Tutorials SOA Web ServicesIn the 1980s, applications were mostly vertical, built to meet the customer requirements in a vertical market segment. The software solutions were sufficient to meet the needs of a vertical industry.
For example, an automobile industry never felt the need for interacting with its suppliers by electronic means. The same was true in the case of most other industries. Very rarely there was a need to communicate with other businesses. This is shown in the following figure:
In the late '80s and early '90s, we saw the need for business applications to grow horizontally to cooperate with business partners. The industry saw the evolution of B2B (Business-to-Business) collaborations through components now spreading across several industry verticals. These components were now distributed giving rise to an extended supply chain, providing customers and business partners access to services. This is illustrated in the following figure.
In today's world, the way that businesses operate has changed tremendously. Businesses not only want interaction with their partners, but they allow their customers and employees to access their business services electronically. Today, we talk about B2C (Business-to-Customer), whereby customers have a direct access to the services offered by businesses. Exposing the business logic to an untrusted user base poses its own challenges in terms of security, integrity, and so on. Besides, such services must be user friendly and must hide the complexities of the internal business processes from the end customer.
This is where the true need for Service-Oriented Architecture is felt. Businesses should offer services rather than an interface to their business logic. The business logic is implemented in several components—exposing the interface to these components results in tight coupling with the business logic. A client application consumes the service through a well-defined interface to the service and does not care about how it is implemented.
Such interactions are depicted in the following figure of today's complex IT requirements.
The above figure illustrates a typical Travel Agency scenario. A traveler interacts with the travel agency. The travel agency interfaces with several airlines, hotels, and car rental companies. It also interfaces with several banks for online payments, accounting, etc.
Each of these organizations in turn interfaces with several other businesses. The total network soon becomes complex. However, this is the requirement of today's businesses and as IT professionals, we are supposed to provide solutions to these demanding requirements.
