Application integration is often a difficult process, especially when integrating existing legacy applications with new applications or Web services. Given the huge area of this subject, you could literally write a book on doing a successful implementation. However some of the basic business requirements include:
Adequate connectivity between platforms
Business rules and data transformation logic
The longevity of business processes
Flexibility of business processes
Flexibility of hardware, software, and business goals
To meet these needs, the application environment should have a common interface for free communication, including the system’s ability to request Web services and be compatible when interfacing with other platforms and applications.