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: 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: Use in Amateur Radio: Click to call: 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

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