Research On Techniques Of Automatic Network Topology Discovery

Automatic network topology discovery technology is one of the most important parts in the study of network attack and defense. It is the prelude of in-breaking remote network, and the key to set down the attacking strategy. Nowadays, the states of the network development are increasing enhancive attention to network security, increasing complex of topologic link and inclining to isomery in compositing, which cause those old topology discovery algorithms no longer apply to. In this paper, according to task's requirement and aiming to the real network, we divide the network topology into two layers for studying. The main work done by this paper is:1. We propose an improved algorithm based on ICMP. It can be applied to nonsupport-SNMP or unknown-SNMP-community-string network for logical topology discovery.2. We propose an algorithm based on Spanning Tree Protocol. It can be applied to complex subnet contains numb switch and redundant link for physical topology discovery.3. We design logical and physical data file to store topology discovery info, which makes it not only directly and secretly to transplant topology discovery program, but also be convenient to handle the data.4. We use two-thread-asynchronous ping and penetrate-firewall tracert to increase discover speed and depth.5. We adopt a "divide whole into segments" way to solve the problems come from one big-range topology discovery. The problems it brings are long-time discovery and large communication flows, which will cause the network to alarm.The results of the two topology discovery algorithms in real network are both in accord with actual case; the use of data file makes accessing topo-info fast and merging multiple topology discovery results reliable, which proves the algorithms.