Architectural Views
Software Architecture
Richard Thomas
February 24, 2025
Interesting Software is Complex
Many aspects to the design of its architecture.
Architectural Design
Managing technical complexity.
Question
How do you describe a complex architecture,
without making it too difficult to understand?
Question
How do you describe a complex architecture,
without making it too difficult to understand?
Answer
Architectural Views
– Only consider one aspect at a time.
Architectural Views
• C4 Model [Brown, 2023]
− context, structure, behaviour, infrastructure
Architectural Views
• C4 Model [Brown, 2023]
− context, structure, behaviour, infrastructure
• 4+1 Views [Kruchten, 1995]
− logical, process, development, physical, scenario
Architectural Views
• C4 Model [Brown, 2023]
− context, structure, behaviour, infrastructure
• 4+1 Views [Kruchten, 1995]
− logical, process, development, physical, scenario
• Software Architecture in Practice [Bass et al., 2021]
− module, component-and-connector, allocation
Architectural Views
• C4 Model [Brown, 2023]
− context, structure, behaviour, infrastructure
• 4+1 Views [Kruchten, 1995]
− logical, process, development, physical, scenario
• Software Architecture in Practice [Bass et al., 2021]
− module, component-and-connector, allocation
• NATO Architecture Framework [Team, 2020]
− concepts, service, logical, physical resource, architecture foundation
Architectural Views
• C4 Model [Brown, 2023]
− context, structure, behaviour, infrastructure
• 4+1 Views [Kruchten, 1995]
− logical, process, development, physical, scenario
• Software Architecture in Practice [Bass et al., 2021]
− module, component-and-connector, allocation
• NATO Architecture Framework [Team, 2020]
− concepts, service, logical, physical resource, architecture foundation
• The Open Group Architecture Framework (TOGAF) [Forum, 2022]
• ISO/IEC/IEEE 42010:2011 [iso, 2022]
Diagrams & Notation
• A good diagram is worth a thousand words
• A thousand diagrams is just confusing
Diagrams & Notation
• A good diagram is worth a thousand words
• A thousand diagrams is just confusing
• C4 – informal, simple structure [Brown, 2023]
• UML – formal, well-defined language [uml, 2017]
• You probably don’t want to know about alternatives
C4 Model: Levels
C4 Model: Context
How software system fits into broader environment
C4 Model: Containers
Structure of the software system
C4 Model: Components
Elements that implement a container
C4 Model: Code
Structure of code implementing a component
C4 Model: Dynamic
How parts of the model collaborate to deliver behaviour
C4 Model: Deployment
Infrastructure on which system will be deployed
4+1 Views
Logical – Structure of how the software is implemented
• components/classes, relationships, interactions
4+1 Views
Logical – Structure of how the software is implemented
• components/classes, relationships, interactions
Process – Dynamic behaviour
• concurrency & distribution, fault tolerance, process control,
...
4+1 Views
Logical – Structure of how the software is implemented
• components/classes, relationships, interactions
Process – Dynamic behaviour
• concurrency & distribution, fault tolerance, process control,
...
Development – Organisation of the software in the development
environment
4+1 Views
Logical – Structure of how the software is implemented
• components/classes, relationships, interactions
Process – Dynamic behaviour
• concurrency & distribution, fault tolerance, process control,
...
Development – Organisation of the software in the development
environment
Physical – Map executable software containers to hardware
• address non-functional requirements
• availability, reliability, scalability, throughput, ...
4+1 Views
Logical – Structure of how the software is implemented
• components/classes, relationships, interactions
Process – Dynamic behaviour
• concurrency & distribution, fault tolerance, process control,
...
Development – Organisation of the software in the development
environment
Physical – Map executable software containers to hardware
• address non-functional requirements
• availability, reliability, scalability, throughput, ...
Scenario – Demonstrate functionality delivered by architecture
• use case details
• drive functional design of architecture
• validate design of architecture
• illustrate purpose of architecture
Reading...
“Architectural Views” Notes1 [Thomas and Webb, 2023]
1
Remember, I said you had to read the notes.
References
[uml, 2017] (2017).
Unified Modeling Language.
OMG, 2.5.1 edition.
https://www.uml.org/.
[iso, 2022] (2022).
Software, Systems and Enterprise – Architecture Description (ISO/IEC/IEEE
42010:2022).
International Organization for Standardization.
[Bass et al., 2021] Bass, L., Clements, P., and Kazman, R. (2021).
Software Architecture in Practice.
Addison-Wesley, 4th edition.
[Brown, 2023] Brown, S. (2023).
The C4 Model for Visualising Software Architecture.
Leanpub.
https://leanpub.com/visualising-software-architecture.
[Forum, 2022] Forum, T. O. G. A. (2022).
The Open Group Architecture Framework Standard – Architecture Development
Method.
The Open Group, 10 edition.
https://pubs.opengroup.org/togaf-standard/.
[Kruchten, 1995] Kruchten, P. (1995).
Architectural blueprints — the ‘4+1’ view model of software architecture.
IEEE Software, 12(6):42–50.
https:
//www.cs.ubc.ca/~gregor/teaching/papers/4+1view-architecture.pdf.
[Team, 2020] Team, A. C. (2020).
NATO Architecture Framework.
NATO, 4th edition.
[Thomas and Webb, 2023] Thomas, R. and Webb, B. (2023).
Architectural views.
https://csse6400.uqcloud.net/handouts/views.pdf.
