Patent ID: 8238228

Claim:
In a network, a method of enabling a disabled port on a device that relays Medium Access Control (MAC) frames, when the port is disabled due to operation of a link failure propagation protocol, the method comprising the steps of: setting a Link Failure notification mechanism in the device utilizing Internal Sub-layer Service (ISS) status parameters; detecting a link or port failure on a first port of the device; disabling the first port by the device; notifying a second port of the device of the link or port failure; periodically transmitting Link Failure Packet Data Units (LFPDUs) through the second port of the device to a downstream peer entity; determining by the device, whether Acknowledgement PDUs (ACK PDUs) are received from the downstream peer entity in response to the periodically transmitted LFPDUs; when ACK PDUs are not received from the downstream peer entity, initiating the ISS Link Failure notification mechanism to manipulate ISS parameters to signal link failure on the next network segment; monitoring the failed link or port by the device to detect whether the link or port failure is repaired; responsive to detecting that the link or port failure is repaired: stopping the periodic transmitting of LFPDUs by the device; transmitting a Link Failure Terminating Protocol Data Unit (LFTPDU) from the device to the downstream peer entity to signal that the link or port failure is repaired; and re-enabling the first port.