24/08/2005 ip telephony1 guided by: presented by: dr.s.k.ghosh nitesh jain 05it6008 m.tech 1 st year
TRANSCRIPT
24/08/2005 IP Telephony 1
IP Telephony
Guided by: Presented by: Dr.S.K.Ghosh
Nitesh Jain 05IT6008
M.Tech 1st year
24/08/2005 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
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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
• 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
• 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
• 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
• 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.
• 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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