5. Software Architecture

Any complex system is composed of subsystems that interact under the control of system design such that the system provides the expected behavior. When designing such a system, therefore, the logical approach is to identify the subsystems that should compose the system, the interfaces of these subsystems, and the rules for interaction between the subsystems. This is what software architecture aims to do.
 

Software architecture is a relatively recent area. As the software systems increasingly become distributed and more complex, architecture becomes an important step in building the system. Due to a wide range of options now available for how a system may be configured and connected, carefully designing the architecture becomes very important. It is during the architecture design where choices like using some type of middleware, or some type of backend database, or some type of server, or some type of security component are made. Architecture is also the earliest place when properties like reliability and performance can be evaluated for the system, a capability that is increasingly becoming important.
 

In this chapter, we will discuss:

• The key roles an architecture description plays in a software project.
• The multiple architectural views that can be used to specify di erent structural aspects of the system being built.
• The component and connector architecture of a system, and how it can be expressed.
• Di erent styles that have been proposed for component and connector view that can be used to design the architecture of the proposed system.
• How architecture of a system can be evaluated.