NTP is the short form of Network Time Protocol. It is widely utilized for the time transfer across the internet networks. The main function of NTP is to deal with the synchronisation of network time clients in accord with precise time source.

The latest release is the version 4 of NTP. All previous versions of this internet protocol can be considered backward in comparison to this current release. There is a significant modification in this version as compared to the prior version 3. In version 4 of NTP, the header re-interpretation has been done so as to accommodate IPv6.

When it comes to the mode of operation of the NTP server systems the entire process of operation can be divided into three categories namely unicast, multicast and anycast. It is in the hands of client to initiate either unicast or anycast modes. The NTP server counters this use with a time message for the synchronisation process. Multicast is basically all about broadcasting. In multicast the time messages are broadcasted to the complete sub-domain at periodic intervals. The paradigm NTP division can deal with multiple external time references. GPS (Global Positioning System) is widely preferred as it provides with global accurate time reference.