The impact of design changes on verification using MDGs

In this paper, we investigate the impact of design changes on formal verification using the MDG (Multiway Decision Graphs) tools. In particular, we would like to determine whether the design changes that make verification by interactive theorem proving simpler, also make verification by automated decision diagram approach simpler as well. The design we consider is the Fairisle 4 by 4 switch fabric which has been used for real applications in the Cambridge ATM Fairisle network. A major consideration was that design change decisions should not compromise other design goals such as performance and functionality. The specification and verification obtained in MDG demonstrated the expected positive impact of these design changes