I've been running this activity for the past year or so and have been promising to write it up for a while. With Computer Science Education Week happening this week, it seems like the perfect opportunity to get my act together.
I'll be posting this activity in 4 separate parts:
(1) Overview and setting up
(2) The phone system (switching network)
(3) The internet (routing network)
(4) DNS (Domain Name Server)
This activity is an interactive demonstration of what happens when you type a URL into a browser.
In this activity the students will be guided to act out the various parts of the internet: websites, routers, name servers, ISPs and home computers. In this activity, students will:
- Learn the difference between a switching (phone system) and routing (internet) network
- See how packets are routed through the internet
- See how the internet routes around damage
- See how domain name servers are used to lookup an IP address
- 30 minutes printing and creating signs
- 1 hour room prep (creating network on the floor using tape)
- plus whatever time you need to familiarize yourself with the material
Note: Because of the room preparation required for this activity, you may want to present it multiple times back-to-back to different groups of students.
You will need the following materials:
- Masking tape/chalk to mark network on floor
Masking tape is useful indoors, chalk works well on hard surfaces outdoors
You'll want at least a couple of rolls of masking tape for this
Alternately, if outdoors, you can use hula hoops and rope to mark the network
Note that you'll need to attach labels to each rope
- Rope (50' is more than enough)
This is used to show the phone switched connection
- Manilla folders
Used to label the network nodes
You can skip this if you have another way of labelling nodes
To write labels on the masking tape and manilla folders.
- Print out the following:
- Scissors (to cut out holes for the “images” from the web page printout)
- Props (optional):
Small, personal address book
City phone book (as thick as possible, perhaps have a few from different cities)
(1) Draw the network map on the floor
Draw the following network map on the floor using masking tape:
You'll want an open space roughly 20'x20' (6m x 6m) in size for this.
If you're outdoors, you can use chalk or you can use anything else convenient: hula hoops connected by rope would also work. The important thing is that you're able to label each node and link in the diagram.
Make each node (circles/boxes) large enough for a student to stand/sit within. Circles are hard to do with masking tape, so squares are fine (the shape of each node does not matter). Each square should be about 3' (1m) on each side. Nodes 10-13 can be a different shape (like a triangle) if desired.
Make sure there's enough space between each node so that the links between them are easy to see. Ideally it should take from 2-3 steps (~5' or ~1.5m) to go from one node to another.
The graph is easier to make if you start with the 3 central nodes (1, 2, and 3) and label them for identification. Add the other nodes to this core network, but don't label them yet (since they will change function during the activity) – you will make signs for these nodes. See the next section (about creating signs) for information about labeling each of the nodes.
Each of the links between the nodes should be labeled so that they are easy to identify. If using masking tape, write the label directly on the tape.
- Write the label more than once along the tape. At least mark the points closest to each node, but it is preferable to mark all along the tape (separated by ~1' (~30cm)).
- Note that the students will be walking around and viewing the labels from all angles, so make sure that they are easy to read.
- We use both upper-case and lower-case letters to label each link (e.g., "Aa"). This is because the labels will be viewed from all angles as the students walk around and using just upper or lower case letters leads to cases where the labels are ambiguous ("p" vs. "d" or "H" vs. capital "I" with serifs) .
(2) Create signs to place on the internet nodes
Only 3 of the nodes that you just created can be labeled permanently (i.e.: for the duration of the activity): “1”, “2” and “3”. You can label these using tape or chalk or whatever is convenient.
Don't give permanent labels to the other 10 nodes because we need to give them more descriptive names during the presentation (and these names will change during the course of the activity). You should create name tags for these nodes - I just use manilla folders and wrote the node names on them, but you can label them however you see fit.
You will need to create the following 10 signs:
For Part II (phone system):
For Part III (internet):
For Part IV (DNS):
- “root name server” (rns)
- “.com name server” (.com ns)
- “.org name server” (.org ns)
- “ISP name server” (ISP ns)
Print out all of the switching/routing tables and internet packets in the PDF files. They should all be printed single sided.
[Links to these files will be in the following posts.]
(4) Cut out holes for the “images” from webpage in last set of packets
The last set of printouts requires that you cut out the squares where the images should be displayed in the web page.
[to be continued...]