The document provides an overview of Service-Oriented Architecture (SOA), its principles, reference architecture, and the evolution towards microservices. It details the components, integration patterns, and types of services involved, including SOAP and RESTful web services. Additionally, it contrasts traditional SOA with microservices in terms of messaging, programming style, and deployment models.

1. Service Oriented
Architecture & Beyond
Imesh Gunaratne
Senior Technical Lead, WSO2

2. Agenda
▪ An Introduction to SOA
▪ SOA Reference Architecture
▫ Horizontal Layers
▫ Vertical Layers
▪ SOA Principles
▪ Enterprise Application Integration (EAI)
▪ Service Development
▪ Microservices

3. An Introduction
to SOA
The concepts and evolution
1

4. Service Oriented Architecture (SOA)
An architectural pattern in
computer software design in
which application components
provide services to other
components via a communications
protocol, typically over a network.
https://en.wikipedia.org/wiki/Service-oriented_architecture

5. Evolution of SOA
http://www.pwc.com/us/en/technology-forecast/2014/cloud-computing/features/microservices.html

6. Evolution of SOA
http://www.pwc.com/us/en/technology-forecast/2014/cloud-computing/features/microservices.html

7. SOA Reference
Architecture
A reference architecture for
designing enterprise solutions
2

8. SOA Reference Architecture (RA)
https://www.opengroup.org/soa/source-book/soa_refarch/layers.htm

9. SOA RA Horizontal Layers
▪ Consumer Interfaces
▫ End user applications
▪ Business Processes
▫ Choreographed services representing business use-
cases
▪ Services
▫ Business services
▪ Service Components
▫ Components that build services
▪ Operational Systems
▫ Data models, enterprise data repository, technological
platforms
https://en.wikipedia.org/wiki/Service-oriented_architecture

10. SOA RA Vertical Layers
▪ Integration
▫ Platform integration, data integration, service
integration, application integration
▪ Quality of Service (QoS)
▫ Security, availability, performance etc. constitute the
quality of service parameters
▪ Information
▫ Provides business information
▪ Governance
▫ Governing the entire SOA strategy
https://en.wikipedia.org/wiki/Service-oriented_architecture

11. SOA Principles
Best practices to be followed
3

12. SOA Principles [1]
▪ Standardized service contract
▫ Services adhere to a communications agreement, as
defined collectively by one or more service-
description documents.
▪ Service loose coupling
▫ Services maintain a relationship that minimizes
dependencies and only requires that they maintain an
awareness of each other.
▪ Service abstraction:
▫ Beyond descriptions in the service contract, services
hide logic from the outside world.
https://en.wikipedia.org/wiki/Service-oriented_architecture

13. SOA Principles [2]
▪ Service reusability
▫ Logic is divided into services with the intention of
promoting reuse.
▪ Service autonomy (govern itself)
▫ Services have control over the logic they encapsulate,
from a Design-time and a Run-time perspective.
▪ Service statelessness
▫ Services minimize resource consumption by
deferring the management of state information when
necessary.
https://en.wikipedia.org/wiki/Service-oriented_architecture

14. SOA Principles [3]
▪ Service discoverability
▫ Services are supplemented with communicative meta
data by which they can be effectively discovered and
interpreted.
▪ Service composability
▫ Services are effective composition participants,
regardless of the size and complexity of the
composition.
▪ Service granularity
▫ A design consideration to provide optimal scope and
right granular level of the business functionality in a
service operation.
https://en.wikipedia.org/wiki/Service-oriented_architecture

15. SOA Principles [4]
▪ Service normalization
▫ Services are decomposed or consolidated to a level of
normal form to minimize redundancy (performance
optimization, access, and aggregation).
▪ Service Location transparency
▫ This refers to the ability of a service consumer to
invoke a service regardless of its actual location in
the network.
https://en.wikipedia.org/wiki/Service-oriented_architecture

