Timing Vision -Timing Modes ?

Basics are DRC Phase is for static phase defined in Constraint Manager, Timing is default delay mode for timing groups (Prop delay etc) Smart phase and timing examine the relationship between all the clines in the timing group, compares them to the required delay constraints (Min/Max, Matched, Relative and their associated Targets) and computes a min/max range for each cline that will let it meet the timing group delay constraints.

There is quite a lot of info on the Cadence support site (search for Timing modes) or there is a RAK (rapid adoption kit) for High Speed Design and Planning which covers this subject.