SNR S2940-8G-v2, Configuration Manual

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SNR S2940-8G-v2 Switch Configuration Guide
SNTP Configuration
Chapter 63
SNTP Configuration
63.1 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 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.
Switch implements SNTPv4 and supports SNTP client unicast as described in RFC2030; SNTP
client multicast and unicast are not supported, nor is the SNTP server function.
63.2 Typical Examples of SNTP Configuration
All switches in the autonomous zone are required to perform time synchronization, which is done
through two redundant SNTP/NTP servers. For time to be synchronized, the network must be
properly configured. There should be reachable route between any switch and the two SNTP/NTP
servers.
Example: Assume the IP addresses of the SNTP/NTP servers are 10.1.1.1 and 20.1.1.1,
respectively, and SNTP/NTP server function (such as NTP master) is enabled, then configurations
for any switch should like the following:
Switch(config)#sntp server 10.1.1.1
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