IT Scale and Perspectives

The challenge with architecture in e-engineering is dividing the problem space and creating a reference model that is flexible enough to support optimal partitioning for most business domains. Addressing the challenges of architecture in e-engineering, particularly in dividing the problem space and creating a flexible reference model, involves several key considerations:
Division of the Problem Space:

• Modularity: Breaking down complex systems into smaller, manageable modules is crucial. This allows for easier development, testing, and maintenance. Each module should have a clear purpose and interface with other modules through well-defined APIs.
• Domain-Driven Design (DDD): Employing DDD can aid in identifying the core business domains and bounding contexts within the system, which helps in aligning the software architecture with business objectives. This approach emphasizes understanding the business domain before technical implementation.
• Microservices or Service-Oriented Architecture (SOA): These architectural styles can facilitate partitioning by allowing each part of the business logic to be developed, deployed, and scaled independently. However, they introduce complexity in managing services and ensuring their interoperability.

Creating a Flexible Reference Model:

• Abstraction: A good reference model should abstract common patterns and concepts across different business domains. This abstraction helps in creating reusable components or services that can be adapted to various scenarios.
• Layering: Use of layered architecture where each layer (e.g., presentation, application, domain, data) can be independently modified. This supports flexibility by allowing changes in one layer without necessarily impacting others.
• Patterns and Standards: Adopting established architectural patterns (like MVC, CQRS) and standards can provide a framework for flexibility. These patterns offer proven solutions to common design problems, making the architecture adaptable to different business needs.
• Scalability and Adaptability: The model should be designed with scalability in mind, allowing it to grow with the business. This includes considerations for horizontal scaling, load balancing, and ensuring the architecture can adapt to new technologies or changes in business strategy.
• Interoperability: Ensure that the architecture supports various protocols and data formats to facilitate integration with existing systems or future technologies. This might involve using middleware or APIs that are not tightly coupled to specific technologies.
• Governance and Documentation: Strong governance over the architecture ensures that as the system evolves, all parts continue to fit within the reference model. Comprehensive documentation of the architecture, including the rationale behind decisions, helps maintain this flexibility over time.

Challenges:

• Complexity Management: As flexibility increases, so does complexity. Managing this complexity without losing the benefits of flexibility requires careful planning, continuous refactoring, and possibly automated tools for dependency management.
• Balancing Specificity and Generality: A model too general might not provide enough guidance for actual implementation, while one too specific might not be adaptable to different domains.
• Performance Overhead: Flexible architectures might introduce performance overhead due to additional abstraction layers or communication between services.
• Cultural Shift: Adopting such an architecture might require a cultural shift within the development team towards more collaborative and iterative approaches to software development.

In summary, the key to creating a reference model that supports optimal partitioning for various business domains in e-engineering involves a deep understanding of both the technical and business aspects, strategic use of architectural patterns, and a commitment to continuous improvement and adaptation of the architecture as business needs evolve.

The IT scale represents natural partitions and perspectives of the architectural effort, moving from external, environmental concerns of the CEO (the global level) to internal, operational concerns of the programmer ( the build level).
As architectural artifacts are developed to support each level, they address finer and finer details of the architectural structures they describe. The surrounding frames indicate the audience (top of box) and the generator/producer (bottom) of the architecture artifacts for the levels contained within the frame.

1. Global Level Architecture: Ensure enterprise coordination and collaboration impact of business processes that cross enterprise boundaries between trading partners .
   Question: What are their drivers to obtain participation? This level addresses the CEO's concerns regarding improving connectivity and opening new channels in the marketplace.
   Example: Extranet decisions on security access protocols for the Inter-enterprise communication key issue impact of business processes that crosses enterprise boundaries.
2. Enterprise level: Intra-enterprise coordination and collaboration: A single span of control for cross departmental solutions.
   Question: How to improve collaboration and knowledge sharing across departments.
   The CEO's concerns regarding the internal operations of the enterprise are addressed. At this level, for example ERP common systems decisions, middleware standards, common email or messaging platform.
   Key issue: coordination of system level decisions to allow graceful transitions
3. Management level: Management of integration and complexity within the enterprise focus on adaptability and flexibility in the solution portfolio of applications data an infrastructure example gateways and compatibility decisions network management tools key issue managing integration complexity of business processes applications data and infrastructure
4. Application level: Mitigation of performance overhead suitability of functionality point solutions and the degree of satisfaction to the Business Journal requirements performance stability quality example user administration tools logs and reports key issue migrating performance overhead
5. Framework level: Reconfiguration strategies leveraging micro architecture to provide user level adaptability example development frameworks such as CORBA EJB standards Key issue: development of reconfiguration strategies leveraging one or more micro architectures.
6. Micro level: programmer view of grouping of component usability isolation of lower level components to support modification and extension examples class libraries Sessions beans key issue isolation of lower level solution components to handle future changes.
7. Build level: Programmer's view of definition of solution components for customization and delivery consistency examples programming languages and compilers key issue definition and management of lower level solution components

The development of a new framework for architecture must take into consideration that architecture is now a major factor in the success or failure of an Internet-based business venture and therefore must be communicable to a broad range of stakeholders, not just the IT department. The IT architecture scale reconciles the classic IT (BIT) architecture approach as it evolved from the initial Zachman and James Martin frameworks with the concepts of perspectives and domains. As discussed earlier, perspectives are segments on the scale axis and these segments partition the scope of issues and concerns of the major stakeholders.