Introduction

A hub in computer networks is a simple physical hardware component that links several devices in a network, usually in a Local Area Network (LAN). It functions at the physical layer (Layer 1) of the OSI model. A hub, unlike a switch, does not intelligently forward data to the appropriate device, but instead broadcasts the message it receives to all its ports. Hubs lack packet inspection and switching capabilities.

Hubs are best for local networking arrangements that are very basic and inexpensive. But they also have drawbacks like collisions, half-duplex transmission, and shared bandwidth. Hubs are replaced mainly by switches today, but the reason to learn about hubs is that they are the basis of networking technologies and are still in use in various applications like testing, monitoring, and legacy systems. In this blog, we will help you understand “What is Hub in Networking?” We will also discuss its different types along with its functioning. At the end, we will discuss its advantages and disadvantages.

Let us begin by first understanding the most basic question, “What is Hub in Networking?”  

What is a Hub in Computer networks?

A hub in networking is often described as a multi-port repeater. It links dissimilar devices such as computers, printers, and servers in a network. The hub is joined to each device by an Ethernet cable. On transmitting data by one of the devices, the hub will pass the data to all the other ports without focusing on where it is to be sent.

For example, when device A sends the message to device B, the message is not only sent to device B, but also to C, D, and E, which will discard the message since they are not the intended recipient of the message; however, the bandwidth is squandered by the broadcasting, and this increases the chance of a collision.

In simple terms, a hub works as a shared communication medium where all devices operate within the same collision domain.

Now that we have a good understanding of a hub in Computer networks, let us move on to the next section, where we will discuss the features of a hub.

Features of Hub in Computer Networks

Hubs are defined by several key characteristics:

• Operates at Layer 1: Hubs function at the physical layer of the OSI model.
• Non-intelligent device: Hubs cannot filter or analyze data; they forward everything to all ports.
• Broadcasting: Every message received by a hub is broadcast to all devices connected.
• Half-duplex transmission: Devices cannot send and receive data at the same time; they must take turns.
• Collision domain: All devices share the same collision domain, increasing the chances of data collisions.
• No routing tables: Unlike switches or routers, hubs do not store MAC addresses or maintain a routing table.
• Limited ports: Most hubs have 4, 8, or 12 ports, although larger hubs may exist.
• Passive in nature: Many hubs do not include software or advanced features.

These are the characteristics that make hubs extremely easy to operate since they relay signals to every device. It is this simplicity, however, that also makes them inefficient, which leads to collisions and performance bottlenecks in large modern networks.

How Does a Hub Work?

The operation of a hub in computer networks is easy and straightforward. It simply accepts data and transmits it to all other network devices. It basically works on three stages, these are:

• Data reception: A device sends a data frame to the hub through its port.
• Broadcasting: The hub replicates the data and sends it to all other ports.
• Reception by devices: All connected devices receive the data, but only the device with the matching MAC address processes it; others discard it.

Example

Consider a hub with five devices (A, B, C, D, and E). If device A sends data to device B:

• The hub forwards the data to B, C, D, and E.
• Device B accepts the data since its address matches the destination.
• Devices C, D, and E discard the message.

When devices A and B attempt to send data at the same time, their signals interfere with each other, and therefore, data is lost. The hub will then transmit a jam signal, and both devices will have to wait before resending. This reduces the speed of communication in general.

Let us now discuss different types of Hubs.

Types of Hubs

There are three major types of hubs, depending on their functionality and purpose in computer networks: passive hubs, active hubs, and smart hubs with management capabilities.

1. Passive Hubs

Passive hubs act as basic connectors in computer networks. They join multiple devices together at a central point from which data flows through unchanged. This means no signal boosting happens inside these simple devices.

Picture a passive hub like a junction box for network cables. All computers in a star network plug into this central box, and the hub passes electrical signals from one cable to another. It works without power because it performs no processing. The internal wiring connects all ports together.

This basic design leads to various problems, such as weakening of network signals over distance. Each connected device must stay within standard cable length limits. For larger networks, this becomes a fundamental constraint that forces teams to consider powered alternatives.

2. Active Hubs

Active hubs need power to boost network signals. They take weak incoming signals and make them strong again. Think of them as signal cleaners, as distorted or fading signals get rebuilt before moving to the next computer.

Power cables feed these hubs the electricity they need. Inside, electronic circuits amplify data signals. This lets networks span greater distances than passive hubs allow. Active hubs play two key roles:

• They repeat signals like a booster station.
• They also connect many computers to one central spot.

This double duty solves real problems. Offices can spread computers across larger areas. Long cable runs work fine because the hub refreshes signals. Network designers pick active hubs when passive ones can’t reach far enough.

