Research And Realization Of Network Topology Discovery

With the development of the technology of computer networks and the worldwide popularity of Internet, the scale of computer network is getting larger and larger the structure of network is becoming more complex. Therefore the demand of network topology discovery becomes more and more urgent. The network topology discovery is an important functional component in the network management. Correct network topology information can directly and effectively provide the whole network structure and its states to the network administrator. It is a common issue for many network institutes to discover and obtain network topology information quickly and accurately. The purpose of this thesis is to study the technique of topology discovery, then improve on the question of the old algorithms and implement an accurate and effective topology information discovery system on this condition.Firstly,this paper introduces the related knowledge,concepts and commonly-used technology about network topology discovery and makes an analysis and general comparison among them from the subject of load, speed, accuracy and applied scope. The algorithm of network topology discovery based on SNMP is the most fast and widely used algorithm. Secondly, the author analyzes the algorithm of topology discovery based on SNMP in detail, and points out the advantages and disadvantages about it. The author puts forward of an improved algorithm of topology discovery .It resolved the problems of repeat determinant of a more IP address router ,and improved the integrality of finding the devices in a subnet .Lastly,it proves the availability of the improved algorithms though test.Furthermore, the paper describes the realization of topology discovery system. New algorithm has been used into this topology discovery system and it has been implemented and tested in the real networks. It is shown that the new algorithm is efficient and accurate. It introduces the way of the topological map displaying in the paper at the same time.The thesis uses the WinSNMP API to achieve topology discovering system on the development platform of Visual C++ and minutely analyses Router-level and Subnet-level topology discovery technology based on SNMP. The thesis also analyses the technology of topology analysis and topology graph minutely.There are many points need to be improved in this research. The last chapter summarizes the whole work, and ponits out the later work.