Network Topology

What is Star Topology? Definition | Examples | Advantages | Disadvantages

Hi, and Welcome to another exciting article which will help in answering you question: What is Star Topology? Star Topology is by far the most commonly used Network Topology in Computer Networks. Like Bus Topology, it is very simple and easy to establish a Computer Network that uses Star Topology. If you look around then you will find quite a large number of Star Topology Examples in Real Life. In fact, you can find millions of Star Network Topology Examples in Banks, Educational Institutes, Hospitals and even in Airports.

star topology

What is Star Topology?

Star Topology is alternatively known as Star Network. If I talk about the Physical Topology of Star Network, then it simply comprises of a central device referred as Hub and all the Network Nodes run wires to this central device. You may also use a Switch as a central device. Although the physical layout of this topology is not actually like a star. However, if you create a schematic diagram of this Type of Topology then you will virtually draw a Hub or Switch in the middle.

Similarly, you will connects Servers, Clients and other Network Devices to the central Hub with the help of patch cables. Like Bus Topology, the central device is of chief importance in Star Topology Network. In case of any problem, the communication through whole Computer Network fails. One of the main quality of this one is that it exists in both wired and wireless forms (I will explain these in further coming sections).

Star Topology Definition

In Star Topology, all the Network Nodes like Clients, Servers and other Network Devices like printers, scanners, switches connect to a central device. Usually a Hub or Switch is the best choice for the central device. It is yet another simple Type of Topology. You can find this Network Topology in different organizations including Banks, Schools, Computer Labs, Libraries, Bus Terminals and Departmental Stores.

Star Topology Network Design, Diagram and Description

Here is the Star Topology Layout Picture for proper understanding this concept. It is clearly evident from the diagram that this Type of Topology works by using a central device to which all other Nodes like Clients, Servers and other Network Nodes are connected. There is no Node that can directly communicate with the other. But, each Node has a direct point-to-point connection with the central device. So, each data message has to pass through this central device before reaching the destination. Logical Star Topology Picture reflects the phenomenon very well.

star topology diagram

Star Topology Examples

Now its the time to elaborate this Type of Network Topology with the help of real life examples. This will help you to understand it in a much better way. After the complete understanding of it, I will provide you with the applications and working mechanism of Star Topology. Following are the two main examples for depicting a typical Star Topology Setup.

Example 1: Star Topology LAN

Some of you might have noticed a locked box in different offices. This lock box contains a device in it with different lights blinking all over it. You might also have noticed a bunch of cable coming out of the box. Well that`s wired setup of Star Topology for you. This type of thing is often found in offices and computer labs. In this type of scenario, each device in the Network has a Wired LAN Card. A patch cable connects each individual device to the central Hub. No matter whether the Node is a Server or Client or any other device like printer, scanner etc, you always need patch cable to connect the device to the Computer Network.

star wired topology

Example 2: Star Topology Wireless LAN

Most of you have Internet connection at your home or offices. In most of the cases today, we like to use it with the help of WiFi. Internet Service Providers (ISPs) provide us with Wireless Modem. Due to this fact, we have Wireless Modem at our home or office. When anybody wants to connect to the Internet there is no restriction on him/her in terms of location. Moreover, a Wireless Modem can spread signals throughout a room or group of rooms or even a building. So, we connect our laptops, tablet PCs and Smartphones to the Wireless Modem for accessing the Internet. Hence, all our devices connect to a single central device known as Hub. So, this is probably the best Example of Star Topology.

wireless star topology

Star Topology Applications or Uses of Star Topology

As a Network Engineer you can use Star Topology in Networking in a variety of places. Due to readily available and cheap Star Topology Equipment, you can find its applications all around yourself. However, some common applications are:

  • Most of computer labs in educational institutes use this topology for connecting Nodes in the lab
  • In banks, there are a variety of banking users present. All of these are connected with each other using this Type of Topology
  • Our home networks are obviously configured in this Network Topology

How can You Setup Star Topology Experiment at Home?

