US Patent 9654242 Node and method for selecting synchronization source

The disclosure relates to a node capable of selecting a first port to receive a first synchronization source in a system comprising a plurality of nodes. The node comprises a memory configured to memorize states of each port of the node in a corresponding tree. At least one tree is formed with ports of the plurality of connected nodes according to a second synchronization protocol. The node further comprises a first synchronization source selection unit configured to select the first port according to states of the ports of the node. The first synchronization source so selected will not form a loop in the network. There is also provided a method used in the node.