The document discusses IP telephony and provides details on various aspects of the technology. It describes how IP telephony uses the internet protocol to send audio, video and data in real time between users. Different types of IP telephony are examined, including PC-to-PC, phone-to-phone over IP using gateways or adapter boxes, and PC-to-phone or phone-to-PC. Standards for IP telephony like H.323, SIP and MGCP are covered as well. The H.323 standard and its components such as terminals, gateways, gatekeepers and MCUs are explained in depth. Advantages and disadvantages of IP telephony are also highlighted.

1. A TECHNICAL
SEMINAR
ON
IP TELEPHONYIP TELEPHONY
BY
JAISHANKAR
KUMAR
(1201214265)(1201214265)
ELECTRONICS &
TELECOMMUNICATION
ENGINEERING

2. Introduction
• Internet telephony uses the Internet protocol
to send audio, video an data between two
or more users in the real time.
• IP telephony is the integration and
convergence of voice and data networks,
services, and applications.
• . In 1996, Vocaltec with an Intel Company
announced to produce the first IP telephony
gateway.

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Different Types Of
IP Telephony
• PC to PC
• Phone-to-phone over IP
• PC-to-Phone
• Phone-to-PC

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PC to PC
Figure 1 (ref: www.iec.com)

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Phone-to-phone over IP
using Gateways
Figure 2 (ref: www.iec.com)

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Phone-to-phone over IP
using Adapter Boxes
Figure 3 (ref: www.iec.com)

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PC-to-Phone or Phone-to-
PC
Figure 4 (ref: www.iec.com)

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Different type of IP telephony
Standard
• H.323 standard
• Session initiation protocol (SIP)
• Media gateway to media controller protocol
(MGCP)

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What is H.323
• The H.323 standard for the transmission of
real-time audio, video, and data
communications over packet-based
networks based on IP telephony.
• Currently the most widely-supported IP
telephony signaling protocol.

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H.323 Components
• Terminals
• Gateways
• Gatekeepers
• Multipoint Control Units (MCUs)

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• Terminals :
H.323 terminal can either be a personal
computer or a stand-alone device, running
an H.323 and the multimedia applications.
• Gateways :
An H.323 gateway provides connectivity
between an H.323 network and a non-H.323
network.

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Gatekeepers
• Call Authorization
• Call Management

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Multipoint Control Units:
• MCUs provide support for conferences of
three or more H.323 terminals. All terminals
participating in the conference establish a
connection with the MCU.

14. Protocols Specified by H.323 :
• real-time transfer protocol (RTP)
• real-time control protocol (RTCP)
14

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Real-Time Transport
Protocol
• Real-time transport protocol (RTP) provides
end-to-end delivery services of real time
audio and video.
• RTP is used to transport data via the user
datagram protocol
Real-Time Control Protocol
(RTCP)
• RTCP provides control services for RTP.

16. Advantages:
1.Guaranteed service delivery
2.Effectively bring together mobile and remote employees
3.free of cost

17. Dis-advantages:
• Exposure to Denial of Service attacks
• Challenging emergency calls
• Easy congestion

18. Conclusion
• Internet telephony is cost savings and
integrating new services.
• Internet Telephony is a powerful and
economical communication options by
combination of the telephone networks and
data networks.

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