用Visual C++在局域网实现IP多播。一个数字电话会议系统由多个会场组成，当在其中一个会场的参会人发言时，要求其它会场都能即时的得到此发言的内容，这是一个典型的一对多的通信应用，通常把这种一对多的通信称为多播通信。采用多播通信技术，不仅可以实现一个发送者和多个接收者之间进行通信的功能，而且可以有效减轻网络通信的负担，避免资源的无谓浪费。-Using Visual C++ in the Local Area Network for IP multicast. A digital telephone conference system composed by a number of venues, as a venue in which participants speak, ask the other site can instantly get the content of this statement, which is a typical one to many communications applications, usually This to-many multicast communication called. Using multicast technology, not only the realization of a sender and multiple receivers to communicate between the functions, and can effectively reduce the burden of network traffic, to avoid unnecessary waste of resources.