Description:
The authors of Voice over IP Fundamentals--three packet-voice specialists at Cisco Systems--initiate their exploration of next-generation technologies for supporting conversations across large distances: the switched telephone network as implemented on large (intercontinental) and small (building and enterprise) scales. They then point out problems with the old way of doing things and illuminate the standards and regulatory conditions that have made Internet telephony attractive. Signaling System 7 (SS7) gets particularly insightful coverage, with ample graphical support for the clear, fact-rich, example-laden prose. The authors do a great service for readers by breaking packet telephony into its component technologies and explaining each one carefully. Coverage of the various protocols that enable voice over IP, particularly H.323 and Session Initiation Protocol (SIP), is simultaneously clear and deep. The same goes for media gateway protocols and various schemes for translating sounds into digital signals and back again, while retaining maximum clarity. There's even some practical material; concluding chapters diagram Cisco router configurations for voice traffic and flesh out solutions with case studies. You'll like this book if you need to implement a voice over IP system and know more about IP than you do about traditional voice telecommunications. The patient and detailed explanations of traditional telephony concepts and voice over IP protocols will mesh nicely with your existing data communications knowledge, enabling you to make wise design and product decisions. --David Wall Covered topics: The Public Switched Telephone Network (PSTN), signaling specifications (including Bell System, ISDN, and Signaling System 7), the basics of Internet Protocol (IP), modulation and compression of voice, Quality of Service (QoS), H.323, Session Initiation Protocol (SIP), and gateway protocols. Business considerations of Internet telephony are also addressed.
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