IP电话会议系统包括客户端和服务器两部分，通过客户端的邀请，服务器响应后决定是否建立会话。-IP telephone conference system includes both client and server parts of the invitation by the client, the server decide whether to establish a session after the response.

sipp的异常呼叫测试脚本，包含了404/486/500等异常响应返回，以及混合场景下概率触发异常的脚本-sipp abnormal call test scr ipts, including the 404/486/500 and other abnormal response is returned, and mixed scenario probability of triggering abnormal scr ipt