分组多播通信的低层实现

针对Linux操作系统提供的低层应用程序开发接口－packet套接字，探讨基于数据链路层的分组多播通信（multicast）方式的实现技术，分析了packet套接字的类型和特征，阐述利用该开发接口实现分组从播通信的具体方法与步骤，给出了相应的系统调用和程序段分析，实验表明，利用packet套接字可以有效地在数据的链路层实现分组多播，这一结论对实施网络监控以及一些特殊应用领域有着大参考价值。

Realization of Multicast Based on Low Level

The realization techniques of multicast based on data link level (DLL) are discussed, considering the application program interface (API)--packet socket, a low level communication interface provided by Linux system. The features and types of packet socket are analyzed. The programming methods and steps of multicast by using packet socket are expatiated and the related system calls and analyses of the program are presented. It is proved to be effective for multicast on DLL. This conclusion is valuable for network monitors and some special application areas.