实现这个算法需要如下的信息，首先算法要有己形成的多播路由树T 到所有目的节点的最短路信息，为此算法采用一个树组TD 记录已形成的多播路由树到每一个目的节点的最短路消息-The realization of this algorithm needs the following information, first of all algorithms have been formed by multicast routing tree T for all purposes to the most s