Assisted Partial Timing Support on Routing Platforms

APTS which is a GNSS backed by PTP delivers accurate timing and synchronization in mobile backhaul networks. GNSS is the primary source of synchronization. In case of the GNSS failure, a PTP path serves as a backup or secondary source of synchronization.

This feature is supported on Junos OS Evolved Release 24.2R2 only.

The assisted partial timing support (APTS), which is a Global Navigation Satellite System (GNSS) backed by Precision Time Protocol (PTP), delivers accurate timing and synchronization in mobile backhaul networks.

GNSS is the primary source of synchronization to the end application. In case of the GNSS failure, a PTP path serves as a backup or secondary source of synchronization.

GNSS is vulnerable to spoofing, jamming attacks and natural phenomenon like solar storm. Without a backup source, the end application would need to maintain proper holdover, which requires expensive oscillators to maintain synchronization until the cell can lock onto the restored GNSS signal. Alternatively, in an APTS deployment, the system can measure the delay asymmetry that is experienced by the PTP messages, while the timeReceiver clock is locked to a GNSS reference. Then, upon the GNSS signal loss, when the APTS timeReceiver clock switches to the backup PTP timing reference, it can use the previously measured PTP delay asymmetry to maintain a phase or frequency backup.