A loosely coupled integration architecture lets you build and deploy IT systems that directly serve the goals of your business. The idea is to adapt the systems to the business needs, instead of the other way around. Today, flexibility and the ability to adapt are features that determine the competitiveness of an enterprise.
With a well-designed architecture your organization can keep its focus on the actual business as it allows your IT systems to constantly develop in an ever-changing world. Business and IT processes are integrated into a framework that uses and enhances the capacity of existing systems, allowing easy and quick changes following the demands of business.
Basically, your enterprise demands certain business services and has a number of different IT tools to fulfill them. No single tool can provide all services – some of them are very good at providing certain services while other systems can perform other services well.
The keywords in a well-designed integration architecture are:
- Distributed and loosely coupled.
- Designed around business processes.
- Generic and reusable services.
This means that the business requirements determine what the IT systems will do. With a traditional IT architecture the business often has to accept the limitations of the individual systems. With a loosely coupled structure, services may be reused where they are needed. The systems will be like a hidden toolbox providing the exact services required.
Loosely coupled services
In a well-designed integration architecture you develop services so that they can be joined together on demand to create composite services, regardless of the system technologies used, or, just as swiftly, be disassembled into their functional components. The integration interfaces have minimal "assumptions" between the sending and receiving parties. This means that there is no risk that a change in one application will affect the other application, regardless of their interaction.
Reuse existing systems and applications
One of the main ideas behind a well-designed integration architecture is that it lets you reuse your existing applications and systems. Some of your IT systems may be old and have limited functionality, but they hold much data and still provide valuable functionality. So, the idea is to take the best things from your current software assets and repackage them in the most useful way. And the most useful way means so that you can use them effectively, and then reuse them in other ways – again and again and again…
The concept of reuse is also connected to the concept of standards. By using industry standard interfaces your organization will have a greater freedom to adapt to the constantly changing demands of customers, partners and other business associates. To achieve this without doing any hard coding in your legacy systems, you need to use “adapters”. The adapters will enable your systems to follow the industry standard. They work just like the adapters you use in order to plug in your electric appliances when traveling abroad: Once the adapter is configured the "translation" will be automatic.
Enterprise Service Bus
The Enterprise Service Bus (ESB), is the messaging and integration backbone of an enterprise. It is an application that gives access to other applications and services. The image below shows an ESB acting as integration bus or "broker". The services are black boxes, accessible only through adapters. An adapter is an intelligent connection between the ESB and an application. The adapter exposes services, for example 'Add order', which may be reused in other integrations. Using adapters lets you handle integration on a higher abstraction level, without having to deal with technical details on a granular level. The essential characteristic of the service is reusability.