说明：  ns2下dsdv实现代码。DSDV（Destination-Sequenced Distance-Vector）协议是先应式路由协议，是由传统的Bellman-Ford 路由协议改进得到的，其特点是利用目的节点序列号解决了DBF算法的路由环路和无穷计数问题。
(dsdv the realization of the code under ns2. DSDV (Destination-Sequenced Distance-Vector) protocol is proactive routing protocol, is the traditional Bellman-Ford Routing Protocol has been improving, and its destination node is characterized by the use of the serial number of the DBF algorithm to solve the routing loop and count the issue of infinity.)