VOIP Voice Over Internet Protocol

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VOIP (Voice Over Internet Protocol)

• CDA 4527
• Fall 2006

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Definition

• also called IP Telephony, Internet telephony,
  Broadband telephony, Broadband Phone and Voice
  over Broadband
• the routing of voice conversations over the
  Internet or through any other IP-based network

Cisco IP Phone 7941G
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Big Picture

• Modes of operation
• PC to PC
• PC to phone
• Phone to PC
• Phone to Phone
• Traffic go through Packet Switched Network
  instead of Public Switched Telephone Network
  (PSTN)

From Wikipedia, the free encyclopedia
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Why VOIP?

• Much cheaper
• Rich functionalities
• Free phone numbers for use with VoIP are
  available in the USA, UK and other countries.
• 3-way calling, call forwarding, automatic redial,
  and caller ID
• Integrated with data, video communication
• Mobility
• Incoming phone calls can be automatically routed
  to your VoIP phone, regardless of where you are
  connected to the network

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Challenges

• Quality of Service (QoS)
• Internet provides best of service
• No guarantee for latency, jitter
• Need Internet connection
• Home broadband is not reliable
• Power issue
• VOIP phone, Cable Modem/DSL, Computer

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Challenges

• Security
• Most unencrypted
• VOIP spam challenges
• Integration into global telephone number system
• Emergency call availability functionality
• Power, Internet connection
• Call routing, location service

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QoS

• Deal with Jitter
• Smoothed by playback buffer
• Bandwidth
• 64 kbps or less
• Depends on codec and use of silence supression