Hub is a layer 1 device. It will out the signal from all of its port except the one from where It’s insert. It is unable to detect the collision. It works on single collision and a single broadcast domain. Switch is layer 2 device. It maintains a CAM table that store the MAC address of devices attached to its port. CAM table is used to make the forwarding decision. It works on per port collision and single broadcast domain.   _{Your Comment}