Ntp Overview - Huawei AR150 Series Configuration Manual

Huawei AR150&200&1200&2200&3200 Series Enterprise
Routers
Configuration Guide - Device Management

5.1 NTP Overview

This section describes the definition, purpose, and version evolution of NTP.
Definition
The Network Time Protocol (NTP) is an application layer protocol in the TCP/IP protocol suite.
NTP is used to synchronize the time among a set of distributed time servers and clients. NTP is
implemented based on the Internet Protocol (IP) and User Datagram Protocol (UDP). NTP
packets are transmitted using UDP port 123.
Purpose
As network topologies become increasingly complex, clock synchronization becomes more
important for devices on the entire network. If a system clock is modified manually by network
administrators, the workload is heavy and the modification is error-prone, which affects clock
precision. NTP is formulated as a networking protocol for clock synchronization between
devices on a network.
NTP applies to the following situations where all the clocks of the devices on a network need
to be consistent:
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Version Evolution
NTP is evolved from the Time Protocol and the ICMP Timestamp message but is specifically
designed to maintain accuracy and robustness.
Table 5-1 NTP version evolution
V
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Issue 05 (2014-01-16)
In network management, analysis of logs or debugging messages collected from different
routers requires time for reference.
An accounting system requires that the clocks of all the devices be consistent.
When several systems work together to process a complicated event, they have to refer to
the same clock to ensure a correct execution order.
Incremental backup between a backup server and clients requires that their clocks be
synchronized.
Some applications need to obtain the time in which a user logs in a system and a document
is modified.
Date Proto Description
col
Num
ber
June RFC NTPv1 puts forward complete NTP rules and algorithms for the
1988 1059 first time, but it does not support authentication and control
messages.
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Table 5-1 shows the NTP version evolution.
5 NTP Configuration
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