Holdover with Enhanced Sync-E Support

During this test, a chain of boundary clocks was configured to use Enhanced Synchronous Ethernet (eSyncE).
eSyncE provides physical layer frequency support to PTP-aware devices in full-timing support networks, enhancing performance to enable the stringent synchronization requirements of modern telecommunication networks.
The goal was to maintain acceptable time error values during the loss of the GNSS reference and PTP throughout the chain using eSyncE. 

During this test, the Microchip TimeProvider® 4500 acted as the Telecom Grandmaster (T-GM) and propagated PTP and eSyncE downstream to the eight Telecom Boundary Clocks (T-BCs). Six of these eight T-BCs supported eSyncE input and output; however, two of these, the Ciena 5134 and the Arrcus S9600-72XC, devices only supported eSyncE input but not output. Therefore, these two devices were branched off the main chain, each put at the end of the chain. After all the devices were locked on PTP and eSyncE, the PTP generation at the T-GM was stopped, while eSyncE was kept intact. Following this, T-BC-1 assumed the role of Master, with the downstream T-BCs locking to it on PTP, with the advertised ClockClass for PTP being 135 and the Ethernet Synchronization Message Channel (ESMC) quality for SyncE being ePRTC.
  
Looking at the results, all the devices and the whole network passed with remarkable results. We observed Time Error (TE) between -4 nanoseconds (ns) to -31ns on average, with the TE limit being 130ns for Clock Accuracy Level 6A, according to ITU-T G.8271, section 6, table 1. 

The measured MTIE reached a peak of between 6.359ns and 11.808ns per device, being well below the threshold defined by the ITU-T G.823 E1 SEC wander limit mask.