What is a Tiered Architecture?
Organises software into layers (presentation
When do N-tier architectures emerge?
- When resource layer includes complex 2/3-tier systems. 2. When web servers add tier to presentation layer.
What are the challenges of N-tier?
Lack of standards (interoperability issues) and middleware complexity (integrating multiple systems).
What is SOA (Service-Oriented Architecture)?
Architecture where applications deliver functionality as reusable services, invoked through platform-independent interfaces.
What paradigm shift does SOA represent?
From object-oriented to message-oriented systems.
What is a Service in SOA?
Reusable component as building block for complex functionality. Accessed through message exchanges.
Give examples of services.
Web services, weather forecast, stock quote, translation engine, credit check, fraud detection.
What are the 5 components of SOA vision?
Resources (computing/storage), Services (discovery/access), Connectivity (reduces distance barriers), Technologies (create services), Communities (collaboration procedures).
What are the 3 roles in SOA?
Provider (publishes via broker), Requestor (finds and binds to service), Broker (Yellow Pages directory).
How does SOA differ from N-tier in middleware?
SOA has decentralised middleware supporting inter-service discovery within each service’s environment.
How does SOA differ from N-tier in coupling?
SOA has loose coupling - minimises interdependencies between services.
How does SOA differ from N-tier in standards?
SOA follows well-supported standards (OASIS
What does loose coupling mean in SOA?
Services have minimal dependencies on each other
