Symmetricom SyncServer S100, Руководство пользователя

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S100 User Guide – Rev. D – June 2005 7
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Chapter 2
S100 Technology
Overview
This chapter gives a review of the S100 technology.
There is additional information in “S100 Specifications” on page 119 .
S100 Product Overview
The S100 network time server synchronizes secure network time. The following sections
describe this technology.
Sources of Time
The S100 obtains time from GPS, ACTS, or another S100, and delivers it to computers and
other devices on a network. It acquires UTC (Universal Coordinated Time) from GPS signals,
or using ACTS dial-up to the National Institute of Standards and Technology (in the U.S.). If
there are several S100s on your network, only a few S100s need acquire UTC directly. They
can then distribute that time to other S100s.
On the Network
Clients on a network synchronize with a time source using NTP, the Network Time Protocol,
to exchange packets of time. The S100 implements NTP Version 4. This prevents intruders
from spoofing time packets and using NTP to gain access to your systems. Unlike previous
versions, NTP Version 4 implements asymmetric encryption. This is the same technique used