此外还需要sipp的一个实例，这是一种开源工具，用于模拟sip用户代理。

It also requires a single instance of sipp, which is an open source tool used to simulate an sip user agent.

youdao

此外还需要sipp的一个实例，这是一种开源工具，用于模拟sip用户代理。

It also requires a single instance of sipp, which is an open source tool used to simulate an sip user agent.

youdao