METHOD FOR DISCOVERING THE PHYSICAL TOPOLOGY OF A TELECOMMNICATIONS NETWORK

摘要

A network (NWl) has switches (S1-S7), routers (R1-R4) and a management node (NMSl) interconnected by links (PLl) in a spanning tree (STl) and links (PL2) to blocked interfaces. Switches and routers have the IP address of the management node. The nodes are discovered by the management node (NMSl) broadcasting a ping message (PiI) and on reply (RPiI) adds the nodes to the topology. The spanning tree (STl) is discovered in that the management node retrieves address forwarding tables from the switches and assigns them a ranking value. From the highest ranked node successively lower ranked nodes are connected. The blocked interfaces (PL2) are discovered by configuring a VLAN (VLANl) to include only the spanning tree (STl) and disabling the latter. The blocked interfaces are turned off and on, matching link down traps are noted and the corresponding link (PL2) is discovered. The status of the interfaces (1, 2, 3...) are cyclically checked for changes and new links and network segments are added. Only basic management features of the switches are needed and all nodes and links are discovered.