NATIONAL INSTITUTE OF SCIENCE & TECHNOLOGY VOICE OVER INTERNET PROTOCOL SHREETAM MOHANTY [1] VOICE...

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VOICE OVER INTERNET PROTOCOL


SHREETAM MOHANTY ROLL # EC200118010

UNDER THE GUIDANCE OF

N. SRINIVASU

SUBMITTED

BY


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INTRODUCTION

What is VOIP ?

Voice over Internet Protocol transfers voice through IP packets through the Internet. VoIP can use special hardware or a PC environment to achieve this purpose.

How does VOIP works:

Voice (source) - - ADC - - - - Internet - - - DAC - - Voice (dest)


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PACKET FREQUENCY

●Packet frequency as the number of packets containing voice samples which are sent per second

Components of H.323● Terminals● Gateways● Gatekeepers


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H.323 TERMINAL SUPPORTING OTHER PROTOCOLS

●H.245 : allowing the usage of the channels.

●Q.931: call signaling and setting up the call

●RTP: carries voice packets

●RAS: interacting with the gatekeeper


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GATEWAYS

●Interface between the PSTN and the Internet

●Translator : H.225 to H.221 or audio to video


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GATEKEEPERS

●Controls the end points under its zone

Function

●Address Translation ●Admissions Control ●Call signaling ●Call Authorization ●Bandwidth Management


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H.323 PROTOCOL STACK


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DEFINITIONSZoneThe collection of a gatekeeper and the endpoints registered with it is called a zone Network AddressFor each H.323 entity, a network address is assigned and this address uniquely identifies the H.323 entity on the network TSAP Identifier These TSAP identifiers allow multiplexing of several channels sharing the same network address


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CALL SETUP IN H.323

Endpoint enters the call setup phase Discovering a gatekeeper which would take the management of that endpoint

The capability exchange takes place between the endpoint and the gatekeeper

Registration of the endpoint with its gatekeeper

The call is established


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MULTIPOINT CONTROL UNITS (MCU)


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SESSION INITIATION PROTOCOL (SIP)

●It is an application layer control protocol for creating, modifying and terminating sessions with one or more participants


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SIP MESSAGES

INVITE: for inviting a user to a callBYE: for terminating a connection between the two end points ACK: invitation for reliable exchange of messages OPTIONS: for getting information about the capabilities of a call REGISTER: gives information about the location of a user to the SIP registration server. CANCEL: for terminating the search for a user


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SAMPLE SIP OPERATION


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SUPPORTING PROTOCOLS


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CONCLUSION

●Like everything else, as the technology changes so At first, only a few companies like Cisco and Lucent offered VoIP services, but the large telecommunications carriers – such as AT&T and Sprint -- are catching on

●VoIP is predominately used for personal instead of enterprise-wide use, but will the people who use it.

NATIONAL INSTITUTE OF SCIENCE & TECHNOLOGY VOICE OVER INTERNET PROTOCOL SHREETAM MOHANTY [1] VOICE...

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