Patent ID: 8213339

Claim:
An RSTP processing system in a network that has a ring topology wherein multiple IEEE 802.3 compliant nodes are connected via prescribed transmission lines, wherein each of the nodes comprises: two physical layer (PHY) units, each of which is connected to one of the transmission lines and executes processing according to the physical layer of an open system interconnection (OSI) reference model; two media access control (MAC) units, each of which is connected to one of the PHY units and executes processing according to a lower sublayer of the data link layer of the OSI reference model; an RSTP processing unit, which is connected to the MAC units and processes a rapid spanning tree protocol; Bridge protocol data unit (BPDU) send/receive buffers, each of which is provided to one of the MAC units and sends and receives BPDU data in the rapid spanning tree protocol; and two BPDU data buses, which transfer the BPDU data between the BPDU send/receive buffers and the RSTP processing unit; and wherein the RSTP processing unit: receives BPDU data, which is received from the network by one of the PHY units and stored in the BPDU send/receive buffer of the MAC unit that is connected to that PHY unit, via the BPDU data bus that is connected to that MAC unit; decodes the received BPDU data; performs a prescribed process; transfers prescribed BPDU data, via the BPDU data bus that is connected to the other MAC unit, to the other BPDU send/receive buffer; and transmits that BPDU data from the PHY unit connected to the other MAC unit to the network, and wherein the PHY unit has a link signal line that is used to notify the RSTP processing unit of a failure in the physical layer level; and wherein the RSTP processing unit, when it is notified via the link signal line of one of the PHY units of a failure in the physical layer level, transmits to the network via the other PHY unit notification BPDU data from the BPDU send/receive buffer that has the MAC unit connected to the other PHY unit.