We've all seen cities that don't quite seem to have a sense of place, where the zoning didn't yield a coherent set of uses or designs, and things appeared thrown together. This results from a lack of planning. Imagine the difficulty and danger of living in a place where there were few building standards, multiple electrical voltages, and roads were put in place willy-nilly.
This is a situation that most enterprises find themselves in with their digital identity infrastructure. The systems are thrown into place with little thought to standards or interoperability. Solving the problem of the day, week, or month becomes standard operating procedure. The end result is a tangled mess of systems that are brittle and unreliable. Heroic efforts are required to make small changes or even keep the systems running day to day.
In the same way that city planning creates a set of standards and rules for buildings to ensure that neighborhoods are safe and pleasant, an enterprise architecture is a set of standards and rules that creates an interoperable and flexible enterprise-wide IT infrastructure.
The work of city planners provides a model that helps us understand the work required of enterprise architects. This work can be divided into three primary categories :
Dimensioning of pipes, voltage, roadways, etc.
Regulated and standardized qualifications for workers
Rules, notifications, permits, approvals, enforcement, ...