Amer Networks SS2R48G4i V2 - Manual (Page 182)

SS2R24G4i/SS2R48G4i
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Chapter 21 SNTP Configuration
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.
SS2R24/48G4i switch 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.
21.1 Commands for SNTP
21.1.1 sntp server
Command sntp server <server_address> [version <version_no>]
no sntp server <server_address>
Function Configure the addresses and the version of the SNTP/NTP server; the “no” form of this
command cancels the configured SNTP/NTP server addresses.
Parameter <server_address> is the IPv4 unicast address of the SNTP/NTP server, <version_no> is
the version No. of the SNTP on current server,ranging between 1-4 and defaulted at 1.
Default No sntp/ntp configured by default.
Command Mode Global Mode
21.1.2 sntp polltime
Command sntp polltime <interval>
no sntp polltime
Function Sets the interval for SNTP clients to send requests to NTP/SNTP; the “no sntp polltime”
command cancels the polltime sets and restores the default setting.Resume default value seconds
Parameters < interval> is the interval value from 16 to 16284
Default The default polltime is 64 seconds.
21.1.3 sntp timezone