Patent ID: 7664052
Filing Date: 2010-02-16
Classification: H04L

Abstract:
1. A ring network, comprising: a plurality of nodes that transfer a packet referring to a database for packet transfer, wherein the plurality of nodes are connected in a ring; at least one of the nodes is a master node that transmits a probe packet for checking a condition of the network where the plurality of nodes are connected in the ring and the other nodes are slave nodes that process according to an instruction from the master node; the master node transmits one or a predetermined number of probe packets of which each hop count is initialized in both directions of the ring via a first port and a second port every predetermined time or irregularly; each of the slave nodes increments a hop count included in the probe packet when each of the slave nodes receives the probe packet via one of two ports connected to the ring; each of the slave nodes transmits the probe packet including the incremented hop count to the adjacent slave node or the master node via the other port different from the port via which the probe packet is received; each of the slave nodes generates a hop count report packet including the incremented hop count and transmits it to the master node via the port via which the probe packet is received; the master node receives a plurality of hop count report packets from each of the slave nodes via the first port and the second port and manages a maximum value of hop counts included in the hop count report packets for every port; the master node calculates the sum of a maximum value of hop counts corresponding to the first port and a maximum value of hop counts corresponding to the second port and acquires the total number of slave nodes communicable with the master node based upon the calculated sum; the master node detects the occurrence of multiple faults on the ring and the recovery of at least one of the multiple faults based upon the variation of the acquired total number of communicable slave nodes; and the master node updates a database in itself every time the master node detects these events and/or transmits a packet for updating the database for packet transfer to the slave node.