At level 1 (top-left corner), the enterprise user needs are rudimentarily addressed by a collection of siloed applications.
At level 2 (top-right corner), the enterprise user needs are better addressed through a service portfolio, each consisting of related applications offering a more complete set of functionalities.
Level 3 (bottom-left corner) is about service-portfolio optimization. The service portfolio is enhanced with additional options coming from SaaS providers, allowing the enterprise to further optimize its IT strategy and cost-allocation decisions.
At level 4 (bottom-right corner), in-the-cloud and on-premise services are seamlessly integrated, offering a platform for composing applications closely aligned with business tasks.