Field Details

• SECONDS_PIVOT

  private static final double SECONDS_PIVOT

  Seconds since Jan. 1 1900 at the pivot: Jan. 19, 1968, halfway through era 0, the earliest date we can handle, where dates switch from the 21st to the 20th century.

  See Also:

  • Constant Field Values

• SECONDS_ERA

  private static final double SECONDS_ERA

  Seconds in one NTP era: Feb. 8, 2036, the start of era 1.

  See Also:

  • Constant Field Values

• SECONDS_END

  private static final double SECONDS_END

  Seconds since Jan. 1 1900 at the end: Feb. 26, 2104, halfway through era 1, the latest date we can handle, where dates switch back to the 21st century.

  See Also:

  • Constant Field Values

• leapIndicator

  public byte leapIndicator

  This is a two-bit code warning of an impending leap second to be inserted/deleted in the last minute of the current day. Its values may be as follows:

  Value Meaning ----- ------- 0 no warning 1 last minute has 61 seconds 2 last minute has 59 seconds) 3 alarm condition (clock not synchronized).

• version

  public byte version

  This value indicates the NTP/SNTP version number. The version number is 3 for Version 3 (IPv4 only) and 4 for Version 4 (IPv4, IPv6 and OSI). If necessary to distinguish between IPv4, IPv6 and OSI, the encapsulating context must be inspected.

• mode

  public final byte mode

  This value indicates the mode, with values defined as follows:

  Mode Meaning ---- ------- 0 reserved 1 symmetric active 2 symmetric passive 3 client 4 server 5 broadcast 6 reserved for NTP control message 7 reserved for private use

  In unicast and anycast modes, the client sets this field to 3 (client) in the request and the server sets it to 4 (server) in the reply. In multicast mode, the server sets this field to 5 (broadcast).

• stratum

  public short stratum

  This value indicates the stratum level of the local clock, with values defined as follows:

  Stratum Meaning ---------------------------------------------- 0 unspecified or unavailable 1 primary reference (e.g., radio clock) 2-15 secondary reference (via NTP or SNTP) 16-255 reserved.

• pollInterval

  public byte pollInterval

  This value indicates the maximum interval between successive messages, in seconds to the nearest power of two. The values that can appear in this field presently range from 4 (16 s) to 14 (16284 s). However, most applications use only the sub-range 6 (64 s) to 10 (1024 s).

• precision

  public byte precision

  This value indicates the precision of the local clock, in seconds to the nearest power of two. The values that normally appear in this field range from -6 for mains-frequency clocks to -20 for microsecond clocks found in some workstations.

• rootDelay

  public double rootDelay

  This value indicates the total roundtrip delay to the primary reference source, in seconds. Note that this variable can take on both positive and negative values, depending on the relative time and frequency offsets. The values that normally appear in this field range from negative values of a few milliseconds to positive values of several hundred milliseconds.

• rootDispersion

  public double rootDispersion

  This value indicates the nominal error relative to the primary reference source, in seconds. The values that normally appear in this field range from 0 to several hundred milliseconds.

• referenceIdentifier

  public final byte[] referenceIdentifier

  This is a 4-byte array identifying the particular reference source. In the case of NTP Version 3 or Version 4 stratum-0 (unspecified) or stratum-1 (primary) servers, this is a four-character ASCII string, left justified and zero padded to 32 bits. In NTP Version 3 secondary servers, this is the 32-bit IPv4 address of the reference source. In NTP Version 4 secondary servers, this is the low order 32 bits of the latest transmit timestamp of the reference source. NTP primary (stratum 1) servers should set this field to a code identifying the external reference source according to the following list. If the external reference is one of those listed, the associated code should be used. Codes for sources not listed can be contrived as appropriate.

  Code External Reference Source ---- ------------------------- LOCL uncalibrated local clock used as a primary reference for a subnet without external means of synchronization PPS atomic clock or other pulse-per-second source individually calibrated to national standards ACTS NIST dialup modem service USNO USNO modem service PTB PTB (Germany) modem service TDF Allouis (France) Radio 164 kHz DCF Mainflingen (Germany) Radio 77.5 kHz MSF Rugby (UK) Radio 60 kHz WWV Ft. Collins (US) Radio 2.5, 5, 10, 15, 20 MHz WWVB Boulder (US) Radio 60 kHz WWVH Kaui Hawaii (US) Radio 2.5, 5, 10, 15 MHz CHU Ottawa (Canada) Radio 3330, 7335, 14670 kHz LORC LORAN-C radionavigation system OMEG OMEGA radionavigation system GPS Global Positioning Service GOES Geostationary Orbit Environment Satellite.

• referenceTimestamp

  public double referenceTimestamp

  This is the time at which the local clock was last set or corrected, in seconds since 00:00 1-Jan-1900.

• originateTimestamp

  public double originateTimestamp

  This is the time at which the request departed the client for the server, in seconds since 00:00 1-Jan-1900.

• receiveTimestamp

  public double receiveTimestamp

  This is the time at which the request arrived at the server, in seconds since 00:00 1-Jan-1900.

• transmitTimestamp

  public final double transmitTimestamp

  This is the time at which the reply departed the server for the client, in seconds since 00:00 1-Jan-1900.

• _DATE_FORMAT

  private static final ThreadLocal<DateFormat> _DATE_FORMAT

  Returns a timestamp (number of seconds since 00:00 1-Jan-1900) as a formatted date/time string.