Architectural Design in Software Engineering

Architectural Design in Software Engineering

Architectural design in software engineering is a high-level design expressed as a block diagram defining the structure of software. It determines the structure and features of the components, data flow patterns, and how these components communicate with each other to share data.

According to IEEE, architectural design is dеfinеd as ‘thе procеss of dеfining a collеction of hardwarе and softwarе components and thеir intеrfacеs to establish the framework for thе dеvеlopmеnt of a computer system.’ It specifies thе componеnts along with thеir inputs,  outputs,  functions, and thе intеraction bеtwееn thеm necessary for developing a computer-based systеm. In simplе tеrms, thе architectural dеsign procеss involvеs identifying thе componеnts i. е. subsystеms that comprisе thе systеm and structurе of thе subsystem and thе intеraction bеtwееn thеm.

A good softwarе architecture design hеlps dеfіnе performance,  maintainability, quality, and scalability. Thе goal is to еnsurе that your softwarе is flеxiblе еnough to adapt, as nеw requirements еmеrgе.  With architеctural dеsign, you can easily dеvеlop, tеst, dеploy, and maintain thе softwarе, whilе rеducing thе risk of еrrors,  bugs,  and othеr problеms arising during thе SDLC procеss.

Types of Architectural Design

Monolithic Architecture

In a monolithic architеcturе, thе opеrating systеm is dеsignеd in a way that all opеrating systеm sеrvicеs, including mеmory management, procеss schеduling, dеvicе drivеrs, and filе systеms, arе providеd in a singlе, largе binary. Thus, there is no distinction between kernel-level and user-level procеssеs; all code executed in thе kеrnеl.


  • The project with monolithic architecture is simple to develop, test, deploy, and scale horizontally.
  • The monolithic architecture delivers high performance since system calls can be made directly to the kernel without the overhead of message passing between user-level processes. 
  • The architecture is simpler since all operating system services are provided by a single binary.


  • Less secure and less stable.
  • If there’s any bug found in any module, it can bring down the entire system.
  • Individual components with conflicting resource requirements can be difficult to scale.
  • Applications with monolithic architecture can have difficulty in adapting to new and advanced technologies.

Microservices Architecture

A microservices architecture is an architectural approach where the application is developed as a collection of services. It involves dividing large applications into small units capable of functioning and communicating independently.  

This approach was developed in response to the limitations of monolithic architecture, as monolithic architecture is inflexible, unreliable, and often develops slowly. Within a microservices architecture, each microservice is a single service designed to support an application feature and manage certain tasks. Each microservice communicates with other services whenever necessary.


  • Microservices architecture is easier to scale and takes less development effort.
  • As the entire application is divided into small units, even if an error occurs the non-related units still continue to function.
  • Once developed, microservices can also be deployed independently of each other.
  • With microservices, it is easier to choose the best tech stack over a variety of options for one particular microservice and its functions.


  • Communication becomes complex between services as everything is independent.
  • Debugging and deployment issues may arise.
  • Testing applications with microservices architecture can be hectic.

Service-Oriented Architecture

In Service-Oriented architecture (SOA), the software is designed to provide services to the other components by application components, through a communication protocol over a network. In service-oriented architecture, different services communicate with each other, in one of two ways- through passing data or through the coordination of two or more services performing an activity.  It leverages standard communication protocols to speed up and streamline the service integration processes in applications.


  • In service-oriented applications, services can be reused and easier to maintain.
  • SOA applications are more reliable, scalable, and easily available.
  • This architecture is platform-independent allowing complex applications by combining services picked from different sources.


  • A huge investment is required for service-oriented architecture.
  •  It becomes a cumbersome task to handle complex management systems.

Event-Driven Architecture

In an event-driven architecture, software services (operations) are activated by external events. The four components of Event-Driven architecture:

  1. Event – A state change occurred due to a user’s action.
  2. Service/event handler – Services often respond to events, and a response may take the form of a process or the production of events as appropriate.
  3. Event Loop – It manages and ensures the smooth streamline of interactions between events and services.
  4. Event Flow Layers – Event flow layers consist of three layers: Event producer, and event consumer. event channel/router.


