Loose Coupling

Loose coupling means low dependency between two systems. It is a way to achieve high fault tolerance and often used in association with Web Services and Service-Oriented Architecture (SOA). Loosely coupled systems are not strongly connected with each other, they have only a minimal coupling between the components in the system. They are obviously the opposite of tightly coupled systems with strong dependencies between the components. In loosely coupled systems, there is a low probability that changes within one module or component will create unanticipated changes within other modules or components. The modular approach to design and develop systems associated with loose coupling makes the applications more agile and flexible, and enables quicker change. A common way to achieve low coupling is to use interfaces and messages: one module does not have to be concerned with the internal implementation of another module, and interacts with another module with a stable interface.

References

Achieving Loose Coupling, David Orchard