MAT 201B / CS 290I-- Media Networks and Services
Homework Assignment #2
TURNED IN BEFORE Class on Tuesday 10/31/00

Assignment Overview

You will be expected to understand what is going on in the network. This is something of a difficult task because network protocol designers have worked so hard to provide so much abstraction to the higher layer protocols. Never fear though, there are tools that we can use.

The two parts of this assignment are:

Assignment Part 1 Details

The goal of the assignment is to examine real protocols in use and understand the communication that takes place in a network by examining the bits that flow across a network segment. For this part of the assignment you will have use your CS UNIX account. The reason is that Windows does not have snoop capability, but most UNIX operating systems do. The command is snoop; however, it requires root privileges to run. This is a good thing because it should be hard to snoop packets on the network! So, I've done the snooping and created a dump file for you to use. Take the hw2-snoop-file.bin.gz file (NOTE: Make sure you download this file, i.e. right click and select ``Save Link As''.) and use it as the source file for snoop (HINT: do a man snoop and look at how to use the -i option... you can do this without having root). You will also want to use some some of the other options that come with snoop. Pay attention to options which give you the most information about packets. Some of the questions below will be about material that we have not, and will not be covering in class. You'll have to use one of the class textbooks as a reference to answer them. I will also try to provide some in-class time to answer questions.

A note about grading: a key to a good grade will be your ability to communicate that you understand most everything about the packet trace. This implies, as usual, a clear, concise write-up! The questions below are designed to help you find the most interesting aspects of the trace, but they are by no means exhaustive. There will be other interesting results that you should find.

Your write-up for this part of the assignment can take any form you like. The most straightforward is to simply answer each question though I would strongly recommend against this. The reason is that the questions are purposely haphazard. My suggestion is to first answer the questions, understand what is going on in the trace, and then create a description of the session filling in the details when appropriate. As a minimum, you should re-order the questions to flow more logically; reduce redudancy (yes, there are some redundant questions); and add any questions that you think are important, but that I have not specifically asked. Here are the sample questions:

Assignment Part 2 Details

Use the following tools to answer the following questions.

Assignment Turnin

Several notes: