What is internet telephony?

IP telephony uses the Internet to send audio, video, fax etc between two or more users in real time, so the users can converse.

Digital voice packets packet switched IP network

Main motivation: Integration of new services, cost effectiveness

encapsulated in to

transmitted over

A Basic IP Telephone System:

The simplest IP telephone system uses two basic components:

- IP telephone: end device allowing humans to place and receive calls.- Media Gateway Controller: providing overall control and coordination between IP phones; allowing a caller to locate a callee (e.g. call forwarding)

Interconnection with Others (1)

IP telephone system needs to interoperate with PSTN or another IP telephone system.

Two additional components needed for such interconnection: Media Gateway Signaling Gateway

Interconnection with Others (2)

Media gateway: translates audio between IP network and PSTN.

Signaling Gateway: translates signaling operations.

How internet telephony works?

In one side gateway connects to the telephone word. It can communicate with any phone in the world.

On the other side, the gateway connects to the Internet world. It can communicate with any computer in the world.

The gateway takes the standard telephone signal, digitizes it, compresses it, packetizes it for the Internet using IP protocol and routes it the destination over the Internet.

IP phones:

GrandstreamGXP2000£64.00 *

GrandstreamGXP-280£54.00 *

GrandstreamGXP2020£99.00 *

snomSNOM300UK£99.00 *

Types of internet telephony:

PC to PC telephony over Internet :

LocalTelephoneNetwork

LocalTelephoneNetwork

IP Network

Multimedia PC Multimedia PCInternet Service

ProviderInternet Service

Provider

PC to Phone Telephony over Internet :

LocalTelephoneNetwork

LocalTelephoneNetwork

IP Network

v

Multimedia PCTelephoneVoIP

GatewayInternet Service

Provider

Phone-to-Phone Telephony Over Internet:

v

LocalTelephoneNetwork

LocalTelephoneNetwork

IP Network

vTelephone TelephoneVoIP

GatewayVoIP

Gateway

Ex. for Protocols Combining a VoIP Solution

– It is a Zoo Station …Signaling

SIP (IETF) H.323 (ITU) MGCP (IETF)

Media Transport RTP (IETF) RTCP (IETF)

Supporting Services ENUM Routing - TRIP (Telephony Routing over IP) Quality of Service – RSVP, 802.1q

GLOBAL SCENARIO:

A) Asian Region:

MalaysiaSingaporeChina Thailand

B)North America:USACanada

C) Europe : European UnionHungary

D) Others: Spain, Belgium and Telefonica

World Internet Telephony BOOM:

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

1997 1998 1999 2000 2001 2002 2003 2004 2005

Consumer & Small Business

Enterprise & Institutions

Wholesale

1997 VoIP calls - $198millian voip calls (220% annual growth)End 1999 $600 million VoIP callsEnd 2001 $1.89 billion VoIP calls

Source: Forrester Research

Yes ,dream come true for Indians also….!

Internet Service Providers Associations of India (ISPAI) are estimated at 200 million minutes a month in which use of illegal net telephony without valid license is estimated at 10 million minutes a month.

In 2008-08-18, the use of internet telephony dream come true for Indians...

(dis)advantages:

Single network infrastructure, Lower costs per call, Real-time billing.

No guarantee of quality of service Not possible made emergency calls Power failure Reliability

Parameters that impact on VoIP-

How much is too much?

Packet loss

Latency

Jitter

Conclusion:

Internet Telephony is a powerful and economical communication options which is gaining its popularity, but the most significant obstacles in reaching the height of success is the unsatisfactory voice quality and the lack of means of commercial deployments. Both of them are under investigation.

Death of PSTN…? No, no… death of PBX….!!!

Thank YOU..!!

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