Physical Topology Discovery in Network with Redundant Links

Precise information of MAC layer topology is important for both network management and network analysis. There are many topology discovery algorithms based on the address forwarding tables but they supposed that the network to discovery hasn't redundant links or these algorithms are not effective to discover redundant links. In this paper, we present algorithms based on address forwarding tables (AFT) for discovering physical topology under the situation that the network has redundant links or loop-links. First we give a method to process the address forwarding tables using the bridge ID which is used by each device to advertise itself in STP. Then remove or mark the blocked ports. Finally produce the relationship of ports which can be found in [1]. The experimental results clearly validate our approach, demonstrating that our algorithm can create logical loop-free topology of transparently switched network.