1. VOICE OVER INTERNET PROTOCOL
SEMINAR TOPIC ON
PRESENTED BY: PRAKASH RANJAN MECE-170-2K10
VOICE OVER INTERNET PROTOCOL
11/7/2018 2:17:49 PM

2. OUTLINE INTRODUCTION WHAT IS VOIP? HISTORY HOW VOIP WORKS?
RQUAREMENTS OF VoIP
CALL SET UP PROCESS
VoIP OVERALL TECHNIQUE
PROTOCLOS H323 AND SIP
ADVANTAGES
LIMITATIONS
APPLICATIONS
CONCLUSION
11/7/2018 2:17:49 PM

3. INTRODUCTION
The traditional method used for transmitting voice is PSTN.
Now more and more communication is done in digital format and transported via data networks such as internet.
As data traffic is much faster than telephone traffic, so we prefer to send voice over data networks.
11/7/2018 2:17:49 PM

4. WHAT IS VOIP ?
Voice Over Internet protocol (VoIP) is a protocol used for the transmission of voice and fax phone calls through the Internet or other packet-switched networks.
It is also called IP telephony, Internet telephony, voice over broadband, broadband telephony.
11/7/2018 2:17:49 PM

5. VoIP
It is a bunch of protocols and standards; and years of research done by organizations all over the world that would bring about this revolution. They call it ‘VOICE OVER IP’
In the near future, if you make a telephone call, it is more than likely that it would be over the Internet or some other packet network.
With the passes of time VoIP replace the PSTN and people will acquaint with the new technology .
VoIP Internet Telephony simply takes advantage of the efficiencies of packet switched networks.
11/7/2018 2:17:49 PM

6. HISTORY OF VOIP Designed for home PC Uses H.323 Protocol
The first Voip software was introduced in 1995 by Vocaltec.
Designed for home PC
Uses H.323 Protocol
Uses Packet Switching
11/7/2018 2:17:49 PM

7. CIRCUIT SWITCHING
PACKET SWITCHING
11/7/2018 2:17:49 PM

8. How VoIP WORKS
Part 1:- Technical over view
11/7/2018 2:17:49 PM

9. Protocols and Encoding
Part 2 : The Protocols
H 323 Protocol
SIP Protocol
Part 3 : Encoding
G audio signal with a bandwidth of 3.4KHz should be encoded for transmission at data rates of 5.3Kbps and 6.4Kbps
G.711 ITU standardised PCM (Pulse Code Modulation) as G.711. audio signals to be encoded for transmission at data rates of 56Kbps or 64Kbps
11/7/2018 2:17:49 PM

10. Jitter and packet loss Part 4 : Hear the Quality
The performance or quality of the speech depends up on encoders at each end, the number of packets lost on route, Latency and Jitter.
5% lost packets distributed evenly will not result in the loss of words lose.
but lose in 5 a row the entire word is lost and this will afect significantly.
Quality also vary with manufacturer .
Overall quality is good if we have good quality of network.
there is a trade off between call quality and bandwidth.
11/7/2018 2:17:49 PM

11. Requirements of a VoIP
Software Requirements:- User interface, Voice Processing Module, Echo Cancellation, Idle Noise Detection
Hardware Requirements:- existence (or installation) of an IP based network.
gateway is required to bridge the differences between packet switching and other networks.
Protocol Requirements :- H.232, Q.391, H.245,SIP, RTP, RTCP, with TCP & UDP DLL protocols.
11/7/2018 2:17:49 PM

12. Need of Gateway for other n/w
11/7/2018 2:17:49 PM

13. CALL SET UP PROCESS
11/7/2018 2:17:49 PM

14. VoIP OVERALL Technique
Audio Codecs (G.723.1, G711)
Data Transport (RTP, RTCP)
Addressing:-
Here phone no. is converted to an IP address.
Simple format addresing:
<user | phone | hostname | IP address>
Signaling (SIP, H.323)
11/7/2018 2:17:49 PM

15. H.323 Recommendation published by ITU in 1996.
It is designed to act above transport layer and is mainly used for transmission of voice, data and video conferencing over packet networks.
11/7/2018 2:17:49 PM

