Skype lab by wpr1947


    PC running Windows 2000 or XP
    400 MHz or faster processor
    128 MB RAM
    15 MB free disk space
    Sound Card, Speakers and Microphone or (preferably a headset with
      microphone). If your computer supports Bluetooth then your cell phone Bluetooth
      headset might be useful.
    Internet Connection (dial-up or broadband)

As you are aware the Public Switched Telephone Network uses TDM (Time Division
Multiplexing) for its network protocol. VoIP (Voice over Internet Protocol) uses IP for its
network protocol. One day all telephony will use IP. Skype today uses IP packets to
transmit voice over the Internet. This lab will demonstrate some characteristics along
with the capability and voice quality of VoIP.

Since Skype is continually improving its functionality and constantly improving its user
interface, the install and documentation which follows may change over time. The
following worked at the time of this publication.

Download: Skype application from:

Install when the option is presented to you

Settings: accept all the default

Configure: Use the wizard to setup your Skype account.

If necessary Setup a proxy server, this may require your instructor assistance

Execute the setup: accept all agreements

You may elect to have Skype startup when you login, your choice depending on your
school policy.

Completed installation: you may launch Skype at any time using its icon on the Start
Menu or the desktop.

CAUTION: You will have an opportunity to enter person data. DO NOT enter any
personal data about yourself since it will become available to millions of Skype users
around the world. You should be aware that there are many predators who want your
personal info to commit criminal acts.

You must ask your classmates for their ids in order to set up a directory which is used to
place calls. Place these ids in to your directory.

Make a call to one of your class mates. After the conversation begins what do you notice
about the sounds? there is a big delay

Why do you think the sound is different on this Voice over IP conversation than on the
public telephone network? Because the voice signals have to be changed from analog
to digital, using a codec, and framed into packets before being sent over the
network. And there is some delay as the packets travel over the network before
reaching their destination and some packets will be lost along the way and perhaps
surrogate packets are formed to replace those lost packets to smooth out the

Go to the Internet and answer this question. What is “delay budget”.


What is the delay budget from source to destination? 150ms. What is the delay budget
from source back to the source? 300ms.

Why is delay budget important in Voice over Internet Protocol? To allow for delays
caused by codecs, switch and router delays, other traffic on the network, security,
and the building packets to replace lost packets.

If the person talking with you over Skype were in another room would you notice the
delay? NO

What value does Skype hold for you? I have an opportunity to talk with anyone
worldwide for free, if they have a computer, an Internet connection, and Skype.

Your have just set up a Skype account that can be used any place in the world where you
have access to the internet.

Skype has a number of other communications features which you might be interested in
Take some time and explore some of these features. Again be careful with disclosing
your personal information on Skype or any other public access Internet applications.

Additional features which may be of interest to you are: Skype-Out and Skype-In. For a
small per minute cost you can call from your PC to a regular telephone using Skype-Out.
Also Skype can provide you a phone number for your PC and for a small per minute cost
anyone can call your computer from a Public Switched Telephone; home phone, cell
phone, 802.11 phones, etc.

Have Fun!

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