在广域网路由器所用的PPP协以小，透明传输及配置选项协商是一些较为复杂的问题。提出了适合于透明传输的发送及接收算法，描述了LCP和NCP配置选项的协商过程，此外还介绍了路由器局域网口和广域网口之间的基本分组转发方法。 The PPP protocol used in WAN routers is somewhat complicated by the fact that small, transparent transport and configuration options are negotiated. A transmission and reception algorithm suitable for transparent transmission is proposed. The negotiation process of LCP and NCP configuration options is described. In addition, the basic packet forwarding method between the router LAN port and the WAN port is also introduced.