Lesson Objective
- Understand the structure of a Bus, Star and Mesh network.
- List and describe the benefits and risks of each network type.
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KS3, GCSE, A-Level Computing Resources
Lesson 5. Network Topologies
Lesson Notes
A LAN can be set up in different ways. Three of these topologies are:
- Star
- Mesh
- Bus
Bus Network
In a bus network, all devices (such as computers, printers, and peripherals) connect to a main cable (the bus) directly. This shared cable acts as the communication channel for data transmission.
Advantages:
- It is easy to connect nodes to the network.
- Less cabling is needed compared to a star topology, making it cheaper to install.
Disadvantages:
- The whole network fails if the backbone cable is broken.
- Terminators must be installed at each end of the backbone.
- Having one backbone increases the chances of data collision.
Star Network
In a star network, all nodes indirectly connect to each other through a switch (or a hub). The switch acts as a central point through which all data can pass through.
Advantages:
- Fast data transfer as there are fewer data collisions - data goes from the switch to the workstation that requested it.
- If one cable fails the other workstations are not affected.
- New nodes can be added to the network simply by connecting them to the switch.
- Star networks tend to have higher performance as a message is passed on to its intended node only.
Disadvantages:
- Requires additional hardware such as the central hub or switch and lots of cabling - can be expensive.
- If the central device fails the whole network goes down.
Full Mesh Network
In a mesh topology there is no central connection point. In a full mesh topology, every node is connected. This allows data to be sent through many individual routes.
Partial Mesh Network
In a partial mesh topology, only some node are connected. There are fewer routes for data to travel along in a partial mesh. However, it is much simpler to implement.
Advantages:
- Data can be received more quickly if the route to the intended recipient is short.
- Data should always get through as they have many possible routes on which to travel.
- Each node can transmit to and receive from more than one node at the same time.
- New nodes can be added without interruption or interfering with other nodes.
Disadvantages:
- Full mesh networks can be difficult to implement because of the high number of connections needed.
- High maintenance (lots of connections).
Client Server Model
Here is a client server model that uses a Star Topology:
Peer to Peer Model
Here is a peer to peer network model that uses a Star Topology:
