Transcript Emergency calls

VoIP
Voice over Internet Protocol
Katarzyna Wolny
Lech Olszak
Tomasz Podgórski
Agenda
1) History
2) Fuctionality
3) Implementation- basics
4) Implementation- details
5) Jajah
6) Adoption
7) Legal issues
9) GG
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.
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
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
• Voicemail
• SMS sending
• Forwarding calls to phones
• Personalise Skype (ex. WeeMee)
• Skype Prime
Implementation- basics
Basics of VOIP technology:



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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
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.460.9 Annex B (for H.323), H.248.30 and MGCP
extensions
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
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
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
www.jajah.com
Adoption
 Mass-market telephony
 Corporate and telco use
 Use in Amateur Radio
 Click to call
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
Adoption
Corporate and telco use:
-
IPMultimedia Subsystem
Electronic Numbering
Video Conferencing
Use in Amateur Radio:
-RoIP
Click to call:
- customer service
Legal issues in different
countries
 Regulations
 Charges
 Other restrictions
 Emergency Calls
Gadu-Gadu
Thank you for your attention