Ntp Configuration; Ntp Overview; Applications Of Ntp; Advantages Of Ntp - H3C S3100V2-52TP Configuration Manual

NTP configuration

NTP overview

Defined in RFC 1305, the Network Time Protocol (NTP) synchronizes timekeeping among distributed
time servers and clients. NTP runs over the User Datagram Protocol (UDP), using UDP port 123.
The purpose of using NTP is to keep consistent timekeeping among all clock-dependent devices within a
network so that the devices can provide diverse applications based on the consistent time.
The time of a local system that runs NTP can be synchronized to other reference sources and used as a
reference source to synchronize other clocks..

Applications of NTP

An administrator is unable to keep time synchronized among all the devices within a network by
changing the system clock on each station, because this would be a huge workload and would not
guarantee clock precision. NTP, however, allows quick clock synchronization within the entire network
and ensures a high degree of clock precision.
NTP is used when all devices within the network must be consistent in timekeeping. For example:
In analysis of the log information and debugging information collected from different devices in
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network management, time must be used as reference basis.
All devices must use the same reference clock in a charging system.
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• To implement certain functions, such as scheduled restart of all devices within the network, all
devices must be consistent in timekeeping.
To ensure the correct execution sequence, when multiple systems process a complex event in
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cooperation, the systems must all use the same reference clock.
For incremental backup between a backup server and clients, timekeeping must be synchronized
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between the backup server and all the clients.

Advantages of NTP

NTP uses a stratum to describe clock precision, and is able to synchronize time among all devices
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within the network.
NTP supports access control and MD5 authentication.
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NTP can unicast, multicast or broadcast protocol messages.
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NOTE:
• Clock stratum determines the accuracy of a server, which ranges from 1 to 16. Clock accuracy decreases
as the stratum number increases. The stratum of a reference clock ranges from 1 to 15. A stratum 16
clock is in unsynchronized state.
The local clock of a switch cannot operate as a reference clock. It can serve as an NTP server only after
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it is synchronized.
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