Ensure that the clock time on the router is synchronized with the time on the NTP server.
To check NTP peers, enter the following JUNOS CLI operational mode command:
user@host> show ntp associations remote refid st t when poll reach delay offset jitter ============================================================================== *coetanian.junip .GPS. 1 u 22 64 377 6.861 -1.297 0.811
user@jhost> show ntp associations> remote refid st t when poll reach delay offset jitter > ============================================================================== > ntp1.usno.navy. PSC. 1 - 44 64 77 86.829 -1830.3 915.177 > Tick.UH.EDU USNO. 1 - 36 64 77 42.560 -1835.3 917.667
Sample output 1 is synchronized with the NTP server because there is an asterisk (*) at the beginning of the output. Also, the router with the asterisk (*) is the master router and the system is synchronizing with this NTP server.
Sample output 2 shows that the time on the server and router is so far apart that NTP will not attempt to synchronize. The offset value of 1830 is too large a difference and the jitter value of 917.667 is also too large to provide reliability to the offset value.
In ordinary conditions, the NTP server synchronizes the router clock in small steps so that the timescale is effectively continuous. In conditions of extreme network congestion, the NTP server discards sample offsets exceeding 128 ms, unless sample offsets are greater than 128 ms, for longer than 900 seconds. In this case, no matter what the next offset, the NTP server adjusts to the indicated time.
For more detailed information on configuring the NTP server, see the JUNOS System Basics Configuration Guide.