What is Network Hub and How it Works?

Hub in networking plays a vital role in data transmission and broadcasting. A hub is a hardware device used at the physical layer to connect multiple devices in the network. Hubs are widely used to connect LANs. A hub has multiple ports. Unlike a switch, a hub cannot filter the data, i.e. it cannot identify the destination of the packet, So it broadcasts or sends the message to each port.

What is HUB?

A hub is a multi-port repeater. A hub connects multiple wires coming from different branches, for example, the connector in star topology which connects different stations. Hubs cannot filter data, so data packets are sent to all connected devices.  In other words, the collision domain of all hosts connected through hub remains one. Hub does not have any routing table to store the data of ports and map destination addresses., the routing table is used to send/broadcast information across all the ports. 

How Does a Network Hub Work?

A hub is a multiport device, which has multiple ports in a device and shares the data to multiple ports altogether. A hub acts as a dumb switch that does not know, which data needs to be forwarded where so it broadcasts or sends the data to each port. 

Suppose there are five ports in a hub A, B, C, D, and E. Consider A wants to send any data frame, or let’s say A is acting as a sender, so the hub will forward the data transmitted by A to B, C, D, E. Now, at the same time B also wants to send the data then data received from A and B will collide and can cause data loss. In this situation, the data gets destroyed, and the hosts send a jam signal to all the hosts informing them about the collision, and each sender needs to wait for a certain amount of time. 

Note: In the hub, data is sent to all ports but each port accepts only that data whose destination address matches their MAC address. 

Types of Network Hubs

Networks hubs are classified into three types:

1. Active Hub: They have a power supply for regenerating, and amplifying the signals. When a port sends weak signalled data, the hub regenerates the signal and strengthens it, then send it further to all other ports. Active hubs are expensive in costs as compared to passive hubs. 
2. Passive Hub: Passive hubs are simply used to connect signals from different network cables as they do not have any computerised element. They simply connect the wires of different devices in the star topology. Passive hubs do not do any processing or signal regeneration and that’s why do not require electricity the most they can do is they can copy or repeat the signal. It can’t clean the message, and it can’t amplify or strengthen the signal. 
3. Intelligent Hub: Intelligent hubs as the name suggests are smarter than active and passive hubs. The intelligent hub comprises a special monitoring unit named a Management Information Base (MIB). This is software that helps in analysing and troubleshooting network problems. Intelligent hubs work similarly to active hubs but with some management features. Like it can monitor the traffic of the network and the configuration of a port. 

Features of Hubs

Hubs are the hardware device that operates in the physical layer of the OSI model. 

• It supports half-duplex transmission
• It works with shared bandwidth and broadcasting.
• The hub can provide a high data transmission rate to different devices. 
• It can detect collisions in the network and send the jamming signal to each port. 
• Hub does not support Virtual LAN(VLAN) and spanning tree protocol.
• It is unable to filter the data and hence transmit or broadcast it to each port. 
• It cannot find the best route/ shortest path to send any data, which makes it an inefficient device. 

Difference Between Network Hub And Switch

Hub	Switch
It works on the physical layer of the OSI model.	It works on the data link layer of the OSI model.
It performs frame flooding, which includes broadcast, multicast and unicast as well.	It mainly performs broadcasts and performs multicast, and unicast whenever required.
The transmission mode is half-duplex.	The transmission mode is full-duplex.
It cannot perform data filtering.	It can filter data and send the frame to the desired destination.
There is no spanning tree.	A switch may contain more than one spanning tree possible.
It can not store the MAC address of the ports and the destination address of the frame that arrived.	It can store the data in a routing table and it helps in further sending the data.
It is a passive device.	It is an active device.
Hub can operate at a speed of 10Mbps.	The switch can operate at a speed of 10-100Mbps and 1- 10 Gbps.

Does a Network Hub Affect Speed?

Because network hubs are unable to prioritise data between devices, they can have an effect on a network’s speed. As a result, when numerous devices are in use at once, the total network speed is decreased because all connected devices share the same bandwidth. Communication delays are further slowed down by the fact that data must be provided to all linked devices even if only one of them requires it. A network hub rather than a switch may be advantageous for particular applications, such as gaming or streaming, even though it’s not the best option for contemporary networks.

Does Network Hub Have an IP Address?

Network hubs generally do not have an IP address, as they are designed to be transparent and forward information between connected devices on the same network. This means that any device can send data through a hub without communicating directly with the hub itself. Additionally, a hub is typically unaware of the IP addresses of the devices it connects, making assigning an address unnecessary.

Advantages of Network Hubs

• It is less expensive.
• It does not impact network performance. 
• Hub support different network media.

Disadvantages of Network Hubs

• It cannot find the best/ shortest path of the network. 
• No mechanism for traffic detection. 
• No mechanism for data filtration. 
• Not capable of connecting to different network topologies like token ring, ethernet, etc. 

For more details please refer Advantages and Disadvantages of Hub article.

Frequently Asked Question on Network Hub – FAQs

Why do you need a hub?

We need Hub because a hub is a networking device that connects several computers and other devices. A hub is the core component of a local area network (LAN); it is also known as a repeater or concentrator. Every device linked to a hub is on the same subnet and receives all data transferred there.

Can a network hub be connected to a switch?

Yes Network hub can be connected with a switch.

How many ports does a network hub have?

Hub have different port configration. For ex: 4 , 8 ,16 , 24 .

Which network topology uses hub?

Star topology uses Hub.