DETECTION OF TIMING LOOP AND CLOCK SELECTION IN A SYNCHRONOUS ETHERNET NETWORK BASED ON HOP COUNT

摘要

A Synchronous Ethernet Network consists of network element (NE) which recover clock from the underlying Ethernet PHY and the quality of clock is conveyed using Ethernet Synchronous Messaging Channel with QL information embedded in QL-TLV. This enables clock selection for the downstream node. This paper describes a method to detect Timing Loop in synchronous network by modifying the current clock selection algorithm by adding another TLV to ESMC. A new parameter 'hop count' define this new TLV which is incremented by '1' on each hop as the ESMC messages propagate on a synchronous ethernet network. This paper also shows the modified clock selection algorithm which each NEs uses to select the best available clock from a set of clocks. Also this paper captures the MTIE/TDEV graph for the frequency error/noise respectively with the proposed solution.