说明：  ns2中，实现的基于传染病模型的蠕虫实现。该实现中有一个抽象节点，代表了20万个节点，然后有一个501个节点的具体网络。在抽象望中，只要能反应传播特征即可，具体网络中的扩散，更直观。
(ns2, the realization of the infectious disease model based on the realization of the worm. The realization of the abstract, there is a node, representing the 200,000 nodes, and then there is a specific 501-node network. Look in the abstract, so long as we can react to the spread of the characteristics of the specific network proliferation, more intuitive.)