Patent ID: 8244838
Filing Date: 2012-08-14
Classification: G05B,H04L

Abstract:
1. A ring network comprising: a plurality of switching nodes providing layer 2 functionality to forward data frames between ports based on dynamically learnt MAC address routing tables, each switching node having at least a first and second port connectable to network media, the switching nodes arranged in a ring wherein the first and second ports of each switching node connect to different switching nodes of the ring and wherein at least one of the switching nodes is an active ring supervisor, at least one of the switching nodes further including first and second frame processing circuitry, wherein the first frame processing circuitry is faster than the second frame processing circuitry, wherein the active ring supervisor is adapted to operate to: (a) transmit beacon frames out of each port at a first rate and monitor the other port for reception of beacon frames, wherein the beacon frames indicate a state of operation of the ring network as a closed mode or an open mode, the beacon frames further including identifying data directing them to be processed by the first frame processing circuitry; (b) transmit announce frames out of one port at a second rate slower than the first rate wherein the announce frames indicate the state of operation of the ring network as closed mode or open mode, the announce frames not having identifying data directing them to be processed by the first frame processing circuitry, the announce frames processed by the second frame processing circuitry; (c) respond to a receipt of beacon frames between the first and second ports by blocking data frames between the first and second ports in an open mode; (d) respond to failure of the beacon frames to traverse the ring by changing to a closed mode passing data frames between the first and second ports; and wherein switching nodes that are not the active ring supervisor are adapted to operate to: (a) pass beacon frames between the first and second ports; (b) pass announce frames between the first and second ports; and (c) respond to a change in the state of operation of the ring network deduced from either (i) non-receipt of beacon frames on either port or; (ii) receipt of beacon frames or announce frames indicating a change in operating between closed mode or open mode to reset their MAC address routing tables.