voip power point presentation

8/9/2019 VOIP Power Point Presentation

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VOIPVOIP(Voice Over Internet Protocol)(Voice Over Internet Protocol)

By:-Nikhil Garg

ECE-030

New age digital technology for convergence of voice ,video and data


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INTRODUCTIONINTRODUCTION

Voip is one of the fastest growing

Technology

The basic concept behind this technology isthe transportation of real time voice over

network such as internet


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Why VOIPWhy VOIP

A major implementation of VoIP is to bypasslong distance calls by transporting calls over

an IP network

VoIP allows communications on existing IPnetworks without adding additional lines or

bandwidth

Wireless handsets can roam and still beconnected to the main office via IP


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Communication TechniqueCommunication Technique

There are two Techniques for commuter &

Telecommunication network.

Circuit Switching:- Whenever a call place onnetwork, System seek out a physical path

between your phone and destination phone,

communication takes place after an end to end

connection is established. It will continue untilthe call is finished


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Communication TechniqueCommunication Technique

Packet Switching:- In this technique

whole data can be divided into packets

with full information. These packetstransmitted by the network. So it not

require any fixed path.


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ITEM CIRCUIT

SWITCHED

PACKET

SWITCHED

Dedicated path Yes No

Bandwidth available Fixed Dynamic

Store and Forward

Transmission

Not Possible Possible

Each packet follows the

same packet route

Yes No

Call setup Required Not Required

Comparison OfCircuit Switched and Packet

Switched


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Components of a VoIPComponents of a VoIP

SystemSystem Gateway :-Gateways perform the following function

1. Search Function :- Conversion of phone no into IPaddress

2. Connection Function :- Connection Between

originating gateway to destination gateway

3. Digitizing Function :- Convert into digital form

4. Demodulation Function:- Re-conversion

5. Compression Function:- Used for compression


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GatekeeperGatekeeper A Gatekeeper is device that knowA Gatekeeper is device that knowhow many users are connected and where they arehow many users are connected and where they are

located.located.

IP TelephonesIP Telephonesprovide enhanced service

suited to VoIP.

PC Software Phone:- Used forPC

(Microphone & Software that permits voice

over internet)


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How it works ?How it works ?

Analog voice is received by a CODEC (coder / de-

coder)

Complex circuitry then samples the voice and

compares the voice to a codebook. This codebook is

used by both the coders and decoders.

Once sampled and matched with the codebook thevoice is now presented as data

Some codebooks are of different sizes and have a

different fidelity


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These codebooks are recommended standards that

copies voice samples into different sizes

Once voice is sampled and replaced by code thevoice can then be formed into data and transported.

The usual transport method uses the IP (Internet

Protocol) standard.

IP uses many layers associated with the OSI model

to form, control, administer, and transport data.


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Voice to IP

Network

Compress

Create Packet

Add Headers

CODEC

Voice


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IP to Voice

CODEC

Process Header

Decompress

Network

Voice


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AdvantagesAdvantages

Integration of voice & data:- Large Enterprises shifttheir business from private network to public network to

achieve better economics of scale, still they require voice on

network .

Simplification :- It support all form of communicationover one network rather than to build up separate network.

Network Efficiency :- Integration of voice of dataeffectively fills up the data communication channels, so it

provide bandwidth consolidation.


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Cost Reduction :- It is cheaper to make an IPtelephony call, then to make a call by PSTN

Engineering Economics:- It is economical touse IP telephony which takes up 6-8 Kbps for one

call while PSTN call takes 64 Kbps.


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Application & Services Of VoIPApplication & Services Of VoIP

Sound Grading :- PSTN supports one grade i.e. 4KHz while VoIP can supports higher grade.

Web Call Center :- More information about product (e-commerce).

Video Telephony

Remote Telephony:- By this service remote userscan use the resource available to the network.


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Teleconferencing :Teleconferencing :-- User can share documentsthrough electronic means, Files can be transmitted.

IntegratedIntegrated Messaging :-User can get all themessage at one location from where he can access

them according to his convenience (Unified

Messaging).


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ArchitectureArchitecture

There are two different architecture.There are two different architecture.

PC to PC :- A user places a call by specifying the IP

address of the recipients. All sampling ,compressionand packetization of the voice signal occurs in sender

PC, While play out of the receiving signal occurs

through a sound card on the receiverPC.


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Gateway To Gateway (Phone to Phone) :Gateway To Gateway (Phone to Phone) :--

First user call an gateway that is near to centerFirst user call an gateway that is near to centeroffice, user identified and asked to enter phone no.office, user identified and asked to enter phone no.of the intended recipents.Then sender gatewayof the intended recipents.Then sender gatewaythan looks up and initiate session with the IPthan looks up and initiate session with the IP

address of gateway that is close as possible to theaddress of gateway that is close as possible to therecipient.An end to end communication canrecipient.An end to end communication canproceed with voice sent in IP packet between twoproceed with voice sent in IP packet between twogateway. Encoding and packetization occur in thegateway. Encoding and packetization occur in thesender gateway. Central office digitize the voicesender gateway. Central office digitize the voicebefore passing it to gateway.before passing it to gateway.


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Packet LossPacket Loss

In IP network, IP packets from many sources are

queued for transmission over an outgoing link in a

router, packets are transmitted one by one from

the head queue.A

n arriving packet is lost if thereis no space in the queue, router become congested

resulting in a Packet Loss. Packet Loss can cause

severe damage to voice quality forIP technology.

Each IP packet contain 40 to 80 ms of speechinformation.


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A

no. of technique used to solve packet lossproblem.

Network Up gradation :- Upgrade IP network

infrastructure

Silence Substitution:-Silence substitute in place ofpacket loss.

Packet Repetition :- Replaying the last correctly

received packet in place of the lost one

Packet Interpolation


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Packet DelayPacket Delay

Timing is an important characteristic of voice, twosyllables of a word are uttered with an interval.This time should be as small as possible. Toomuch delay can impair voice in several ways.

Following is a discussion of a various sources ofdelay in VoIP.

Codec Delay :- The primary function of thiscodec is to a conversion, compression to reduce

the bandwidth requirement. This will introducedelay in codec.


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Serialization Delay :- The time to take to place a

packet on the transmission line, higher line speeds, it can be greatly reduced

Queuing Delay:-Queuing delay occurs at various

switching and transmission point of the network

such as router & gateway (Waiting Time). Network Jitter :- Variance in the inter frame

arrival time at the receiver is called jitter and is

potentially more disruptive for VoIP than delays.


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THANK YOU!THANK YOU!

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