1. Introduction

Enterprises are in a state of flux. New business requirements are challenging enough to drive innovations in information technologies. Such advancements are pushing enterprises to newer business challenges. Significant innovations always impact architectural requirements. This has transformed enterprises from a state in which there was no concept of architecture to a state in which a significant amount of architectural planning is the most important step in an enterprise solution. Although the functionality of enterprise applications drove the requirements of the enterprises in an earlier era, the nonfunctional parts are now controlling the enterprise architecture requirements. The multifarious nature of enterprise businesses has necessitated that businesses reorient the architecture to enable automation. This is advantageous to the enterprises and their partners and collaborators in the long run.

Service Oriented Architecture (SOA) is the latest architectural buzzword to take the enterprises by storm. Business requirements for the enterprises are changing more rapidly than ever and are posing several challenges that put tremendous pressure on enterprise stakeholders to push businesses to hunt for long-lasting solutions. Although there are no silver bullets architecting (or rearchitecting) the enterprise solution to implement, SOA seems to promise a lasting and, perhaps, even futuristic solution to the enterprises. But, is SOA the newest trend? If we look at the historical trends in architectural evolution, we can see that the attempts for service orientation in the architecture existed but never were recognized by that terminology. In the following sections, we explore the evolution of the term SOA and explain its impact on enterprises.