OSF DCE Administration Guide--Core Components

Time-Providers and Time Services
Transmits at 2.5, 5.0, 10.0, 15.0 MHz to North America and South America.
• WWVB
Transmits at 60 kHz primarily to the United States, providing high-quality frequency
information because atmospheric propagation effects are relatively minor.
• WWVH
Transmits at 2.5, 5.0, 10.0, 15.0 MHz to Alaska, Hawaii, Australia, New Zealand,
Japan, and Southeast Asia.
The following stations are available in Europe:
• MSF
Broadcasts from England at 60 kHz.
• DCF77
Broadcasts from Germany at 77.5 kHz.
In addition to the stations previously listed, more than 30 radio stations worldwide
provide UTC time. Consult the national standards organization in your country for
further information.
C.2.3 Network Time Protocol
Nodes that have Internet access can use the Network Time Protocol (NTP) as a source of
UTC time for DTS. (See Chapter 26 for an explanation of how to use NTP as a time-
provider.)
C.2.4 Satellite
Satellites have worldwide availability; they can provide relatively precise times if their
delays are known and compensated for. See the following list for satellite sources of
UTC:
• GOES
Geostationary Operational Environment Satellite
• TRANSIT
A U.S. Navy satellite system consisting of four tracking systems and two ground
satellite communications sites
• GPS
Global Positioning System, a satellite receiver
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