What is Network Hub and How does it Works?

Hub is a hardware device used at the physical layer to connect multiple devices in the network. A Hub is just a connector that connects the wires coming from different sides. There is no signal processing or regeneration. It is an electronic device that operates only on physical layers of the OSI model. As a network product, a hub may include a group of modem cards for dial-in users, a gateway card for connections to a local area network (for example, an Ethernet or a token ring), and a connection to a line. Hubs are used on small networks where data transmission is not very high.

How Does a Network Hub Work?

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, if 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. 

Types of Network Hubs:

  1. Active Hub: They have a power supply for regenerating, and amplifying the signals. When a port sends weak signaled 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 computerized 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 analyzing 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:

  • 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 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

LayerPhysical layer. Hubs are classified as Layer 1 devices per the OSI model.Data Link Layer. Network switches operate at Layer 2 of the OSI model.
FunctionTo connect a network of personal computers together, they can be joined through a central hub.Allow to connect multiple device and port can be manage, VLAN can create security also can apply
Data Transmission formElectrical signal or bitsFrame (L2 Switch) Frame & Packet (L3 switch)
Transmission TypeHubs always perform frame flooding; may be unicast, multicast or broadcastFirst broadcast; then unicast & multicast as needed.
Ports4/12 portsSwitch is multi-port Bridge. 24/48 ports
Device TypePassive Device (Without Software)Active Device (With Software) & Networking device
TableA network hub cannot learn or store MAC address.Switches use content accessible memory CAM table which is typically accessed by ASIC (Application Specific integrated chips).
Transmission ModeHalf duplexHalf/Full duplex
Broadcast DomainHub has one Broadcast Domain.Switch has one broadcast domain [unless VLAN implemented]
DefinitionAn electronic device that connects many network devices together so that devices can exchange dataA network switch is a computer networking device that is used to connect many devices together on a computer network. A switch is considered more advanced than a hub because a switch will on send MSG to device that needs or request it
Speed10Mbps10/100 Mbps – 1 Gbps
Address used for data transmissionUses MAC addressUses MAC address
Device CategoryNot Intelligent DeviceIntelligent Device
CollisionsCollisions occur commonly in setups using hubs.No collisions occur in a full-duplex switch.
Spanning-TreeNo Spanning-TreeMany Spanning-tree Possible

Advantages of Hub

Connectivity –The primary function of the hub is to permit clients to attach to a network in order that they will share and have conversations. For this purpose, hubs use network protocol analyzer.
Performance –Hub is understood for having very less number of performance impacts on the network. This is often because it operates using a broadcast model which rarely affects the network.
Cost –Comparing to switches, hubs are really inexpensive. Basically thanks to its sort of simplicity. Therefore, they will assist you to save lots of money. And also due to their products they are widely available within the market. 
Device Support –Hubs can connect different types of media all at once with a central hub. Albeit the media want to operate at different speeds they will be wont to support them.
Area Coverage –Area coverage of a network is restricted to a certain distance. Hub extends the space of the network such communication is formed easy.

Disadvantages of Hub

  • Collision Domain –The function of the collision domain and again transfer of packet does not affect actually it increases more chances of collision in between domains. 
  • Full-Duplex Mode –Hubs cannot communicate fully duplex mode, it can only operate in half-duplex mode. Half-duplex mode, in essence, means data are often transmitted just one occasion at a given time. Therefore, the hub must constantly switch its modes.
  • Specification –Hubs cannot support networks that are large like a token ring. This is often because hubs must share data among all the devices within the network. 
  • Network Traffic –As the attachment was received in the packet so it cannot reduce traffic. Hence, hubs make a high level of network traffic.
  • Bandwidth Wastage –Hubs cannot provide dedicated bandwidth for every device, it is to share them. When sending large pieces of information all the bandwidths are going to be occupied by the two computers leaving other computers with slow network.

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