice stream is established between the MGW and the PSTN/ISDN switch. Through the MGW conversion, the user A and the user B can make a call. In the case where the user terminal A wants to hang up, it issues an on-hook request to the PSTN/ISDN switch, and then the PSTN/ISDN switch returns the on-hook response to the user terminal A (steps S309-S314). 4 is a schematic flow diagram showing a conference service procedure in which a typical NGN IMS terminal and a PSTN/ISDN terminal participate together. For the sake of simplicity, the network devices such as P-CSCF and S-CSCF are omitted in the figure, and the MGCF and the MGW are integrated, and the PSTN/ISDN terminal is not marked, which does not affect the description of the present invention. In Figure 4, the conference service server is located in the NGN and is used for all users. Provides conference service functions, and can establish a voice path with multiple users at the same time, and then mix and send to each user. As shown in FIG. 4, the method includes the following steps: Steps S401 to S406, the NGN user A first sends an invitation request (INVITE) to the conference service server, and creates a conference resource at the conference service server through a normal session establishment process. Assigning a specific conference resource number); Step S407, establishing a call between the user A and the conference service server; Steps S408 - S409, if the NGN user A wants to invite the PSTN/ISDN user B to join the conference, the conference can be The service server sends a conference invitation request, and the conference invitation request uses a REFER (indication) message in the SIP protocol, where the number of the PSTN/ISDN user B is provided; Steps S410 to S411, the conference service server returns an acceptance response, and adopts 202. Accepted response; and steps S412-S417, the conference service server sends an invite request (INVITE) to the PSTN/ISDN user B according to the REFER request, and is converted by the MGCF/MGW, and finally in the conference service server and the PSTN/ISDN user B. Establish a call between each other, so that user B joins the current meaning. In addition, the NGN user A can also inform the PSTN/ISDN user C through various channels, and the user C dials the conference resource number by itself, that is, the following steps as shown in FIG. 4: Step S418, PSTN/ The ISDN user B establishes a call with the conference service server; Step S419, the PSTN/ISDN switch sends an IAM request to the MGCF (the called number is the conference resource number); Step S420, the MGCF converts the request into an INVITE request, and sends the request to the conference service server; And in steps S421 - S423, the conference service server returns a response message, indicating that the call request is accepted, and a call channel is also established between the conference service server and the PSTN/ISDN user C, so that the user C also joins the conference. After the user joins the conference, the user can exit the conference by releasing the call with the conference service server. A conference may have a lot of users involved. When a user joins a conference, they may be concerned about which users have joined or logged out of the conference. In NGN, NGN users can get this information by subscribing to conference events. FIG. 5 is a schematic flow diagram of an NGN user subscription conference event. As shown in FIG. 5, the following steps are included: Step S501: NGN user A successfully joins the conference; Steps S502 ~ S503, sending a SUBSCRIBE message to the service server, where the message destination is the conference resource number, Event The parameter is conference; steps S504 ~ S505, the conference service server returns a success response (200 OK); steps S506 ~ S508, when other users join or leave the conference, the service server sends a NOTIFY message to user A, The message body contains information such as a user number, a user action (joining or exiting the conference), and steps S509 to S510, and the user A returns an acknowledgment response (200 OK) to confirm receipt of the notification message. In a PSTN/ISDN network, when a user joins or leaves a conference, the conference system will actively send a notification message to the PSTN/ISDN user (using the CPG (Call Progress) message in the ISUP between the switches) without the user having to subscribe in advance. . It can be seen from the above that the notification mechanism of the NGN and the PSTN/ISDN network is different. When the NGN IMS terminal and the PSTN/ISDN terminal participate in a conference together, there is a problem. For example: When using the conference server in the NGN, the NGN IMS terminal can obtain the notification information by subscribing to the mechanism of the event, and the PSTN/ISDN terminal does not actively subscribe to the conference event, then the conference server will not send to the PSTN/ISDN terminal. The notification message is sent, so that the PSTN/ISDN terminal cannot obtain notification that other users