The GNSS receiver port on the 7705 SAR-Ax, 7705 SAR-Wx, or 7705 SAR-H GPS Receiver module, and the GNSS Receiver card installed in a 7705 SAR-8 Shelf V2 or 7705 SAR-18, can provide a synchronization clock to the SSU in the router with the corresponding QL for SSM. This frequency can then be distributed to the rest of the router from the SSU as configured with the ref-order and ql-selection commands; refer to the 7705 SAR Basic System Configuration Guide for information. The GNSS reference is qualified only if the GNSS receiver port is operational, has sufficient satellites locked, and has a frequency successfully recovered. A PTP master/boundary clock can also use this frequency reference with PTP peers.
In the event of GNSS signal loss or jamming resulting in the unavailability of timing information, the GNSS receiver automatically prevents output of clock or synchronization data to the system, and the system can revert to alternate timing sources.
A 7705 SAR using GNSS or IEEE 1588v2 PTP for time of day/phase recovery can perform high-accuracy OAM timestamping and measurements. Refer to the 7705 SAR Basic System Configuration Guide for information about node timing sources.