Patent ID: 8463945

Claim:
A method for synchronizing local clocks in a distributed computer network, where said computer network consists of a number of end systems and at least two switches, where each end system is connected to at least two switches via bi-directional communication links, and where a configured subset of end systems and switches executes the method in form of a synchronization state machine, characterized in that a) the state machine uses at least three different frame types: coldstart frame type, coldstart acknowledge frame type, and integration frame type; b) the states in the state machine are either said to belong to an unsynchronized set of states or belong to a synchronized set of states; c) all end systems that are configured as Synchronization Master periodically send coldstart frames in one of the unsynchronized states; d) all end systems that are configured as Synchronization Master react to the reception of a coldstart frame by sending a coldstart acknowledgment frame a configurable first timeout after the reception of the coldstart frame on all replicated communication channels, provided that the end system is in a state in which the synchronization state machine defines a transition for coldstart frames, and where said first timeout is reset when a consecutive coldstart frame is received before the coldstart acknowledge is sent; and e) all end systems that are configured as Synchronization Master react to the reception of a coldstart acknowledgment frame by starting a configurable second timeout, provided that they are not already executing said first timeout, and entering a synchronized state when said second timeout expires.