Operation Manual – NTPH3C S7500 Series Ethernet Switches Chapter 1 NTP Configuration1-1Chapter 1 NTP Configuration1.1 Introduction to NTPNetwork time protocol (NTP) is a time synchronization protocol defined by RFC1305. Itis used for time synchronization among a set of distributed time servers and clients.NTP transmits packets through UDP port 123.NTP is intended for time synchronization of all devices that have clocks in a network, sothat the clocks of all devices can keep consistent. This enables the applications thatrequire unified time.A system running NTP not only can be synchronized by other clock sources, but alsocan serve as a clock source to synchronize other clocks. Besides, it can synchronize, orbe synchronized by other systems by exchanging NTP packets.1.1.1 Applications of NTPNTP is mainly applied to synchronizing the clocks of all the network devices in anetwork. For example:z In network management, the analysis of the log information and debugginginformation collected from different devices is meaningful and valid only whennetwork devices that generate the information adopt the same time.z The accounting system requires that the clocks of all the network devices beconsistent.z Some functions, such as restarting all the network devices in a networksimultaneously, require that they adopt the same time.z When multiple systems cooperate to handle a rather complex event, to ensure acorrect execution order, they must adopt the same time.z To perform incremental backup operations between a backup server and a host,you must make sure they adopt the same time.As setting the system time manually in a network with many devices leads to a lot ofworkload and cannot ensure the accuracy, it is unfeasible for an administrator toperform the operation. However, an administrator can synchronize the devices in anetwork with required accuracy by performing NTP configuration.NTP benefits from the following advantages:z Defining the accuracy of clocks by strata to synchronize the time of all the devicesin a network quicklyz Supporting access control and MD5 authenticationz Sending protocol packets in unicast, multicast or broadcast mode
