Adding frequency 2.0 causes the color map to be used twice per revolution. The result is six sets of red and white radial stripes evenly spaced around the object. The float after frequency can be any value. Values greater than 1.0 causes more than one copy of the map to be used. Values from 0.0 to 1.0 cause a fraction of the map to be used.
Negative values reverses the map.
The phase value causes the map entries to be shifted so that the map starts and ends at a different place. Sometimes you create a great looking gradient or wood color map but you want the grain slightly adjusted in or out. A phase adjustment will shift everything but keep the same scale. Try animating a mandel pigment for a color palette rotation effect. Frequency and phase have no effect on block patterns checker, brick and hexagon nor do they effect image maps, bump maps or material maps.