When S5600T R2 version connects IBMpower blade, point to point switch mode cannot connect. Using arbitrated loop mode is normal. Do dd operation to disk under arbitrated mode delays seriously.
1. Login in control bench of Brocade switch, type in firmwareshow to confirm recent firmware version. The version less than 6.1.1.x does not support fillword.
2. Use portcfgshow to check padding byte mode of current port,(for 16 port example)