The Big Idea of doing Enterprise Architecture or Solution Architecture is to ensure that there is a structured direction or a blueprint to a program or project before they get executed.
This reduces risks and increases the likelihood of achieving the committed value of the initiative.
Will you build a house without an architectural blueprint?
In the same way, will you build a capability without Enterprise Architecture?
After deciding on the scope of the Enterprise you are going to work on, the next decision is on the scope of the Enterprise Architecture.
Are you supporting Strategy, Portfolio, Project, or Third Parties.
Architecture to Support Strategy is about understanding the key Programs needed in order to deliver the organization’s vision and goals.
Architecture to Support Portfolio is about defining the Projects in scope and their inter dependencies.
At this level of Architecture work, the EA works with the Program Manager
An Enterprise can be likened to a car or a city with multiple components all working together to achieve the same goal.
You could say that Enterprise Architecture is about ensuring that the various components of your enterprise are understood vis-a-vis their performance or non-performance towards certain goals. This understanding will then ensure that plans or roadmaps are put in place in order to operate excellently.