Understanding Software Architecture: Concepts, Layers, and Classifications

Software architecture is defined as the top‑level structure of a software system, created through systematic thinking and trade‑offs within resource constraints, guiding the overall system skeleton, including subsystems, modules, and components, as well as their collaboration, constraints, and guiding principles.

The article first clarifies related concepts: a system is a group of interrelated entities that together achieve tasks beyond individual capabilities; a subsystem is a system that forms part of a larger system. Modules are logical units, while components are physical units; frameworks provide standardized implementations (e.g., MVC, Spring), whereas architecture defines the structural design.

Four core aspects of architecture are highlighted: rational decision‑making, a clear system skeleton, collaboration relationships, and constraints/guidelines to ensure orderly, efficient, and stable operation.

Architectural layers are then classified:

Business Architecture : strategic, defines business planning, modules, processes, and domain models, focusing on solving business problems.

Application Architecture : tactical, maps business architecture to deployable applications, defines responsibilities, interfaces, and collaboration mechanisms.

Data Architecture : guides database and entity model design, as well as physical data storage considerations.

Code (Development) Architecture : provides coding standards, module organization, top‑level file structure, and dependency management for developers.

Technical Architecture : selects runtime components (e.g., Nginx, Tomcat), addresses non‑functional requirements such as availability, performance, scalability, and security.

Deployment (Topology) Architecture : describes physical nodes, network topology, high‑availability setups, and hardware‑software mapping, primarily of interest to operations engineers.

The article emphasizes that architecture design must balance business complexity with technical complexity, ensuring that solutions are appropriate for the system’s scale, lifecycle, and integration needs while maintaining extensibility and stability.