说明：  YDT 1701-2007H.323网络安全技术要求， 规定了H323网络实体间的连接建立，呼叫控制及媒体交换阶段中的所有通信信道安全，包括认证，机密性与完整性三个部分
(YDT 1701-2007H.323 requirements of network security technology, provides H323 Internet connection is established between the entities, call control and media exchange phase in all the communication channel security, including authentication, confidentiality and integrity of the three parts)