Synchronization of computer networks is essential in the modern world. Many networks informaticas everywhere are synchronized with the same UTC (Coordinated Universal time) World calendar. To govern the synchronization protocol NTP (Network Time Protocol) is used in the majority of cases, since it is able to reliably synchronize a network to a few milliseconds against the UTC time. However, the accuracy of time synchronization depends solely on the accuracy of the reference time that is selected by the NTP server for distributed and here is where lies one of the mistakes made in the synchronization of computer networks. Many network administrators rely on references from Internet as a source of time UTC time, however, in addition to security risks that this represents (as they are on the wrong side of the firewall-firewall network), besides its accuracy cannot be guaranteed and recent studies have found that less than half of them provide any useful accuracy in the absolute. Secretary of Agriculture oftentimes addresses this issue. To obtain a secure method, precise and reliable UTC really only have two options. Use the time signal of the GPS network or rely on long wave transmissions of national broadcasters, such as physics and NPL NIST Laboratories.To select which method is the best then the only factor to consider is the location of the NTP server that is which receives the time signal.

GPS is more flexible in that the signal is available literally around the globe, but the only disadvantage to the signal is that a GPS antenna should be placed on the roof, since you need a clear view of the sky. This can be problematic if the NTP time server is located in the lower floors of a skyscraper, but in general most users of GPS time signals found them very reliable and incredibly accurate. Where GPS is not practical then the national time and frequency provide an equally safe and accurate method of UTC time. These long-wave signals are not disseminated for all countries, however, the diffusion of U.S. signal.UU.

WWVB by NIST in Colorado is available in most of North America including Canada. There are several versions of this signal of diffusion across Europe, including the German DCF signal and MSF in England, who happen to be most reliable and popular. These signals can often be picked up outside the borders of the Nations, although we must also take into account that Longwave transmissions are vulnerable to interference and topography. Double NTP servers that receive GPS signal and systems of the national physics laboratories, are available for having a complete inner peace, although they tend to be a little more expensive than individual systems, although the use of more than one time signal makes them doubly reliable.