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Data Fields
ntpMess_t Struct Reference

Data Fields

uint8_t flags
 The flags.
struct ntpTimestamp_t originateTimestamp
 The T1, see RFC 2030.
uint8_t poll
 Maximum interval between successive messages.
int8_t precision
 Servers time precision.
struct ntpTimestamp_t receiveTimestamp
 The T2, see RFC 2030.
ucnt32_t referenceIdentifier
 Identifies the particular reference clock.
struct ntpTimestamp_t referenceTimestamp
 The timestamp of the last setting of the local clock.
ucnt32_t rootDelay
 see RFC 2030
ucnt32_t rootDispersion
 see RFC 2030
uint8_t stratum
 A kind of time server hierarchy level.
struct ntpTimestamp_t transmitTimestamp
 The T3, see RFC 2030.

Detailed Description

NTP message type.

See
  Network Time Protocol Version 4 Protocol and Algorithms Specification [draft]
or see RFC 4330
  Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI
and see also [RFC 2030, cites below]

  NTP client operations [RFC 2030 quoted]:

      Timestamp name         ID   is set when
      -----------------------------------------------------------------------
      originateTimestamp     T1   request sent by client as transmitTimestamp
      receiveTimestamp       T2   request received by server
      transmitTimestamp      T3   reply sent by server
      destinationTimestamp   T4   reply received by client

   The roundtrip delay d and system clock offset t are defined as:

      d = (T4 - T1) - (T3 - T2)     t = ((T2 - T1) + (T3 - T4)) / 2  

For the arithmetic operations on the timestamps use the functions ntpTimestampSum, ntpTimestampDif and ntpTimestampHalf.


Field Documentation

uint8_t flags

The flags.

This byte consists of the leap indicator (2 Bits), a version number (3 bits) and mode (3 bits).

uint8_t poll

Maximum interval between successive messages.

The value is 2**poll s.
Range: 4 .. 17 (16s .. 36h)

int8_t precision

Servers time precision.

The value is 2**precision s.
Range: -6 .. -20 (16ms .. 1µs)

Identifies the particular reference clock.

Not used or evaluated here. See RFC 2030.

The timestamp of the last setting of the local clock.

If the local clock has never been synchronized, the value is zero; see RFC 2030.
Not used or evaluated here.


The documentation for this struct was generated from the following file: