That's not really a question, but here's an answer to a different question.
The AVERAGE input data rate CANNOT exceed the AVERAGE output data rate or you will eventually overflow unless you have a infinitely deep FIFO. Similarly, The AVERAGE output data rate CANNOT exceed the AVERAGE input data rate or you will eventually underflow.
The FIFO will only work if your data comes in bursts; you can't have continuous data in and out. You need to know your burst rate, frequencies, etc. to determine the appropriate size fifo. Maybe if you post more information we can help you.