OSF DCE Administration Guide--Core Components

Appendix C. Time-Providers and Time Services
This appendix explains the criteria to use when selecting a time-provider, and describes
time dissemination services, time-providers (hardware and software) and their interaction
with DTS. The appendix also contains a world time zone map.
C.1 Criteria for Selecting a Time Source
Before you select a time source for your network, ask the following questions:
• How accurate is the time that is provided?
Accuracy is affected by the time source itself, as well as the transmission media. As
long as the inaccuracy is known, it can be compensated for.
• How reliable is the time source?
The time source must be available. If it is not , the server connected to the time-
provider uses times from other servers and compensates for any time difference when
the source again becomes available.
• What is the extent of coverage?
The time source must be available in the geographical area where the time-provider
server is located.
• What is the level of known inaccuracy?
If this is known, DTS can compensate for it. Most sources have known inaccuracy
levels.
• What is the cost?
• Does the source conform to the operating environment?
The available power supply and physical conditions must be compatible with the
source; consult the supplier for the specifications.
Table C-1 summarizes the selection criteria for each type of time source.
TABLE C-1. Time-Provider Selection Criteria
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