Why does Ethernet specify a minimum frame size.

Ethernet frame gives a minimum frame size of 46 bytes. Whereas a data field of zero byte is legal, this causes a problem. While a transceiver detects a collision, this truncates the current frame that means that stray bits and pieces of frames show on the cable all the time. To make this easier to distinguish valid frames from garbage, Ethernet gives that valid frame should be at least 64 bytes long from destination address to checksum. If data portion of frame is less, the pad field is used to fill out the frame to the minimum size.