[ixp1200] Behavior of the RFIFO.

Good day to everyone, I am new to development on IXP1200 and I have a few questions about the RFIFO's behavior. How do we know/test that the RFIFO is full? When the RFIFO is full, what is the default behavior? Does the previous content get overwritten by incoming packets or nothing gets inside until the RFIFO has space? Is the default behavior customable? Thank you for your time. Mohamed Kone College of Computing @ Georgia Tech Email: lechefs@cc.gatech.edu