Gar The majority of failed application development projects over the past decade resulted from overly complex distributed computing architectures. Defining EAI As corporate dependence on technology has grown more complex and far reaching, the need for a method of integrating integratoin applications into a unified set of business processes has emerged as a priority. Mainframes, UNIX servers, NT servers, and even proprietary platforms whose names have been forgotten, constitute the technological base for most enterprises. You also may like to try some of these bookshopswhich may s. Then set up a personal list of libraries from your profile s.
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After creating islands of automation through generations of technology, users and business managers are demanding that seamless bridges be built to join them.
In effect, they are demanding that ways be found to bind these applications into a single, unified enterprise application. The development of Enterprise Application Integration EAI , which allows many of the stovepipe applications that exist today to share both processes and data, allows us to finally answer this demand.
Interest in EAI is driven by a number of important factors. With the pressures of a competitive business environment moving IT management to shorter application life cycles, financial prudence demands that IT managers learn to use existing databases and application services rather than recreate the same business processes and data repositories over and over see Figure 1. Ultimately, finances are a prime concern. The integration of applications to save precious development dollars creates a competitive edge for corporations who share application information either within the corporation or with trading partners.
Figure 1. Mainframes, UNIX servers, NT servers, and even proprietary platforms whose names have been forgotten, constitute the technological base for most enterprises. These technologies, new and old, are all providing some value in the enterprise, but their value is diminished if they are unable to leverage other enterprise applications.
Moreover, the need to integrate those systems with packaged systems has been intensified by the popularity of packaged applications such as SAP, PeopleSoft, and Baan.
The case for EAI is clear and easy to define. Accomplishing EAI, however, is not. Forester Research estimates that up to 35 percent of development time is devoted to creating interfaces and points of integration for applications and data sources.
Most problems with developing software derive from attempts to integrate it with existing systems. What Is EAI? So, if EAI is the solution, what exactly is it? EAI is not simply a buzzword dreamed up by the press and analyst community. It is, at its foundation, a response to decades of creating distributed monolithic, single-purpose applications leveraging a hodgepodge of platforms and development approaches.
EAI represents the solution to a problem that has existed since applications first moved from central processors. Put briefly, EAI is the unrestricted sharing of data and business processes among any connected applications and data sources in the enterprise.
The demand of the enterprise is to share data and processes without having to make sweeping changes to the applications or data structures see Figure 1. Only by creating a method of accomplishing this integration can EAI be both functional and cost effective. Now that you know what it is, the value of EAI should be obvious. EAI is the solution to the unanticipated outcome of generations of development undertaken without a central vision or strategy.
For generations, systems have been built that have served a single purpose for a single set of users without sufficient thought to integrating these systems into larger systems and multiple applications. Undoubtedly, a number of stovepipe systems are in your enterprise--for example, inventory control, sales automation, general ledger, and human resource systems.
These systems typically were custom built with your specific needs in mind, utilizing the technology-of-the-day. Many used nonstandard data storage and application development technology.
While the technology has aged, the value of the applications to your enterprise likely remains fresh. Indeed, that "ancient" technology has probably remained critical to the workings of your enterprise. Unfortunately, many of these business-critical systems are difficult to adapt to allow them to communicate and share information with other, more advanced systems.
While there always exists the option of replacing these older systems, the cost of doing so is generally prohibitive. Sharing information among these systems is particularly difficult because many of them were not designed to access anything outside their own proprietary technology. Applying Technology If EAI articulates the problem, then traditional middleware has sought to articulate the solution--sort of. Traditional middleware addresses the EAI problem in a limited manner.
The primary limitation is that middleware that uses message queuing or remote procedure calls RPCs only provides point-to-point solutions--that is, linkage between system A and system B. Unfortunately, any attempt to link additional systems quickly becomes a complex tangle of middleware links.
Worse still, traditional middleware demands significant alterations to the source and target systems, embedding the middleware layer into the application or data store. For example, when integrating a custom accounting system running on Windows with a custom inventory control system running on the mainframe, you may select a message-queuing middleware product to allow both systems to share information.
In doing so, however, you generally have to alter the source system where the information is coming from with the target system where the information is going to in order to make use of the middleware. This is due to the fact that the point-to-point middleware layer only provides a program interface, and thus the programs must change to accommodate the middleware. This is costly and sometimes risky.
The end result is software pipes running in and out of existing enterprise systems, with no central control and central management, and a limited ability to react to change. The end state looks more like an ill-planned highway system that was built by many small integration projects but with little strategic value. An additional complication to this scenario is that IT managers must perform integration projects inside fluid environments using rapidly advancing technology.
In seeking to integrate links, the manager may also encounter additional problems such as: A variety of legacy systems that contain mission-critical applications Several packaged applications with both proprietary and open frameworks A hodgepodge of hardware and operating system platforms A hodgepodge of communication protocols and networking equipment Geographically disbursed applications and databases In addition to these structural limitations, the economics of traditional middleware have placed EAI out of the reach of most IT organizations.
