La Trobe University, Bendigo

Division of Information Technology

BITCNE: Computer Networks

Assignment 2 1999

Your task in this assignment is to investigate one only of the following topics in computer network architecture, and submit a report on your findings. Note that the topics are about, or related to, application-level protocols in the Internet. Each of the topics has a "theory" section, where you have to look up the information somewhere (presumably on the 'net), and a "practical" section where you have to demonstrate how the particular system under discussion actually operates in practice. You must complete both sections to gain a high mark.

Note also that additional topics might appear on this page as they are suggested to me. It could be worth checking back regularly if you don't like any of those given below.

HTTP Proxies

Theory

What gets sent to a proxy server? What happens at the proxy server? What is a squid in the context of proxy servers? Briefly discuss the limitations of proxy servers for HTTP.

Practical

How effective is La Trobe's proxy server? Use Telnet (as described in the lectures) to GET a Web page from the proxy server. Can you tell if the page was cached? How?

PUT Method

Theory

In the lecture, we looked at the GET and HEAD methods of HTTP/1.0, and later we will look at the POST method. We hardly mentioned the PUT method at all. Your task: find out all about the PUT method of HTTP/1.0 and write about how it works. In particular, describe how authentication is handled in the PUT method.

Practical

Use an HTML browser/editor which understands PUT, such as the W3 consortium's amaya (it's possible recent versions of Netscape might work as well). Use the PUT feature and document how it works compared to alternative techniques for achieving the same result.

USENET (Newsgroups)

Theory

Investigate the "Usenet" electronic news system, with attention to the following points: How does the news system actually work, in terms of architecture, storage and transfer of "articles"? What is the function of the Network News Transfer Protocol (NNTP) in the news system? Who is Emily Postnews?

Practical

Post a message to newsgroup latrobe.test, or some other appropriate group. Save your posted message from your favourite news reader software and analyse its headers.

Internet Time Protocols

Theory

Investigate the use of the network to allow systems to set their system time accurately. There are several degrees of complexity in this question: you should not allow yourself to become too immersed in detail, rather your should provide an overview of the techniques and protocols which are used.

Practical

Assuming have a computer which you use to dial in to the Internet, configure your system to set its time from ironbark (or some other timeserver if you know a better one). Document the steps involved. How does your system handle timezones? How accurate would you expect your system's clock to be when set from a remote system? Note that if you don't dial in, you can't really do this question

TELNET Option Negotiation

Theory

Investigate the option negotiation techniques used in the TELNET protocol. Explain what Telnet does in relation to option negotiation when you use it do debug other application level protocols such as HTTP.

Practical

You can only tackle this problem if your version of Telnet (the program, not the protocol it implements) supports logging. This is certainly the case in all Unix versions I'm aware of, but may not be true for all PC or Mac versions. Use the logging feature of Telnet to examine the option negotiation which occurs when you log into one or more of our Unix systems on campus from another system. Document what you find.

Other

Any other appropriate application protocol-related topic with the explicit prior approval of the lecturer.

This assignment carries 15% of your mark for Computer Networks.

Due Date: At the end of May, 1999

Lecturer: Phil Scott, 5444 7277, p.scott@latrobe.edu.au.