Failover to NTP

sfptpd will failover from PTP to NTP if there are active PTP alarms:

pps-no-signal
pps-seq-num-error
no-time-of-day
pps-bad-signal
no-sync-pkts
no-follow-ups
no-delay-resps
no-pdelay-resps
no-pdelay-resp-follow-ups
no-tx-timestamps
no-rx-timestamps
no-interface
clock-ctrl-failure

See PTP Alarms for a description of alarms.

If alarm conditions clear, sfptpd will resume synchronization using PTP.

The selection_holdoff_interval (seconds) can be set to prevent immediate failover caused when only one or two PTP packets are not received.

sfptpd will NOT failover to NTP because of synchronization accuracy.