Backward scheduling calculates deadline dates by subtracting scheduling lead times from a customer's requested delivery date to determine if the date can be met. It works backward from the delivery date to calculate the material availability date. Forward scheduling is used if the material availability date from backward scheduling is in the past or if no product is available on that date. It determines a new availability date and then works forward, adding lead times to calculate the confirmed delivery date. Both backward and forward scheduling are supported to flexibly determine delivery dates.