Well that`s really easy and straight forward task. In order to setup Star Topology Experiment at your home you don`t require any cost. All you need is to download certain Networking Software from the Internet. After downloading and installing these software you can easily design Star Topology Ethernet efficiently. Following are two most common software for this purpose:

  1. Cisco Packet Tracer
  2. Network Simulator 2 (NS2)

It is very easy to create a typical Star Topology in Cisco Packet Tracer. It provides a powerful GUI for you where you can drag and drop hardware items, connect them easily. However, getting the setup of Star Topology in NS2 is little tricky. This is because of the fact that NS2 is a little difficult to install and configure. You can even configure and understand various Star Topology Protocols and meanings in these software programs.

Features / Characteristics of Star Topology

  • It can be used for almost all types of Computer Networks whether small, medium or large.
  • There is absolutely no dependency among computers connected such a topology.
  • You can use the daisy chain arrangement to extend the whole network.
  • It is more secure when compared to other types of topological structures.

Star Topology Hardware Equipment

There are a certain number of hardware equipment that is required as Star Topology Hardware. But the type of hardware equipment you use is totally dependent upon the specifications of the Computer Network you are going to develop.

Cable Type in Star Network Topology

If you are opting for Wired Star Network then you can use a variety of cables in it. You have the option for using a Twisted Pair Cable or Coaxial Cable. In the old days, Network Engineers used the Coaxial Cable. But Twisted Pair is the most common option. For establishing high speed Computer Networks you can even use Fiber Optic Cable.

Hub or Switch

These devices serve as the central device. In establishing a typical Star Network Topology you can use Hub or Switch. These are the devices where the cables from individual nodes are plugged in. Both of these serve as an intermediate device through which data passes. Each time a sender wants to send data to the receiver, the data has to pass through the central device. There are three types of Hub:

  1. Passive Hub
  2. Active Hub
  3. Intelligent Hub or Switch

What is Passive Hub? - Passive Hub Definition

A Passive Hub simply receives the data from sender and transmits it to all the Network Nodes without any form of processing or amplification. It is used in Passive Star Topology.

What is Active Hub? - Active Hub Definition

An Active Hub works as a repeater. It not only transmits the data to the all other Network Nodes but also amplifies it. This is done so that signals may not loose strength. It is the basic device in Active Star Topology.

What is Intelligent Hub or Switch? - Intelligent Hub or Switch Definition

An Intelligent Hub / Switch also works as a repeater and is used in Switch Star Topology. It transmits sender`s data to a single receiver rather than all the Network Nodes.

Types of Star Topology – Due to Network Media

One the basis for connecting devices with the central Hub you can use either wired setup or wireless setup. So, due to this factor, you can say that there can be two major Types of Star Topology. Each topology provides you with some features and drawbacks. But which topology you want to use is absolutely dependent of your decision and convenience. I will thoroughly explain advantages and disadvantages of each one for the sake of your understanding.

Wired Star Topology

In this type of Star Topology, each device has a point to point wired connection with the central device. Each Network Device is connected to the central device with a patch cord. This patch cord may run throughout a room or a whole building. Although it is being still used in many organizations. Due to high reliability and data transfer speeds, most of the organization use it for high end tasks such as Bank ATMs etc. But due to popularity of wireless devices, users have now started to discourage its use. Moreover, a lot of drawbacks are associated with the wired setup and most of the users don`t like it. (For more details you can refer to Example 1)

Pros & Cons of Wired Star Topology

Pros

Pros
  • Wired Star Topology is highly reliable in terms of data transmission.
  • It doesn`t overload the whole Computer Network because for connecting to the Network you need to plugin the cable.
  • Wired setup of this topology provides high data transfer rates in comparison to the wireless setups.
  • Troubleshooting is easy because you are sure that either there is problem in the patch wire or Network Devices.

