ECS4660-28F_Management Guide-R03

C HAPTER 24 | System Management Commands
Precision Time Protocol
– 965 –
ptp priority1 This command sets a preference level used in selecting the master clock.
Use the no form to restore the default setting.
SYNTAX
ptp priority1 priority-value
no ptp priority1
priority-value – Slave devices use the priority1 value when selecting
a master clock. (Range: 0-255)
DEFAULT SETTING
128
COMMAND MODE
Global Configuration
COMMAND USAGE
◆ Specify the priority1 preference level to override the default criteria for
best master clock selection. Lower values take precedence.
◆ The best master clock algorithm (BMC), performs a distributed
selection of the best candidate clock based on the following clock
properties.
■
Priority – An administratively assigned precedence hint used by the
BMC to help select a grandmaster for the PTP domain.
■
Class – An attribute defining the clock’s International Atomic Time
(TAI) traceability.
■
Accuracy – An attribute defining the accuracy of the clock.
■
Variance – A clock's estimate of its stability based on observation of
its performance against the PTP reference.
■
Quality – Clock quality based on expected timing deviation,
technology used to implement the clock or location in a stratum
schema.
■
Identifier – A universally unique numeric identifier for the clock.
This is typically constructed based on a device's MAC address.
◆ PTP uses a hierarchical selection algorithm based on the following
properties in the order indicated.
■
Priority 1
■
Class
■
Accuracy
■
Variance
■
Priority 2
■
Unique identifier (tie breaker)