The document discusses IP Telephony and the H.323 standard. It describes how IP Telephony uses the internet protocol to send audio, video, and data in real-time. The H.323 standard specifies protocols for multimedia communications over packet-based networks, including signaling protocols for call setup and control, as well as protocols for audio and video transport. The document outlines the components, protocols, call flows, and benefits of IP Telephony and the H.323 standard.

1. IP Telephony
Presented by:
Syed Iftekhar Hussain Rizvi
09/03/2013 IP Telephony 1

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
09/03/2013 IP Telephony 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.
09/03/2013 IP Telephony 3

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.
09/03/2013 IP Telephony 4

5. Different Types Of
IP Telephony
• PC to PC
• Phone-to-phone over IP
• PC-to-Phone
• Phone-to-PC
09/03/2013 IP Telephony 5

6. PC to PC
Figure 1 (ref: www.iec.com)
09/03/2013 IP Telephony 6

7. Phone-to-phone over IP
using Gateways
Figure 2 (ref: www.iec.com)
09/03/2013 IP Telephony 7

8. Phone-to-phone over IP
using Adapter Boxes
Figure 3 (ref: www.iec.com)
09/03/2013 IP Telephony 8

9. PC-to-Phone or Phone-to-
PC
Figure 4 (ref: www.iec.com)
09/03/2013 IP Telephony 9

10. Different type of IP telephony
Standard
• H.323 standard
• Session initiation protocol (SIP)
• Media gateway to media controller protocol
(MGCP)
09/03/2013 IP Telephony 10

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.
09/03/2013 IP Telephony 11

12. H.323 Components
• Terminals
• Gateways
• Gatekeepers
• Multipoint Control Units (MCUs)
09/03/2013 IP Telephony 12

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.
09/03/2013 IP Telephony 13

14. Gatekeepers
• Address Translation
• Admission Control
• Bandwidth Control
• Zone Management
• Call-Control Signaling
• Call Authorization
• Call Management
09/03/2013 IP Telephony 14

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.
09/03/2013 IP Telephony 15

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)
09/03/2013 IP Telephony 16

17. H.225 RAS
• Gatekeeper discovery
• Endpoint registration
• Endpoint location
• Admission control
09/03/2013 IP Telephony 17

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
09/03/2013 IP Telephony 18

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.
09/03/2013 IP Telephony 19

20. H.323 Call Establishment
Figure 5 (ref: www.iec.com)
09/03/2013 IP Telephony 20

21. H.323 Control signaling
Flows
Figure 6 (ref: www.iec.com)
09/03/2013 IP Telephony 21

22. H.323 Media stream &
media control flow
Figure 7 (ref: www.iec.com)
09/03/2013 IP Telephony 22

23. H.323 Call Release
Figure 8 (ref: www.iec.com)
09/03/2013 IP Telephony 23

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.
09/03/2013 IP Telephony 24

25. References :
• Book on “IP Telephony“Olivier Hersent,
David Gurle & Jean-Pierre Petit.
• www.iec.org/online/tutorials/
• www.cis.ohio-state.edu/~jain/
• www.cs.columbia.edu/~coms6181/
• www.cisco.com/
• www.tmcnet.com/
• www.javvin.com/
09/03/2013 IP Telephony 25