join or leave the conference. When the conference system in the PSTN/ISDN network is used, because the conference system does not have the ability to accept user subscriptions, the NGN IMS terminal cannot adopt the mechanism for subscribing to conference events, and can only passively receive all notifications sent by the conference system. Therefore, there is an urgent need for an improved method to solve the problem that users in the network cannot subscribe to conference events using the subscription mechanism. SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a conference service notification method for providing a conference event notification function for an NGN user or a PSTN/ISDN user across a network. The conference service notification method of the present invention includes the following steps: after the PSTN/ISDN user establishes a call with the conference service server in the NGN, the MGCF sends a subscription request for the conference event to the conference service server on behalf of the PSTN/ISDN user; and the MGCF will come from the conference service. The server's conference event notification message is translated into a call progress message in the PSTN/ISDN and sent to the PSTN/ISDN user. In addition, the conference service notification method may further include the following processing: After receiving the subscription request, the conference service server returns a success response to the MGCF. While the MGCF converts the conference event notification message, it returns a confirmation message to the conference server to confirm receipt of the event notification message. In the present invention, the MGCF determines whether the PSTN/ISDN user establishes a call with the conference service server by the following method: The MGCF detects a call setup process between the PSTN/ISDN user and the user in the NGN, and if the user in the NGN is found to be provided in the session establishment message The contact address includes a preset attribute, and the user in the NGN is determined to be a conference service. Among them, the default attribute is "isfocus". The source address of the subscription request is the number of the PSTN/ISDN user, the destination address of the subscription request is the conference resource number, and the event parameter of the subscription request is the conference. In addition, the conference event notification message includes a user number and user action information, where the user action information includes the user joining the conference action information and the user exiting the conference action information. Thus, with the method of the present invention, a conference event notification function can be provided for an NGN user or a PSTN/ISDN user across a network. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a block diagram showing an implementation architecture of a typical service in a next generation network; 2 is a block diagram showing an implementation architecture of interworking between NGN and PSTN/ISDN networks; FIG. 3 is a schematic flow diagram showing a process of establishing a call and release between an IMS terminal of an NGN and a PSTN/ISDN terminal; FIG. 5 is a schematic flow diagram of a conference service event in which an NGN user subscribes to a conference in the prior art; FIG. 6 is a flow diagram of a conference service notification method according to the present invention; FIG. 7 is a schematic flow diagram of a process in which an NGN conference service server provides a conference event notification function for a PSTN/ISDN user according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention are described with reference to the accompanying drawings. For the case where the conference service server is in the NGN, the main problem is that in the existing PSTN/ISDN mechanism, the PSTN/ISDN terminal does not actively subscribe to the conference event, and there is no corresponding message available for the subscription operation; In the NGN conference service mechanism, the user does not subscribe, and the conference service server does not send a notification message to the user. In the present invention, the MGCF sends a conference event subscription request to the service server on behalf of the PSTN/ISDN terminal. Figure 6 is a flow chart of a conference service notification method in accordance with the present invention. As shown in FIG. 6, the method includes the following steps: Step S602: After a PSTN/ISDN user establishes a call with a conference service server in the NGN, the MGCF sends a subscription request for the conference event to the conference service server on behalf of the PSTN/ISDN user; S604. The MGCF converts the conference event notification message from the conference service server into a call progress message in the PSTN/ISDN, and sends the call progress message to the PSTN/ISDN user. In addition, the conference service notification method may further include the following processing: After receiving the subscription request, the conference server returns a success