NTP Check

Leap Indicator:

• 0: No leap second adjustment.
• 1: Last minute of the day has 61 seconds.
• 2: Last minute of the day has 59 seconds.
• 3: Clock is unsynchronized.

Version Number:

• NTP Version Number.

Mode:

• 0: Reserved.
• 1: Symmetric Active.
• 2: Symmetric Passive.
• 3: Client.
• 4: Server.
• 5: Broadcast.
• 6: NTP control message.
• 7: Private use.

Stratum:

• 0: Unspecified or invalid.
• 1: Primary reference.
• 2-15: Secondary reference.
• 16: Unsynchronized.
• 17-255: Reserved.

Poll Interval:

• The maximum interval between messages in seconds to the nearest power of two.

Precision:

• Precision of the local clock in seconds to the nearest power of two.

Root Delay:

• The total roundtrip delay to the primary reference source, in seconds with the fraction point between bits 15 and 16.
• Positive and negative values are valid.

Root Dispersion

• The maximum error relative to the primary reference source in seconds with the fraction point between bits 15 and 16.
• Only positive values greater than zero are valid.

Reference ID

• Used to identify the particular reference clock.
• In the case of stratum 0 (unspecified) or stratum 1 (primary reference), this is a four byte, left-justified, zero padded ASCII string.
• In the case of stratum 2 and greater (secondary reference) this is the IPv4 address of the primary reference host.

Examples of Reference ID's

• GPS: Global Position System
• GAL: Galileo Positioning System
• PPS: Generic pulse-per-second
• WWVB: (North America) Radio Time Signal at 60 kHz
• MSF: (United Kingdom) Radio Time Signal at 60 kHz
• DCF: (Germany) Radio Time Signal at 77.5 kHz

Reference Timestamp

• The local time at which the local clock was last set or corrected.

Originate Timestamp

• The local time when the client sent the request.

Receive Timestamp

• The local time when the request was received by the server.

Transmit Timestamp

• The local time when the reply was sent from the server.

Round Trip Delay

• The time between the departure of request and arrival of reply in miliseconds.

Local Clock Offset

• The offset of the local clock relative to the primary reference source in miliseconds.