1. VoIP Voice over Internet Protocol
Katarzyna Wolny
Lech Olszak
Tomasz Podgórski

2. Agenda
1) History 2) Fuctionality 3) Implementation- basics 4) Implementation- details 5) Jajah 6) Adoption 7) Legal issues 9) GG

3. History
1973- Voice was being transmitted over the early Internet (Network Voice Protocol)
1990’s- Technology available to end users
1996- Vocaltec Internet Phone Release 4
to speak only with other Vocaltec Internet users…
Breakthoughs- Realtime voice compression
1997- Development of softswich
A softswitch is a central device in a telephone network which connects calls from one phone line to another, entirely by means of software running on a computer system.

4. Functionality
Ability to transmit more than one telephone call down the same broadband-connected telephone line.
Additional services such as: 3-way calling, call forwarding, automatic redial, and caller ID.
VoIP can be secured with existing off-the-shelf protocols such as Secure Real-time Transport Protocol.
VoIP is location independent, only an internet connection is needed to get a connection to a VoIP provider.
VoIP phones can integrate with other services available over the Internet

5. Basic Services:
Phoning other users of Skype
Forwarding calls to other Skype users
Video calls
Chat
Teleconference between up to 9 people
Advanced services:
Phoning mobile and traditional telephones
SkypeIn- Anwsering a VOIP call on normal telephone
Voic
SMS sending
Forwarding calls to phones
Personalise Skype (ex. WeeMee)
Skype Prime

6. Implementation- basics
Basics of VOIP technology:
Telephony signals as digital audio
Based on packet swiched networks
Speech data compression techniques
Encapsulation in a data packet stream over IP
Two types of PSTN (ang. Public Switched Telephone Network) :
- Direct Inward Dialing (DID) - Access numbers
VOIP challenges:
Available bandwidth
Delay/Network Latency
Packet loss
Jitter
Echo
Security
Reliability
Pulse dialing to DTMF (Dual Tone Multi Frequency) translation

7. Implementation- details
Reliability:
- sensitive to power failures (lack of back-up generators or batteries)
- the broadband carrier itself may experience outages
- lower restoration level than in PSTN
Quality of service:
- loss or delays in packet delivery cause drop-outs of voice (esp. highly congested networks, long distances, interworking of the endpoints)
- minimazing loss of packets (multi – path routing)
- new protocols defined (RTCP XR(RFC3611), SIP RTCP, Summary Reports, H Annex B (for H.323), H and MGCP extensions

8. Implementation- details
Difficulty with sending faxes:
- Fax-over-IP (T.38 protocol)
- another idea: solutions that do not need real time data transmission
Emergency calls:
- problem with localizing users
- difficult to route a call to the nearest call center
- physical address required at regestration
- emergency call centers of VoIP carriers

9. Implementation- details
Integration into global telephone number system:
- not compatible with global standard E.164
Mobile phones & hand held devices:
- „dual – mode” telephone sets
- hand held devices
- MoIP

10. Implementation- details
Security:
- easy to eavesdrop on VoIP while calls not encrypted
- patented audio codecs, compression
Pre- paid phone cards:
- normal phones and internet cafes with telephone services
VoIM:
- VoIP – another communicational mode

12. Adoption Mass-market telephony Corporate and telco use
Use in Amateur Radio
Click to call

13. Mass-market telephony
Digital Phone and Softphone
Portable phones
Services that rely on a software client
Advantages and Disadvanteges of VoIP in comparison to PSTN

14. Adoption Corporate and telco use: Use in Amateur Radio: Click to call:
IPMultimedia Subsystem
Electronic Numbering
Video Conferencing
Use in Amateur Radio:
-RoIP
Click to call:
- customer service

15. Legal issues in different countries
Regulations
Charges
Other restrictions
Emergency Calls

16. Gadu-Gadu

17. Thank you for your attention