Basic System Configuration Guide System Management
Edition: 01 3HE 11010 AAAC TQZZA 253
Specifically when the G.8275.1 profile with IP encapsulation is used, the
synchronizationUncertain flag is added to the Announce message. The use of this
flag is optional. The 7705 SAR PTP grand master, boundary, and slave clocks will
optionally support the processing of the synchronization state as follows.
• If a grand master clock has its synchronous equipment timing source (SETS)
frequency clock and time clock locked to GNSS and its clockClass equals 6, it
is in a “synchronization certain” state. The synchronizationUncertain flag in the
Announce message is set to FALSE.
• If a grand master clock does not meet the above criteria, it is in a
“synchronization uncertain” state. The synchronizationUncertain flag in the
Announce message is set to TRUE.
• In order for a boundary clock to be in the “synchronization certain” state, its
parent clock’s clockClass must be “synchronization certain”, its SETS must be
locked and PRS/PRC traceable, and PTP must have sufficient time to stabilize
to the parent clock. At that point, its PTP port state will transition from an
Uncalibrated state to a Slave state.
• A boundary clock can fall back to the “synchronization uncertain” state if its
parent clock changes to the “synchronization uncertain” state, its SETS
becomes unlocked or not PRS/PRC traceable, or the local clock is restarted or
reset. The PTP port state will transition away from the Slave state.
This behavior is shown in Figure 22.
Figure 22 Synchronization Certain/Uncertain States
After 20 s
Parent clock Sync-uncertain = True or
PTP clock restarted
clockClass changes from 6 or
SETS unlocked or not PRS/PRC or
Parent clock Sync-certain = False or
PTP clock restarted
clockClass changes to = 6 and
SETS locked to PRS/PRC and
Parent clock Sync-certain = True
Normal Synchronized State
clockClass = 6
SETS locked to PRS/PRC
Parent clock Sync-certain = True
Uncalibrated State
Unsynchronized
State
Calibration
processing
25905
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