Difference between a hub, switch & router

What’s the difference between a router, switch & a hub..?

A question that is often asked is what are the differences between hubs, switches and routers.?

The most basic device that you can use on a network to send data from one device to another is the hub. The hub is a layer 1 device (Physical layer) and doesn’t check any information stored within the data (frame) such as source/destination address, all it does is receive the data on one port and forward it out of every other port except for the one that it received it on. Bandwidth on a hub link is shared between all the devices.

The switch on the other hand is a layer 2 device (DLL) and is much smarter more efficient. It creates a MAC address table by storing the MAC addresses of devices on each interface so that it knows which port to forward a frame to get to it’s intended destination.

 A switch also has multiple collision domains which eliminates data collisions and uses CSMA/CA, while a hub only has one collision domain and uses CSMA/CD,  This also means that each port on a switch can has its own dedicated bandwidth and can transmit and receive data up to 1Gbps although generally it’s 100Mbps.

While switches and hubs are generally used on the local area network, a router is used to connect multiple LANs. Routers operate at layer 3 (Network layer) and are used to forward packets between networks and to make decisions about which interface or direction to send a packet to get to it’s destination.