Thinking About Networks Midterm Project: Design and Implement a Network

The midterm assignment is in two parts. This document describes Part 2, executing your network and producing materials that will help you explain your network to the class. Note that you are executing your network in order to describe it, and the description of how it was designed and what happened when you executed it is the important part of the assignment.

Part 2 is due March 29th.

GOALS

Your goal for Part 2 is to execute your network, and then to describe and discuss your network in both general and specific terms. This description and discussion should be in the form of a web page or a small set of linked Web pages. (ACHTUNG: Do not go crazy on Web design -- simple is good. Concentrate on the contents of the pages, not their form.)

Your description and discussion must be in 4 parts:

Part 1: Basic Description of Your Network's Characteristics
(Note that you may only need to update what you have done so far.)

You must briefly describe the following 6 characteristics, and how they relate to one another. Do not get hung up on the terminology. Where appropriate, I have listed synonyms here, e.g. Protocols or Rules, so you can use whichever of those words best helps you think about your network.

  • Nodes or Points of Change: What are the nodes or points of change in your network made of? (In our postcard network, the nodes were the members of the class, and various post offices.)

  • Protocols or Rules: What are the protocols or rules your network uses in arranging its connections? (In our postcard network, the transmission layer used the standard US post protocols of street address, and the application layer used a numbering scheme to re-assemble the drawing at the final destination.)

  • Transport: How are the contents of the data actually passed from one node to the next? (In our postcard network, we used the existing postal network to make connections between nodes.)

  • Packages: How are the contents packaged for your network? In particular, how is a package that has both contents and address created? (In our postcard network, a package was an envelope with an intermediary address, containing a postcard with the final address.)

  • Contents or "Stuff": What stuff travels on your network? (In our postcard network, this was the drawing I made in class. In the intermediary phase, the contents were postcards, each with a piece of this drawing on them.)

  • Addresses: How is a location specified on your network? What are addresses in your network? How is each node addressed? (In our postcard network, a node address was a postal address.)

    Part 2: Your Network's Stack
    (Note that you may only need to update what you have done so far.)

    You must explain a simple stack for your network, including at least:

  • Application Layer: What does your network do?

  • Transmission Layer: How does it do it?

  • "Physical" Layer: What is it made out of? (Physical is in quotes here because some of these networks could be implemented in software, or on top of other ephemeral networks, such as social networks.)

    Part 3: Visual Explanation
    (Note that you may only need to update what you have done so far.)

    You must make some sort of drawing, model, or other visual prepresentation of your network that will help your audience understand what your network is for, and how it works. If your visual explanation is made of pipe cleaners, Cheerios, or other physical material, please photograph it for your Web page, and bring the actual model to class.

    Part 4: Predictions and Discussion
    (This is the bulk of the new work -- lessons learned from running the network.)

    You should have made predictions about how your network will perform, like How fast will your network run? What is the longest possible route in your network? the shortest? Is it possible for some content never to reach its destination? What percentage? and so on. These predictions need to be simple and obvious, in order to be able to tell whether your predictions were correct or incorrect.

    NOTA BENE: It does not matter whether your predictions turn out to be right or wrong. The goal here is to build a network and test assertions against reality, not to make reality fit the assertions. In fact, if you seem unusually prescient in your guesses, I will suspect a little creative anachronism.

    You must explain in writing what your network was designed to do, what predictions you made about its operation, what you learned in implementing it, and what you would do differently if you were going to build it again. This description should be at least 750 words.

    When you have finished these 4 aspects of documenting your network, you should email me the URL when your are finished describing your network. I anticipate spending a small part of the next several classes asking each of you to talk briefly about your experience with your network.