The  design  contains  high-fanout  nets  whose delays will be computed<br>       using a simplified delay model that assumes a fixed fanout number.  The<br>       rationale  behind this is that delays of high-fanout nets are expensive<br>       to compute, but such nets are often unconstrained (as in  the  case  of<br>       global  reset  nets,  scan  enable nets, and so on).  Those high-fanout<br>       nets that are constrained  should  eventually  be  replaced  by  buffer<br>       trees.  In  both  ca