The SWF period refers to the weeks where you are teaching, and therefore, have an active SWF: take a look at the start and end dates on your SWF. During this period, you are assigned work (the work is documented on your SWF). However, a "non-teaching period" is a time where you are not teaching, and work cannot be assigned. Activities during non-teaching periods are decided mutually between the manager and the faculty member. Consent from both parties is required for work assignments during non-teaching periods.