All PC's and networking devices use clocks to maintain an internal system time. These clocks, called Real Time Clock chips RTC provide time and date information. The chips are powered by batteries, so that even during power outages, they can synchronise and maintain accurate time.
Need for accurate NtpServer
Computer networks rely on timekeeping for nearly all their applications, from sending an email to saving data, a timestamp is necessary for computer to keep track. All routers and switches need to run at the same rate, out of sync devices can lead to data and even entire connections being lost.
Critical time operations
For some transactions it is necessary for computers to be perfectly synchronised, even a few seconds difference between machines can have serious effects, such as finding an airline ticket you had booked had been sold moments later to another customer or you could draw your savings out of a cash machine and when your account is empty you could quickly going to another machine and withdraw it all again.
Sensitive transactions, what's the time?
However, personal computers are not designed to be perfect clocks, their design has been optimized for mass production and low-cost rather than maintaining accurate time. However, these internal clocks are prone to drift and although for many application this can be quite adequate, often machines need to work together on a network and if the computers drift at different rates the computers will become out of sync with each other and problems can arise particularly with time sensitive transactions.
Simple solution: external NtpServer
NtpServer devices are like other computer servers in the sense they are usually located on a network. An NtpServer gathers timing information, usually from an external hardware source and then synchronises the network to that time. NtpServer Rackmount is a rack mountable NtpServer, which can be mounted along other servers.
NtpServer by a Professor
Most NtpServer devices use NTP which is one of the Internet's oldest protocols still used, invented by David L. Mills, PhD, Professor from the University of Delaware, it has been in utilized since 1985. NTP is a protocol designed to synchronize the clocks on computers and networks across the Internet or LANs.
NTP utilises an external timing reference and then synchronises all devices on the network to that time.
There are various sources that an NtpServer can use as a timing reference. The Internet is an obvious source, however, internet timing references from the Internet such as nist.gov and windows.time can not be authenticated, leaving the NtpServer and therefore the network vulnerable to security threats.
Often NtpServer devices are synchronised to a UTC source which is the global standard time scale and allows computers all over the world to synchronised to exactly the same time. This has obvious importance in industries where exact timing is crucial such as the stock exchange or airline industry. With great success GPS NtpServer emerged. They are synchronised to satellites around the globe and provide very accurate time information. GPS NTP manufactures such NtpServer devices.