The Research And Implementation On Arithmetic About Automatic Topology Discovery On The Datalink Layer

It is very critical for many important network managing tasks to discover the topology on the datalink layer in the IP network, At present, most network management software can only carry through the topology discovery on the network layer, So the network management software developed by the effective arithmetic which can discover the topology on the datalink layer must own a bright future in the market.In this thesis firstly we introduce the necessity about the topology discovery of the datalink layer of the network, and some related knowledge about the network management, such as the general construction , mutual cooperation, and the development tendency, then we introduce the SNMP protocol, and it's managing model, basic conception, MIB and also running process; followed with the function of some familiar network equipments and how to make the familiar tools (eg Ping, Traceroute)to carry through the topology discovery. In succession, we analyse the arithmetics of topology discovery in the field which contains one or more subnets, and prove the three lemmas of the arithmetic, the critical technology , .the kernel idea.and the steps to realize it, then we carry out this arithmetic on the platform of VC, and make improvement on it's application in the concrete network environment., that is in the precondition of ensure the correctness of the data which comes out from the discovery of topology, make the resource and time which the arithmetic caused fall to the least. At last, we compare this arithmetic with other three arithmetics, they are separately based on the MAC addresses on the port, the flux on the port and the router table in the Router. We point out that in the appropriate condition of the actual network, if we combine several different arithmetics to discover the topology of the network, it is very likely to achieve good results.