| A key characteristic of an ESB is to provide the underpinnings to support the needs of distributed, loosely coupled business units and business partners automating supply chains. These capabilities in an ESB were born out of necessity, as a result of middleware vendors working with industry professionals who were trying to create an architecture for large-scale integration. These industry professionals included IT architects in large corporations, and innovators in the e-Marketplace trading hub community who needed to build a B2B trading exchange backbone based on shared services, messaging, XML, and numerous connectivity options, while adhering to industry standards for each component. Chapter 3 will discuss the many catalysts that contributed to the creation of the ESB concept. At the same time, the biggest needs that had yet to be addressed included how to effectively provide integration capabilities such as application adapters, data transformation, and intelligent routing in a way that could be used for general-purpose integration projects across a variety of integration situations. Also required was a more universal technology and an architectural approach that could be used to connect applications beyond the needs of individual tactical integration projects. IT professionals had been disappointed by some previous technology trends such as CORBA and EAI. CORBA had the right idea with SOA, but turned out to be too complex to implement and maintain due to its reliance on tightly coupled interfaces between applications and services. EAI also suffered from steep learning curves and expensive barriers to entry on individual projects (more on this in the next chapter). What was really needed was a simple approach to SOA, with an architecture that could be adapted to suit the general needs of any integration effort, large or small. In addition, there needed to be a durable architecture that was capable of withstanding evolutions in protocols, interface technology, and even process modeling trends. The ESB concept was created to address all these needs. |
