A star network topology is a type of network layout where all the devices are connected to a central point. The central device can be a network switch or a hub. The layout of the network has the hub or switch at the center of the network and then all other network components are connected to it.
The main feature of star topology is it has a central device that controls all other devices on the network. The direct cable link to the central device means the data transfer is fast and troubleshooting where the problem is simple. However, it requires an expensive hub and connection cables.
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Characteristics of a star topology
For a network topology to be identified as a star topology it should at least have the following features.
- Connected to a central point. All devices are connected to a central networking device such as a hub or network switch.
- Point-to-point connection. Each device on the network has a cable that runs directly from the device to the central hub. Computers and other components within the network don’t share the cable.
- Fast data transfer. Due to point-to-point connections where each device has its own cable, they move data faster than other topology setups.
How star topology works
A star topology layout is the most common type of topology used in many organizations within the LAN. It is connected using ethernet cables and RJ45 connectors. Each device is connected to a central point or hub.
When a device wants to send data to another device, it sends it first to the hub which then redirects the message to the right destination. Depending on the device used as the central hub the message can be broadcasted to all devices on the network or sent directly to the destination device.
If the central point is a switch/intelligent hub then it determines the destination address of the message and it is sent to that device directly. However, if it is a hub then the message is broadcasted to all nodes within the network for the destination device to pick the message.
Star topology diagram/architecture
The star topology diagram below shows the physical layout of the topology. Each device is connected to a central hub or switch.
Advantages of star topology
- The star topology network is simple to implement and manage. This is simply because each device is connected directly to the central device and not directly to other nodes.
- Users can add another device to the network without affecting the operation of others. They only need to get a cable from the hub to the new device for connection.
- The topology is reliable since the failure of one device on the network doesn’t affect the entire network. The failure is isolated to that devices.
- Troubleshooting when the network has a problem is simple. Since each device is isolated with its own connection cable it is easy to identify problems on the network.
- Data move faster in star topology since each device has a dedicated communication cable to the central point. This means they are not sharing the channel hence high speed.
- It works well for a large network with a high data load compared to bus topology.
Disadvantages star layout
- It has a single point of failure. When the central point device has a problem it affects the whole network.
- The distance of data transmission within the network is limited within the central point reach. If the distance between different nodes in the network is wide then you may need to use more than one hub/switch.
- The ports available for connection on the central device determine the number of computers that can be connected to the network. The hub/switch becomes a bottleneck in terms of the number of devices and traffic within the network.
- Star topology is relatively expensive compared to bus topology. It requires a powerful central point device and cable to run from each device to the hub.