The Research Of Network Topology Discovery Algorithm Based On SNMP

With the development of the computer networks and the worldwide popularity of Internet, computer network has been applied to government, business, military, education and other areas. The structure of network is becoming more and more complex. Management of network by a suitable way, performance improvement and the quality of services, ensurence the information with more security and reliable transmission are necessary and significant. As the foundation of network management, the network topology discovery (NTD) algorithm is studied and enhancement. And an improved NTD algorithm based on SNMP is proposed.With Simple Network Management Protocol (SNMP) and other tools, NTD algorithm could find the network elements including routers, switchers and their relationship. These elements can be showed explicitly. Because of complexity and instability of network elements, how to obtain network topology information quickly and accurately becomes the focus of computer network related department.For using SNMP in NTD has a highest speed, the article elaborates the concepts and principle of SNMP and introduces the function of every parts in SNMP structure, its formats and how to use the SNMP in algorithm. Then the author analyzes the algorithm of NTD in network layer and data link layer.It's found that the routers with more IP address are attained repeatedly in network layer. The author resolves the problems of repeat determinant for the routers of more IP address by ipAddrEntry after studying the Management Information Base (MIB).For the date link layer, the author provides a method to find connections between switches, which based on Spanning Tree Protocol and incomplete Address Forwarding Table. After modify the existing arithmetic, the new arithmetic can find more switches. And the results close to reality.By coding related software and testing, the result shows the accuracy of topology arithmetic is improved greatly.