Cons

Cons
  • Due to the limited length of the wire you are obviously bound to sit at a specific distance from the Modem. So, it affects the mobility of a user.
  •  There is not port in our Tablet PCs and Smartphones where we can plug the cable for using the Internet. In fact, these devices involve high mobility features.
  • Wired Modems provide you with a limited number of connecting devices. A normal Wired Modem provides you the space for connection up to 8 devices.
  • Using extensive number of cables make the Computer Network look messy.
  • You require a lot of capital expense to establish this setup as you have to purchase considerable amount of wire. Not only this, you even have to pay for wire ducts and connectors also.
  • Troubleshooting and management is difficult. For extension, you may require additional Hubs and wire.
  • A wire is more susceptible to damage due to many reasons including bird bytes and weather conditions. So, it is not that much reliable.

Wireless Star Topology

This type of Star Topology requires the central Hub to be wireless in nature. Hence, all the device connect to the central device with the help of wireless signals preferably WiFi technology. We get a lot of benefits from this implementation. One of the major driving force behind its usage is obviously liberty or freedom of use. By employing this technique you are not restricted. In fact, you can connect to the Computer Network in wireless manner. (For more details you can refer to Example 2)

Pros & Cons of Wireless Star Topology

Pros

Pros
  • You can sit anywhere in a room and connect to the Network. Not only this, you can feel relax and comfortable in another room in a building while still having access to the Network.
  • There is no limit on the number of devices that can be connected. However, you can still impose a limit if you want.
  • Wireless setup offers more security in comparison to the wired setup. In most of the cases you require a passkey to connect to the Network.
  • Such setups look neat and clean because there are no messy cables.
  • You feel comfort in connecting various devices to your Network as most device manufacturers  like Smartphone, Tablet PC and even Printer are using WiFi technology in their devices for communication.
  • It is less expensive as you have to purchase Wireless LAN Cards. However, in most of the cases you don`t even require this as most of the devices come with built-in WLAN Card.
  • Management of such Network Topology is quite easy.
  • Wireless Star Topology is reliable.

Cons

Cons
  • Troubleshooting a Wireless Star Topology is sometimes very tricky and difficult.
  • Such a Network Topology provides lowered data transfer rates in comparison to the Wired Star Network Topology.
  • For imposing a limit on number of users, you have to perform manual settings and if you are not technically sound you may feel difficulties.
  • Security is a big question in Wireless Network Topology. Although we use security keys but yet there are certain cracking software available that can crack the security key.

How Star Topology Works?

Working of Star Topology is really simple and straight forward t0 understand. In this Type of Network Topology, there is no direct communication between different Nodes. Instead there is a central device in the Network. This central device is responsible for receiving message from the sender and transmit it to the receiver. As I have mentioned earlier that the central device can be Passive Hub, Active Hub or a Switch. In each of the scenario, working of the central device is little different. So according to working mechanism, we can divide Star Topology in further three different types:

  1. Passive Star Topology
  2. Active Star Topology
  3. Star Topology Using Switch

However, in all these three cases the Star Topology Layout is the same. What makes different is the working mechanism of each one. Don`t get worried. I am going to explain each one in detail in the coming section.

Passive Star Topology

A Passive Star Topology simply contains a Passive Hub. A Passive Hub simply acts as a central device in a Network. Passive Hub simply receives signal from the sender and broadcast it to other stations in the Computer Network. This type of Hub simply allows the signals to pass without any intervention. In other words, the Passive Hub doesn`t reprocess or regenerate the communication signals.

