H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – NTP

H3C S7500E Series Ethernet Switches Chapter 1 NTP Configuration

1-4

LI VN Mode Stratum Poll Precision

0 7 15 23 31

Root delay (32 bits)

Root dispersion (32 bits)

Reference identifier (32 bits)

Receive timestamp (64 bits)

Transmit timestamp (64 bits)

Authenticator (optional 96 bits)

Reference timestamp (64 bits)

Originate timestamp (64 bits)

Figure 1-2 Clock synchronization message format

Main fields are described as follows:

z LI: 2-bit leap indicator. When set to 11, it warns of an alarm condition (clock

unsynchronized); when set to any other value, it is not to be processed by NTP.

z VN: 3-bit version number, indicating the version of NTP. The latest version is

version 3.

z Mode: a 3-bit code indicating the work mode of NTP. This field can be set to these

values: 0 – reserved; 1 – symmetric active; 2 – symmetric passive; 3 – client; 4 –

server; 5 – broadcast or multicast; 6 – NTP control message; 7 – reserved for

private use.

z Stratum: an 8-bit integer indicating the stratum level of the local clock, with the

value ranging from 1 to 16. The clock precision decreases from stratum 1 through

stratum 16. A stratum 1 clock has the highest precision, and a stratum 16 clock is

not synchronized and cannot be used as a reference clock.

z Poll: 8-bit signed integer indicating the poll interval, namely the maximum interval

between successive messages.

z Precision: an 8-bit signed integer indicating the precision of the local clock.

z Root Delay: roundtrip delay to the primary reference source.

z Root Dispersion: the maximum error of the local clock relative to the primary

reference source.

z Reference Identifier: Identifier of the particular reference source.

z Reference Timestamp: the local time at which the local clock was last set or

corrected.