The PTP messages are used by sfptpd
to synchronize the adapter clock with the master clock. sfptpd
runs a second clock servo to synchronize the system clock to the adapter clock as illustrated by Figure 1. This unique two stage synchronization has a number of benefits including:
- Improved accuracy with the ability to more frequently discipline the system clock than is supported by standard PTP masters.
- Ability to discipline the system clock to a high precision clock during periods, for whatever reason, whereby the upstream PTP master is inaccessible or offline.Figure 1. sfptpd 2-stage Synchronization