The concept of the graph form of a blocking optical cross-connector is introduced so as to investigate the blocking situation . the principle is that the blocking node can be replaced by a graph which is composed of nonblocking nodes and capacity limited edges . three graphs of typical optical cross-connector nodes are demonstrated . several uniform result are derived from these examples 该方法的基本思想是用图来替代交换能力受限制的节点,而此图由交换能力不受限制的节点和容量受限的边组成。文中以典型的阻塞oxc节点为例,给出了它们的图表示,并通过例子得出一般的oxc节点图表示求法的一些普遍结论。