Hubs (Old Technology)

Connects devices in the network together

For example, when host A sends data to host C, the hub receives this data and repeats it to every port except the originating one (A).

Hub disadvantages:

• Cannot send and receive data simultaneously, causing data collisions and corrupted data
• Functions only as a Layer 1 device - merely repeats data
• Creates a single collision domain
• Operates in half-duplex mode only
• Wastes bandwidth
• Poses security risks since all connected hosts receive the data

Bridges (no longer used)

• Introduced to combat hubs' shortcomings. Bridges segment networks by deciding whether to forward data based on MAC source and destination addresses.
• Layer 2 device - can understand and learn MAC addresses
• Creates two collision domains - allowing data to be sent and received simultaneously
• Has fewer ports

Switches

• Combines the functions of hubs and bridges, learning which port connects to which host
• Capable of learning and storing MAC addresses
• Transmits data only to the destination host, preventing data theft and conserving bandwidth
• Operates in full-duplex mode, allowing simultaneous sending and receiving of data

Routers

• Acts as a gateway between internal and external networks
• Directs traffic between different networks
• In home setups, router and bridge functions are combined in one device, while enterprise environments use separate dedicated devices
• Uses both MAC and IP addresses for routing decisions
• Operates as a Layer 3 device

As I am a visual learner, for reference of what each device looks like