future of voip by karan singh cypher

7/27/2019 Future of VOIP by Karan Singh Cypher

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The Future of Voice

over Internet Protocol


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Introduction

What is Voice Over Internet Protocol (VoIP)?

The two-way transmission of audio over a

packet-switched IP network.

When used in a private intranet or WAN, it is

generally known as 'voice over IP,' or 'VoIP.'

When the transport is the public Internet or the

Internet backbone from a major carrier, it isgenerally called 'Internet telephony.


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Introduction

Voice Over Internet Protocol (VoIP)

History

Implementation Service Types

Benefits

Drawbacks

Current and Projected Use


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History of VoIP

Network Voice Protocol

Created in 1973 by Danny Cohen at USC

Project Goals Wanted to create digital high-quality, low-bandwidth,secure voice handling capability

Control Protocol

Data Transport Protocol


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Circuit Switching

Current Phone Systems

Dedicated line with a constant connection

Originally very expensive Each call transmits at 64 kilobits per second

64 kbps x 2 directions = 128 kbps

128 kbps = 16 kilobytes per second During a 10 minute call, about 10 MB

Highly inefficient


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Packet Switching

Example: Packet Switching
http://electronics.howstuffworks.com/ip-telephony3.htmhttp://electronics.howstuffworks.com/ip-telephony3.htm


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Quality of Service (QoS)

Defined in the International

Telecommunication Union standard X.902

A set of quality requirements on thecollective behavior of one or more objects.

Control mechanisms to provide different

priorities to different users or data flows Important for real-time streaming applications


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VoIP Implementation

Sender picks up the phone

Analog telephone adapter (ATA)

Data converted by a codec Soft Switch

Receiver picks up ringing phone

Data transfer during calls is handled bycurrent internet infrastructure


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Analog Telephone Adapter (ATA)

Converts audio between analog and digital

signals

Need one on each end of the call Sends signal to handle connect and

disconnect


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Codecs

Coder-decoder or codecs

Conversion from analog audio signal to

digital signal Most common codec is the G.729A

sampling rate of 8,000 times per second

Conjugate-structure Algebraic-code-excitedLinear Prediction algorithm (CS-ACELP)

Responsible for the large gap in performance


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Soft Switches

Database mapping program

Endpoint-to-Endpoint

Location Phone Number

IP address

Allows phones, computers, and WiFi phonesto work together


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Industry Protocol Standards

H.323 Protocol Suite

Main flaw not designed for VoIP


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Industry Protocol Standards

Session Initiation Protocol (SIP)

Smaller, more efficient

Designed specifically for VoIP

Handles

User location

User capabilities

User availability Call setup

Call handling


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VoIP Service Types

Home Phones

Requires an ATA

Usually provided for free

IP Phones

ATA technology built in

Ethernet Phones

WiFi Phones Computer-to-Computer calls


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Computer-to-Computer VoIP

Simplest and cheapest way to use VoIP

Requires

Microphone

Speaker

Sound card

Broadband internet

Costs: Software and ISP service Calls: Free

Example: Skype Download Service
http://c/Program%20Files/Skype/Phone/Skype.exehttp://c/Program%20Files/Skype/Phone/Skype.exe


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Benefits

Uses technology already in common use

Cost

Bundled Services

Caller ID

Voice Mail

Call Waiting

Call Forwarding Many Others

Long Distance and International Rates


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Benefits

Cost of Calls Made from US to Foreign Countries


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Drawbacks

911 Emergency Calls

Dependence on Wall Power

Latency issues, jitter, and packet loss

Viruses, worms, and hackers

Integration with land-line dependanthardware

DVRs, digital television service, and homesecurity systems


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Drawbacks

Security

Problems sending faxes

Dependence on Internet Service Providers

Requirement of broadband connectivity

WiFi hotspot dependence


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Current and Projected Use

Roughly 6 million in US in 2006

Expected to climb to 24 million by the end of2008

Increase in service providers

Traditional phone companies At&T, Sprint, Nextel, Time Warner

VoIP companies Skype, Vonage, VoIP Inc.


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Conclusion

VoIP will be a dominate force in the 21stcentury

Probably at least another 10 years before

possibly replacing current phone systems If the current flaws are fixed sooner rather

than later, it could be much sooner than a

decade

future of voip by karan singh cypher

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