The first subsystem is the control subsystem base on sip. sip is proposed by IETF .it is the core protocol of soft-switch.

• 第二子系统为基于DirectShow技术的多媒体交流子系统。DirectShow采用组件化的开发模式,能够加快多媒体软件开发过程并能够灵活高效地满足各种业务需求。