To support IP fragmented packet on virtual server , First the packet get reassembled before passing the packet to atcp and 

The reassmbled packet will go through processing for SLB  and when the packet in buffered on the real server , At the time of processing packet to output interface payload will get fragmented based on output interface MTU.

Unit testing:
The testing is done for different MTU configuration on the REAL server and VIRTUAL server .
The tcp buffer get fragmented on the real server based on the output interface config.