Get the Whitepaper called TippingPoint IPS Signature Evasion through Packet Fragmentation.
You can download it from the following link: https://packetstormsecurity.com/files/download/75439/tp-evasion.pdf
Source: https://packetstormsecurity.com/files/75439/TippingPoint-IPS-Signature-Evasion-Through-Packet-Fragmentation.html