Most of us are aware of the term NTP servers as these are commonly used network elements and perform the very important role of synchronizing the clocks of network client and other devices. But how many of us know about the algorithms that enable these servers to perform this sync task? Here is a quick overview of the behind the scenes of any NTP server.
The key algorithms that act behind every NTP server are the Marzullo's algorithm and the Intersection Algorithm. Marzullo's algorithm was invented by Marzullo in the year 1984. This is an agreement algorithm that is used to select the correct sources for finding the accurate time from different time sources. The algorithm acts at a great speed and produces the result in optimal time. According to this, the best estimate from a list of estimates is the smallest interval that is consistent with the largest number of sources. In more stringent form it the smallest interval that is consistent with all the sources and if no such interval is found then, the one that matches large number of sources is the winner. The algorithm also states that the desired result is the best value from this chosen interval and it it's the center value of the interval.
The key disadvantage or demerit of the original Marzullo algorithm is that the returned result does not include the center point or the calculated offset of the different sources the intersection. To overcome this modified version of the original algorithm was introduced and was named the Intersection algorithm. This new mechanism is now the part of the current version of NTP. This algorithm returns the best interval that is returned by the Marzullo's but will also include the center points and hence may be larger than the one returned by the Marzullo's algorithm.
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Dave is an expert technical author in the field of LCD enclosures, as well as being an expert and major supplier of NTP servers and Network Time Servers. Article Source: http://EzineArticles.com/?expert=Dave_Bradley |