A hub is a basic networking device that connects multiple devices in a local area network (LAN). Let’s delve into its features and functionalities:

Function:

  • The primary role of a hub is to take data from one device and broadcast it to all other connected devices. It operates at the physical layer (Layer 1) of the OSI model.

Features:

  • Broadcasting: Unlike switches, which can learn and store MAC addresses to direct data to specific ports, hubs simply broadcast incoming data to all ports.
  • Simple Design: Hubs are less complex in design compared to other networking devices like switches and routers.
  • LED Indicators: Hubs typically have LED indicators for each port to indicate the status of the connection and data activity.

Types:

  • Passive Hub: Simply forwards the data without amplifying the signal.
  • Active Hub (also known as Multiport Repeaters): Amplifies the incoming signal before broadcasting it. This can be useful in situations where the signal strength might degrade over longer cable lengths.
  • Smart Hub: Comes with additional features like remote management capability.

Limitations:

  • Collision Domains: All devices connected to a hub share a single collision domain. This means that if two devices transmit data simultaneously, a collision will occur, potentially leading to data loss.
  • Bandwidth Sharing: All devices connected to the hub share its total bandwidth, which can lead to network slowdowns when many devices are active.
  • No Intelligent Data Handling: Hubs lack the intelligence to send data only to the intended recipient. They broadcast data to all connected devices regardless of the destination, leading to potential security concerns and inefficiencies.

Usage Scenario:

  • Hubs are less common in modern networks due to their limitations. However, they might still be found in older installations or in scenarios where the network requirements are basic, and the cost is a significant concern.

Conclusion:
While hubs served as foundational networking devices in the early stages of LAN development, advances in technology and the inherent limitations of hubs have led to their replacement by more advanced devices like switches in most contemporary network setups.