Patent ID: 8154991

Claim:
A method for detecting and localizing a failure or fault in an Ethernet based carrier or access network managed by a management system and comprising a number of management domains on different levels, each with a number of end point or edge nodes and a number of intermediate nodes, the method comprising the steps of: implementing fault detection by sending localization or connectivity check messages from each edge node to all other edge nodes in the management domain, and in each edge node monitoring detection of such messages from all other edge nodes; at detection, in a first edge node, of a fault on the path between said first edge node and a second edge node: fetching information about the path, containing the intermediate nodes on the path, from holding means in or communicating with the first edge node; identifying a target intermediate node substantially in the middle of the path containing the fault; sending, directly, a loop back message to the identified target intermediate node; identifying a fault path portion as the portion of the path containing the fault based on whether a response is received or not from the identified target intermediate node, wherein: if a response is received, the fault path portion is identified as the distant path portion, connecting to the second edge node, whereas if no response is received, the fault path portion is identified as the path portion connecting to the first edge node; then, until the fault is localized, identifying a respective new target intermediate node and a new fault containing path portion, step by step, until the fault is localized.