SOA Concepts

• Service
• ESB
• Loose Coupling
• Policies and Processes
• Web Services
• SOA Strategy
• Governance

Service

A service is a piece of self-contained business functionality. The functionality might be simple (storing or retrieving customer data), or complex (a business process for a customer’s order). Because services concentrate on the business value of an interface, they bridge the business/IT gap.

ESB

• ESB is the infrastructure that enables high interoperability between distributed systems for services.
• It makes it easier to distribute business processes over multiple systems using different platforms and technologies.
• TCP network + DNS may be consider a type of ESB

Loose Coupling

• Concept of reducing system dependencies.
• Minimize the effects of modifications and failures.
• Price for loose coupling: complexity.
• Loosely coupled distributed systems are harder to develop, maintain, and debug.

Policies and Processes

You need clearly defined roles, policies, and processes

• service lifecycle
• implementing model-driven service development
• set up several processes for distributed software development.
• agile project management

Web Services

• Web Services are one possible way of realizing the technical aspects of SOA
• Web Service can be based on SOAP or REST

Governance and Management support

• Central team that will determine general aspects of your specific SOA.
• The ultimate goal is decentralization
• Right people (large systems are different from small systems)
• Requirements driven development
• You need support from the CEO and CIO. SOA is a strategy that affects the company as a whole.

Technical Concept of SOA

• Services
• Interoperability
• Loose coupling

SOA Ingredients

• Infrastructure
• Architecture
• Processes
• Governance

SOA Terminology

• A provider is a system that implements a service (a business functionality) so that other systems can call it.
• A consumer is a system that calls a service (uses a provided service).
• Other names: requestor, client, server....
• A participant (AKA service agent) is either a provider or a consumer

SoaML Notation

Another definition of SOA

SOA is an architectural paradigm

• for dealing with business processes
• distributed over a large landscape of existing and new
• heterogeneous systems
• that are under the control of different owners.

Different Perspective

Questions

• What are the three technical concepts of SOA?
• What are the key ingredients of SOA?
• Is SOA a technology?
• What is the difference between services and web services?
• Does SOA have to use Web Services?