For this exercise / lesson, you will need some string to simulate connections between different devices (I used actual CAT 5 cables to "connect" my students together).
Explain what a Topology and that there are many different ways that computers can be connected together. The simplest network consists of two computers. Pair up the students so that each pair takes a cable (or piece of string) with their partner and ask them to work out how to communicate a number over their cable so that their parent will be able to say the number ( and so that their partner can say the number being communicated based on only the movement of the cable or how the cable is used).
Students might want to consider:
1. How will they work with large numbers – say 255?
2. How so you they when the other person has stopped communicating?
Test it out my secretly giving the number to one end of each pair and see if they can communicate it to the "computer" on the other end
Feed the information back to the class in discussion and now set the students into In groups of four or five so they can create the different network topologies: A bus network, a ring network and a star network.
Once again, test each network to ensure that a number can be communicated from one "computer" on the network to another one using that particular Network Topology
Ring Network: Pupils stand in a circle with a string between them. Pupils need to pass on the message onto the next computer in one direction only.
In this type of Network, one student acts as a central computer with all other students connected directly to it. The central computer acts as hub for the whole system and passes all the messages on (you can get two students to link arms back to back to simulate the central computer that has the role of communicating with all devices on the network.
- Which Network Topology is most reliable and why?
- What happens when a cable breaks?
- What happens when a computer breaks?
- What could break on the star network?
- What happens when two computers talk at once?
- What about security – what if you didn’t trust a computer on the network?
A little light consolidation can be done with student completing a table showing the benefits and disadvantages of each type of Network. The powerpoint for the lesson can be seen here.