With this customer/supplier pattern, the supplier is upstream and the customer is downstream. However, the customer can factor their priorities into the planning of the upstream project.

Example

In the drawing below, for example, payment uses the model of the order process. However, payment defines requirements for the order process. Payment can only be done successfully if the order process provides the required data.

So, payment can become a customer of the order process. That way the customer’s requirements can be included in the planning of the order process.