Star Topology : Working, Features, Diagram, Fault detection & Its Applications

The arrangement of different components like nodes, network devices, and links of a communication network is known as network topology. Network topology plays an essential role in defining how telecommunication networks are connected in computers, industrial field buses, radio networks, and also helps in determining the network performance, device monitoring, visualizations of the network & diagnosing network issues. There are different types of network topologies like bus, star, ring, tree, mesh & hybrid. This article discusses one of the types of topologies like star topology – working with applications.

What is Star Topology?

A star topology or a star network is one kind of network topology where every device is simply connected to a middle hub. This type of network topology is one of the most popular computer network configurations. In this type of network, the devices connected to a central network look like a star model hence its name.

Star Topology Working Principle

The star topology diagram is shown below. In this type of topology, every device within the network is simply connected to a central device known as a hub. The working principle of star topology is; it doesn’t allow communication directly between different connected devices like in a mesh. But the communication is possible by using a central device like a hub available within the network. This central device/hub might be an active hub, passive hub, or switch which is responsible for both transmitting & receiving messages from the sender.

If a single device within this network wants to transmit data to other devices, then first it has to transmit the data to a central hub, after that the hub transmits that data to the selected device. The hub & other devices which are connected to the hub are known as clients. Here these clients are connected to the hub by using RJ-45/ Coaxial cable cables.

Here the hub works like a server and connected devices works like clients. In this topology, the coaxial cable or RJ45 is used based on the type of network card connected to every computer. Similar to a bus topology, a computer network establishment with a star topology is very easy & simple. In this,  If the hub gets any problem then the communication throughout the entire computer network fails.

Star Topology Diagram

In Star topology, all the nodes are simply connected to each other with a switch/hub and the central computer. These are also called a server whereas the nodes that are allied are called clients. These nodes are connected with twisted pair cable, optical fiber, and coaxial/ RJ-4 cable. In this type of topology, nodes (hosts) are connected indirectly to each other by a central hub.

The computer/central device is mainly responsible for guiding & controlling all the traffic within the network. The network performance mainly depends on the capacity of the hub/switch or computer. If the computer (central device) cannot handle several nodes then additional nodes cannot be included in the network. In this network, the nodes, as well as the hub’s physical appearance, will look like a star model, so this network is named a star topology. This topology handles with a huge amount of data & works well within a large network.

The connection of nodes by a central hub is of 4 types: Hub/repeater, bridge/switch, gateway/router, and computer. If a host needs to transmit a message to any other host, first the message is sent to the hub, router, or switch after that passed toward the target host.

Every node within the network contains some unique address, used for transmitting & receiving a message within the network. Suppose the switch in the network works like a server then it stores all the node’s addresses that are connected to it. Once any node wants to transmit a message to one more node next switch identifies which node to transmit a message to because it has a replica of all the addresses.

if the hub acts like the server, then the hub cannot store addresses so the hub will transmit a message to all the nodes & the target machine will notice the address & gets the message. In the network, if any node finds the bug & stops functioning then it will not influence the remaining nodes although if the central hub stops working then the network will not work.

To include an additional node to the network simply extra cables are necessary which make it economical however star topology is expensive as compared to a bus topology. In addition, server like a switch, hub, the router is costly in the star topology.

Protocols Used In Star Topology

The protocol used in star topology is generally Ethernet. This protocol simply uses access methods like CSMA (Carrier sense multiplier access) & CD (Carrier detection). So as to avoid a crash, traffic within the line is first verified before transmitting any data pocket. If the link is busy in some case, then the node will remain & again sends the data packet. The physical layer protocol of the OSI model is utilized in hubs and network layer & data link layer protocols are used within switches for communication across the local area networks & wide area networks. Please refer to this link to know more about Ethernet Protocol.

Fault Handling in Star Topology

Fault handling is very easier in Star topology as compared to the Bus topology because in it each node is directly connected to the central device. Thus, if the node in the topology is faulty then it will stop working & the rest of the nodes can work continuously processing whereas in a bus topology if one node is faulty then it will affect the entire system.

 Bus vs Star Topology

The difference between bus and star topology includes the following.

 Star Topology Vs Mesh Topology

The difference between star and mesh topology includes the following.

Features

The features of star topology include the following.

• The star topology network installation is very easy.
• It has less maintenance.
• This topology uses excessive cables as compared to the bus network topology.
• The primary device used in this topology is a central device known as SWITCH/ROUTER/ HUB.
• The whole network is controlled, commanded & changed through HUB.
• This kind of network is extremely scalable.
• Each node in this network is connected to the Hub.

Star Topology Characteristics

The characteristics of star topology include the following.

• Based on the central hub specification, this network is very simple to expand.
• Identifying the fault in this topology is very easy.
• This topology needs more cable as compared to the bus topology.
• If a single cable in this topology breaks, then the computer which is connected to that single cable is incapable to utilize the network.
• Once the network changes/grows, then computers are added/removed simply from the central hub.

Advantages and Disadvantages

The advantages of star topology include the following.

• It is very simple to add an additional computer to this network.
• If a single computer within the network stops working, then the rest of the network will work normally.
• This topology is very reliable.
• It is not expensive because every device simply requires a single I/O port & needs to be connected through a hub using a single link.
• It is simple to install.
• It is strong in nature.
• Fault detection is simple because the links are identified frequently and easily.
• When devices are connected or removed there is no interruption to the network.
• Every device needs just a single port to connect to the hub.

The disadvantages of star topology include the following.

• It needs high maintenance.
• It depends on the central hub.
• It needs extra equipment.
• The cables/wires utilized within the network can damage very easily
• It needs more cables as compared to a linear bus topology.
• If the central hub gets damaged then the devices connected to the network will not work properly.
• The central hub needs regular maintenance & more resources.

Applications/Uses

The applications of star topology include the following.

• This topology is used by most businesses to connect computers to various printers as well as other stations.
• Star topology is a popular & most frequently used topology with LANs.
• This type of topology is used in small organizations, small networks, etc.
• These topologies use LAN connections for up to 100MBPS maximum speed.
• This topology is utilized within small institute’s.
• Star topologies are used in many networks, large and small
• Star topology is used in high-speed LANs
• This topology is frequently used in offices & homes.
• This topology is also utilized for transmitting data through the central hub between different nodes of the network.

Thus, this is all about an overview of a star topology – working with applications. This kind of topology is applicable in smaller networks and if this topology has a limited no. of nodes then it works efficiently. But one has to make sure that the central node/hub is always working or not because the hub is the heart of this network topology. Here is a question for you, what is ring topology?