Operation Manual – NTPH3C S5600 Series Ethernet Switches Chapter 1 NTP Configuration1-2z To perform incremental backup operations between a backup server and a host,you must make sure they adopt the same time.NTP has the following advantages:z Defining the accuracy of clocks by stratum to synchronize the clocks of all devicesin a network quicklyz Supporting access control (see sectionz Configuring Access Control Right) and MD5 encrypted authentication (see sectionConfiguring NTP Authentication)z Sending protocol packets in unicast, multicast, or broadcast modeNote:z The clock stratum determines the accuracy, which ranges from 1 to 16. The stratumof a reference clock ranges from 1 to 15. The clock accuracy decreases as thestratum number increases. A stratum 16 clock is in the unsynchronized state andcannot serve as a reference clock.z The local clock of an S5600 Ethernet switch cannot be set as a reference clock. Itcan serve as a reference clock source to synchronize the clock of other devices onlyafter it is synchronized.1.1.2 Implementation Principle of NTPFigure 1-1 shows the implementation principle of NTP.Ethernet switch A (Device A) is connected to Ethernet switch B (Device B) throughEthernet ports. Both having their own system clocks, they need to synchronize theclocks of each other through NTP. To help you to understand the implementationprinciple, we suppose that:z Before the system clocks of Device A and Device B are synchronized, the clock ofDevice A is set to 10:00:00 am, and the clock of Device B is set to 11:00:00 am.z Device B serves as the NTP server, that is, the clock of Device A will besynchronized to that of Device B.z It takes one second to transfer an NTP message from Device A to Device B orfrom Device B to Device A.
