I would like to know if somebody has ever tried to make a BIG-IP appliance as an IPS solution, in order to replace for example any of the Gartner IPS leaders' quadrant solutions... I would think we are not able to do so, but I think I heard somebody saying that we can... could you please help me with this doubt? Thanks in advance!!
AFM has an IPS now, Protocol Inspection. It provides protocol compliance checks that implement a positive security model (the traffic must match or it is alerted/dropped/rejected), and signatures that implement a negative security model (matching traffic generates alerts/is dropped or rejected). The signatures implement a subset of the Snort rules language syntax, but the matching engine is different. There's a subscription service available for updated signatures, and users can write their own custom signatures. Custom signatures are a pain due to some validation bugs, but they show a lot of promise.
As a drop-in replacement for an industry-leading IPS, it's probably not viable at this point. As an enhancement where there's already a BIG-IP, yeah it could completely avoid the need to add another device.