Computer Network Time Synchronization: The Network Time Protocol

by David L. Mills

Book Overview

What started with the sundial has, thus far, been refined to a level of precision based on atomic resonance: Time. Our obsession with time is evident in this continued scaling down to nanosecond resolution and beyond. But this obsession is not without warrant. Precision and time synchronization are critical in many applications, such as air traffic control and stock trading, and pose complex and important challenges in modern information networks...

• Format: Hardcover
• Language: English
• ISBN: 0849358051
• ISBN13: 9780849358050
• Release Date: March 2006
• Publisher: CRC Press
• Length: 286 Pages
• Weight: 1.25 lbs.
• Dimensions: 0.8" x 6.3" x 9.6"

Customer Reviews

The Bible of NTP

It is interesting that the so called 'Atomic' clocks you can buy in supermarkets or WalMart/Target are more accurate than anything you could have gotten only a few years ago and for a very little money. But when it comes to computers, they tend to use very inexpensive clocks and on a network there is normally no effort made to synchronize the individual machines. 'This book,' to quote the opening sentence. 'is all about wrangling a herd of network computers so that all display the correct time.' It is specifically is about the Network Time Protocol (NTP), a twenty year old standard that is now well defined, robust, and heavily used. Heavily used means some 25 million clients getting the time from the National Institute for Science and Technology (NIST). A properly set up network can have all participating computers synchronized to less than a millisecond with a time check every fifteen minutes or so. This book is the Bible of the subject. It is suitable for a network administrator, or if you want to go deeper into the subject it contains enough information to take you just as far as you want to go. You might miss it if you don't read it carefully, but Dr. Mills is the original developer of NTP. He can take you down into the mathematics of the algorithms in one chapter, and write casually like he does in the opening sentence.

A must for NTP Administrators

This is the Bible of NTP. Having administered NTP for several years I am pleased to see this work has been completed and published. It is a valuable reference. Setting up NTP is a very simple task but to understand the nuts of bolts of NTP requires patients and devotion to the subject matter and this text greatly aids in that process. The book is also very lightweight which is nice because it doesn't weigh down my backpack and I can take it wherever I go. Long story short if you administer NTP this book is must.

The definitive reference on how to deploy and use NTP

For most people, having their clocks accurate to within a few millionths of a second is excessive. Yet there are plenty of reasons to ensure that clocks on networks and production systems are that accurate. In fact, the need for synchronized time is a practical business and technology decision that is an integral part of an effective network and security architecture. The reality is that an organizations network and security infrastructure is highly dependent on accurate, synchronized time. From a practical perspective, nearly every activity requires synchronized time to operate at peak levels, from plane departures and sporting events, to industrial processes, IP telephony, GPS and much more. Within information technology, technologies from directory services, collaboration, to authentication, SIM and VoIP all require accurate and synchronized time to work effectively. Computer Network Time Synchronization: The Network Time Protocol is a valuable book for those that are serious about network time synchronization. David Mills, the author of the book, is one of the pillars of the network time synchronization community, and an original developer of the IETF-based network time protocol (NTP). The book is the summation of his decades of experience and a detailed look at how to use NTP to achieve highly accurate time on your network. While network time synchronization is indeed crucial to corporate networks, this is only the second book on the topic. Last year saw Expert Network Time Protocol: An Experience in Time with NTP, which is a most capable title. But this book is clearly the indisputable reference on the subject, given its extraordinary depth and breadth. While Expert Network Time Protocol gets into the metaphysics of time, Mills's book takes a much more rationalist and pragmatic approach, which explains the myriad mathematical equations. Mills is an electrical engineer by training and a significant part of the books 15 chapters involve advanced mathematics. But even for those who can't manage such equations, there is enough relevant material to make the book most rewarding. Chapters 1 and 2 provide an excellent overview of the basics of network timekeeping and an overview of how NTP works. We often take for granted that network computers have the capabilities to set their internal clock. But while the capabilities are there, the reality is that these clocks are rarely accurate and subjected to many externalities that affect their ability to provide accurate time. The book shows how highly accurate time is easily achievable; often without the need for additional hardware. The goal of book is to show the reader how they can use NTP to synchronize the time on their network hosts to within a few milliseconds. Chapters 3 - 11 detail the internals of NTP and time synchronization. Topics such as clock discipline algorithms, clock drivers and more are detailed. For many readers, the information may be overkill, but remember that this is not a