Network Topologies
Devices in a network are arranged and connected together using network topologies.
Any device on a network is called a node.
There are two common LAN topologies you need to be able to describe: star, bus.
Star Network Topology
Each computer is connected individually to a central node.
The central node can be a file server, switch or hub.
The star topology is the most common layout.
Star Network Topology
Generally fast and reliable, because each node is directly connected to the central node.
Network traffic is minimised, reducing data collisions.
Large organisations, such as schools or businesses tend to use star networks.
Star Network Topology
The switch can screen data packets, rejecting any that are corrupt, increasing security on the network.
It is easy to add devices to the network as they just need to be connected to the switch.
If a connection to one device fails, then the rest of the network should not be affected.
Star Network Topology
Star networks require a lot of cabling, as every computer is connected to the switch individually, this can become expensive.
If the central server or switch fails, the entire network fails.
Bus Network Topology
Each node is connected directly to a single cable, known as the backbone.
Each end of the backbone has a terminator.
Bus Network Topology
All the devices share this cable to transmit data around the network.
The data is sent to all the other nodes.
Each node decides whether to accept the data by checking the destination MAC address.
Bus Network Topology
Only one node can successfully transmit data at any one time.
When multiple transmissions are sent at the same time there will be data collisions.
This will require the data to be resent.
This can slow the network transmission rates.
Bus Network Topology
Bus networks are not common.
Best suited to a temporary network, as they are quick to set up and dismantle.
Questions
- State what is meant by a network topology.
- Describe a star topology.
- Explain one advantage and one disadvantage of using a bus technology.
Questions
- State what is meant by a network topology.
The physical or logical arrangement of nodes that make up a communication network.
- Describe a star topology.
Each computer or client is connected individually to a central point, usually a switch or a hub.
Questions
- Explain one advantage and one disadvantage of using a bus technology.
Advantages:
- Cheap to set up as less cabling is required compared to other topologies.
- Relatively easy to connect devices.
Disadvantages:
- Only one node can transmit data at a time.
- If the backbone fails, the whole network will fail.