Transcript IP Telephony

IP Telephony
Guided by:
Dr.S.K.Ghosh
Presented by:
Nitesh Jain
05IT6008
M.Tech 1st year
24/08/2005
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CONTENTS
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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
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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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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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Different Types Of
IP Telephony
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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.
• 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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H.323 Components
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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
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Address Translation
Admission Control
Bandwidth Control
Zone Management
Call-Control Signaling
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.
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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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H.225 RAS
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Gatekeeper discovery
Endpoint registration
Endpoint location
Admission control
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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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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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H.323 Call Establishment
Figure 5 (ref: www.iec.com)
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H.323 Control signaling Flows
Figure 6 (ref: www.iec.com)
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H.323 Media stream & media
control flow
Figure 7 (ref: www.iec.com)
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H.323 Call Release
Figure 8 (ref: www.iec.com)
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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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References :
• Book on “IP Telephony“Olivier Hersent,
David Gurle & Jean-Pierre Petit.
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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/
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THANK YOU
?
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