Ethernet Link Layer Topology Discovery Using Probe Frame

This dissertation is mainly about topology discovery in Ethernet link layer. At present, most of the topology discovery methods are using SNMP protocol to query topology information from the Switch. But, there are some problems with those methods. For example, many low-cost switches don't support SNMP protocol. The topology discovery method described in this dissertation is as follow:Firstly, probe frame is sent to the network by some host. Secondly, the flows of those probe frames are observed. Thirdly, the Ethernet link layer topology can be inferred from those observations. The design and analysis of the topology discovery algorithm are given with proving of completeness and correctness. At last, the design and implementation of simulation software are given and the experiment using the simulation software. The main contents of this dissertation are as follows:Firstly, the general description of Network Management System's function and architecture is given. Secondly, we design and analyze the Ethernet link layer topology discovery algorithm using probe frames. We summarize the forwarding behaviors of Switch, Hub and Host in the Ethernet link layer. Based on the behavior summary, we design the segment tree construction algorithm. From the segment tree and special test, the segment-shared switch and border switch can be discovered. And then, by testing and analyzing the border switch, we deduce the gap analyzing method. At last, the algorithm's completeness and correctness are given.Design and implement the topology simulation software are also given. At first, we study the forwarding mechanisms of the network element such as:Switch, Hub. Using the Object-Oriented technique, we abstract and encapsulate the Switch, Hub and Host. Switch Object, Hub Object and Host Object are used to simulate the real network element. Those objects and the connection relationship between them in the memory establish the image of the Ethernet link layer network and simulate the real network. The topology discovery algorithm coding in Java language runs in the network simulator. We also describe the topology display algorithm that displays the topology discovery result in visualization.