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Chapter 12 SNTP Configuration
12.1 Introduction to SNTP
The Network Time Protocol (NTP) is widely used for clock synchronization for global
computers connected to the Internet. NTP can assess packet sending/receiving delay in
the network, and estimate the computer’s clock deviation independently, so as to achieve
high accuracy in network computer clocking. In most positions, NTP can provide
accuracy from 1 to 50ms according to the characteristics of the synchronization source
and network route.
Simple Network Time Protocol (SNTP) is the simplified version of NTP, removing the
complex algorithm of NTP. SNTP is used for hosts who do not require full NTP functions,
it is a subset of NTP. It is common practice to synchronize the clocks of several hosts in
local area network with other NTP hosts through the Internet, and use those hosts to
provide time synchronization service for other clients in LAN. The figure below (Fig 3-1)
depicts a NTP/SNTP application network topology, where SNTP mainly works between
second level servers and various terminals since such scenarios do not require very high
time accuracy, and the accuracy of SNTP (1 to 50 ms) is usually sufficient for those
services.
GPS receiver
Level 1 server
Level 2 server
DNS server
Campus users
Campus users
router
