basics voip

8/3/2019 Basics Voip

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Voice Over Internet Protocol

By

Sanjeet Singh

Do not copy



1. Introduction

2.Need of VoIP

3. Functionality

4. Want of it.

5. How It Works?

6. VoIP Protocols7. Security

8. VoIP in INDIA

9. Conclusions

Voice Over Internet Protocol



1. Introduction

• Very simply, VoIP, or Voice over Internet

Protocol, is the technology that allows usto have phone service over the Internet.

• VoIP may be a new term for you, but the

technology isn’t new.

• The telephone companies, who use what

is referred to as the public switched

telephone network (PSTN), have been

employing VoIP technology for years.



2. Need of VoIP

• The most obvious answer is to save

money.

• VoIP acts as a bridge between your Internet connection and the PSTN.

• Allowing you to have phone service

without requiring an account with the

phone company.

• That, coupled with VoIP’s uniquepricing model, means that users can

often cut their long-distance calling

expenses dramatically.



3. Functionality

• Ability to transmit more than one telephone call

down the same broadband-connectedtelephone line.

• Many VoIP packages include PSTN features.

• VoIP is location independent.

• VoIP phones can integrate with other servicesavailable over the Internet.



4. Why we want it?

• The most obvious answer is to save money.

• VoIP acts as a bridge between your Internetconnection and the PSTN.

• Allowing you to have phone service without requiringan account with the phone company.

• That, coupled with VoIP’s unique pricing model,means that users can often cut their long-distancecalling expenses dramatically.



5. Working

• VoIP works by taking analog signals and

converting them to digital data that can be sentover a network—the Internet in most cases,also any private network.

• It requires that you have a broadband network

connection, the necessary items to create thatbroadband connection—

• a broadband modem, your computer, a router,etc.—and a device to convert the data.



6. Protocols used in VoIP

• Session Initiation Protocol (SIP)

• Megaco(H.248)

• Skinny Client Control Protocol

• MIME



SIP

– SIP is an application-layer control (signalling)protocol for creating, modifying and terminatingsessions with one or more participants.

– Sessions include Internet Multimedia,

conferences, Internet Telephone calls andMultimedia distribution.

– Provides toolkit (methods, headers) from whichfeatures can be assembled



SIP contd….

• Message Waiting Indication about to bepublished

• Call transfer, history information (for call

diversion), presence, instant messaging under study.



Megaco

Media Gateway Control Protocol

• This protocol creates a general framework

suitable for gateways, multipoint control units and

interactive voice response units (IVRs).



Skinny Client Control protocol

The skinny client (i.e. an Ethernet Phone) usesTCP/IP to transmit and receive calls and RTP/UDP/IPto/from a Skinny Client or H.323 terminal for audio.Skinny messages are carried above TCP and use

port 2000.



MIME

This set of standards, collectively called theMultipurpose Internet Mail Extensions, or MIME,redefine the format of messages to allow for textualmessage bodies in character sets other than US-ASCII,an extensible set of different formats for non-textual

message bodies, multi-part message bodies, andtextual header information in character sets other thanUS-ASCII.



Skype

Skype is a software program created by theentrepreneurs Niklas Zennström and Janus Friis.Skype allows users to make telephone calls fromtheir computer to other Skype users free of charge,or to Landlines and cell phones for a fee



VoIP, because it uses the Internet as its conduit, is

subject to the same sorts of attacks as any other Internet traffic. Your VoIP network can suffer fromviruses, Trojans, denial-of-service attacks and other sorts of dangers such as a SYN flood or Ping of Death.

It's also possible for an attacker with publicly availablehacking tools to intercept VoIP packets and eavesdropon your conversations.

7.VoIP Security



In India, it is legal to use VoIP, but it is illegal to haveVoIP gateways inside India. This effectively meansthat people who have PCs can use them to make aVoIP call to any number, but if the remote side is a

normal phone, the gateway that converts the VoIPcall to a POTS call should not be inside India.

8.VoIP in INDIA

Major VoIP Providers in India – Sify, Tata Indicom, MTNL&VSNL.



9.Conclusions

– Evolution of the voice network is important to

many enterprises – Traditional and IP networks will continue to co-

exist in the enterprise

– Exploitation of new services and applications in IP

network – But needs to be complemented by extending

existing services to IP and mixed environments

basics voip

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