Ntp Configuration; Overview; Applications Of Ntp - 3Com Switch 4500 26-Port Configuration Manual

Overview

Applications of NTP

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NTP C
ONFIGURATION
Network time protocol (NTP) is a time synchronization protocol defined in
RFC1305. It is used for time synchronization between a set of distributed time
servers and clients. NTP transmits packets through UDP port 123.
NTP is intended for time synchronization between all devices that have clocks in a
network so that the clocks of all devices can keep consistent. Thus, the devices can
provide multiple unified-time-based applications.
A local system running NTP can not only be synchronized by other clock sources,
but also serve as a clock source to synchronize other clocks. Besides, it can
synchronize, or be synchronized by other systems by exchanging NTP packets.
NTP is mainly applied to synchronizing the clocks of all devices in a network. For
example:
In network management, the analysis of the log information and debugging
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information collected from different devices is meaningful and valid only when
network devices that generate the information adopts the same time.
The billing system requires that the clocks of all network devices be consistent.
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Some functions, such as restarting all network devices in a network
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simultaneously require that they adopt the same time.
When multiple systems cooperate to handle a rather complex transaction, they
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must adopt the same time to ensure a correct execution order.
To perform incremental backup operations between a backup server and a
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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 clocks of
devices in a network with required accuracy by performing NTP configuration.
NTP has the following advantages:
Defining the accuracy of clocks by stratum to synchronize the clocks of all
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devices in a network quickly
Supporting access control and MD5 authentication
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Sending protocol packets in unicast, multicast, or broadcast mode
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The clock stratum determines the accuracy, which ranges from 1 to 16. The
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stratum of a reference clock ranges from 1 to 15. The clock accuracy decreases
as the stratum number increases. A stratum 16 clock is in the unsynchronized
state and cannot serve as a reference clock.
Overview 293