Chapter Nine. Integration Servers and Application Integration

Integration servers are the center of the universe when it comes to application integration. They are not "general-purpose" middleware products such as message queuing or transactional software. Indeed, integration servers were built from the ground up to solve the application integration problem, both intra- and intercompany. Therefore, this chapter is very important, considering that integration servers are part of the solution set for most application integration problems.

As we'll see later in this book, integration servers continue to evolve as the needs of the marketplace evolve. Rather than support simple information exchange between source and target systems, integration servers can now provide support for SOAI using the same integration technology.

Integration servers are sophisticated pieces of software that sit between applications many applications intra- or interenterprise, and facilitate the exchange of information and sometimes application services. Integration servers are relatively new and exist solely to solve the application integration problem.

However, while they offer "one-stop shopping" for application integration technology in many respects, the approaches that each integration server vendor takes are very different, and thus solve very different types of problems. Vendors that sell this technology include Mercator, WebMethods, SeeBeyond, and IBM. As such, you need to understand the approaches in order to select the proper technology for your problem domain. Selecting the wrong technology is disastrous. A wrong decision can take many months and many millions of dollars to fix. Hence, the length of this chapter reflects its importance.