Chapter 1 Ntp Configuration; Introduction To Ntp; Applications Of Ntp - H3C S5600 series Operation Manual

Operation Manual – NTP
H3C S5600 Series Ethernet Switches-Release 1510

Chapter 1 NTP Configuration

1.1 Introduction to NTP

Network time protocol (NTP) is a time synchronization protocol defined by RFC1305. It
is used for time synchronization among a set of distributed time servers and clients.
NTP transmits packets through UDP port 123.
NTP is intended for time synchronization of all devices that have clocks in a network, so
that the clocks of all devices can keep consistent. This enables the applications that
require unified time.
A system running NTP not only can be synchronized by other clock sources, but also
can serve as a clock source to synchronize other clocks. Besides, it can synchronize, or
be synchronized by other systems by exchanging NTP packets.

1.1.1 Applications of NTP

NTP is mainly applied to synchronizing the clocks of all the network devices in a
network. For example:
In network management, the analysis of the log information and debugging
information collected from different devices is meaningful and valid only when
network devices that generate the information adopts the same time.
The accounting system requires that the clocks of all the network devices be
consistent.
Some functions, such as restarting all the network devices in a network
simultaneously require that they adopt the same time.
When multiple systems cooperate to handle a rather complex event, to ensure a
correct execution order, they must adopt the same time.
To perform incremental backup operations between a backup server and a host,
you must make sure they adopt the same time.
As setting the system time manually in a network with many devices leads to a lot of
workload and cannot ensure the accuracy, it is unfeasible for an administrator to
perform the operation. However, an administrator can synchronize the devices in a
network with required accuracy by performing NTP configuration.
NTP benefits from the following advantages:
Defining the accuracy of clocks by strata to synchronize the time of all the devices
in a network quickly
Supporting access control and MD5 authentication
Sending protocol packets in unicast, multicast or broadcast mode
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Chapter 1 NTP Configuration