Topologies Teacher’s Notes

Lesson Plan

Length 60 mins Specification Link 216/d

Candidates should be able to: Learning objective (a) describe, using diagrams or otherwise, the ring, bus and star network topologies

Time (min) Activity Further Notes

5 • Explain to the students that there are different ways that computers and peripherals can be connected together to form a network.

• Explain that the structure or arrangement is called the .

15 Watch the set of videos, pausing to discuss the content.

5 Discuss the videos to assess learning. Ask questions such as: • What is meant by a network topology? A network topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines.

• List three different network topologies. Ring, bus and star.

• State an advantage of a star network over the other In bus and ring networks, if the cable to two. one breaks then the whole network will be down but in a star network each computer is connected separately to a central hub through its own cable.

30 Worksheet 1 Pupils to complete Worksheet 1 either on paper or on Answers provided. computer. They may need access to the Internet to Ask students with the correct responses research some of the questions. to explain to the class how they arrived at In Worksheet 1, the students are asked to access Inter- their answers. active Activity 1 and work completed in that should be included in their answers to the worksheet. Ask individual students for their answers and discuss with the class so that all students have the correct answers. Extension Challenge/Homework Students to complete and submit Worksheet 2 for homework. 5 Plenary – Peer revision Ask the students to work in pairs. Each one has to quickly draw diagrams to show the three network topologies covered and they are then marked by their partner.

® WORKSHEET 1 ANSWERS

1 What is meant by a network topology? A network topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines.

2 Open Interactive Activity 1 and follow the instructions to create screenprints showing client-server networks with ring, bus and star topologies. Either paste the screen prints below or if you are answering on paper, print them out and hand in with your answers.

Ring network

Star network

® WORKSHEET 1 ANSWERS

3 Describe each network topology and give the advantages and disadvantages of each. (a) Ring topology Each computer is connected to the network in a closed loop or ring. The signal passes through each machine or computer connected to the ring in one direction, from device to device, until it reaches its destination. Advantages Each machine or computer connected to the ring act as a signal booster or repeater. Simple structure and easy to install and reconfigure and easy to identify the problem if the entire network shuts down. Disadvantages Only one machine can transmit on the network at a time. The failure of one machine will cause the entire network to fail. Data sent from one node to another has to pass through all the intermediate nodes making the transmission slower.

(b) Bus topology Each machine is connected to a long, single cable which acts as a backbone to link all the devices in a network. Each computer or server is connected to the single bus cable through a connector called a T-piece. A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable. Advantages Easy to connect a computer or peripheral to the linear bus. Requires less cable length than star topology. Disadvantages The cable length is limited. This limits the number of network nodes that can be connected. Each device on the network “sees” all the data being transmitted, th