The Research On The Topology Discovery Of The Network Management System

With the rapid development and wide application of network technology, computer network has come into every field of society and plays a greater role in social economy. Meanwhile as the scale of network has been expanding and its structure becomes more and more complicated, the demand of Network Management System becomes more urgent. The Network Management System is based on the network topology information which is important obviously. The correct and advanced network topology information can provide the holistic network structure and state to network managers effectively. It is a common issue for those network institutes to automatically discover and obtain network topology information with completeness, robustness, accuracy and efficiency. Firstly, this paper introduces the related knowledge about network management, including concept, common model structure, functions and the commonly-used management protocol. It outlines the discovered object, function and signification of network topology. Then it introduces various protocols and basic tools of topology discovery, and makes an analysis and synthetical comparison among them. Secondly, it researches, summarizes, and respectively analyzes the existing algorithms of logic network topology discovery, and points out the advantages, disadvantages and applicable environment of each algorithm. It emphasizes on the widely applied topology discovery algorithm based on SNMP, proposes solutions for the existing problems of traditional algorithm, and designs data structure and procedure in details. Finally, it analyzes three kinds of existing algorithms of physical network topology discovery, and points out the limitation of them, which is that all switches must support SNMP protocol strictly. Aiming at this insufficiency, we propose a new physical Network topology discovery algorithm based on address forwarding table. This algorithm can find the connections between switch and switch, switch and host, even though there exists switch or HUB which does not support SNMP protocol in the sub network. And then it can obtain intact and correct topology connection graph. Compared with the existing topology discovery algorithm, the algorithm which we propose has better applicability and veracity. Afterward we implement the new algorithm with JAVA language, and confirm the validity of it through environment test.