16. Enterprise
Application
Integration (EAI)
Integration patterns
4

17. Point to Point Integration
Inventory
SCM
Billing
CRM ERP
HR

18. Using an Enterprise Service Bus
Inventory
SCMBilling
CRM ERP
HR
Enterprise Service Bus (ESB)
▪ Protocol switching
▪ Message
transformation
▪ Content/header
based routing
▪ Failover handling
▪ Load balancing
▪ Request throttling
▪ Response caching
▪ Security
▪ Logging & monitoring
▪ Enterprise
Integration Patterns
(EAI)

19. Integration Pipeline
http://www.enterpriseintegrationpatterns.com/patterns/messaging/

20. Sample Integrations
http://www.ossmentor.com/2014/11/camel-and-enterprise-integration.html

21. Enterprise Integration Patterns
(EAI)
http://www.enterpriseintegrationpatterns.com/patterns/messaging/

22. Message Oriented Middleware
(MOM)
https://docs.oracle.com/cd/E19316-01/820-6424/aerar/index.html
MOM is software or hardware infrastructure supporting the sending and receiving
of messages between distributed systems - Wikipedia

23. Service
Development
Service types & frameworks
5

24. Elements of SOA
https://en.wikipedia.org/wiki/Service-oriented_architecture

25. Service Types
▪ SOAP Web Services
▫ Transport: HTTP/HTTPS
▫ Content type: XML
▫ Service definition: WSDL
▫ Message payload: SOAP
Header + SOAP Body
▫ Service method: SOAP
Method
▫ Security: WS-Security
(BasicAuth, Signature,
IDAssertion, LTPA), SAML
▫ Java spec: JAX-WS
▪ RESTful Web Services
▫ Transport: HTTP/HTTPS
▫ Content type: Mostly JSON
▫ Service definition: WADL
▫ Message payload: JSON
message
▫ Service method: URI + HTTP
Method
▫ Security: OAuth, BasicAuth
▫ Java spec: JAX-RS

26. Frameworks
▪ SOAP Web Services
▫ Apache Axis (Java, C++)
▫ Apache Axis2 (Java)
▫ Apache CXF (Java)
▫ Java EE: GlassFish, JBoss
(Java)
▫ .NET Framework (C#, VB.
NET)
▫ Spring Web Services (Java)
▪ RESTful Web Services
▫ Apache CXF (Java)
▫ Jersey (Java)
▫ Java EE: GlassFish, JBoss
(Java)
▫ .NET Framework (C#, VB.
NET)
▫ Restbed (C, C++)

27. Microservices
Designing an application as a
collection of micro services
6

28. Microservices
An approach for developing a
single application as a suite of
small services, each running in its
own process and communicating
with lightweight mechanisms,
often an HTTP resource API.
http://martinfowler.com/articles/microservices.html

29. Monoliths Vs Microservices
http://martinfowler.com/articles/microservices.html

30. Deployment Model
http://martinfowler.com/articles/microservices.html

31. Decentralized Data Management
http://martinfowler.com/articles/microservices.html

32. Traditional SOA Vs Microservices [1]
http://www.pwc.com/us/en/technology-forecast/2014/cloud-computing/features/microservices.html
Traditional SOA Microservices
Messaging Type Synchronous: wait to
connect
Asynchronous: publish
and subscribe
Programming Style Imperative model Reactive programming
(event/callback driven)
Lines of Code per
Service
Hundreds/Thousands Hundreds or fewer
State Stateful Stateless
Databases Large RDBMS NoSQL + RDBMS

33. Traditional SOA Vs Microservices [2]
Traditional SOA Microservices
Code Type Procedural Functional
Means of Evolution Each service evolves and
becomes larger
Each small service is
immutable and can be
abandoned or ignored
Means of systemic
change
Modify the monolith Create a new service
Means of scaling Optimize the monolith Scale individual services
System-level awareness Less aware and event
driven
More aware and event
driven
http://www.pwc.com/us/en/technology-forecast/2014/cloud-computing/features/microservices.html

34. THANKS!
Any questions?