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Computer Network Time Synchronization

The Network Time Protocol

Hardcover

Published: 24th March 2006
RRP $165.00
$149.50
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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. Penned by David L. Mills, the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol takes a broad look at the architecture, protocols, and algorithms involved in time dissemination, distribution, and synchronization. Focused on the fourth generation of NTP, Mills' magnum opus gives an in-depth configuration and performance analysis of typical deployed NTP networks as well as a detailed error budget showing the influence of network and computer delay variations on accuracy. Mills demonstrates the algorithms used to select measurements accessed via diverse pathways to achieve the best accuracy, addresses security issues in depth, and describes the engineering principles underlying NTP architecture and timestamping exchange procedures. Opening the door to highly precise time synchronization in both public and private networks, Computer Network Time Synchronization offers in-depth analysis, theory, and practical concerns in a unified and authoritative reference.

Basic Conceptsp. 1
Time Synchronizationp. 2
Time Synchronization Protocolsp. 3
Computer Clocksp. 5
Processing Time Valuesp. 7
Correctness and Accuracy Expectationsp. 8
Securityp. 10
NTP in the Internetp. 12
Parting Shotsp. 13
Referencesp. 14
How NTP Worksp. 15
General Infrastructure Requirementsp. 16
How NTP Represents the Timep. 17
How NTP Reckons the Timep. 19
How NTP Disciplines the Timep. 21
How NTP Clients and Servers Associatep. 22
How NTP Discovers Serversp. 24
How NTP Manages Network Resourcesp. 25
How NTP Avoids Errorsp. 26
How NTP Performance Is Determinedp. 28
How NTP Controls Accessp. 29
How NTP Watches for Terroristsp. 30
How NTP Clocks Are Watchedp. 31
Parting Shotsp. 32
Referencesp. 33
Further Readingp. 33
In the Belly of the Beastp. 35
Related Technologyp. 36
Terms and Notationp. 38
Process Flowp. 39
Packet Processingp. 40
Clock Filter Algorithmp. 43
Selection Algorithmp. 47
Clustering Algorithmp. 50
Combining Algorithmp. 53
Huff-'n-Puff Filterp. 54
Mitigation Rules and the Prefer Peerp. 55
Poll Processp. 57
Parting Shotsp. 58
Referencesp. 59
Further Readingp. 60
Clock Discipline Algorithmp. 63
Feedback Control Systemsp. 64
Phase and Frequency Disciplinep. 66
Weight Factorsp. 68
Poll Interval Controlp. 71
Popcorn and Step Controlp. 72
Clock State Machinep. 74
Parting Shotsp. 76
Referencesp. 76
Further Readingp. 76
NTP Subnet Configurationp. 77
Automatic Server Discoveryp. 78
Manual Server Discovery and Configurationp. 80
Evaluating the Sourcesp. 81
Selecting the Stratump. 81
Selecting the Number of Configured Serversp. 83
Engineering Campus and Corporate Networksp. 86
Engineering Home Office and Small Business Networksp. 87
Hardware and Network Considerationsp. 88
On Computer Selectionp. 88
On Networking Technologiesp. 89
Parting Shotsp. 91
Referencesp. 91
Further Readingp. 91
NTP Performance in the Internetp. 93
Performance Measurement Toolsp. 94
System Clock Latency Characteristicsp. 95
Characteristics of a Primary Server and Reference Clockp. 96
Characteristics between Primary Servers on the Internetp. 99
Characteristics of a Client and a Primary Server on a Fast Ethernetp. 105
