This document provides an overview of IP telephony and the H.323 standard. It describes the different components of H.323 including terminals, gateways, gatekeepers, and MCUs. It explains the protocols specified by H.323 such as H.225, H.245, RTP, and RTCP. It also provides high-level descriptions of H.323 call establishment, control signaling flows, media streams, and call release. The document concludes that IP telephony provides cost savings and new services by combining telephone and data networks into a powerful and economical communication option.

1. Seminar
On
IP Telephony

2. CONTENTS
 INTRODUCTION
 DIFFERENT TYPES
 WHAT IS H.323
 H.323 COMPONENTS
 PROTOCOL SPECIFED BY H.323
 H.323 CALL ESTABLISHMENT
 H.323 CONTROL SIGNALING FLOW
 H.323 MEDIA STREAM & MEDIA
CONTROL FLOW
 H.323 CALL RELEASE
 CONCLUSION 2

3. 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.
 The main motivation of development of IP Telephony
is the cost saving & integrating new services.
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4. Introduction (cont…)
 Vocaltec introduced the first Internet telephony
software product in early 1995. Running a multimedia
PC, the Vocaltec Internet Phone.
 In 1996, Vocaltec with an Intel Company announced
to produce the first IP telephony gateway.
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5. Different Types Of
IP Telephony
 PC to PC
 Phone-to-phone over IP
 PC-to-Phone
 Phone-to-PC
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6. PC to PC
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7. Phone-to-phone over IP
using Gateways
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8. Phone-to-phone over IP
using Adapter Boxes
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9. PC-to-Phone or Phone-to-PC
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10. Different type of IP telephony
Standard
 H.323 standard
 Session initiation protocol (SIP)
 Media gateway to media controller protocol (MGCP)
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11. 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.
 H.323 is a standard produced by the ITU-T Study
Group 16.
 Currently the most widely-supported IP telephony
signaling protocol.
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12. H.323 Components
 Terminals
 Gateways
 Gatekeepers
 Multipoint Control Units (MCUs)
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13.  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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14. Gatekeepers
 Address Translation
 Admission Control
 Bandwidth Control
 Zone Management
 Call-Control Signaling
 Call Authorization
 Call Management
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15. 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.
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16. Protocols Specified by H.323
 audio CODECs
 video CODECs
 H.225 registration, admission, and status (RAS)
 H .225 call signaling
 H.245 control signaling
 real-time transfer protocol (RTP)
 real-time control protocol (RTCP)
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17. H.225 RAS
 Gatekeeper discovery
 Endpoint registration
 Endpoint location
 Admission control
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18. H .225 call signaling
 H.225 call signaling is used to set up connections between
H.323 endpoints over which the real-time data can be
transported.
 Two types :
 Direct call signaling
 Gateway routed call signaling
H.245 Control Signaling
 Capabilities Exchange
 Logical Channel Signaling
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19. 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.
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20. H.323 Call Establishment
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21. H.323 Control signaling Flows
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22. H.323 Media stream & media control flow
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23. H.323 Call Release
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24. 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.
 Many public telecommunication operators are
establishing their own IP telephony services, and
using IP-based networks as alternative transmission
platforms.
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25. Thanks