Patent ID: 7580373

Claim:
A ring network comprising: a plurality of nodes each having a memory and a processor, wherein only one of the plurality of nodes serves as a master node at any given time, the master node having responsibility for periodically initiating topology discovery for the ring network by causing a token, which includes one or more discovery markers, to be circulated among the plurality of nodes; and each of the plurality of nodes that is not the master node executing a topology discovery process by the processor comprising: receiving the token originated by the master node; if the one or more discovery markers of the token includes a discovery marker associated with the master node, then (i) clearing all topology information for the plurality of nodes currently stored in the memory of the node and after said clearing (ii) for each of the one or more discovery markers, storing topology information associated with the discovery marker to the memory of the node; if the one or more discovery markers of the token includes a discovery marker associated with the node, then (i) removing the discovery marker and (ii) for each of the one or more discovery markers associated with another node of the plurality of nodes, storing topology information associated with the discovery marker to the memory of the node; if the one or more discovery markers of the token does not include a discovery marker associated with the node, then (i) for each of the one or more discovery markers, storing topology information associated with the discovery marker to the memory of the node, (ii) adding the discovery marker to the token as well as topology information for the node; and passing the token to an adjacent node of the plurality of nodes; whereby the token circulates around the ring network at least twice providing all active nodes of the plurality of nodes participating in the ring network an opportunity to see topology information for all other active nodes of the plurality of nodes participating in the ring network.