Patent ID: 7512147

Claim:
A communications system transporting data over a redundant ring network formed from first and second ringlets running in opposite directions, the system comprising: (a) a plurality of station devices, each comprising: a bandwidth reservation initiator that sends out a bandwidth reservation message in both ring directions to announce how much bandwidth should be reserved for a network path, the bandwidth reservation message containing a source identifier, a logical network identifier, and a bandwidth reservation value, a topology database that manages hop counts of other station devices on the ring network, the hop counts including first hop counts measured along the first ringlet and second hop counts measured along the second ringlet, a path setup initiator that examines a source identifier and logical network identifier in a bandwidth reservation message received from other station devices, thereby recognizes that the local station device is an egress node of a logical network segment specified in the received bandwidth reservation message, consults the topology database to retrieve the first and second hop counts of the source station device of the received bandwidth reservation message, and, if the retrieved first hop count is smaller than the retrieved second hop count, sends a working path setup message back to the source network device over the first ringlet, as well as transmitting a protection path setup message to the same source device over the second ringlet, and a bandwidth reservation unit that reserves bandwidth on the second ringlet to establish a working path of the specified logical network segment when a working path setup message is received from the first ringlet, and reserves bandwidth on the first ringlet to establish a protection path of the specified network when a protection path setup message is received from the second ringlet; and (b) a plurality of transmission media interconnecting the station devices to form the first and second ringlets.