What is the difference between Bridge, Router, Hub, Switch and Gateway ?

Bridge :A bridge goes one step up on a hub in that it review the destination of the packet before sending. If the destination address is not on the other side of the bridge it will not transmit the data.
Routers : A router is a device like a switch that routes data packets based on their IP addresses. Router is mainly a Network Layer device. 
Hub : A hub is the simplest of these devices. Any data packet coming from one port is sent to all other ports. 
Switch :Switch is data link layer device. Switch can perform error checking before forwarding data, that makes it very efficient as it does not forward packets that have errors and  forward good packets selectively to correct port only. 
Gateway :A gateway, as the name suggests, is a passage to connect two networks together that may work upon different networking models.