Viewing the PTP Configuration on a Port

After you enable PTP on a network port, you can view the port’s clock state and other details of PTP configuration in the PTP Port State page. To view the page, go to Settings > Date and Time > PTP Port State. Figure 1 shows the PTP configuration details.

 

Figure 104 PTP Port State

Following table lists the PTP port states and their descriptions:

PTP Port State

Description

Port ID/Port Alias

The identifier of the port on which PTP is enabled.

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 standard.

Delay Request Interval

The minimum interval allowed between PTP delay request messages when the port is in the source state.

Clock Port State

Based on the role defined for the port, the clock state will be Master or Slave. Following are the clock port states:

● Initializing—The port is initializing it’s datasets, hardware, and communication facilities. The port does not place any PTP messages on it’s communication path during this state. If one port on the boundary clock is in the Initializing state, all the other ports on the boundary clock will also be in the same state.
● Listening—Only signaling messages or management messages that are responses to another management message are placed on the port’s communication path.
● Faulty—The fault state of the protocol. Only signaling messages or management messages that are responses to another management message are placed on the port’s communication path. In a boundary clock, any activity on the port with the Faulty clock port state does not affect the other ports in the device. If any activity on the faulty port is not restricted to the port, all other ports in the device changes to the Faulty state.
● Disabled—The port does not place any messages on it’s communication path. In a boundary clock, the port’s activity does not affect the activity in other ports that are part of the boundary clock. A port in this state discards all PTP received messages except the management messages.
● Pre-master—The port acts like a source but does not place any messages on it’s communication path, except for signaling or management messages.
● Master—The port becomes the source.
● Passive—The port does not place any messages on it’s communication path.
● Uncalibrated—One or more source ports are detected in the domain. The appropriate source port has been selected, and the local port is preparing to synchronize to the selected source port. This is a transient state to initiate the servo synchronization, datasets updates, and other implementation-specific activities.
● Slave—The port is synchronizing to the selected source port.

Local Priority

The priority value used to determine the PTP source when the BMC algorithm chooses more than one clock as the source. This value overrides the default criteria for the BMC selection. The clock with the lower priority value will be selected. The valid range is between 1 and 255.

For example, on a particular device, the local priority of a port is compared with the local priority of the clock. Based on the following criteria, thesource is determined:

● If the local priority of the port is greater than the local priority of the clock, the clock becomes the source.
● If the local priority of the port is lesser than the local priority of the clock, the port becomes the source.
● If the local priority of the port is equal to the local priority of the clock, the clock identity of the port and the clock is compared and the one that has the lower value becomes the source.

Peer Delay Request Interval

The minimum interval allowed between PTP delay request messages between peer ports.

Sync Interval

The time interval between PTP synchronization messages on the port.

Announce Interval

The time interval, in log seconds, between PTP announce messages in the port.

Announce Receipt Timeout

The maximum number of consecutive announce messages that the port fails to receive. When the number of consecutive announce messages that the port failed to receive is greater than the value specified in this field, the port’s clock state changes to source.

VLAN ID

The identifier of the VLAN interface.

Clock Port ID

The port identifier assigned by the PTP clock.

PTP Version

The PTP version that is enabled in the port.

Delay Mechanism

The mechanism used to determine the delay between a source and a receiver. Following is the delay mechanism that Gigamon supports:

● End-to-End—The source and the receiver send delay requests and delay responses back and forth between themselves to measure the delay. Once the delay is measured, the receiver synchronizes the time with the source.

Peer Mean Path Delay

Reserved for future use.