When you use a Passive Hub in your Star Network, the central device receives data message from the sender. After receiving the data message, it just broadcasts the message to all the Nodes attached to the Hub. One thing you must note that Passive Hub doesn`t regenerates the signal. Each Node receives the data message and checks the destination address. If the destination address and address of a Node matches then the matching one keeps the message. Node whose address is not same as that of destination discards the data message. This type is not suitable for long distance and large Computer Networks.

passive star topology

In Passive Star Network Topology, Passive Hub receives the message and broadcasts it without any processing

Active Star Topology

In an Active Star Topology there is an Active Hub serving the purpose of central device. Active Hub performs additional functions in addition to passing the communication signals. In fact, an Active Hub receives sender communication signals, reprocess/regenerate the signals and broadcast to all other Nodes in the Computer Network. In this way, an Active Hub also serves the purpose of a Repeater as well.

This arrangement uses an Active Hub that broadcasts the message to all the Nodes after regenerating it. Signal regeneration results in increasing the strength of communication signal. Rest of the working is similar to the Passive Hub. The use of Active Hub in Star Network makes it very much suitable for Computer Network having larger number of nodes or having long cable lengths.

active star topology

Active Hub receives the message, processes/regenerates it and broadcasts it

Star Topology Using Switch

In Star Topology Switch is another good option in place of a Hub. It may also known as Switcher Star Network Topology. In this scenario, an intelligent device plays the role of central device rather than an Active Hub or Passive Hub. The most common intelligent device for this purpose is a Switch. A Switch is simply an Intelligent Hub that performs a lot of functions. A Switch doesn`t broadcast the communication signal. Instead it reads the destination address of data message and transmits it to the intended receiver. Following are some additional functions that a Switch can perform:

  • Processing or regeneration of signal
  • Network management
  • Routing
  • Bridging

A Switch receives the data message from the sender in a similar way as Hub does. But after receiving the data message, the Switch itself checks the destination address. It then forwards the data message to the specific destination instead of broadcast. This type of transmission is Uni-cast. Star Network Topology using Switch should be your first choice as it is intelligent in terms of routing, destination identification and regeneration.

star topology switch

Switch/Intelligent Hub receives the message, processes/regenerates it and uni-casts it

Star Topology Advantages and Disadvantages

I hope that up to now you people might have understood all the concepts that I have tried to explain. Now, it is the turn of the most important thing that helps you in deciding whether to go for it or not. Just like in products, you try to find out plus points and negative points because this helps you in your decision. So, I am going to present Star Topology Pros and Cons in this section.

Pros and Cons of Star Topology

Pros

Pros
  • Establishment and Management of this topology is really easy. All you need is a proper central device. Rest of the need is just to connect other Network Nodes either using wired media or wireless media.
  • You can easily add or remove Network Nodes from the Computer Network.
  • The whole Network continues its operation even when one or more Nodes are out of order. It means that problem in one computer doesn`t affect the whole Network of Computers.
  • Problem diagnosis and troubleshooting is easy because of individual point-to-point connections.
  • You can use Star Topology for Small Business as well as large scale businesses too.

Cons

Cons
  • The central device is really critical. If there is a problem in the central device then you cannot use the Computer Network.
  • This Type of Topology is costly to implement and extend as it requires more cables, connectors and even additional Hubs or Switches.
  • One of the critical factors in terms of Network Performance is central Hub or Switch. So, you need to be very careful in selection of these devices.

What is Extended Star Topology?

You have noticed that I have talked a lot about the flexibility and extension of Computer Network. Obviously it is very necessary as a growing business needs extension in terms of computing resources. With this increase you have to extend your network in order to provide the sharing facility to all of your workers. Extended Star Topology comprises of with multiple Hubs or Switches. All of these are interconnected to provide flexibility for connecting more Nodes in the Network.

The phenomena of extension is really simple one. Suppose we have a Hub or a Switch with four ports. This means that we can connect maximum of four devices in this Computer Network. Suppose we want to connect six Nodes. What will we do? The answer is simple. We will purchase an additional Hub (four ports or more) or Switch as we want to facilitate six users. With the first central device (called A) we will only connect three nodes. Similarly to the second central device (called B) we will again connect three nodes. Now rest of the task is to join the two sub parts. Notice that each central device has an empty port. So, we will connect the empty port of A with the empty port of B.

