Computing 205/406 & IT8

Tutorial #21

1. This subject does not use the OSI protocols as examples of how computer networking is done, yet some topics (notably ASN.1) are straight out of OSI. How is this?

2. The HTTP protocol can specify to a server the type of browser making a request. Some servers then respond with customised pages for different browsers. In the lecture, it was claimed that this "doesn't scale" and is therefore not a good practice. What is meant by this? Why is it considered good practice to use standard HTML?

3. Give some examples of HTML extensions which have been introduced by some browser companies but which are not generally recognised by other browsers.

4. Why is it considered difficult to measure the effectiveness of WWW advertising? How can this be improved?

5. What does a WWW CGI program generate as output?

6. (Extension question) What is the "Mbone"? Why is it more useful for audio and video distribution than the current WWW approaches?

7. (Philosophical question) Is there any potential for you to make money by selling advertising on your home page? Discuss.

Practical exercises:

• Use some WWW browsers other than Netscape (eg, xmosaic, lynx, and possibly arena, Internet Explorer, Cyberdog, MacWeb etc ) to view some "optimised for Netscape" pages. The La Trobe home page, www.latrobe.edu.au, is a good example. How do they look?

• Look up the RFC for HTML. Are there any markups which are commonly seen which are not in the standard? Are there any other sources of (possibly newer) standards information for HTML?

• Investigate CGI programming. Are there any particular difficulties in writing CGI programs?