通过IP网络中的消息方式直接拨打SIP RUI

IMS（IP多媒体子系统）用户不再使用传统的E．164格式的电话号码，而是使用SIPURI。可是因为受到电话终端设备本身的限制，一些电话用户无法直接拨打由字符组成的SIPURI。因此，在现有的解决方案中，用户还是需要继续使用E．164格式的电话号码，然后由网络将其号码翻译成SIPURI，再在网络中进行路由。本文介绍了一种新的解决方案，可以让用户直接拨打SIPURI，而不需要从E．164号码再进行转换。主叫用户可以通过email、即时消息或者手机短消息的方式输入被叫方的SIPURI地址，然后将其发送到IMS网络中。IMS网络中的应用服务器收到这个消息后，将被叫方的SIPURI地址取出。然后应用服务器可以先回叫主叫用户，待主叫用户接听电话后，应用服务器即可通过被叫方的SIPURI连接到被叫方．实现主叫方到被叫方的通话过程。

SIP URI dialing through IP Messaging

IMS （IP Multimedia Subsystem） users are using SIP URI （Uniform Resource Identifier） instead of E.164 format telephone numbers. Unfortunately, some of SIP/legacy end device users cannot dial URI directly due to the restriction of phone keypads. Therefore, in existing solutions, dialing the E.164 number is still needed and the number will be translated into the real URI when routing the call to the destination. This paper presents a new solution in which callers with SIP/legacy devices can dial URI directly through a text message without the E.164/URI translation. The caller edits the destination URI through an email, instant message or short message and sends it to the network. The IMS AS （Application Server） extracts the destination URI and the caller＇s address from the message, and creates a call instance. The AS rings back to the caller first. When the caller answers, the AS then connects to the URI destination directly.