Ccna routing and Switching Complete Study Guide

Network Time Protocol (NTP)

Kudos to Professor David Mills of the University of Delaware for coming up with this handy 

protocol that’s used to synchronize the clocks on our computers to one standard time source 

(typically, an atomic clock). Network Time Protocol (NTP) works by synchronizing devices 

to ensure that all computers on a given network agree on the time (Figure 3.9).

This may sound pretty simple, but it’s very important because so many of the transac-

tions done today are time and date stamped. Think about databases—a server can get 

messed up pretty badly and even crash if it’s out of sync with the machines connected to it 

by even mere seconds! You can’t have a transaction entered by a machine at, say, 1:50 a.m. 

when the server records that transaction as having occurred at 1:45 a.m. So basically, NTP 

works to prevent a “back to the future sans DeLorean” scenario from bringing down the 

network—very important indeed!

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TCP/IP and the DoD Model 

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I’ll tell you a lot more about NTP in Chapter 7, including how to configure this protocol 

in a Cisco environment.