We do now have a good idea of how the different attack routines (315 & 417) fit together. In a nutshell, Stuxnet attacks its target (uranium enrichment centrifuges) from two vectors. It’s like an assassination with two shooters from different angles for a sure kill. Vector one (315) is the rotor speed control, and vector two (417) is the process & safety system which controls things like valves and pumps.
While the 315 attack code operates only on one cascade, the 417 attack code operates on six cascades. In order to put this into perspective, we created the following diagram. Each single centrifuge cascade corresponds to the diagram with the frequency converters that you have seen in Symantec’s Stuxnet dossier.