180 Configuring and managing IP interfaces and services

NN47250-500 (Version 03.01)

Configuring and managing NTP

The Network Time Protocol (NTP) allows a networking device to synchronize its system time and date with the time and
date on an NTP server. When used on multiple devices, NTP ensures that the time and date are consistent among those
devices.
The NTP implementation in WSS Software is based on RFC 1305, Network Time Protocol (Version 3) Specification,
Implementation and Analysis.
You can configure a WSS to consult up to three NTP servers. The switch compares the results from the servers and
selects the best response. (For information, see RFC 1305.)
After you enable the NTP client and configure NTP servers, WSS Software queries the NTP servers for an update every
64 seconds and waits 15 seconds for a reply. If the switch does not receive a reply to an NTP query within 15 seconds,
the switch tries again up to 16 times. You can change the update interval but not the timeout or number of retries.
WSS Software adjusts the NTP reply according to the following time parameters configured on the WSS:
Offset from UTC (configured with the timezone command; see “Setting the time zone” on page 176)
Daylight savings time (configured with the set summertime command; see “Configuring the summertime period”
on page 177)
The NTP client is disabled by default.
Note. If NTP is configured on a system whose current time differs from the NTP server
time by more than 10 minutes, convergence of the WSS time may take many NTP update
intervals. Nortel recommends that you set the time manually to the NTP server time before
enabling NTP to avoid a significant delay in convergence.