Sntp/Utc Time Clock; Figure 28 Sntp/Gmt Time Clock - WaveRider LMS4000 User Manual

3 Detailed Description

3.6.3 SNTP/UTC Time Clock

The Simple Network Time Protocol (SNTP)/UTC feature provides LMS4000 devices with an
accurate clock for time stamping events in the log file.
SNTP/UTC Time Clock operation is illustrated in
NTP Server
The CCU, acting as an SNTP time client, regularly resynchronizes to one of several NTP
Servers from which it obtains UTC (Universal Coordinated Time). The CCU resynchronization
and retry periods can be set by the operator. The resynchronization period is the time between
a successful CCU resynchronization and the next CCU resynchronization attempt, typically
set to one hour. The retry period is the time between an unsuccessful resynchronization
attempt and the next resynchronization attempt, typically set to 30 seconds.
The operator can configure the CCU to act as an SNTP time server to the EUMs and
broadcast time information to all EUMs after it has synchronized with the NTP server. It also
broadcasts this information whenever an EUM powers up and registers.
UTC, the international time standard, is based on a 24-hour clock. It is the current term for
what was commonly referred to as Greenwich Mean Time (GMT). Universal time is based on
a 24 hour clock. SNTP, specified in RFC1769 and RFC2030, is a simplified version of NTP,
which is specified in RFC1305.
By default, the CCU SNTP client is disabled. Once SNTP is enabled, the CCU tries to
synchronize with an NTP server. The operator can configure the CCU to synchronize with
• a local router or network device, if the router or network device is configured as an
NTP time server,
• any open-access NTP server of the operator's choosing, or
• one of the five factory-default open-access NTP servers listed below:
•
•
•
•
•
50
Internet
Time Request
Figure 28
132.246.168.148 time.nrc.ca
140.162.8.3 ntp.cmr.gov
136.159.2.1 ntp.cpsc.ucalgary.ca
192.5.5.250 clock.isc.org
127.0.0.1 local host (the CCU itself)
Figure 28.
Antenna
Time
CCU3000
SNTP/GMT Time Clock
Time
Broadcast
EUM3000
stratum 2, Canada
stratum 2, US
stratum 2, Canada
stratum 1, US
APCD-LM043-4.0