VOIP (Voice Over Internet Protocol) CDA 4527 Fall 2006

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

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

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

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

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

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