这是一份讲得比较好的文档，看过以后至少可以对PPP协议有一个大致的理解 PPP(Point-to-Point Protocol点到点协议)是为在同等单元之间传输数据包这样的简单链路设计的链路层协议。-This is a good document put it, read it at least to the PPP agreement has a broad understanding of PPP (Point-to-Point Protocol PPP) is the same uni