ABSTRACT
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book demonstrates that the ultimate accuracy at the application program interface of a modern computer with access to a precision timing source is on the order less than a microsecond. Computer scientists like to model timekeeping in a distributed computer network as a happens-before relation; that is, every event that occurs in one computer must happen before news of that event gets to another computer. Network Time Protocol is more than a protocol; it is an integrated technology that provides for systematic dissemination of national standard time throughout the Internet and affiliated private and corporate networks. A reliable network time service requires provisions to prevent accidental or malicious attacks on the servers and clients in the network.
