Any Enterprise architecture needs to take care of two important things, processes and data. A standardized process makes sure certain operations are done in a certain way no matter who is performing them. Data ofcourse is a very important part for any organization, it helps in every aspect of business from fulfilling sales orders, maintaining inventory, making decisions for future etc. So it is important that data is shared across units in effective and secured manner.
Based on the business, need for data sharing and process standardization might vary. We know a standard process adds to predictability (less flexible = agile) but might not work in cases where innovation and flexibility is needed, for example in sales or research. So if we are looking at a business like McDonald’s, we know that each unit needs to follow similar process. Hence process will be part of my core architecture. But in case we are dealing with a Insurance sales business, where each unit might need a different strategy, we will not be be standardizing the process to detail level.
Similarly, decisions needs to taken on centralization of data. For example in a car manufacturing and sales unit, it is important to keep data on inventory, sales, production in sync. Whereas, for an insurance company, it might need flexibility of keeping car insurance and personal insurance data separately. Though you might need to keep products available information at common place. Nonetheless, the data definitions should be strict through out the organization, a completed sales mean same in all aspects.
Based on decisions made as per above analysis, we will be able to create our core architecture effectively. We will know what to add to core and what to keep flexible. The good core design will help business in maintainability and scalability. Adding a new business unit (or a new product or service) and integrating to existing business will depend on readiness of architecture we have finalized.