Designing Scalable and Loosely Coupled Architectures
By now, you should understand what is meant by loosely coupled. Let us recap anyway. Loosely coupled is a design principle where components of a system have minimal or no direct dependencies on each other. This means that if one component of the application were to break, the application may still continue to operate.
Begin with the single-region three-tier architecture that is shown in Figure 13.4. You have this architecture split into three tiers because it helps the application to be more scalable and resilient. If you had just one tier for the web frontend and application tiers, then if the server went down, it would take down the whole application. However, right now, this architecture is not particularly scalable and everything is very tightly coupled. If the application tier were to go down, the whole application would stop working. It might go down for a number of reasons, but one reason might be that there is too much...
