System integration

System integration is the bringing together of the component subsystems into one system and ensuring that the subsystems function together as a system. In information technology, systems integration is the process of linking together different computing systems and software applications physically or functionally. [ [http://www2.cis.gsu.edu/cis/program/syllabus/graduate/CIS8020.asp Systems Integration Course Syllabus] , Georgia State University, webpage, retrieved June 27, 2007] The system integrator brings together discrete systems utilizing a variety of techniques such as computer networking, enterprise application integration, business process management or manual programming. A system is an aggregation of subsystems cooperating so that the system is able to deliver the over-arching functionality. System integration involves integrating existing (often disparate) subsystems. The subsystems will have interfaces. Integration involves joining the subsystems together by “gluing” their interfaces together. If the interfaces don’t directly interlock, the “glue” between them can provide the required mappings. System integration is about determining the required “glue”. System integration is also about value-adding to the system, capabilities that are possible because of interactions between subsystems.

In today’s connected world, the role of system integration engineers is becoming more and more important: more and more systems are designed to connect together, both within the system under construction and to systems that are already deployed.

Required skills

A system integration engineer needs a broad range of skills and is likely to be defined by a breadth of knowledge rather than a depth of knowledge.

These skills are likely to include software and hardware engineering, interface protocols, and general problem solving skills. It is likely that the problems to be solved have not been solved before except in the broadest sense. They are likely to include new and challenging problems with an input from a broad range of engineers where the System Integration engineer 'pulls it all together'.

Methods of integration

Vertical Integration is process of integrating subsystems according to their functionality by creating functional entities also referred to as silos. The benefit of this method is that the integration is performed fast and with involving only the necessary vendors, therefore, this method is cheaper in short term. On the other hand, cost-of-ownership can be substantially higher than seen in other methods, since in case of new or enhanced functionality, the only possible way to implement (scale the system) would be by implementing another silo. Reusing subsystems to create another functionality is not possible.

Star Integration or also known as Spaghetti Integration is process of integration of the systems where each system is interconnected to each of the remaining subsystems. When observed from the perspective of the subsystem which is being integrated, this reminds of a star, but when the overall diagram of the system is presented, the connections look like spaghetti, therefore the name of this method. The cost of this method of integration can vary from the interfaces which subsystems are exporting. In case in which the subsystems are exporting vendor-specific interfaces, the integration cost can substantially rise. Time and costs needed to integrate the systems is exponentially rising by adding additional subsystems. From the perspective of implementing new features, this method is preferable since provides extreme flexibility to reuse the functionalities from existing subsystem into new system.

Horizontal Integration or Enterprise service bus is a method in which a specialized subsystem (BUS) is added to the system which is dedicated to communicate with other subsystems. This allows cutting the number of connections (interfaces) to only one per subsystem which will connect directly to the BUS. The BUS is capable to translate the interface into another interface. This allows cutting the costs of integration and provides extreme flexibility. With systems integrated with this method, it is possible to completely replace one subsystem with another subsystem which provides similar functionality but exports different interfaces, all this completely transparent for the rest of the subsystems. The only required thing is to implement the new interface between the BUS and the new subsystem..

ee also

Enterprise application integration

External links

* [http://www.sharpy.dircon.co.uk/ System Integration Information]
* [http://www2.cis.gsu.edu/cis/program/syllabus/graduate/CIS8020.asp Systems Integration Course Syllabus]

Notes