What is FIB (Forwarding Information Base)?

A forwarding information base (FIB), also called a forwarding table or MAC table. It is usually utilized to track down the proper output network interface to which the input interface should forward a packet in network bridging, routing, and comparable capacities. It is most generally utilized in network bridging, routing, and similar functions to find the proper interface to which the input interface should transmit a packet to be communicated by the router.