Saturday, June 6, 2009

Exploring Open Group Architecture Framework

TOGAF has been pretty much in vogue due to spread of open source frameworks. TOGAF is the standard enterprise architecture framework, to govern open source based applications. The goal of TOGAF is to bridge the gap between business architecture and technology architecture.

TOGAF comprises of a well documented architecture development method or simply ADM. ADM consists of a process to develop architecture step by step elaboration. Let us see how this works in real time using SOA - which is a design architecture.

Development of architecture starts with gathering preliminary requirements. We need to identify the business vision and goals of the organisation, where SOA would fit in this. Define the scope of SOA in achieving these goals. With this we move on to the next step of defining the architecture view.

The Architecture View defines at high level scope and priorities of: Business Architecture, Data Architecture, Application Architecture, Technology Architecture. SOA would involves identifying - business processes related to line of businesses for BA, alternative data models the processes will deal with for DA, alternative domain models for services required for AA and technology alternatives to implement these services for TA. And also entails identifying stakeholders and getting their approval. Having got a bird view of Architecture View, we proceed with further ADM steps.

The other steps of the ADM involve elaboration of different levels of architecture to support the Architecture View. At each step you have an architecture definition document as deliverable.

Business Architecture would involves development of BPM of each business process identified and any dependencies between them. It aligns the architecture with business goals and concerns of stakeholders

Information Systems Architecture involves elaboration of Data Architecture and Application Architecture. Data Architecture elaborates on alternative data models required by these processes and analyzes of these alternatives. Data management, data migration, data governance, architecture repository aspects fall under this step

Application Architecture will elaborate on specifics of each service and relationship of services to implement each business process. The services will interact with data model through their service component implementations. So it'll also define the relationship between services and the data architecture. And services and the business architecture.

Technology Architecture will elaborate on technologies which could be used to implement these services and their SLA and their BLAs. All aspects of service oriented development methodologies will be defined. This could be implemented using web services, JMS et al. Technology Architecture defines the physical realization of an architectural solution. It has strong links to implementation and migration planning step.

Opportunities & Solutions will elaborate on delivery of concrete solutions or target architecture identified by the previous phases or steps. Which means the selection of alternatives after thorough analysis. In our case, specifics of how services are used to implement business processes. And how services themselves are implemented or composed from other services. Business processes get mapped to their services and services to their service components.

Migration planning elaborates formulation of implementation and migration planning. Transition architectures for services and processes, identified in the previous step get realized here.

Implementation Governance will involve organisation of SOA Governance through suitable solution. It ensures compliance to architecture contract and target architecture. Which includes BLAs and SLAs for processes and their services.

Architecture Change Management and ADM Architecture Requirement Management deal with management of changes in architecture. SOA will involve planned maintenance of services to provide agility to business in a changing business scenario.

The various artifacts delivered by each step is stored in a structured architecture repository defined, previously. The artifacts of each step become the input of the next step of the ADM, apart from external inputs.

BPM acts as bridge between TOGAF - enterprise architecture framework and SOA - design architecture. In the process the overall architecture lends itself to better align with business vision and goals of the organisation. Security Architecture shows how security is involved at each phase or step.