Operation Manual – NTP
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 NTP Configuration
1-2
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In analysis of the log information and debugging information collected from
different devices in network management, time must be used as reference basis.
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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.
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When multiple systems process a complex event in cooperation, these systems
must use that same reference clock to ensure the correct execution sequence.
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For increment backup between a backup server and clients, timekeeping must be
synchronized between the backup server and all the clients.
Advantages of NTP:
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NTP uses a stratum to describe the clock precision, and is able to synchronize
time among all devices within the network.
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NTP supports access control and MD5 authentication.
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NTP can unicast, multicast or broadcast protocol messages.
1.1.2 How NTP Works
shows the basic work flow of NTP. Device A and Device B are
interconnected over a network. They have their own independent system clocks, which
need to be automatically synchronized through NTP. For an easy understanding, we
assume that:
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Prior to system clock synchronization between Device A and Device B, the clock
of Device A is set to 10:00:00 am while that of Device B is set to 11:00:00 am.
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Device B is used as the NTP time server, namely Device A synchronizes its clock
to that of Device B.
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It takes 1 second for an NTP message to travel from one device to the other.
