A Tool for Enterprise Architecture Analysis

Abstract:

The discipline of enterprise architecture advocates the use of models to support decision-making on enterprise-wide information system issues. In order to provide such support, enterprise architecture models should be amenable to analyses of various properties, as e.g. the availability, performance, interoperability, modifiability, and information security of the modeled enterprise information systems. This paper presents a software tool for such analyses. The tool guides the user in the generation of enterprise architecture models and subjects these models to analyses resulting in quantitative measures of the chosen quality attribute. The paper describes and exemplifies both the architecture and the usage of the tool.

Introduction:

During the last decade, enterprise architecture has grown into an established approach for holistic management of information systems in an organization. Enterprise architecture is model-based, in the sense that diagrammatic descriptions of the systems and their environment constitute the core of the approach. A number of enterprise architecture initiatives have been proposed, such as The Open Group Architecture Framework (TOGAF) [27], Enterprise Architecture Planning (EAP) [24], the Zachman Framework [29], Intelligrid [7], Federal Enterprise Architecture (FEA) [19] and the military architectural frameworks such as DoDAF [1], MODAF [16] and NAF [17]. What constitutes a “good” enterprise architecture model has thus far not been clearly defined. The reason is that the “goodness” of a model is not an inherent property, but contingent on the purpose the model is intended to fill, i.e. what kind of analyses it will be subjected to. For instance, if one seeks to employ an enterprise architecture model for evaluating the performance of an information system, the information required from the model differs radically from the case when the model is used to evaluate system interoperability.

Enterprise architecture analysis is the application of property assessment criteria on enterprise architecture models. For instance, one investigated property might be the information security of a system and a criterion for assessment of this property might be “If the architectural model of the enterprise features an intrusion detection system, then this yields a higher level of information security than if there is no such system.” Criteria and properties such as these may be extracted from academic literature or from empirical measurements.

This paper presents a software tool for the analysis of enterprise architecture models. The tool guides the creation of enterprise information system scenarios in the form of enterprise architecture models and generates quantitative assessments of the scenarios as they evolve. Assessments can be of various quality attributes, such as information security, interoperability, maintainability, performance, availability, usability, functional suitability, and accuracy.

A number of enterprise architecture software tools are available on the market, including Metis [28], System Architect [26], Aris [23], and Qualiware [21]. Although some of these provide possibilities to sum costs or propagate the strategic value of a set of modeled objects, none have significant capabilities for system quality analysis. Within the software architecture community, various analysis methods and tools do however exist, including the Architecture Tradeoff Analysis Method (ATAM) [2], Abd-Allah and Gacek [6], Wright [1] and the Chiron- 2 Software Architecture Description and Evolution Language (C2SADEL) [15]. None of these are, however, applicable in the enterprise architecture domain.

The outline of this paper is as follows. Section 2 describes the method for enterprise architecture analysis which the presented tool supports. This section also introduces an example that is elaborated throughout the paper. Section 3 briefly describes the architecture of the tool. Sections 4 to 8 go through the central components of the architecture in greater detail. The paper is concluded with a discussion and summary in Sections 9 and 10.

Illustration of the Overall Process of Enterprise Architecture Analysis:

Discussion:

At the time of writing, we have developed a prototype for the core functions, reading evidence and abstract model and from these creating a concrete model with the values of the attributes calculated. Apart from validating the current prototype further there are two major research questions that will be focused upon within the nearest future, first there is the issue of the exponential growth of the conditional probability matrices, some approaches to tackle this have already been mentioned and others that are being discussed are the introduction of intermediary attributes [18] or removing arcs where the influence is weak [13]. The second question is how to best select which evidence to collect, a topic that becomes even more important as the models grows larger [9].

Summary:

In this paper, we have presented a tool for analysis of enterprise architecture scenarios. The tool guides the development of enterprise architecture models and from these derives a measure of the quality of the modeled architecture. In the paper, the exemplified quality measure is the availability of a certain information system function, but the tool supports the analysis of various quality attributes, such as information security, interoperability, maintainability, performance, and more. Information system decision making is supported by allowing quantitative comparisons of the qualities of possible future scenarios of the enterprise information system and its context. The tool also provides an estimate of the credibility of the quantitative assessment.