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

KIST

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.

Protocols Specified by H.323 :

• real-time transfer protocol (RTP)

• real-time control protocol (RTCP)

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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.

Advantages:

1.Guaranteed service delivery

2.Effectively bring together mobile and remote employees

3.free of cost

Dis-advantages:• Exposure to Denial of Service attacks

• Challenging emergency calls

• Easy congestion

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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