DrDoof
3cd6d60e0b
The switch has no battery backed clock, only a seconds counter that starts at zero on every boot. An SNTP client keeps UTC as the time of the last answer plus the seconds counted since: "ntp server <name|ip>", "ntp interval <minutes>", "ntp timezone <+hh:mm>", "ntp dst off|eu|us", "ntp on|off", "ntp" and "time". A server given by name goes through the DNS resolver, an answer from an unsynchronised server is ignored, and a failed attempt is repeated after 30 seconds. The local time adds the time zone offset and, while the European or United States rule says so, one hour. The date is split with a shift and subtract division and a walk over the years, so no 32-bit division from the library ends up in the common area. The System page gets the NTP settings and shows the local time.
1.4 KiB
Time
The switch has no battery backed clock. It counts seconds from power on, and it can take the date and time from an NTP server once the network is up. The time is lost at every restart and set again at the first synchronisation.
ntp server <name|ip> # default pool.ntp.org
ntp interval <1-1440> # minutes between two synchronisations, default 60
ntp timezone <+hh:mm> # offset from UTC, -12:00 to +14:00
ntp dst off|eu|us # daylight saving rule
ntp on
ntp off
ntp # settings and time
time # local date and time
The client speaks SNTP version 4 and synchronises at once when turned on, then after every interval. A server given by name is resolved through the DNS resolver before every synchronisation. An answer from an unsynchronised server is ignored, and a failed attempt is repeated after 30 seconds.
The local time is UTC plus the time zone offset, plus one hour while daylight saving time applies:
eu: from 01:00 UTC on the last Sunday of March to 01:00 UTC on the last Sunday of October;us: from 02:00 local time on the second Sunday of March to 02:00 local time on the first Sunday of November.
The same settings, with the current local time and the last synchronisation, are in the Time card of the System page. Settings made there or on the console are kept only once the configuration is saved.