Architectural goals provide the motivation and rationale for decisions. These goals are often driven by the software requirements, particularly system-wide requirements [ALL02].

Architectural goals define how the system needs to respond to change over time. Architectural goals tend to address the following questions:

• What is the expected lifespan of the system?
• Will the system need to respond to technological changes over that time, such as new versions of middleware or other products?
• How frequently is the system expected to adapt to change?
• What changes can we anticipate in the future, and how can we make them easier to accommodate?

These considerations will have a significant effect on the structure of the system.