i'm confusing in choosing the suitable supervisor engine for a cat 6506 switch.we require that this swich be layer 3 and 4 enabled.i think that WS-X6K-SUP1A-MSFC or WS-X6K-S1A-MSFC2 could be suitable?but not WS-X6K-SUP1A-2GE. am i right?then , cou...