Expert Network Time Protocol: An Experience in Time with NTP (Expert's Voice) 1st ed. Edition

I wanted a book that explains how NTP works, so I gambled $4.00 on a used copy of this one.I lost.If you want some lightweight handholding in setting up an NTP configuration, especially on Unix/Linux systems, this book would be OK. It's no substitute for the reference documentation that comes with NTP software, but it does give a reasonable overview--the sort of thing that could be easily conveyed in a ten-page white paper, not a whole book.However, if you want a robust explanation of what NTP does to handle errors, clock drift, and communication problems, this isn't it. There are a few packet dumps, but the explanation doesn't say much about what the packets mean, and doesn't begin to touch on how the protocol actually works.I fund no outright errors in the book, just an extraordinary percentage of fluff. I should have bought Computer Network Time Synchronization: The Network Time Protocol in the first place.

This book contained less than 100 pages of useful information. The relevant information was good, but whether it was worth the price is debatable. I bought the book used for half price and still didn't feel I got my moneys worth.

I had been hoping that someone would come out with a good book on NTP, so when I saw Apress had such an offering, I jumped at the chance to get my hands on a copy. And while having read the book I came away with a better understanding of the protocol itself, I wish the book had done better at covering the implementations of the protocol. Plenty of "what", but not enough "how."The book is divided into two parts. The first part is short (about 40 pages) and presents Sam, a being who dwells in the center of the Sun and is impervious to the effects of time. Sam takes us on a tour of the various ways in which humans have attempted to make sense of time through scientific means such as classical mechanics, special and general relativity, quantum mechanics, and superstring theory. Sam also muses on philosophical approaches to time, and the advances of time-keeping through human history.This first section is thought-provoking and enjoyable to read. Thinking about how NTP implementations on intergalactic networks of the future will have to take into effect things like time-dilation affecting starships travelling at near light-speed to synchronize clocks throughout the network is a good stretch of the mind, for example. From a stylistic point of view, however, that enjoyment is dampened by the frequent shifting of tense between past and present in the section, which is distracting. Perhaps such can be explained away as the character Sam isn't constrained by such concepts of past, present, and future, but for those of us mortals who are under such constraints, the frequent shifting between tenses calls for better editing.The second section of the book consists of 3 chapters. The first offers a general description of the Network Time Protocol itself, describes the various packets that are transmitted in the protocol, and covers the historical development of the protocol. The next chapter covers NTP architecture including the various modes in which NTP can operate, security issues surrounding NTP implementations and a discussion of different NTP time sources. The final chapter of the book covers different deployment topologies and scenarios, and gives examples of NTP configurations on 3 common platforms, UNIX/Linux, Juniper's JUNOS, and Cisco's IOS.The first 2 chapters of the second part of the book are very good, and are useful for anyone trying to better understand the NTP protocol itself, and the various issues related to deploying NTP on networks of any size. The "theory" and fundamentals are well covered here. Unfortunately, the final chapter of the book leaves something to be desired. I would like to see a more thorough discussion of various configuration scenarios, with a lot more examples than were given. Instead only a few examples are given for each of the 3 platforms, and the surrounding discussion is rather shallow.To be fair, the author explains the situation in the following words at the end of the book:"This book could have been larger! It could have catalogued every NTP implementation on every conceivable networking device and operating system since the protocol's inception. But ironically, in that case the effort would have suffered the ravages of time and never reached the printed page. Thus, what's behind you represents a compromise that time forces all writers to make."While I agree that to exhaustively catalog every NTP implementation in existence would be fruitless, I really think the author and editors could have done a better job than the handful of pages devoted to configuration on the 3 platforms (UNIX/Linux, Cisco, Juniper). I think a chapter dedicated to each of the 3 platforms offering some deeper discussion and more examples of different types of configurations would be ideal.As a final note, I wish the various algorithms used by NTP to do the actual time synchronization were given more attention. Perhaps the algorithms used aren't specified in the RFCs, but it would be nice to see a few examples of what algorithms are commonly used.Overall the book is good. If you're thinking of deploying NTP in your network you'll find plenty of helpful information here and plenty of good reasons for doing so as well. But if you're looking for specific examples of how to configure, say, ntpd on a Linux machine, you might want to look elsewhere also.

I once heard a Buddhist master, speaking of the nature of maya declare, "Time is not; space is not." But when I have to catch a bus, I find myself much less interesrted in philosophy than in being at the bus stop at the same illusory time as the bus.Now, if you think that concept is a bit too commonplace to be worth mentioning, consider the consequences when said bus is carrying "passengers" traveling at the speed of light, such as the electronic denizens of our computers.As Elvis would put it, "There's a whole lot a shakin' goin' on in there." And for a guy like me, whose tolerance for complexity doesn't extend beyond rebuilding a 1960 Chevy standard tranny, I think stuff like Network Time Protocol is a Godsend. Keeping track of differences in clock precision, different operation modes--server, client, host and peer, symmetric active, symmetric passive, broadcast, multicast, manycast/anycast, and a veritable multitude of variables determining the success or failure of the transmission and reception of a simple message could definitely affect your ability to get a good night's sleep. Praise NTP.But that's just the beginning. As Rybaczyk points out, there is more to this univese than us poor Horatios ever dreamt of in our philosophy. If we are ever to succeed in deep space travel, for instance, we will have a lot more than wristwatch consulting to keep us busy as we attempt to coordinate extraterrestrial events. Rybaczyk even joins forces with Pandora as he forces us to peer into the black box of life at the quantum level. "Different strokes for different folks," they say. Well, how does one know when the stroke of, say 9 pm, occurs when the operational time frame is in billionths of a second and even the concept of a "second" is relative conjecture?Personally, I am content with "Que sera sera" and enjoying the modulating frequencies of a setting sun. But some of our species seems bent on other schemes. They would do well to study Rybaczyk's very first chapter, "Multiple Views of Time," before burying themselves in untimely assumptions. Sam, Rybaczyk's protagonist, adroitly navigates the temporal stream, punctuating the story liberally with asides--humorous, informative, dramatic, zealous, some even a bit caustic--only to finally arrive at the conclusion that NTP lies at the heart of a possible future (silly concept) in which memory is shorn of its mystery, time is transcended, and the past, present and future are found to be mere figments of minds mired in mythical maya, mostly oblivious to Shakespeare's observation, "we are such stuff as dreams are made on."Get Rybaczyk's book. Even if you have no professional interest in computing, read the first three chapters. Partake of the author's fantastic ability to draw analogies between everyday and historical events and the inner workings of the computers we have become so dependent upon. Share his amusement at time's seemingly innocent and subtle, yet fantastically determinative influence upon the experience of our unique down-to-earth version of the timeless beyond.