For extending this infrastructure, we will need more Hubs. In this way we can keep on connecting Hubs or Switches and extend our Network to support increasing demands of users. Commonly it is also known as Daisy-Chain Arrangement. It is basically the same concept that we use with USB devices. When we compare this type of extension with Bus Topology, then you can easily find that it is not only much easier but also very favorable. You don`t need to puncture cables for getting drop lines out. All you need is just to find or create an empty port in the Hub or the Switch.

Star Topology vs Bus Topology

In this section, I will give you detail on comparison between the two. We can compare these two on a number of parameters. By comparison you can infer that Star Topology Benefits are far more promising. You can easily say that a Star Network is far better on the base of following features:

  • A Star Network is much more reliable and secure than a Bus Network Topology.
  • While establishing, managing, extending and troubleshooting you will find Star Network mighty easy.
  • You can set it up in both wired and wireless forms.
  • As with Bus Topology, we don`t require any special hardware for preventing signal reflection.

FAQs

1. Where do we use Star Topology?

Well the answer is very simple one. You can use it anywhere you want. However, it is commonly found in hospitals, banks, small offices, homes and clinics.

2. Why Star Topology is better than Mesh Topology?

Mesh Topology is costly to build as it involves dedicated point-to-point connections. Mesh Network Topology requires extensive amount of cabling because you need to connect one Node with all other Nodes on a network through a dedicated link. However, in Star Topology Network, you only need one point-to-point wire for connecting a Node to all other Nodes in the Network.

3. Why do we use Star Topology?

One of the main reasons for this is that, this Network Topology is commonly preferred because of its advantages. First of all, establishment, management and troubleshooting is very easy in it. Secondly, it is very flexible in nature. Thirdly, your Network performs well even if there is any problem in one or more computers.

4. What are the advantages of Star Topology over Bus Topology?

Well due to the use of Switch in Star Topology, the whole Network becomes more secure. This is because the Network becomes point-to-point. However, in Bus Topology the whole communication is broadcast.

5. What might make a Star Topology better than a Ring Topology?

In Ring Topology, if a single Node fails then whole Network stops working. This is because in Ring Topology, each Node is responsible for transmitting message to the device right next to it. However, there is no such responsibility in Star Topology. Failure of one node doesn`t affect the network.

6. How does Star Topology works?

The working mechanism is very simple one. No two devices configured in star topology can communicate directly. Instead sender sends data to the central hub. Central hub or switch receives the data and forwards it to other nodes.

7. Is Star Topology peer-to-peer?

Well that`s not a rule. It can take both forms: peer-to-peer and client-server. This totally depends upon how you have established the network. If you are to establish a network at home then you can go for peer-to-peer. However, in offices the client-server model is more preferable.

8. Which cable is used in Star Topology?

You can use either the twisted pair cable or coaxial cable. But the twisted pair cable is probably the best choice for this topology. Moreover, twisted pair cable is probably the best choice of Network Engineers now-a-days.

9. Why is Star Topology the best?

It is preferred by most of Network Specialists because it is easily extendable. Fault detection and recovery is not a big issue or time consuming process in it. Moreover, with the passage of time it has become a De-Facto standard for even large sized computer networks.

10. Why is Star Topology more reliable?

It is highly reliable due to the fact that communication between two devices is perfectly independent from other devices. There are no chances of signal reflection in it. Further, it is secure due to point-to-point connections and uni-cast communication.

Final Words

So here we are. I have tried my level best to cover up all the necessary things to convey proper knowledge about the selected topic to you. I have tried to explain each and every aspect in a very simple manner. Being the most flexible, manageable, secure and commonly used, Star Network Topology is probably the best choice for you if you are planning to create a Network setup at your office or shop or whatever so. I personally recommend you to go for this option. In case of any ambiguity or problem please feel free to contact me. That`s all for now. See you again with a new topic. So, stay tuned.

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