Research And Implementation Of Physical Topology Discovery Method In VLAN Based Network

Topology of a network is important to a number of critical network management tasks, including resource management, server deployment, event correlation, and troubleshooting. Given the dynamic nature of today's network, keeping track of topology information manually is a daunting task. Automatic discovery of network topology is proposed to solve this problem. To discover the physical topology in morden VLAN based network automatically, accurately and effectively has great requirements and applicable foreground. Now, the popular framework of the network establishmet in enterprises and other industries is as follows. Router connets the WAN; firewall is the border of LAN and WAN; the core switch has 3 layer switching and it routes between VLANs; the 2 layer switch connets servers and hosts primarily.In this thesis, we studied the algorithms of physical topology discovery and compared them. And we gave a novel physical topology discovery method in VLAN based network, which is more effective and more practical. We also implemented the physical topology discovery system in VLAN based nework. The physical topology discovery algorithm in VLAN based network is based on the SNMP MIB-II (RFC1213), SNMP Bridge MIB-II (RFC 1493) and Q-Bridge-MIB (RFC 2674). It also can discover redundant connections, the VLAN in the network and can deal with the devices, which cannot support SNMP protocol. The new algorithm proposed discovering the physical topology of network through trunking and the new method to deal with the devices, which don't support SNMP. New algorithm can get the correct data in the lab experiment.