Given these significant limitations, it follows that EAI represents a very different method of application integration than that using traditional middleware see Figure 1. EAI provides a set of integration-level application semantics. Put another way, EAI creates a common way for both business processes and data to speak to one another across applications. More importantly, we approach this old problem with a new set of technologies designed specifically for EAI.
So, keeping this information in mind, we can focus on the following differences between traditional approaches and the vision of EAI: EAI focuses on the integration of both business-level processes and data, whereas the traditional middleware approach is data oriented.
EAI includes the notion of reuse as well as distribution of business processes and data EAI allows users who understand very little about the details of the applications to integrate the applications. EAI answers the problem of integrating systems and applications. But how did the problem come about? The answer depends to a great extent on perspective.
In the early days of computing, information was processed on centralized platforms. As a result, process and data existed in a homogeneous environment. Integrating applications both processes and data within the same machine rarely created a problem beyond some additional coding.
As technology developed, platforms changed. Smaller and more open platforms, including UNIX and Windows NT in addition to new programming paradigms such as object-oriented and component-based development , challenged traditional mainframes, once the backbone of IT.
Whether correctly or not, traditional IT leveraged the power of these newer, more open platforms. A number of factors contributed to this. Users wanted applications that were driven by newer and more attractive graphical user interfaces. Misreading or ignoring this desire, traditional legacy systems lagged in adopting "user-friendly" graphical user interfaces, abandoning the field to the newer platforms. Perhaps more importantly, the press trumpeted the claim that the cost of applying and maintaining the newer platforms was less than traditional systems.
Sometimes this claim was correct. Often it was not. In the rush to incorporate these new systems, most enterprises applied minimal architectural foresight to the selection of platforms and applications. IT managers made many of their decisions based on their perception of the current technology market. Today, the same is true of Windows NT.
Clearly, the installation of these systems has been a textbook example of "management-by-magazine. While acknowledging that smaller and more open systems can hold a very important place in the enterprise, this decision-making process lacked the perspective and foresight that might have minimized, or possibly avoided, many integration problems.
The success of these smaller, more open systems was that they met the requirement of commodity computing but with a steep price--the need for integration with the existing, older system. The need for EAI is the direct result of this architectural foresight, or rather, the lack of it. Until recently, architecture at the enterprise level had been virtually nonexistent.
Information technology decisions tended to be made at the department level, with each department selecting technology and solutions around its own needs and belief structures. For example, accounting may have built their information systems around a mainframe, while human resources leveraged the power of distributed objects, and research and development might have used distributed transaction processing technology.
The end result could have been a mixing and matching of technologies and paradigms. As a result, the enterprise as a whole was left with a "system" that is nearly impossible to integrate without fundamental re-architecture--and a significant investment of precious funds. To address the problem of architectural foresight, many organizations have created the role of the enterprise architect.
This person or office is responsible for overseeing a centralized architecture and making sure that technology and solutions selected for the enterprise are functionally able to interact well with one another. As a result, departments will be able to share processes and data with a minimum of additional work.
Enterprise architects will be called upon to make some unpopular decisions. They will be charged with making decisions regarding the commitment to a single programming paradigm and technology religion. If the enterprise goes to distributed objects, it must do so as a unified whole. Tough, centralized decisions must be made. Corporate America is finally shutting down the playground that was once information technology. Chaos Today, Order Tomorrow The establishment of enterprise architects is a significant and positive development.
Often, in addition to developing a central long-term strategy for the future, the role of the architect is to coordinate the technology that is already in place. Most enterprises leverage many different technologies. The integration of these technologies is almost always a difficult and chaotic proposition.
Traditional middleware technology, such as message-queuing software, ties applications together, but these "point-to-point" solutions create single links between many applications as we mentioned previously. When using the point-to-point approach, integrating applications comes down to altering each application to be able to send and receive messages.
This can be accomplished with any number of message-oriented middleware MOM products e. While this is easily managed within the context of integrating two applications, integrating additional applications demands additional pipes. If you have successfully integrated application A with application B and would like to include applications C and D, you will have to create a pipe between each involved application.
In no time, the process will grow so complex as to render it almost unmanageable. See Figure 1.
ENTERPRISE APPLICATION INTEGRATION DAVID S.LINTHICUM PDF
After creating islands of automation through generations of technology, users and business managers are demanding that seamless bridges be built to join them. In effect, they are demanding that ways be found to bind these applications into a single, unified enterprise application. The development of Enterprise Application Integration EAI , which allows many of the stovepipe applications that exist today to share both processes and data, allows us to finally answer this demand. Interest in EAI is driven by a number of important factors. With the pressures of a competitive business environment moving IT management to shorter application life cycles, financial prudence demands that IT managers learn to use existing databases and application services rather than recreate the same business processes and data repositories over and over see Figure 1.
Enterprise Application Integration
Enterprise application integration EAI is the use of technologies and services across an enterprise to enable the integration of software applications and hardware systems. Many proprietary and open projects provide EAI solution support. EAI is related to middleware technologies. Other developing EAI technologies involve Web service integration, service-oriented architecture, content integration and business processes. Thus, EAs do not share common data or business rules. EAI links EA applications to simplify and automate business processes without applying excessive application or data structure changes.
Enterprise applications integration