Enterprise architectures are becoming more important today as the level of complexity and inter-operation between systems and business increases, and as there is even more need for business-system alignment and cost-effective use of IT to deliver business benefit.

Enterprise architecture (and project-level technical architecture) provides valuable input into application architecture and detailed design by helping architects understand the business as a whole and by placing the solution being designed into the overall business and technical context within which the project is being delivered.

The key objectives of an enterprise architecture are to understand:

• The relevant parts of whole business, in context (incl. external partners)
• The end-to-end processes (including external processes/actors)
• Non-functional requirements (including security & governance)

which results in a solution that ...

• Supports the non-functional requirements. This may need specific component organization to support, for example, specific cross-domain security requirements, or a service-based approach to provide the required flexibility.
• Is seen in the context of the whole business and end-to-end processes. For example, service level objectives may exist for overall transaction times that span more than one business—understanding the limitations of this allow these measures to be refined.
• Links to, and is traceable to, the business principles so that the impact of changes, some of which may result from the design stage, can be evaluated in business terms.
• Drives, contextualizes, and constrains the design. The design for the application or infrastructure will need to be governed by the architecture in order to fully deliver the complete solution including the non-functional requirements.
• Is clearly scoped, understood and clearly defines the responsibilities of each element
  
  and provides the rationale ...

For decisions, standards and product selections that support the business goals and drivers.