A hub is prone to collisions as pc's connected to a hub 
form a single collision domain.
Where as in a switch each port is a collision domain and 
the bandwith of each port is fully utilized.
Each port is  a collision domain in a swith.

A hub is prone to collisions as pc's connected to a hub 
form a single collision domain.
Where as in a switch each port is a collision domain and 
the bandwith of each port is fully utilized.
Each port is  a collision domain in a swith.

hub works on physical layer and hub do not break up 
broadcast domain and do not break up collision domain.

switch works on DataLink layer and it break up collision 
domain but do not break up broadcast domain .

Router works on network layer and router break up both 
collision and broadcast domain .

Hub is a multiport repeator. Works at the Physical layer.

Switch switches frames from one port to another. Works at 
the Data Link Layer.

Router is a device which is used to connect two different 
networks together. It works at the Network Layer.