Patent ID: 7274656

Claim:
A method for failure protection between interconnected Resilient Packet Rings (RPRs) in a multiple RPR network, including at least two adjacent RFRs, including a first RPR and a second RPR, for sending or receiving inter-ring messages using a path; the first RPR including at least one node to be used as a source node provided for sending messages and a first RPR interface node and a second RPR interface node; the second RPR including at least one node to be used as a destination node provided for receiving messages and a third RPR interface node and a fourth RPR interface node, the method comprising the steps of: detecting a failure in the path between the first RPR and the second RPR; and rerouting messages from the source node in the first RPR to the destination node in the second RPR, upon detection of the failure; wherein the step of detecting the failure between the first RPR and the second RPR, comprising the steps of: providing a regular path for routing inter-ring traffic between the two adjacent RFRs when no failure has occurred in the path; and providing a protection path for routing inter-ring traffic between the two adjacent RPRs, when a failure occurs in the regular path; wherein the step of providing the regular path, comprising the steps of: providing a first interconnection device connecting the first RPR interface node and the fourth RPR interface node, associated with the regular path between the first RPR and the second RPR; and providing a first set of interconnection links, including a first interconnection link and a fourth interconnection link, for connecting the first RPR interface node and the fourth RPR interface node respectively, to the first interconnection device; wherein said step of detecting the failure comprising the step of exchanging Type-2 keep alive messages between any one of the four RPR interface nodes and the interconnection device it is directly connected with; the Type-2 keep alive message being sent at a regular interval of time, with a time period of T 2 ; and wherein the step of detecting the failure, further comprising the step of detecting a segment failure from the absence of the Type-2 keep alive message arrivals for number of successive periods of N 2 at any RPR interface node or interconnection device.