16. Terminals User End point.
either be a personal computer (PC) or a stand-alone device, running an H.323 & the multimedia applications.
Function of the Terminal:
Provides real-time 2 way communication.
Optional : Video & data streaming.
Mandatory voice streaming
11/7/2018 2:17:49 PM

17. Gateways A gateway connects two dissimilar networks.
An H.323 gateway provides connectivity between an H.323 network and a non-H.323 network.
The Functions of the gateway can be stated as follows:
Task-translation.
Audio Codec
Video codec
H.245  H.221 (ISDN Conference)
H.245  H.242 (Audio-Visual terminals)
11/7/2018 2:17:49 PM

18. Gatekeepers
A gatekeeper can be considered the brain of the H.323 network.
It is the focal point for all calls within the H.323 network .
Although they are not required, gatekeepers provide important services such as
addressing, authorization and authentication of terminals and gateways; bandwidth management; accounting; billing; and charging.
Gatekeepers may also provide call-routing service.
11/7/2018 2:17:49 PM

19. Multipoint Control Unit
MCU’s provide support for conferences of three or more H.323 terminals.
All terminals participating in the conference establish a connection with the MCU.
The functions of the MCU is to maintain all audio, video data & control streams mandatory for conferences.
The gatekeepers, gateways and MCU’s are logically separate components of the H.323 standard but can be implemented as a single physical device.
11/7/2018 2:17:49 PM

20. SIP SIP stands for Session Initiation Protocol.
Developed by IETF since 1999.
It is an text-based application-layer control protocol for creating, modifying and terminating sessions with one or more participants.
Sessions include Internet Multimedia conferences or Internet Telephone calls.
11/7/2018 2:17:49 PM

21. SIP LOGICAL ENTITIES User Agent (UA):-
In SIP, a User Agent (UA) is the endpoint entity.
Proxy Server
A Proxy Server is an intermediary entity that acts as both a server and a client for the purpose of making requests on behalf of other clients.
Redirect Server
A Redirect Server is a server that accepts a SIP request.
Registrar
A Registrar is a server that accepts REGISTER requests for the purpose of updating a location database .
11/7/2018 2:17:49 PM

22. ADVANTAGES Cheaper call rates, not depend on distance. Simplification
High efficiency
Free calls within organization .
Better Voice Quality Using Wideband Codecs
Adding new features and applications over time is easy.
Integration of voice, data, fax, video is possible.
11/7/2018 2:17:49 PM

23. 11/7/2018 2:17:49 PM

24. LIMITATIONS Packet Delay
Packet Loss (no guarantee of delivering packets)
Jitter (variable delay)
11/7/2018 2:17:49 PM

25. Security- The concern (Flaws)
An interesting example of an identified Cisco VoIP vulnerability  is shown below: -
11/7/2018 2:17:49 PM

26. Security- The counter measure
These are some what analogues to general PC “Anti Virus”.
One of the popular vender provides following solutions :-
VoIP Vulnerability Assessment (VVA) and penetration testing .
VoIP Intrusion Prevention System (VIPS).
VoIP PBX configuration management tool enables PBX.
VoIP PBX monitoring tool provides around the clock monitoring  for hardware failures.
11/7/2018 2:17:49 PM

27. APPLICATONS OTHERS: Integration of data,voice and fax Video telephony
Real time applications:
Telephony ( two-way)
Radio-TV Broadcast (one-way)
Non-real time applications:
e_mail
OTHERS:
Integration of data,voice and fax
Video telephony
Enhanced teleconferencing
Used in Amateur Radio
11/7/2018 2:17:49 PM

28. Can we make VoIP through mobile?
Yes . By two ways:-
1. One of the ways to do that, offered by Rebtel - VoIP connection is established via a local access number.
2. Another way is to use special Internet phone applications for mobile phones. The most well known of such applications is fring.
11/7/2018 2:17:49 PM

29. 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 .
This technology has enormous growth potential and it is expected that it will be very popular in future with advancement in network technology.
The availability of high-quality audio using wideband codecs, video conferencing, and document sharing enables more effective and pleasant communication.
“It is not Voice over IP, it is Everything over IP…”
11/7/2018 2:17:49 PM

30. 11/7/2018 2:17:49 PM

31. QUERIES?
11/7/2018 2:17:49 PM

32. THANK YOU
11/7/2018 2:17:49 PM