Installation and Operation Guide

1-8 TS-3000i Web Clock Installation & Operation Guide
Time Servers General Information
A time server is a server computer that reads the actual time from a
reference clock and distributes this information to its clients using a
computer network. The time server may be a local network time server or
an Internet time server.
The most important and widely-used protocol for distributing and
synchronizing time is the Network Time Protocol (NTP), though other
less-popular or outdated time protocols continue in use.
The time reference used by a time server could be another time server
on the network or the Internet, a connected radio clock or an atomic
clock. The most common true time source is a GPS or GPS master
clock. Time servers are sometimes multi-purpose network servers,
dedicated network servers, or dedicated devices. All a dedicated time
server does is provide accurate time.
An existing network server (e.g. a file server) can become a time server
with additional software. The NTP homepage provides a free and widely-
used reference implementation of the NTP server and client for many
popular operating systems. The other choice is a dedicated time server
device.
The term "stratum" is used to label the closeness to a central or high
quality time server. The stratum indicates the place of a particular time
server in a hierarchy of servers. The scale is 0 to 16 where 0 is the most
accurate and likely a highly specialized physical hardware device. Some
time clients will reject a time update from a server whose stratum is too
high, and most will prefer lower strata time sources to higher ones. This
can be a pitfall for administrators setting up an in-house time server with
no true time source.