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Made by: Yuzhao Li Student ID:u3035801 Skype A case study of VoIP applications
How many of you are using Skype, or have ever used Skype? Do you know what the VoIP is? Warming-up questions
Voice over Internet Protocol A general term for a family of methodologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol networks, such as the Internet. VoIP
People’s voice or other sounds record by the computer as samples Then the samples are send as packets over IP network to another computer and played there. How does VoIP work
Different from traditional Public Switched Telephony Network, VoIP has several advantages Cost saving Flexibility Better voice quality Advantages of VoIP services
A software application that provides telephone service using VoIP technology facilitating voice communication over the internet. Available free for both PC and Macintosh platforms as well as Linux and pocket PC’s Skype
Founded in 2003 by the Swedish entrepreneur Niklas Zennstro, and a Dane Janus Friis In October 2005, eBay purchased Skype In October 2006, Skype 2.0 for Mac was released In 2009, Skype 4.0 was released On October 14 2010, Skype 5.0 for Windows was released with a slew of improvements and feature additions History of Skype
Skype offers a number of features to its users, such as: Features
Rate control mechanism Voice codec Error-resilience mechanism Better relaying mechanism to go through NAT servers or firewalls Reasons of Skype improvement
Can find and locate users Highly scalable Strong NAT/ firewall traversal capability Security feature Integrated buddy list, presence information, chat, and audio conferencing Highlights of Skype
Quality of service Susceptibility to power failure Still difficult to make a emergency calls Lack of redundancy The security issues Challenges
MSN sends smaller packets with higher sending rate than Skype MSN has higher variance in packet’s inter-arrival time while Skype sends packets in a stable fashion Skype has better performance than MSN in MOS score Skype can increase its throughput to recover missed data when suffering from higher loss rate, but MSN can’t Skype has better mechanisms to go through NAT than MSN Skype vs. MSN
Clarity Reliable Can call any phone, local or international, not just computers Quality of voice Have many different options Why people use Skype?
Skype have a lot of impacts on its users, and also may influenced people’s daily life. For example, its impact on teaching and learning. It opens up numerous options to teacher and students interactions and the Skype offers can potentially revolutionize the teaching and learning process. So that teachers can envision students exchanging ideas, cultures, and information using the free Skype to Skype feature from one classroom to another or one student to another. Impacts on users
Weicheng Xiao. (2006). A performance Study of VoIP Applications: Skype vs. MSN. National Taiwan University LaniRexius. (2007). Skype- An Emerging Technology. London: Oxford University About Skype. (2010). Retrieved October 26, 2010. from http://about.skype.com/ History of Skype. (2010).Retrieved October 26,2010. from http://en.wikipedia.org/wiki/Skype References:
Thank you for listening!And hope you enjoy this presentation!