The pipe should be surrounded by crushed stone. Directly around the pipe should be 3-4 inches of 3/8" stone and then I would put a layer of 3/4" stone over that.
It is common here for no pipe to be used at all. Place the fabric to line the trench and then fill with stone. The fabric is then wrapped around the top of the stone and backfilled before raising to grade with topsoil.