Viewing the PTP Clock Details

Use the PTP Clock page to view the local PTP clock, parent clock state, and the time property for the devices for which you have configured PTP. To view this page, go to Settings > Date and Time > PTP Port State. Figure 1: PTP Clock Details shows the PTP clock details.

 

Figure 126 PTP Clock Details

Following table lists the PTP clock attributes and their descriptions:

PTP Clock Attribute

Description

Local PTP Clock

Alias

The unique name for the PTP template that you configured globally for the device.

Box ID

The box identifier of the device.

Clock Identity

The clock identity of the device. It is a 64-bit global identifier (EUI-64) as defined by the IEEE 1588 standard.

Ptp Time (sec)

The actual PTP time with nanosecond resolution.

Mean Path Delay

The forward and reverse path delay in steady state is used to calculate the mean path delay.

Steps Removed

The number of boundary clocks between the local clock and the foreign master clock.

Domain

The network within which PTP operates, that is all the clocks within a domain are in synchronization.

Offset From Master

The time difference between the master and the slave, measured in nanoseconds. Once this is computed, the slave will readjust its clock to align with the master.

Priority2

The priority value used to determine the grandmaster in a network. For example, if there are two clocks in a network that match the default criteria, the clock that has the lower priority value will be selected as the grandmaster.

Mode

The clock modes. The values are:

• Ordinary clock—A clock that has only one PTP-enabled port and maintains the timescale used in the domain. It can serve either as a master or a slave.
• Boundary clock—A clock that has multiple PTP-enabled ports and maintains the timescale used in the domain. The ports can serve either as a master or a slave.

Port Ptp Count

Number of ports on which the PTP template is enabled. Gigamon supports a maximum of 10 boundary clock ports in a device.

Clock Quality Accuracy

The clock quality announced by the master. This value is used to select the best clock source between two PTP master clocks and switches dynamically to the clock that has greater accuracy.

Step Type

The timestamp mode that is used by PTP. The values is:

• One-step mode—PTP master does not send any follow up message because the synchronization message itself contains the transmit timestamp as well as the correction filed to obtain the precise transmit timestamp.

Local Clock Time

The actual local clock time on the device.

Local Priority

The priority value used to determine the PTP master when the BMC algorithm chooses more than one clock as the master. This value overrides the default criteria for the BMC selection. The clock with the lower priority value will be selected.

Clock Quality Class

Attribute of an ordinary or boundary clock that denotes the traceability of the time or frequency distributed by the grandmaster clock.

Clock Quality Offset

The time difference in clock quality between the master and the slave, measured in nanoseconds.

Parent Clock State

GM Clock Identity

The clock identity of the grandmaster. It is a 64-bit global identifier (EUI-64) as defined by the IEEE 1588 standard.

GM Priority1

The priority value of the grandmaster clock. Lower value takes precedence.

GM Priority2

The priority value of the grandmaster that is used when GM Priority1 value is the same for different masters in a network.

Observed Offset

The time difference that is observed between the master and the slave.

Clock Port ID

The port identifier assigned by the PTP clock.

Stats

Indicates whether the values of parentDS.observedParentOffsetScaledLogVariance and parentDS.observedParentClockPhaseChangeRate have been measured and are valid.

Observed Phase Change Rate

An estimate of the parent clock's phase change rate as measured by the slave clock.

GM Clock Quality Accuracy

The expected accuracy of the grandmaster clock.

GM Clock Quality Class

The grandmaster clock’s traceability of the distributed time or frequency.

GM Clock Quality Offset

The time difference in clock quality between the grandmaster and the slave, measured in nanoseconds.

Time Property

Current UTC Offset

The time difference between International Atomic Time (TAI) and Universal Coordinated Time (UTC).

Leap59

The last minute of the current UTC day has only 59 seconds (instead of the 60 SI seconds).

Leap61

The last minute of the current UTC day has only 61 seconds (instead of the 60 SI seconds).

Time Traceable

The timescale and the UTC offset are traceable to a primary reference.

Frequency Traceable

The frequency that determines the timescale is traceable to a primary reference.

Time Source

The time source that is external to PTP. The time source is traceable to the international standards laboratories maintaining clocks that form the basis for the TAI and UTC timescales. Examples of these are GPS, NTP, and National Institute of Standards and Technology (NIST) timeservers.

Ptp Time Scale

The time scale to use when advertising time for PTP.