The planning process that determines how the actual customer demand is fulfilled is called demand fulfillment. The demand fulfillment process calculates the first promise date for customer orders and-thus-strongly influences the order leadtime and the on time delivery.1 In today's competitive markets it is important to generate fast and reliable order promises in order to retain customers and increase market share. This holds particularly true in an e-business environment: Orders are entered on-line in the e-business front end, and the customer expects to receive a reliable due date within a short time period.Further, e-business solutions have to support on-line inquiries where the customer requests a reliable due date without committing the order. The fast generation of reliable order promises gets more complex as • The number of products increases • Products are configured during the ordering process • The average product life cycles get shorter • The number of customers increases • Flexible pricing policies are being introduced • Demand variations increase and get less predictable. 1 In the following, we use the terms order promising and order quoting synonymously, as well as the terms promise and quote.