To support the multimedia operation and supply the function such as call building and session control, the signal protocol is absolutely necessarily.

为了支持多媒体业务，提供呼叫建立、会话控制、接纳控制等功能的信令协议必不可少。

youdao

To support the multimedia operation and supply the function such as call building and session control, the signal protocol is absolutely necessarily.

为了支持多媒体业务，提供呼叫建立、会话控制、接纳控制等功能的信令协议必不可少。

youdao