By Serge Thorn, Architecting the Enterprise
This is the third and final installment of a series discussing how to implement SOA through TOGAF®. In my first blog post I explained the concept of the Center of Excellence, and creating a vision for your organization, my second blog post suggested how the Center of Excellence would define a Reference Architecture for the organization.
SOA principles should clearly relate back to the business objectives and key architecture drivers. They will be constructed on the same mode as TOGAF 9.1 principles with the use of statement, rationale and implications. Below examples of the types of services which may be created:
- Put the computing near the data
- Services are technology neutral
- Services are consumable
- Services are autonomous
- Services share a formal contract
- Services are loosely coupled
- Services abstract underlying logic
- Services are reusable
- Services are composable
- Services are stateless
- Services are discoverable
- Location Transparency
Here is a detailed principle example:
- Service invocation
- All service invocations between application silos will be exposed through the Enterprise Service Bus (ESB)
- The only exception to this principle will be when the service meets all the following criteria:
- It will be used only within the same application silo
- There is no potential right now or in the near future for re-use of this service
- The service has already been right-sized
- The Review Team has approved the exception
As previously indicated, the SOA Center of Excellence (CoE) would also have to provide guidelines on SOA processes and related technologies. This may include:
- Service analysis (Enterprise Architecture, BPM, OO, requirements and models, UDDI Model)
- Service design (SOAD, specification, Discovery Process, Taxonomy)
- Service provisioning (SPML, contracts, SLA)
- Service implementation development (BPEL, SOAIF)
- Service assembly and integration (JBI, ESB)
- Service testing
- Service deployment (the software on the network)
- Service discovery (UDDI, WSIL, registry)
- Service publishing (SLA, security, certificates, classification, location, UDDI, etc.)
- Service consumption (WSDL, BPEL)
- Service execution (WSDM)
- Service versioning (UDDI, WSDL)
- Service Management and monitoring
- Service operation
- Programming, granularity and abstraction
Other activities may be considered by the SOA CoE such as providing a collaboration platform, asset management (service are just another type of assets), compliance with standards and best practices, use of guidelines, etc. These activities could also be supported by an Enterprise Architecture team.
As described in the TOGAF® 9.1 Framework, the SOA CoE can act as the governance body for SOA implementation, work with the Enterprise Architecture team, overseeing what goes into a new architecture that the organization is creating and ensuring that the architecture will meet the current and future needs of the organization.
The Center of Excellence provides expanded opportunities for organizations to leverage and reuse service-oriented infrastructure and knowledgebase to facilitate the implementation of cost-effective and timely SOA based solutions.
Serge Thorn is CIO of Architecting the Enterprise. He has worked in the IT Industry for over 25 years, in a variety of roles, which include; Development and Systems Design, Project Management, Business Analysis, IT Operations, IT Management, IT Strategy, Research and Innovation, IT Governance, Architecture and Service Management (ITIL). He is the Chairman of the itSMF (IT Service Management forum) Swiss chapter and is based in Geneva, Switzerland.