F5 (NASDAQ:FFIV) is trying to make the most out of Cisco's (NASDAQ:CSCO) application delivery controller (ADC) retreat: the company has doubled the payouts it's offering for customers trading in Cisco's ADC hardware for F5's. An F5 exec says the company has already seen many Cisco customers switch. Oppenheimer thinks the opportunity equals 16% of F5's 2011 sales, and notes Radware (NASDAQ:RDWR) has also launched Cisco trade-in promotions.