Results from an Internet Surveyp. 108
Server and Network Resource Requirementsp. 110
Parting Shotsp. 112
Referencesp. 112
Primary Servers and Reference Clocksp. 113
Driver Structure and Interfacep. 114
Reference Clock Driversp. 117
Modem Driverp. 119
Local Clock Driverp. 120
PPS Driverp. 121
Audio Driversp. 122
Further Readingp. 123
Kernel Timekeeping Supportp. 125
System Clock Reading Algorithmp. 127
Clock Discipline Algorithmsp. 129
Kernel PLL/FLL Disciplinep. 131
Kernel PPS Disciplinep. 132
Clock Adjust Algorithmp. 134
Proof of Performancep. 135
Kernel PLL/FLL Discipline Performancep. 136
Kernel PPS Disciplinep. 141
Parting Shotsp. 143
Referencesp. 143
Further Readingp. 144
Cryptographic Authenticationp. 145
NTP Security Modelp. 146
On the Provenance of Filestampsp. 148
On the Naming of Thingsp. 149
On Threats and Countermeasuresp. 149
NTP Secure Groupsp. 150
Autokey Security Protocolp. 154
Session Key Operationsp. 155
Protocol Operationsp. 157
Parting Shotsp. 158
Referencesp. 158
Further Readingp. 159
Identity Schemesp. 161
X509 Certificatesp. 164
Private Certificate (PC) Identity Schemep. 165
Trusted Certificate (TC) Identity Schemep. 165
Schnorr (IFF) Identity Schemep. 166
Guillou-Quisquater (GQ) Identity Schemep. 168
Mu-Varadharajan (MV) Identity Schemep. 170
Parting Shotsp. 173
Referencesp. 173
Further Readingp. 174
Analysis of Errorsp. 175
Clock Reading Errorsp. 176
Timestamp Errorsp. 177
Sawtooth Errorsp. 179
Maximum Error Budgetp. 180
Expected Error Budgetp. 182
Parting Shotsp. 184
Referencesp. 185
Modeling and Analysis of Computer Clocksp. 187
Computer Clock Conceptsp. 188
Mathematical Model of the Generic Feedback Loopp. 193
Type-I Feedback Control Loopp. 195
Type-II Feedback Control Loopp. 196
Synthetic Timescales and Clock Wranglersp. 198
Parting Shotsp. 201
Referencesp. 202
Further Readingp. 202
Metrology and Chronometry of the NTP Timescalep. 203
Scientific Timescales Based on Astronomy and Atomic Physicsp. 205
Civil Timescales Based on Earth Rotationp. 207
How NTP Reckons with UTC Leap Secondsp. 209
On Numbering the Calendars and Daysp. 211
On the Julian Day Number Systemp. 213
On Timescales, Leap Events, and the Age of Erasp. 214
The NTP Era and Buddy Epochp. 216
Comparison with Other Computer Timescalesp. 218
Primary Frequency and Time Standardsp. 219
Time and Frequency Disseminationp. 221
Parting Shotsp. 224
Referencesp. 225
Further Readingp. 226
NTP Reference Implementationp. 227
NTP Packet Headerp. 228
Control Flowp. 231
Main Program and Common Routinesp. 234
Peer Processp. 235
System Processp. 240
Clock Discipline Processp. 243
Clock Adjust Processp. 247
Poll Processp. 247
Parting Shotsp. 250
Referencep. 250
Further Readingp. 251
Technical History of NTPp. 253
On the Antiquity of NTPp. 254
On the Proliferation of NTP around the Globep. 256
Autonomous Authenticationp. 257
Autonomous Configurationp. 258
Radios, We Have Radiosp. 259
Hunting the Nanosecondsp. 261
Experimental Studiesp. 263
Theory and Algorithmsp. 264
Growing Painsp. 266
As Time Goes byp. 267
Parting Shotsp. 267
Referencesp. 268
Further Readingp. 271
Bibliographyp. 273
Indexp. 283
Table of Contents provided by Ingram. All Rights Reserved.

ISBN: 9780849358050
ISBN-10: 0849358051
Audience: Professional
Format: Hardcover
Language: English
Number Of Pages: 304
Published: 24th March 2006
Dimensions (cm): 23.5 x 15.6  x 1.9
Weight (kg): 4.31