Integration Technologies - Guide to Cloud Computing for Business and Technology Managers - page 107

5
Integration Technologies
Comprehensive enterprise-wide integration infrastructure usually requires
more than one technology. Typically, also, because of the existing technol-
ogies, we will have to use a mixture of technologies. When selecting and
mixing different technologies, we have to focus on their interoperability.
Interoperability between technologies will be crucial because we will use
them to implement the integration infrastructure. Achieving interoperabil-
ity between technologies can be difficult even for technologies based on
open standards. Small deviations from standards in products can deny the
on-paper interoperability. For proprietary solutions, interoperability is even
more difficult. It is not only the question of if we can achieve interoperability
but also how much effort we have to put in to achieve it. Technologies used
for integration are often referred to as middleware.
5.1 Middleware
Middleware is system services software that executes between the operating
system layer and the application layer and provides services. It connects two
or more applications, thus providing connectivity and interoperability to the
applications. Middleware is not a silver bullet that will solve all integration
problems. Due to overhyping in the 1980s and early 1990s, the term middle-
ware has lost popularity but is coming back in the last few years. The middle-
ware concept, however, is today even more important for integration, and
all integration projects will have to use one or many different middleware
solutions. Middleware is mainly used to denote products that provide glue
between applications, which is distinct from simple data import and export
functions that might be built into the applications themselves.
All forms of middleware are helpful in easing the communication between
different software applications. The selection of middleware influences the
application architecture, because middleware centralizes the software infra-
structure and its deployment. Middleware introduces an abstraction layer in
the system architecture and thus reduces the complexity considerably. On
the other hand, each middleware product introduces a certain communica-
tion overhead into the system, which can influence performance, scalability,
throughput, and other efficiency factors. This is important to consider when
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