Research On And Implementation Of Topology Management In SNMP-based NMS

Management of network topology is of importance in the field of Network Management. A lot of network management functions benefit from accurate and up-to-date knowledge of topologies, such as performance evaluation, event correlation, fault location, resource allocation and etc.This paper mainly deals with the design and implementation of the Topology Management Subsystem (TMS) in a SNMP-based NMS which supports three parts of functions: discovering of OSI layer-3 and layer-2 topologies, visualizing them as topology graphs, and editing the graphs.The paper begins with some backgrounds of topology management in the first chapter and then discusses methods of discovering network topologies, especially of layer-2 in the second chapter. Building topology of Bridged LANs has two steps. The first is to compute bridge-to-bridge connections, for which a practical algorithm is presented in this paper. Different from current algorithms relying on Address Forwarding Information, the method is based on information supported by STP MIB group which is part of standard SNMP Bridge MIB. The second step is to determine connections between bridges and end points based on results of the first step. I develop a formal algorithmic solution for it. Chapter 3 introduces a novel scalable 4-layer topology model, which serves as the infrastructure of the TMS. Then comes the forth chapter, in which I describe the design and implementation of the subsystem. Topology information is acquired through topology discovery and stored as the model organized. The visualizing function generates graphs from the topology information. The editing function supports interfaces to users to do modifications on those topology graphs, such as deleting , adding of devices, links and etc. Chapter 5 draws the conclusion and a view of further works.