Patent ID: 8576689

Claim:
A method of handling failures in a tree-structured packet network having a plurality of interconnected edge nodes and switching nodes, wherein at least two different virtual local area networks (VLANs) each connect a predefined set of the nodes, said method comprising the steps of: periodically broadcasting alive messages on the different VLANs, said alive messages being broadcast within a restricted time interval by a first portion of the edge nodes of the VLANs configured as emitter nodes; listening for the alive messages by a second portion of the edge nodes of the VLANs configured as notifiers; determining by a given notifier that at least one of the alive messages failed to arrive within first and second periodically repeated detection time intervals; broadcasting on the VLANs by the given notifier, a failure message for the VLAN associated with the missing alive message within a predefine keep-alive time period after determining that the missing alive message failed to arrive within the second detection time interval; receiving the failure message in the edge nodes; stopping transmission of traffic messages on the associated VLAN in response to the failure message; subsequently receiving by the given notifier, the missing alive message; broadcasting by the given notifier, a repair message on at least the associated VLAN indicating that the associated VLAN is repaired; receiving the repair message in the edge nodes; and restarting transmission of traffic messages on the associated VLAN in response to the repair message.