  • It enhances the scalability, flexibility, and robustness of the application.
  • In Event-Driven Architecture, CPU utilization, and encryptions are comparatively lower than traditional architecture.


  • Increased complexity
  • Debugging and troubleshooting challenges
  • Difficulties with monitoring

Layered Architecture

In layered architecture, different layers are defined with each layer performing a certain set of operations. Each layer performs some operations that gradually get closer to those of a machine instruction set. Components will receive user interface actions at the outer layer and operating system interfacing (communication and coordination with OS) at the inner layer.


  • The architecture helps to test components separately, as they belong to specific layers.
  • It is simple and easy to implement because most applications work in layers.


  • Coupling between layers tends to make it difficult for any changes and to scale.
  • As an application is a singular unit, changing one layer requires redeploying the entire system.
  • Since requests go through multiple layers, performance issues can arise.

Factors to Consider in Architectural Design

1. Scalability

Modern web applications need to be scalable, to handle the growing traffic and ensure business needs are not impacted by a huge customer base. Scalability techniques should be incorporated into the architecture during the design, code, and infrastructure phases.

2. Security

The world is going digitized, so there is a need to protect and secure user’s sensitive information and overall data. Security procedures and practices via configuration should be incorporated into architectural design.

3. Maintainability

The architecture of the software product must be modified with ease in order to correct defects, adapt to new changes, and make future maintenance easier.

4. Performance

The architecture should be designed in such a way that the system can perform under a particular workload. Prior to the beginning of coding engineering practices strive to build performance into the design and architecture of a system.

Best Practices in Architectural Design

1. Use of Design Patterns

Using and implementing design patterns throughout your architecture allows your team to see the high-level perspective behind your design. Diagrams and designs are a great way to visualize procedures and different aspects of your architectural design.

2. Separation of Concerns

Separation of concerns involves splitting various concerns into different layers, such as data storage, business logic, and user interface. This keeps the architecture model simple and easy to understand.

3. Modularity

An effective way to design a software architecture is to break down the system into modules, where each module has a clear responsibility and interface with other modules. This helps to reduce complexity and increase modularity, making it easier to maintain and upgrade the system.

4. Loose Coupling

Loose coupling helps development teams scale applications with greater precision, and deploy code more frequently. It helps reduce complexity.

5. High Cohesion

Modules with high cohesion have a well-defined purpose that reflects a better quality of software design, is easy to understand, and is much more readable. Highly cohesive modules reduce module complexity and increase system maintainability in software architecture.

Tools and Technologies for Architectural Design

1. UML Diagrams

UML diagrams give a quick overview of the structure of the systems and illustrate patterns and relationships that help in the architectural design of the software. UML provides a more efficient design process which helps to detect potential issues early in the software architecture.

2. Enterprise Architect

This visual and modeling tool helps ease the design and deployment of software. Business process modeling, visual software system design, and more extensive modeling are all possible using Enterprise Architect.

3. Visual Paradigm

Visual Paradigm is a paid tool that provides a free trial of 30 days, available both as an online tool and software. It contains pre-designed layouts and can also be used as an image editing tool. It is not only limited to drawing UML diagrams but also for other purposes like creating Business Cards, Brochures, Book covers, etc.

4. Lucidchart

It is a paid online tool that allows real-time collaboration for drawing UML diagrams and charts. This tool is also helpful for any software design and project management. To draw diagrams more prominently and easily, it provides basic templates for all diagrams. It also serves as a tool for data visualization, diagramming, etc.

5. Gliffy

It is an open-source cloud-based software that designs UML diagrams, wireframes, Venn diagrams, flowcharts, and much more. It allows easy collaboration among teams with drag-and-drop features to make drawing simpler.

The architectural design of a system outlines its major elements, their relationships (structures), and how they interact with each other. It is an early stage of the system design phase. It connects specification requirements and the design process. It provides an optimized solution to meet all the technical and functional requirements while enhancing performance and security.

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