Building a Stratum-1 GPS Based NTP Server with a Soekris net4501

Introduction:

If you are reading this article, the first thing you might be asking yourself is... What the heck is NTP? The shortest and simplest answer I can give is: NTP stands for Network Time Protocol which is a protocol for computers to synchronize their clocks with each other over a network.

The crystal inside the common PC is as basic and cheap as one can get, but it functions fine as the source for all the various clock frequencies that a modern PC needs to function. For timekeeping purposes though one will notice that it has a tendency to drift, and if left alone the PC's time can wander off considerably. NTP aims to compensate for this natural drift (and more) by polling other machines (running NTP) regularly and figuring out what the time should be.

Many people are probably familiar with the Internet Time tab when setting their clock in Microsoft Windows. What they are really doing is configuring a SNTP (Simple Network Time Protocol) client that polls a NTP server every so often to figure out what time it is. The full NTP implementation does a lot more, like polling several servers to determine what is the best time. The details of NTP's inner workings and features are really beyond the scope of this article, for more information I suggest you visit the official Network Time Protocol website.

In the corporate world having time synchronized between all your computers is essential for things like domain authentication, time-stamping any and all sorts of records / logs, or even just making sure you get notified about a meeting on-time. There are in fact some requirements in various industries that certain servers have time accurate to within so many milliseconds before they are allowed to process any records.

For the average home user I wouldn't say correct time is as mission-critical, but still necessary. Think about if the time on your HTPC was wrong and it stopped recording your favorite show a several minutes before the end? People with home offices, what if you were printing checks or sending out invoices and the date was completely wrong? Even at home, most people rely on their PC's clock more than they think.