Many organizations have ERP systems in place and are confronted with initiatives from their functional de- partments, consultants or software vendors that aim at im- plementing solutions for Business Networking. This con- cept includes the design and management of IT-enabled relationships between internal and external business part- ners. It provides a holistic perspective on strategies, such as electronic commerce, supply chain management, and customer relationship management. Since a new array of applications to address these inter-business relationships is swiftly implemented, architectural considerations are often left out. Reasons for this include time pressure, a lack of experience, methods, and concepts. Consequently, existing ERP-centric architectures are not modified or have to be modified after the fact. Using a case example from Deutsche Telekom, this article presents a possible proactive solution for a definition of a future application architecture as well as procedures to achieve a Business Networking architecture that meets business requirements.