Transcript What is internet telephony?

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.
encapsulated
transmitted
 Digital voice in to
packets over
packet switched IP
network
 Main motivation:
 Integration of new services,
 cost effectiveness
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:
Grandstream
GXP2000
£64.00 *
Grandstream
GXP-280
£54.00 *
snom
SNOM300UK
£99.00 *
Grandstream
GXP2020
£99.00 *
Types of internet telephony:
 PC to PC telephony over Internet :
Local
Telephone
Network
Multimedia PC
Internet Service
Provider
Local
Telephone
Network
IP Network
Internet Service
Provider
Multimedia PC
 PC to Phone Telephony over Internet :
Local
Telephone
Network
Multimedia PC
Internet Service
Provider
IP Network
v
VoIP
Gateway
Local
Telephone
Network
Telephone
 Phone-to-Phone Telephony Over Internet:
Local
Telephone
Network
Telephone
IP Network
v
v
VoIP
Gateway
VoIP
Gateway
Local
Telephone
Network
Telephone
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:
Malaysia
Singapore
China
Thailand
B)North America:
 USA
 Canada
C) Europe :
European Union
Hungary
D) Others:
 Spain, Belgium and
 Telefonica
World Internet Telephony BOOM:
14,000
12,000
1997
VoIP calls - $198millian
voip calls
(220% annual growth)
End 1999
$600 million VoIP calls
End 2001
$1.89 billion VoIP calls
10,000
8,000
6,000
4,000
2,000
Source: Forrester
Research
0
1997 1998 1999 2000 2001 2002 2003 2004 2005
Consumer & Small Business
Enterprise & Institutions
Wholesale
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 VoIPHow 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..!!
Any