How does VoIP work? A technical guide to functional VoIP |
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| 01 Jun 2006 | SearchVoIP.com |
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By now, you probably have a general idea of what VoIP is, but do you understand how it works? Do you know how many bits are in a conventional PCM voice sample or what "look-ahead" used for? Do you know which two modes a caller can use to set up a call with SIP? If you don't know the answers to these questions, you will after reading SearchVoIP.com's technical guide to VoIP. Learn how call signaling and gateways work and why VoIP calls are particularly susceptible to delay and echo. Uncover the functional elements of SIP, H.323 and MGCP and why softswitches are not really switches at all.
After you've read through guide, test how much you learned in the Do you really know VoIP? quiz. Let us know how many questions you got right and if there is something you'd like to learn more about.
CONTENTS
 Section 1: How is transmitting voice different from sending data?
Section 2: What causes QoS problems with VoIP?
Section 3: How does VoIP work?
How do VoIP gateways work?
What is an IP packet?
Understanding VoIP delay
How do lost packets impact VoIP QoS?
Controlling VoIP echo
Section 4: What are media gateways and how do H.323, SIP, MGCP and other support protocols work?
How does H.323 work?
How does SIP work?
How does MGCP work?
How does Megaco or H.248 work?
Section 5: Quiz: Do you really know VoIP?
Section 6: References
About the author:
Roger Freeman is a widely recognized expert in telecommunications system engineering. Roger has worked in telecommunications since 1946 when he joined the Navy and became an aviation radioman. Later, Roger served as a radio officer in the merchant marine for nearly 10 years. He then held several positions with ITT assigned to their Spanish Standard Electrica subsidiary. He also served the International Telecommunication Union as Regional Planning Expert for Northern Latin America based in Quito, Ecuador. Roger is bilingual. His last employee position was principal engineer with the Raytheon Company, Marlboro, MA where he took early retirement in 1991 to establish Roger Freeman Associates, Independent Consultants in Telecommunications. He has been giving seminars in telecommunication disciplines at the University of Wisconsin, Madison for nearly 20 years. Roger has been writing books on various telecommunication subjects for John Wiley & Sons since 1973. There are seven titles, which he keeps current including the two-volume work, Reference Manual for Telecommunication Engineers, now in 3rd edition. He holds two degrees from NYU. His Web site is www.rogerfreeman.com and his e-mail address is rogerf67@cox.net.
Here are Roger's landmark books:
- Radio System Design For Telecommunications, 2nd Ed. Wiley NY - 1997
- Reference Manual For Telecommunications Engineering, 3rd Ed. Wiley NY - 2001
- Telecommunication System Engineering, 4th Ed. Wiley NY - 2004
- Telecommunications Transmission Handbook, 4th Ed. Wiley NY - 1998
- Practical Data Communications, 2nd Ed. Wiley NY - 2001
- Fundamentals Of Telecommunications, 2nd Ed, Wiley NY - 2005
- Fiber Optic Systems For Telecommunications, Wiley NY - 2002
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