Ethernet topology change notification and nearest neighbor determination

Abstract

It is desirable to be able to automatically map the topology of a computer network. To automatically map the topology of a computer network, a new method is proposed. First, all the network management modules (NMMs) in the network start off broadcasting multicast packets informing other units of their presence. When a network management module detects that only a single unit is connected to a particular slot-port combination, then that network management module designates the single unit as being a downstream unit in a network topology table. After updating its network topology table, the network management module sends a quench packet to the single unit to silence the downstream unit. These steps are repeated for all occurrences of a single unit connected to a particular slot-port combination in that network. After this occurs, the very bottom layer of the network has been detected and it's topology has been mapped. Since this bottom layer has been silenced by the quench packets, the bottom layer units will no longer be sending out the multicast packets. Thus, the next lowest layer can be detected by performing the same set of steps again. Specifically, any slot-pair combination that only has a single unit coupled to it is then marked as being a downstream and a quench message is sent to silence that unit. These steps are performed recursively until the entire network topology is detected.