Research And Development Of The Algorithm Of Ethernet Networks's Topology Discovery And Display

At present most campus networks have larger scales and more complex structures, but the efficient network management system is still wanting. Some are even on very low level. Based on the research of campus network equipment monitoring system in network administration center of our university, this thesis has researched and implemented the algorithm of networks topology discovery and display—the foundation of networks monitoring system.The main researched contents and results as follows:(1) With the study of three typical algorithms of topology discovery and display, many experiments show that there are deficiencies of identifying network equipment's type and multi-homings in the algorithm of network layer's topology discovery based on snmp protocol. This paper gives new judgment rules, and optimizes the algorithms.(2) At present, majority subnets are built using switches most of which supports stp protocol, and minority using hubs. So this paper presents a kind of algorithm of data link layer topology discovery. The main structure of subnet and redundant links configured in subnets are discovered after analysis of switches spanning tree status table firstly. Then analyses the address resolution table with which ports switches are linked other equipments, and finds out the shared segments. This method relies little on the integrity of the address resolution table, and improves the algorithm's precision. The test proves that the algorithms is improved on the running efficiency greatly.(3) A hierarchical topology display algorithm is researched and implemented. Some problems of overlapping, interlacing and unreasonable layout among elements in topology map are solved. Some network management functions are appended to the map. It makes management more visualible.(4) Three-layer architectures based on web services, the topology discovery and display module of the network management system are implemented with java language, using snmp, stp protocol and software's design pattern and so on, on the foundation of the network layer and data-link layer's topology discovery algorithms above-mentioned.This system is debugged successfully in network laboratory. It shows that the developed system has certain practicability.