Configuring Ntp; Ntp Applications; Ntp Advantages - HP 5820X Switch Configuration Manual

Configuring NTP

Defined in RFC 1305, the NTP synchronizes timekeeping among distributed time servers and clients. NTP
runs over the 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.

NTP applications

An administrator is unable to keep time synchronized among all 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 and it ensures
a high clock precision.
Use NTP 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 clients.
NOTE:
• Clock stratum determines the accuracy of a server, ranging from 1 to 16. The 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.
The local clock of an switch cannot operate as a reference clock. It can only serve as an NTP server
•
after being synchronized.

NTP advantages

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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