Operation Manual – NTPH3C S5500-EI Series Ethernet Switches Chapter 1 NTP Configuration1-1Chapter 1 NTP ConfigurationNote:The local clock of an S5500-EI 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.When configuring NTP, go to these sections for information you are interested in:z NTP Overviewz NTP Configuration Task listz Configuring the Operation Modes of NTPz Configuring Optional Parameters of NTPz Configuring Access-Control Rightsz Configuring NTP Authenticationz Displaying and Maintaining NTPz NTP Configuration Examples1.1 NTP OverviewDefined in RFC 1305, the Network Time Protocol (NTP) synchronizes timekeepingamong 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 allclock-dependent devices within the network so that the devices can provide diverseapplications based on the consistent time.For a local system running NTP, its time can be synchronized by other referencesources and can be used as a reference source to synchronize other clocks.1.1.1 Applications of NTPAn administrator can by no means keep synchronized time among all the devices withina network by changing the system clock on each station, because this is a huge amountof workload and cannot guarantee the clock precision. NTP, however, allows quickclock 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, forexample:
