This chapter defines a methodical approach, named Comprehensive Architecture Rationalization and Engineering (CARE), to effectively manage the complexity in architecture design and rationalize the architectural assets of IT application portfolios in a service-oriented paradigm. This comprehensive model comprises a prescriptive method to perform a systematic assessment of information systems applications in an application/project portfolio. The process is broken down to 5 interrelated steps: Data Collection, Reverse Engineering, Technology Assessment, Technical Recommendations, and Action Plan for Rationalization. The details and key artifacts are specified for each step in the overarching process. The outcome of the comprehensive analysis consists of a range of technical recommendations and a course of action, which are characterized along three dimensions: refactoring, reengineering, and rearchitecting. The holistic framework provides a multidisciplinary approach of portfolio analysis and service-oriented architecture planning. Practice guidelines and future trends are also articulated in the context. A case study in the finance industry is presented, to illustrate the use of this framework in real-world scenarios.
Prior work on the IT architecture has strived to address the complexity issue in architecture design, which has grown exponentially as the computing paradigm has evolved from a monolithic structure to a service-oriented architecture. John Zachman (1987) pioneered a framework consisting of a logical structure for classifying and organizing the descriptive representations of an enterprise IT environment’s artifacts that are significant to the management of the organization as well as to the development of the enterprise’s information systems. Zachman Framework takes the form of a two-dimensional matrix, and has achieved a level of penetration in the business and information systems architecture domains. Its primary usage is for planning and problem solving, but it tends to implicitly gear towards the data-driven and process-decomposition approach. It operates above and across the level of individual projects. Likewise, Extended Enterprise Architecture Framework (E2AF) (IEAD, 2004) uses a similar a 2-D matrix structure. Its scope contains business, information, system, and infrastructure. E2AF is more technology-oriented than Zachman Framework.
To overcome the deficiencies in the preceding two methods, Rational Unified Process (RUP) (Kruchten, 2003) attempted a use-case driven, object-oriented and component-based approach by means of Unified Modeling Language (UML). In the concept of 4+1 views, the overall system structure is interpreted from multiple perspectives. RUP tends to be more process-oriented, originated in a waterfall-like approach. It pays little attention to either system operations or software maintenance, and lacks a broad coverage on runtime topology and testing capabilities. Its main focus is on the individual project level. RUP has recently been expanded to Enterprise Unified Process (EUP) (Nalbone, Vizdos & Ambler, 2005), and part of it has been ported to the public domain in the initiative of OpenUP (OpenUP, 2007).
The Open Group Architectural Framework (TOGAF) (Open Group, 2007) is another heavyweight approach, with a set of supporting tools for developing enterprise architecture to meet the business and information technology needs in an organization. TOGAF has three core parts: Architecture Development Method (ADM), Enterprise Architecture Continuum, and TOGAF Resource Base. The scope of TOGAF covers Business Process Architecture, Applications Architecture, Data Architecture, and Technology Architecture. TOGAF is characterized by the concerns of enterprise architecture instead of individual application architecture.