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NTP configuration

This chapter includes these sections:

• NTP overview

• NTP configuration task list

• Displaying and maintaining NTP

• NTP configuration examples

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.

For a local system that runs NTP, its time can be synchronized by other reference sources and can be 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 is a huge amount of workload and cannot

guarantee the clock precision. NTP, however, allows quick clock synchronization within the entire

network while it ensures a high 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

network management, time must be used as reference basis.

• All devices must use the same reference clock in a charging system.

• To implement certain functions, such as scheduled restart of all devices within the network, all

devices must be consistent in timekeeping.

• When multiple systems process a complex event in cooperation, these systems must use that same

reference clock to ensure the correct execution sequence.

• For incremental backup between a backup server and clients, timekeeping must be synchronized

between the backup server and all the clients.

Advantages of NTP

• NTP uses a stratum to describe the clock precision, and is able to synchronize time among all

devices within the network.

• NTP supports access control and MD5 authentication.

• NTP can unicast, multicast or broadcast protocol messages.

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H3c-technologies H3C SecBlade NetStream Cards Uživatelský manuál Strana 205