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Voice over IPVoice over IP
Habib UllahHabib Ullah
12-MS-CSc-1212-MS-CSc-12
Contents
 Abstract
 What isVoIP
 HowVoIP works
 VoIP Architecture
 Components
 Pros & Cons
 Summary
Abstract
 Voice over Internet Protocol
(VoIP) is a technology that
enables one to make and
receive phone calls through
th...
What is VoIP?
 VoIP is packetisation and transport of
classic public switched telephone system
audio over an IP network.
...
PSTN vs. INTERNET
PSTN
 Voice network use circuit
switching.
 Dedicated path between
calling and called party.
 Bandwid...
PBX
Yesterday’s Networks
Circuit Switched Networks (Voice)
CO
PBX
CO
CO
Packet Switched Networks (Data)
Router
Router
Rout...
PBX
IP Phone
Converged Network
PSTN
CO
Gateway
Router
Router
Router
Router
• Converged network
• Separated or integrated a...
VoIP – How does it work?
 Converting the voice signal
 ADC (analog to digital)
 DAC (digital to analog)
Voice (source) ...
VoIP – How does it work?
 The 1-2-3s of VoIP
 1. Compression – voice is compressed
typically with one of the following c...
LT
S©Telcordia Technologies, Inc. Slide 10
IP Network
Multimedia
PC
Multimedia
PC
Initially, PC to PC
voice calls over the...
Components
 VoIP Protocols
 VoIP Gateway
 VoIP Codecs
VoIP Network Model
SIP
RTP, RTCP, RTSP
Transport Layer (UDP, TCP)
Network Layer (IP, IP Multicast)
Data Link Layer
Physica...
PURC
IP Protocol LayeringIP Protocol Layering
Physical Transport (e.g, Cable Modem)
IP (Internet Protocol)
TCP UDP
Applica...
VoIP SIP
VoIP Gateway
 A VoIP gateway is a gateway device that uses Internet
Protocols to transmit and receive voice communication...
VoIP Codecs
 Codecs are used to convert an analog voice signal to
digitally encoded version. Codecs vary in the sound
qua...
Do Companies Want VoIP?
76% Will!76% Will!
Unsure
4%
Not at all
likely
4%
Not very
likely
16%
Likely
28%
Very likely
32%
E...
Key Business Drivers for LAN-Based Telephony and VoIP
81%81%
59%59%
38%38%
26%26%
0 50 100
Save MoneySave Money
Better Uti...
Security Risks
 AsVoIP uses the Internet, for example, it is vulnerable to
the same type as security risks
 Hacking
 De...
Summary
Questions?
Voice Over IP (VoIP)
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Voice Over IP (VoIP)

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Voice Over IP (VoIP)

  1. 1. Voice over IPVoice over IP Habib UllahHabib Ullah 12-MS-CSc-1212-MS-CSc-12
  2. 2. Contents  Abstract  What isVoIP  HowVoIP works  VoIP Architecture  Components  Pros & Cons  Summary
  3. 3. Abstract  Voice over Internet Protocol (VoIP) is a technology that enables one to make and receive phone calls through the Internet instead of using the traditional analogy PSTN (Public Switched Telephone Network) lines.
  4. 4. What is VoIP?  VoIP is packetisation and transport of classic public switched telephone system audio over an IP network.  It allows 2-way voice transmission over broadband connection.  It is also called IP telephony, internet telephony, voice over broadband, broadband telephony.
  5. 5. PSTN vs. INTERNET PSTN  Voice network use circuit switching.  Dedicated path between calling and called party.  Bandwidth reserved in advance.  Cost is based on distance and time. INTERNET  Data network use packet switching.  No dedicated path between sender and receiver.  It acquires and releases bandwidth, as it needed.  Cost is not based on distance and time.
  6. 6. PBX Yesterday’s Networks Circuit Switched Networks (Voice) CO PBX CO CO Packet Switched Networks (Data) Router Router Router Router Router • Separated networks • Separated applications/services
  7. 7. PBX IP Phone Converged Network PSTN CO Gateway Router Router Router Router • Converged network • Separated or integrated applications PBX IP Phone
  8. 8. VoIP – How does it work?  Converting the voice signal  ADC (analog to digital)  DAC (digital to analog) Voice (source) - - ADC - - - Internet - - - DAC - -Voice (dest)  Transmission of voice traffic in packets
  9. 9. VoIP – How does it work?  The 1-2-3s of VoIP  1. Compression – voice is compressed typically with one of the following codecs, G7.11 64k, G7.29AB 8k, G723.1 6.3k  2. Encapsulation – the digitized voice is wrapped in an IP packet  3. Routing – the voice packet is routed thru the network to its final destination
  10. 10. LT S©Telcordia Technologies, Inc. Slide 10 IP Network Multimedia PC Multimedia PC Initially, PC to PC voice calls over the Internet VoIP Architecture? PSTN (DC) Gateway PSTN (NY) Gateway Public Switched Telephone Network Gateways allow PCs to also reach phones …or phones to reach phones
  11. 11. Components  VoIP Protocols  VoIP Gateway  VoIP Codecs
  12. 12. VoIP Network Model SIP RTP, RTCP, RTSP Transport Layer (UDP, TCP) Network Layer (IP, IP Multicast) Data Link Layer Physical Layer
  13. 13. PURC IP Protocol LayeringIP Protocol Layering Physical Transport (e.g, Cable Modem) IP (Internet Protocol) TCP UDP Applications (e.g., email, web pages) Email Data (1000 bytes)TCP Header (20 bytes) IP Header (20 bytes) A Typical IP Datagram
  14. 14. VoIP SIP
  15. 15. VoIP Gateway  A VoIP gateway is a gateway device that uses Internet Protocols to transmit and receive voice communications (VoIP).
  16. 16. VoIP Codecs  Codecs are used to convert an analog voice signal to digitally encoded version. Codecs vary in the sound quality, the bandwidth required, the computational requirements, etc.
  17. 17. Do Companies Want VoIP? 76% Will!76% Will! Unsure 4% Not at all likely 4% Not very likely 16% Likely 28% Very likely 32% Extremely likely 16% Network World asked 500 readers to assess whether they would consider using voice over IP:
  18. 18. Key Business Drivers for LAN-Based Telephony and VoIP 81%81% 59%59% 38%38% 26%26% 0 50 100 Save MoneySave Money Better Utilization of BandwidthBetter Utilization of Bandwidth Support MultimediaSupport Multimedia Improve Network ManagementImprove Network Management
  19. 19. Security Risks  AsVoIP uses the Internet, for example, it is vulnerable to the same type as security risks  Hacking  Denial of service  Eavesdropping
  20. 20. Summary
  21. 21. Questions?

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