The document introduces a group presenting on Voice over Internet Protocol (VOIP). The group members are listed as Akash Bista, Ankur Raj Karn, Arjun Khadka, and Saput Khadka. VOIP allows users to make phone calls over the internet rather than traditional phone lines. It compresses and converts voice signals to digital packets which are then transmitted over the internet. VOIP has advantages over traditional phone lines like lower costs, added features, and ability to transmit voice, data and video simultaneously.

1. Hello!
Our Group Members are :
Akash Bista (071/BEX/05) Ankur Raj Karn (071/BEX/08)
Arjun Khadka (071/BEX/09) Saput Khadka (071/BEX/41)
We are here because we love to give presentations.

2. Voice Over
Internet Protocol

3. 1.
What is VOIP?

4. 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.

5. • 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.

6. 2.
Why not PSTN ?

7. Disadvantages
• It requires a dedicated line for making and completing a call.
• Scalability is limited.
• Features like conferencing, caller ID and call waiting are
available for an extra cost.
• Call charges are higher.
• One cannot use bandwidth optimally with this technology.

8. Yesterday’s Network
Circuit Switched Networks (Voice)
PBX
CO CO
CO
Packet Switched Networks (Data)
Router
Router
Router
Router
Router
• Separated Networks
• Separated applications/services

9. 3.
Why VOIP?

10. Advantages
● VOIP increases the effectivity of data transmission.
● One can transmit data, video and voice at the same time.
● It is scalable to a large extent.
● Bandwidth is well utilized.
● Less hardware is used.
● VOIP is cheap and easy.
● One gets free value added services.

11. Converged/Present Day’s Network
PSTN
PBX
PBX
Router
Router
Router Router
Gateway
CO
IP Phone IP Phone
• Converged Network
• Separated or Integrated Applications

12. 4.
How does VOIP
work?

13. ● Compression – voice is compressed typically with one of the
following codecs, G7.11 64k, G7.29AB 8K, G723.1 6.3K
● Encapsulation – the digitized voice is wrapped in an IP packet
● Routing – the voice packet is routed through the network to its final
destination
● Converting the voice signal
a. ADC
b. DAC
● Transmission of voice in packets
Voice
(Destination)
DACInternetADC
Voice
(Source)

14. 5.
VOIP
Architecture

15. IP Network
Multimedi
a PC
Multimedi
a PC
Initially, PC to PC
voice calls over the
Internet
PSTN
Gateway
PSTN
Gateway
Public Switched
Telephone Network
Gateways allow PCs to
also reach phones
…or phones to
reach phones

16. 6. VoIP Network Model

17. 7. IP Protocol Layering
17
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

18. 8.
Examples of VoIP

19. 9.
Limitations

20. ● Packet delay.
● Packet loss.
● No guaranty of delivering packets.
● Jitter (variable delay).

21. 10.
Disadvantages

22. ● The disadvantage of VOIP include echoes and
unpredictable sound quality.
● As VOIP uses the Internet, it is vulnerable to the same
type as security risks:
a) Hacking
b) Denial of Service
c) Eavesdropping

23. References:
● Tannenbaum, Andrew S. et al. “Computer
Networks” 5th Edition, Pearson Education 2011.
● “VOIP” . Slideshare – LinkedIn.
https://slideshare.net
● “Voice over IP”. Wikipedia – Wikimedia.
https://en.wikipedia.org/wiki/Voice_over_IP

24. THANKS!