What is Hub in Computer Networks?

Imagine a hub as a busy intersection, where multiple roads converge. Cars from different directions enter the intersection and then wait for their turn to proceed.

Similarly, a hub in computer networks is a central point where multiple devices connect. When one device sends data,  the hub receives it and then broadcasts it to all other connected devices.

In this article, we will explain the meaning of a hub in networking and explain how the hub works. We will also learn about the uses of hubs, and their prices and compare them to other devices like switches and routers. 

Further, if you are interested in learning practical skills on hubs like their configuration and troubleshooting, enrolling in our online networking courses will help you master these skills.

Expert Training for CCNAGet online training for industry experts on CCNA Certification.Explore course

What is Hub in Networking 

In networking terms, a hub is a central connection point for devices in a LAN. When a device sends data to the hub, the hub replicates the data and broadcasts it to all other connected devices. 

A hub in computer networks is a fundamental device that serves as a central connection point for devices in a local area network (LAN). Acting as a simple data communication tool, the hub's primary role is to enable data exchange between multiple connected devices.

While largely supplanted by more advanced devices like switches and routers, hubs hold historical significance as one of the earliest networking devices. 

What Does a Hub Do? 

A computer network hub primarily serves two essential functions: receiving and transmitting data across all its connected ports.

● Receiving Data: The hub collects data sent by connected devices. 

● Transmitting Data: The hub broadcasts that data to all other devices connected to it. 

These functions are often labeled as Rx (Receive) and Tx (Transmit).

Since a hub can only send or receive data at one time, it operates in half-duplex mode—meaning it cannot perform both functions simultaneously. 

Key Features of a Network Hub

The following are the main features of Hub 

● A hub transmits incoming data packets to all devices connected to it, regardless of the intended recipient.

● Unlike modern switches, hubs cannot filter traffic or determine the destination of data packets

● Hubs operate at the Physical Layer (Layer 1) of the OSI model, meaning they handle raw data signals without interpreting their content.

● Hubs support half-duplex communication, meaning data can only flow in one direction at a time. 

● Hubs typically offer multiple ports (e.g., 4, 8, 16) for connecting devices, making them suitable for small networks. 

Read More About Port Numbers

Types of Hubs in Computer Networks

There are three main types of network hubs:

1. Passive Hubs: These hubs do not amplify signals and just simply connect various devices and allow data to pass through. They are used in star topologies but do not enhance network performance.

2. Active Hubs: Also known as multiport repeaters, amplify incoming signals, helping to extend the connection distance. They can regenerate signals and may include features like retiming.

3. Intelligent Hubs: These hubs combine the functions of active hubs with additional management capabilities, allowing for monitoring and diagnostics of network traffic. They can adapt data rates for connected devices.

Working of Hub Network Device 

Here's a detailed explanation of how Hub device operates in computer networks: 

1. Data Broadcasting: When a device sends data to the hub, the hub forwards the data to all connected devices—not just the intended recipient. This means that all devices in the network segment, whether they need the data or not, receive it.

2. Collision Domain: All ports on a hub operate within the same collision domain, meaning that all devices connected to the hub share the same communication channel. If two devices try to send data at the same time, a collision occurs, causing data corruption. To manage this, devices wait for a random backoff period before retrying their transmission. 

3. Simultaneous Requests: Since a hub broadcasts data to all devices, only one device can send data at any given time. While one device is transmitting, others are occupied receiving the data. As a result, devices take turns sending data, which can lead to delays, especially in busy networks. 

3. Connecting Multiple Hubs: If more hosts are needed, you can connect multiple hubs using a crossover cable. However, the total number of devices and network segments is limited by the 5-4-3 rule (also known as the repeater rule).

What is 5-4-3 Rule?
This rule states that a maximum of five segments (network cables) and four repeaters (such as hubs) can be used between two end devices to maintain a stable connection. 

4. Bandwidth Sharing: All devices connected to a hub share the same bandwidth. The more devices connected, the greater the bandwidth competition, leading to performance degradation.

Hubs vs. Switches vs Routers

Hubs

1. Connect multiple devices in a network.

2. Broadcast data to all connected devices.

3. Suitable for small, simple networks.

4. Less efficient, not ideal for high traffic.

Switches

1. Connect multiple devices in a network.

2. Send data only to the intended device.

3. Suitable for medium to large networks.

4. More efficient, reduces data collisions.

Routers

1. Connect multiple networks.

2. Direct data between networks.

3. Provide internet access.

4. Essential for home and office networks.

Benefits of Hubs 

The following are the benefits of Hubs:

● Hubs are ideal for expanding an existing network by allowing more devices to be connected.

● With a hub, all connected devices can share data. 

● A hub can simplify network management by centralizing the network's traffic.

● A hub is generally a more cost-effective solution than a switch or a router for small-scale networks.

● Hubs offer low latency, which is the time it takes for a signal to travel from one device to another. This makes them ideal for applications that require real-time data transfer, such as video streaming or teleconferencing. 

Disadvantages of Hubs 

The following are the disadvantages of the hub 

● Hubs broadcast data to all connected devices, which can lead to excessive traffic and slow down the network, especially in larger setups. 

● Since data is broadcast to all devices, sensitive information can be intercepted by unintended recipients, posing significant security concerns. 

● Hubs cannot filter or route data to specific devices. This makes them less efficient compared to switches and routers, which can intelligently direct traffic. 

● Data can only flow in one direction at a time, which reduces overall network efficiency and increases the chances of data collisions. 

● Hubs are not suitable for large or complex networks as they cannot manage or prioritize traffic effectively. 

With advancements in networking, hubs have largely been replaced by more advanced devices like switches and routers, making them less practical in modern applications. 

How to Configure a Computer Network Hub?

Configuring a computer network hub is similar to configuring unmanaged Layer 2 switches. While the exact steps may vary depending on the model, the general procedure is as follows: 

Step 1: Connect Power to the Hub: For active hubs that amplify signals, plug the hub into a power source using an AC power cord, wall adapter, or a similar power connector. 

Step 2: Link Devices to the Hub: Use Ethernet cables with RJ45 connectors to connect your devices to the hub’s network ports. 

Step 3 [Optional]: Use the Uplink Port: While not typically needed in modern networks, some hubs include an "uplink" port to connect to another hub. These ports usually feature pre-configured pins that automatically swap the transmit (Tx) and receive (Rx) signals, eliminating the need for a crossover cable. 

Step 4: Check Connectivity: After setting up, confirm that the network devices are communicating. Most hubs come with diagnostic LEDs that indicate power status, collision events, and port activity. 

Common Troubleshooting with Network Hubs 

Some issues with network hubs are easy to diagnose, while others can be more complicated. Here's a guide to troubleshooting common hub-related issues: 

Conclusion 

A hub in computer networking is a straightforward yet foundational device that played a pivotal role in early LAN configurations. Although largely obsolete, hubs remain an important concept in networking education and history.

By understanding what a hub is and how it works, you can better appreciate the advances in modern networking technology.