1. Made by: Yuzhao Li
Student ID:u3035801

2.  How many of you are using Skype,
or have ever used Skype?
 Do you know what the VoIP is?

3.  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.

4.  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.

5.  Different from traditional Public Switched
Telephony Network, VoIP has several advantages
 Cost saving
 Flexibility
 Better voice quality

6.  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

7.  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

8. 0
10
20
30
40
50
2005
2006
2007
2008
2009
active user (in millions)
active
user (in
millions)
Skype
13%
MSN
11%
some
other
VoIP
service
companies
76%
percentage of market
share (2010)

9.  Skype offers a number of features to its users,
such as:

10. a) Rate control mechanism
b) Voice codec
c) Error-resilience mechanism
d) Better relaying mechanism
to go through NAT servers
or firewalls

11.  Can find and locate users
 Highly scalable
 Strong NAT/ firewall traversal capability
 Security feature
 Integrated buddy list, presence information, chat, and
audio conferencing

12.  Quality of service
 Susceptibility to power failure
 Still difficult to make a emergency calls
 Lack of redundancy
 The security issues

13.  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

14.  Clarity
 Reliable
 Can call any phone, local or
international, not just
computers
 Quality of voice
 Have many different options

15.  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.

16.  Weicheng Xiao. (2006). A performance Study of
VoIP Applications: Skype vs. MSN. National
Taiwan University
 Lani Rexius. (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