3. Intelligent Hubs

Intelligent hubs bring brains to network hardware. Built-in software sets them apart from basic models. These hubs run management programs and monitoring tools. Network teams use MIB systems to watch hub performance and can overview real data about speed, errors, and connections that appear on admin screens.

Smart hubs watch data flow every second. They spot slow spots and failing connections fast. When traffic jams hit, the hub adjusts speeds to keep data moving. No human needs to step in. The hub fixes problems on its own.

This self-management matters when networks get busy. File transfers adapt to available bandwidth. Smart hubs think through problems that simple hubs can’t even see.

Collision Domain in Hubs

The main drawback of a hub in computer networks is that devices in a hub are in the same collision domain. This implies that any one device can only send data effectively at a time.

A collision happens when two or more devices transmit data at the same time, and the information is lost. This hub transmits a jam signal, which causes the devices to pause and transmit their data again.

This issue might not be observable in small networks where there are a few devices. But in larger networks, performance is significantly affected by collisions. This is among the main reasons why switches have taken the place of hubs and provide individual collision domains to every device that is connected.

Difference Between Hub and Switch

The difference between a hub and a switch is data processing: a hub is sending data to all the devices, a switch is selectively sending and processing data and sending to the required destination.

This comparison highlights why switches quickly replaced hubs in modern networking. For better understanding, you can go through the Hub vs Switch vs Router.

Does a Hub in Networking Affect Speed?

Yes, a hub does have the adverse effect of reducing speed due to its broadcast of data to all devices and unnecessary traffic, which further leads to collisions and decreased network performance efficiency.

• All devices share the same bandwidth.
• Collisions reduce the effective speed.
• Data is broadcast to every device, even if only one device needs it.

For example, in a 10 Mbps hub with five active devices, each device effectively gets less than 2 Mbps of data depending on usage. In contrast, a switch ensures each device gets the full bandwidth.

Advantages of a Hub in Computer Networks

Some of the advantages of hubs are:

• Simple to use and configure.
• Inexpensive compared to switches.
• Useful for small networks or temporary setups.
• Can support different types of network cables.
• Effective for monitoring and testing purposes.

Disadvantages of the Hub in Computer Networks

Apart from all the advantages we have discussed, there are some disadvantages too. These are:

• Operates at the physical layer only.
• Cannot filter or route data.
• A single collision domain increases collisions.
• Uses half-duplex mode, slowing communication.
• Inefficient use of bandwidth due to broadcasting.
• Cannot support Virtual LANs (VLANs).
• Limited speed (typically 10 Mbps).

Applications of Hub in Computer Networks

Some of the applications of Hubs are:

• Used in small LAN setups with limited devices.
• Useful in testing and monitoring, where all data needs to be captured.
• Can be employed in education and training to demonstrate basic networking.
• Still used in some legacy systems where upgrading to switches is unnecessary.

Frequently Asked Questions

Q1. What is Hub in Networking?

A Hub in networking is a piece of equipment that links a network of several computers together in a LAN. It transmits packets of received information to all devices connected to it without filtering, as it adds to unnecessary traffic over the network.

Q2. What Are the Types of Hubs?

There are three different types of hubs in computer networks: passive hubs that provide connectivity between devices, active hubs that recreate signals, and intelligent hubs that provide better performance through management and monitoring capabilities, as well as limited troubleshooting.

Q3. Why Are Hubs Replaced by Switches?

Switching technologies replaced the Hub in networking as it is smart enough to pass information, minimize collisions, provide greater speed, allow two-way transmission, and selective traffic, which enhances the overall performance, security, and reliability of contemporary computer networks.

Q4. Does a Hub Have an IP Address?

No, a Hub in computer networks has no IP address. It is a physical layer-based system, which means it sends signals between gadgets without perception of addressing, routing, or protocols, as compared to switches and routers.

Q5. Does a Hub Have an IP Address?

Hubs do not typically have an IP address since they are not intelligent devices. They also do not carry IP addresses or MAC address mapping information, and only pass data signals. The IP address is given to the device connected to the hub, and the hub stays invisible in the communication process.

Conclusion

A hub in computer networks is a simple device that merges several devices and transmits data to every port attached to it. Hubs do not discriminate or redirect traffic at the physical level; thus, they are not as efficient as switches. They also facilitate half-duplex transmission, generate collisions, and use bandwidth among all the devices.

Hubs are no longer commonly in use because switches and routers have replaced them, despite their simplicity and low cost. Nevertheless, hubs continue to find little use in testing, monitoring, and small networks. Knowing about hubs helps us understand how networking has evolved and the basis on which devices in a LAN communicate.