Assignment #2

The goal of this assignment is to help you understand what is going on in the network by examining exactly what flows across the wire. This is something of a difficult task because network protocol designers have worked so hard to provide so much abstraction to the higher layer applications. Never fear though, there are tools that we can use.

Assignment 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 assignment you will either have to have access to a machine running UNIX and with the ``snoop'' utility or you will have to use the parsed version of a snoop file. The command in UNIX 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, the snooping has been done for you, and a snoop file has been created. Take the snoop-file.bin 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 to more closely investigate what is happening in this trace. If you do not have access to a machine with ``snoop'', you can use the snoop-file.txt file. It contains the results of running the snoop command in verbose mode.

Some of the things going on in the trace will contain protocols we have not gone over. If you really want to understand what is going on, you will have to use some reference textbook to help. To help get you started, I have provided a set of sample questions that you will want to answer about the packet trace. However, these questions only serve as examples of the kinds of things I think are important. They serve as a starting point and are not exhaustive. They are only provided as a guide to help you find the most interesting aspects of the trace.