SOA is the dominant super-pattern that governs overall design of modern distributed systems because it enables business alignment, agility, interoperability, and reuse. The MSF mindsets for Qualities of Service and Citizenship bring essential points of view to SOA the consideration of all aspects of experience and creation or application of reuse wherever possible. Contract-first design is an important practice for successful SOA.
The web services standards are the main enabler of SOA. VSTS supports architectural design of web services and composition of systems directly based on these services. VSTS introduces Design for Operations to reduce the complexity of preparing distributed systems for deployment. VSTS provides a Deployment Designer that marries the logical datacenter design to the system design, enabling you to see whether the application as designed will deploy in the datacenter as it is configured
Web Services and SOA
In theory, SOA does not require web services, but in practice, the technology for implementing web services as been almost completely aligned with the WS-* standards, if only for the reason that this enables technical interoperability. When developing with Visual Studio, the Microsoft .NET Framework makes it easy to implement the web services. Of course, there is more to interoperability than just the standards.
Contract-First Design
The key to interoperability is that services describe themselves in terms of interface contracts. For web services, these interfaces are expressed in the Web Services Description Language (WSDL).
A valuable SOA practice is contract-first design, or in other words, specifying the message formats and the WSDL among participating services before being concerned with implementation details. Contract-first design can ensure loose coupling and prevent decisions about how to implement services from creeping into the overall distributed system design.Practices for contract-first design are still evolving. WSDL and XSD do not yet describe message sequence or pre- and post-conditions as examples. Fuller contracts need to specify the messages that the services publish and consume, the sequence of handling, and the constraints in order to isolate the public contracts from the private details of the implementation
VSTS and Service-Oriented Architecture
For all the following reasons, VSTS focuses on the practical aspects of implementing a distributed system using a SOA. VSTS provides four designers that handle the major activities involved:
1. The Application Designer enables you to design the application components that expose and consume web services.
2. The System Designer enables you to compose and configure the applications into systems and potentially reusable subsystems.
3. The Logical Datacenter Designer captures servers (such as IIS), their configurations, and network trust zones as you use them in a datacenter into which one or more systems will be deployed.
4. The Deployment Designer enables you to map each component in a system to the servers in a logical datacenter to specify how the distributed parts of the system need to be deployed.
Okay that’s the facilities for the time being that catered by the VSTS for the SOA designing.
cheers,
Doddy Ch Saputra, MCPD,MCTS,MCT
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