response to the MGCF. While the MGCF converts the conference event notification message, it returns an acknowledgement message to the conference server to confirm receipt of the conference event notification message. The MGCF determines whether the PSTN/ISDN user establishes a call with the conference service server by the following method: The MGCF detects the call establishment process of the PSTN/ISDN user and the user in the NGN, and if the user in the NGN is found to be in the contact address provided in the message establishment message Including the preset attribute, the user in the NGN is determined to be the conference service server. Among them, the default attribute is isfocus (is the focus, the following is marked in English). The source address of the subscription request is the number of the PSTN/ISDN user, the destination address of the subscription request is the conference resource number, and the event parameter of the subscription request is the conference. In addition, the event notification message includes a user number and user action information, where the user action information includes the user joining the conference action information and the user exiting the conference action information. 7 is a schematic flow diagram of a process in which an NGN conference service server provides a conference event notification function to a PSTN/ISDN user according to an embodiment of the present invention. As shown in FIG. 7, the method includes the following steps: Step S701: The PSTN/ISDN user establishes a call with the conference service server in the NGN. Step S702: The MGCF actively sends a subscription request for the conference event to the conference service server on behalf of the PSTN/ISDN user. The source address of the SUBSCRIBE message is the number of the PSTN/ISDN user, the destination is the conference resource number, and the Event parameter is conference; in step S703, the conference service server returns a success response (200 OK); steps S704 ~ S705, when there are other When the user joins or leaves the conference, the conference service server sends a NOTIFY message to the MGCF, where the message body contains information such as the user number, user action (joining or leaving the conference), and the like; Step S706, the MGCF converts the notification message into the ISUP. The CPG (Call ϋ^) message is sent to the PSTN/ISDN switch; and in step S707, an acknowledgment response (200 OK) is returned to the conference service server, and the notification message is acknowledged. Through the above method, after the PSTN/ISDN user joins the conference, the notification message of other users joining or leaving the conference can be owed. In FIG. 7, the MGCF must determine that the PSTN/ISDN user has established a call with the conference service server before sending the conference event subscription message to the conference service server. If PSTN/ISDN The user establishes a call with a normal IMS terminal in the NGN, and the MGCF cannot send a conference event subscription message to the normal IMS terminal on behalf of the PSTN/ISDN user.
MGCF可采用以下方法判断 PSTN/ISDN用户是否与会议业务服务器建 立了通话， 在用户与会议业务服务器建立通话的过程中， 会议业务服务器在 向用户发送的消息中 （如图 4所示的步骤 S412或者步骤 S420 ) 会提供自己 的联系地址（ Contact参数）， 此参数会包含一个 isfocus属性， 表明自己具有 同时与多个用户进行通话的能力。 在普通的两个用户建立会话时， 他们相互 提供的联系地址参数中是不包含此属性值的。 因此， MGCF可利用上述特点， 监测 PSTN/ISDN用户与 NGN用户的 通话建立过程的消息， 判断与 PSTN/ISDN 用户建立通话的另一方是会议业 务服务器 （ Contact参数包含 isfocus属性）， 还是普通 IMS终端 （ Contact参 数不包含 isfocus属性）。 综上所述， 采用本发明方案， 可在 NGN用户与 PSTN/ISDN用户参加 同一会议时，正确地为 NGN用户与 PSTN/ISDN用户提供会议事件通知功能， 而不改变用户的原有使用习惯。 以上仅为本发明的优选实施例而已， 并不用于限制本发明， 对于本领域 的技术人员来说， 本发明可以有各种更改和变化。 凡在本发明的精神和原则 之内， 所作的任何修改、 等同替换、 改进等， 均应包含在本发明的保护范围 之内。
The MGCF can determine whether the PSTN/ISDN user has established a call with the conference service server. In the process of establishing a call between the user and the conference service server, the conference service server sends a message to the user (step S412 shown in FIG. 4). Or step S420) will provide its own contact address (Contact parameter), this parameter will contain an isfocus attribute, indicating that it has the ability to talk to multiple users at the same time. When two ordinary users establish a session, they do not include the value of this attribute in the contact address parameters provided by each other. Therefore, the MGCF can use the above features to monitor the message establishment process of the PSTN/ISDN user and the NGN user, and determine whether the other party that establishes the call with the PSTN/ISDN user is the conference service server (the Contact parameter includes the isfocus attribute) or the common IMS terminal. (The Contact parameter does not contain the isfocus attribute). In summary, the solution of the present invention can correctly provide the NGN user and the PSTN/ISDN user with the conference event notification function when the NGN user and the PSTN/ISDN user participate in the same conference, without changing the original usage habit of the user. The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.