Patent ID: 7139264

Claim:
A communications system, comprising: a) a plurality of interconnected network elements (NE), in which each NE is associated with a unique NE identifier (NEID) value and comprises one or more input ports, and one or more output ports; b) each input port being provided for inputting from an adjacent one of the plurality of NEs, a synchronization signal and a quality level indication (QLI) for indicating a quality of a source of the synchronization signal, and being associated with a source identifier (SID) value that identifies the input port at which each synchronization signal is input from the said adjacent NE, the SID value of each input port comprising the NEID value of the adjacent NE; c) each output port of each NE being provided for outputting to an adjacent NE, a selected one of the input synchronization signals and the QLI, and comprising a QLI setting means for setting a value of a QLI output at that output port, based on a comparison of the SID value at that output port with the SID value at the input port of the selected one of the input synchronization signals; and d) a central management means comprising means for setting the SID value of each port of each NE to the appropriate NEID value.