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Informationen zum Autor WILLIAM A. FLANAGAN is President and founder of Flanagan Consulting. With three decades of telecommunications experience, Mr. Flanagan is an expert in voice and data technologies, products, markets, and customers. His network designs have solved problems for enterprises, government agencies, and carriers. Klappentext Translates technical jargon into practical business communications solutionsThis book takes readers from traditional voice, fax, video, and data services delivered via separate platforms to a single, unified platform delivering all of these services seamlessly via the Internet. With its clear, jargon-free explanations, the author enables all readers to better understand and assess the growing number of voice over Internet protocol (VoIP) and unified communications (UC) products and services that are available for businesses.VoIP and Unified Communications is based on the author's careful review and synthesis of more than 7,000 pages of published standards as well as a broad range of datasheets, websites, white papers, and webinars. It begins with an introduction to IP technology and then covers such topics as:* Packet transmission and switching* VoIP signaling and call processing* How VoIP and UC are defining the future* Interconnections with global services* Network management for VoIP and UCThis book features a complete chapter dedicated to cost analyses and payback calculations, enabling readers to accurately determine the short- and long-term financial impact of migrating to various VoIP and UC products and services. There's also a chapter detailing major IP systems hardware and software. Throughout the book, diagrams illustrate how various VoIP and UC components and systems work. In addition, the author highlights potential problems and threats to UC services, steering readers away from common pitfalls.Concise and to the point, this text enables readers--from novices to experienced engineers and technical managers--to understand how VoIP and UC really work so that everyone can confidently deal with network engineers, data center gurus, and top management. Zusammenfassung The new generation of voice services and telephony will be based on packet networks rather than TDM transmission and switching. This book addresses the evolution of telephony to Voice over IP (VoIP) and Unified Communications (UC), bringing email, voice mail, fax, and telephone services to one user interface. Inhaltsverzeichnis Preface xiii Acknowledgments xv 1 IP Technology Disrupts Voice Telephony 1 1.1 Introduction to the Public Switched Telephone Network 1 1.2 The Digital PSTN 2 1.3 The Packet Revolution in Telephony 8 1.3.1 Summary of Packet Switching 9 1.3.2 Link Capacity: TDM versus Packets 11 1.3.3 VoIP and "The Cloud" 13 IN SHORT: Reading Network Drawings 14 2 Traditional Telephones Still Set Expectations 17 2.1 Availability: How the Bell System Ensured Service 18 2.2 Call Completion 19 2.3 Sound Quality: Encoding for Recognizable Voices 20 2.4 Low Latency 23 2.5 Call Setup Delays 24 2.6 Impairments Controlled: Echo, Singing, Distortion, Noise 25 3 From Circuits to Packets 27 3.1 Data and Signaling Preceded Voice 27 3.1.1 X.25 Packet Data Service 27 3.1.2 SS7: PSTN Signaling on Packets 28 3.1.3 ISDN 29 3.2 Putting Voice into Packets 30 3.2.1 Voice Encoding 31 3.2.2 Dicing and Splicing Voice Streams 32 3.2.3 The Latency Budget 33 4 Packet Transmission and Switching 37 4.1 The Physical Layer: Transmission 39 IN SHORT: The Endian Wars 40 4.2 Data Link Protocols 41 4.3 IP, the Network Protocol 43 4.4 Layer 4 Transport Protocols 47 4.4.1 Transmission Control Protocol 47 4.4.2 User Datagram Protocol ...
