What the directory contains:
- Readme.html: this file
- jwands.jar: the JWANDS package
JWANDS (Java Wide Area Network Delay Simulator) is a tool for simulating the network delays of a 28.8 modem while using an internet browser. It is based on WANDS (Wide Area Network Delay Simulator) software developed by Andrew Sears. In order to introduce delays, JWANDS runs as a proxy server, which acts as a filter between the client browser and an http server.
Why would you use this tool:
JWANDS is used when you are about to administer a usability test. Since TMF site is located on a CD or hard-drive, the network delay for delivering pages to a local browser is unrealistic if compared with a distant site accessed over a modem connection that most users would encounter when viewing the TMF pages.
By simulating network delays, we can heighten the realism of the artificial scenario. This is important in usability testing because it has been shown that delays can influence user actions and satisfaction. Long delays might cause user frustration and failure to complete a task.
- jdk -- You will need to have java interpretation available in order to execute the proxy server. If you do not currently have the jdk package, you can download it from http://java.sun.com/j2se/
- Copy jwands.jar to your hard-drive.
- Start an MS-DOS window on the computer which will serve as the main server for this experiment. (Although a proxy server, including JWANDS, need not reside on the same machine as the user or as the http server, it is convenient to reduce the complexity of the setup to keep them together.)
- Change your location to the directory where you copied the files in Step (1).
- Type into the DOS window: jar xvf jwands.jar
- STARTING THE PROXY SERVER: [Only the main server machine]
- Start an MS-DOS window
- Choose either the default or custom port option
- Default (port 8050): Inside the DOS window, type : java Proxy
- Custom port number: type: java Proxy -port xxxx where xxxx is your preferred port number.
- The proxy server is now running. You may minimize the DOS window but may not destroy it since the server process will only run while the window exists.
- CONFIGURING EACH PARTICIPANT BROWSER TO USE THE PROXY SERVER (INTERNET EXPLORER):
- In IE5, click on Tool and then Internet Options.
- Click on the Connections tab; then click on LAN settings.
- Check the box "Use a proxy server" and fill in the IP address of your web server and the port number that JWANDS is running on (default is 8050).
- Click OK.
- After the browser is configured to use the JWANDS proxy server, all page requests will be routed through the proxy server. When you finish performing a usability test of TMF site, you will need to return to the Tools | Internet Options | Connections | LAN Settings dialog. By unchecking the box labeled "Use a proxy server", your browser will start to route page requests directly to the internet.
- Note that if you do not have the JWANDS proxy server running but do have the browser configured to use the proxy server, all page requests will return a "404 -- Page not found" message.
For more information:
- JWANDS assistance: cifter [at] nist.gov (cifter[at]nist[dot]gov)
- WANDS application and the algorithms, contact Professor Andrew Sears at: asears [at] umbc.edu (asears[at]umbc[dot]edu)
These instructions for configuring the browser to use the proxy server apply only to Internet Explorer 5. For the CIFter experiment, only IE5 is to be used. To use JWANDS with another browser, consult the documentation of that browser.
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