VoIP allows users to make voice calls over the internet instead of traditional phone lines. It works by converting voice signals to digital data packets that are transmitted over the internet and then reconverted at their destination. Key components include gateways, codecs, servers, and protocols like SIP and H.323. VoIP offers advantages like lower costs and integration with other systems but relies on internet connectivity and faces some security risks.

1. P R E S E N T A T I O N
VoIP (Voice over Internet
Protocol)

2. Outlines !
History of VoIP
What is VoIP
PSTN vs. VoIP
VoIP Gateway & Codec’s and Requirement
Components of VoIP ( with Pictures)
Advantages & Disadvantages
Features, Benefits & Security Risk
Protocols of VoIP
SIP (Session Invitation Protocol)

3. History of VoIP :
 Alon Cohen (born in Israel, 1962) is the co-founder of Vocal Tec
Inc. (1989) and the co-inventor of the Audio Transceiver that
enabled the creation of Voice Over Networks products and
eventually the VoIP industry.
 Cohen holds 4 US patents on different communications
technologies.
 Voice over Internet Protocol (VoIP) transmission began in 1973
as a result of the experimental Network Voice Protocol invented
for the ARPANET (Advanced Research Projects Agency
Network). However, it wasn't until 1995 that the first Internet
Phone Software Vocal Tec appeared.
 Less than two decades old, VoIP has revolutionized
communication all around the world.

4. What is VoIP ?
 It is a technology that allows you to make voice calls using a
broadband Internet connection instead of a regular (or analog)
phone line.
 The cost of calling through VoIP from one phone to another is
free. Because we use the shared infrastructure of the web the cost
of connecting N/W together is much less.
 VoIP is far more flexible, that means it works with other
applications on the internet so can integrate it very easily with
things like emails, web browsing, directory services or databases
etc.
 Voice conversations are turned into digitized data and packetized
for transmission across a network.
 It allows 2-way voice transmission over broadband connection.
 VoIP is the transmission of voice “data packets” from one IP
address to another over the Internet.

5. PSTN VoIP
 Voice network use circuit
switching.
 Dedicated path between
calling and called party.
 Bandwidth reserved in
advance.
 Cost is based on distance
and time.
 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.
PSTN vs. VoIP

6. How does VoIP Work?
 Converting the voice signal (Analog to Digital & Digital to
Analog)
o Voice (source) - - ADC - - - Internet - - - DAC - - Voice (dest)
 Transmission of voice traffic in Packets
 Compression - voice is compressed typically with one of the
following codec's, 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 thru the network to its final
destination.

7. VoIP Gateway, Codec & Requirement
VoIP Gateway:
 A VoIP gateway is a gateway device that uses Internet Protocols
to transmit and receive voice communications (VoIP).
VoIP Codec’s:
 Codec are used to convert an analog voice signal to digitally
encoded version. Codec vary in the sound quality, the bandwidth
required, the computational requirements, etc.
VoIP Requirement:
 A broadband (high speed internet)
 A computer or specialized phone.

8. Components of VoIP
Signaling Gateway Connection:
 SGC is the heart of VoIP platform its main role is to connect the
PSTN world with the IP world.
Support of Signaling System 7 (SS7) protocol stack, Full support of voice call control
protocols such as H.323 or SIP, Generate Call Detailed Records (CDRs) for billing
purposes and Support of bandwidth policing mechanisms.
Media Gateway:
 A media gateway is a translation device or service that converts
media streams between such technologies as private branch
exchange (PBX) systems.
Transmission of Voice data using RTP, Support of different Compression algorithms for
fulfilling the requirements of the call as instructed by the SGC & Manage Digital Signal
Processing (DSP) resources for ideal service offering.

9. Components of VoIP
Media Server:
 The sharing of any media file is done through this server. It is used
where added features are needed such as voicemail or video
conferencing.
Voicemail functionality, Voice activated dialing, Voicemail to email transmission - voicemail
can be transmitted as attachment to an email address & Support for Interactive Voice
Response (IVR) - call routing or even service activation can be performed based on dialed
DTMF digits.
Application Servers:
 The major responsibility of an Application Server is to provide
value-added services to the IP network. Each application which is
capable of communicating with network has its own application
server. Application Server is the brain of the VoIP.
Support of customized private dialing plans, Basic service offering - basic services such as
call forward always, call forward on busy, call waiting, call transfer, call park and voicemail
are offered though the Application Server & Generation of Call Detailed Records (CDRs).

10. VoIP Components Pictures

11. Advantages Disadvantages
 Easier to Install, Configure,
and Maintain
 VoIP Integrates With Other
Business Systems
 Even Older Technology Like
Fax Is Supported
 Combine multiple
conversations over existing
data networks
 Highly low cost
communication
 Loss of service during
outages
 Without power VOIP phones
are useless
 No standard protocol is
applicable
 More risk of failure. User
provided backup. Network
latency/echo
 Need Uninterrupted internet
connection
Advantages & Disadvantages

12. Features, Benefits & Security Risk
Features:
 Voicemail,
 Caller ID,
 Conferencing,
 Forwarding &
 Unlimited Long Distance.
Benefits:
 Save money & is cost efficient,
 Integration with Audio, Data & Video Application,
 Flexible,
 Ability to chose your own area code.
Security Risks:
 Hacking, Denial of service and Eavesdropping

13. Protocols of VoIP
H.323:
 In a VoIP environment H.323 is a common protocol running on
voice gateway to connect the VoIP network to PSTN.
SIP:
 Session Initiation Protocol (SIP) is a signaling protocol used for
initiating, maintaining, modifying and terminating real-time
sessions that involve video, voice, messaging and other
communications applications and services. and controlling
multimedia communication sessions in applications of Internet
telephony for voice and video calls.
MGCP:
 The Media Gateway Control Protocol is a protocol for providing
telecom services & controlling devices and transmitting calls via an
internet protocol network.

14. SIP (Session Invitation Protocol)
 Session Invitation Protocol, or SIP, began to take shape in the
early 2000s as well.
 SIP means that a person must initiate a VoIP conversation by
inviting another party or group of people into the conversation.
 This technology has been since widely used in instant messaging
and chat groups, Skype software, group and work conferencing,
and much more.
 SIP is much safer than earlier VoIP standards, providing a secure
network for all parties involved.
 Another benefit of SIP is that it can be used in just about any
device that is associated with communication: PCs, Macintoshes,
phones and smart phones, video devices, etc.
 Microsoft enabled all of its devices to use SIP technology.