Is there a name for circles that show progress through form?

Interfaces that guide users through several steps with one per screen per step often have little circles at the bottom of the page, with each circle representing a step/screen in the sequence. The active circle indicates the number of steps/screen the user has already completed.

Is there a name for this design pattern? I'd like to read more about best practices in this area (the max number of circles / distinct screens that hold user attention, size of circles, interaction patterns, etc).