Hmm, trying to think of the most clear way to explain. Your rear axle is a solid axle, it is a heavy tube beam that goes all the way from one wheel to the other, with a lump in the middle that houses the differential. If you have a solid axle up front, it will look very similar.
IFS (independent front suspension) has a framework in the center that houses the differential and is part of the frame of the truck, so it doesn't move. Then at each side there are arms that go out to the wheels, and the arms move to allow for suspension travel.
Pictures always help.
SFA=Solid Front Axle