Copyright ©2004 Virtusa Corporation | CONFIDENTIAL Service Oriented Architecture Ruwan Wijesinghe

Copyright ©2004 Virtusa Corporation | CONFIDENTIAL

Service Oriented Architecture

Ruwan Wijesinghe

2Copyright ©2004 Virtusa Corporation | CONFIDENTIAL

What is SOA ?

• A loosely-coupled architecture designed to meet the business needs of the organization

• SOA is a standards-based design approach to creating an integrated IT infrastructure capable of rapidly responding to changing business needs.

• SOA provides the principles and guidance to transform a company’s existing array of heterogeneous, distributed, complex and inflexible IT resources into integrated, simplified and highly flexible resources that can be changed and composed to more directly support business goals.


What is Service

• Schema• Message formats (what are the data to be included on each message

type and how they should be organized)

• Contract• Set of operations supported by the service and input and output

messages for each operations• E.g. Operation – AddEmployee

– Input Message – Employee Information– Output Message – Success or failure of the operation

• Policy• Operational details, like communication protocol, security, auditing, etc.


Implementation of SOA


Implementation of SOA

• Expose• Expose existing computing capabilities as services• These capabilities might be currently available in difference

heterogeneous applications• New business capabilities can be developed if required

• Compose• Compose these services to construct business process and

expose them as services• This supports agile, loosely coupled business process• Workflow engines can be used to implement these services

• Consume• Develop UI applications for the users to interact with these

business processes services


Service Aggregation

• Services can have different levels of granularity in offerings.

• Fine grain services can be aggregated to provide coarser grained services.


Extending Classic Architectures with Services

Business Workflows

Business Capabilities

User Interfaces


Business Values

• SOA enables businesses to develop a new generation of dynamic applications that address a number of top-level business concerns that are central to growth and competitiveness.

• SOA solutions promote:

• Stronger connections with customers and suppliers.

• Enhanced business decision making

• Greater employee productivity


Stronger Connections with Customers and Suppliers.

• Expose business services to customers and suppliesBy making available dynamic applications and business services to external customers and suppliers, not only is richer collaboration possible, but customer and partner satisfaction is increased.

• Expose business process as serviceSOA unlocks critical supply and demand chain processes such as outsourcing of specific business tasks from the constraints of underlying IT architectures, thereby enabling better alignment of processes with organizational strategy.


Enhanced Business Decision Making

By aggregating access to business services and information into a set of dynamic and composite business applications

Decision makers gain

• More accurate and comprehensive information

• Flexibility to access that information in different forms of presentation (Web, rich client, mobile device) that meets their needs.


Greater Employee Productivity

By providing

• Streamlined access to systems and information

• Enabling business process improvementbusinesses can drive greater employee productivity.

Employees can focus their energies on addressing the

• Important, value-added processes

• On collaborative, semi-structured activitiesrather than having to conform to the limitations and

restrictions of the underlying IT systems.


SOA Scenarios

Some key scenarios where SOA shows a greater

• Information Integration

• Legacy Integration

• Process Governance

• Consistent Access

• Resource Virtualization

• Process Externalization


Information Integration

• The complete description of a customer might be spread across a dozen business applications and databases.

• Information integration services are an effective means for both

• Presenting your application portfolio with a unified view of these key entities

• Ensuring the consistency of the information across all of your back-end systems

• This supports to have a “single view of the customer problem”


Legacy Integration

• The Legacy Integration scenario focuses on the tactical use of services to preserve existing investments in business applications, while extending the functionality of the capabilities upon which they deliver.

• For example, a service might add support to comply with new regulations in front of an existing ERP package


Process Governance

• In a Process Governance scenario, “message headers” are used to communicate key business metadata; from the turnaround time on customer requests to the identity of the approvers for specific business decisions.

• This metadata is captured by a utility service (as discussed previously), for real-time and/or aggregated analysis. "


Consistent Access

• This scenario enables a services layer to ensure consistent enforcement of a variety of operational requirements when a diverse set of applications needs to connect to a critical back-end resource.

• By mandating that all access be routed through a service facade, an organization might enforce consistent access authorization, cost distribution and load management.


Resource Virtualization

• A Resource Virtualization scenario can be utilized to help enforce loose coupling between resources and consumers, effectively insulating consumers from the implementation details of the targeted resources.

• Typical examples of Resource Virtualization may include:

• Context-sensitive and content-sensitive routing of requests, such as sending a real-estate inquiry to the agent in the specified geography who specializes in farm properties.

• Routing of requests to partitioned information stores (without requiring the requestor to understand partitioning schemes).

• Load balancing requests across available resources; from customer service representatives to streaming video feeds.


Process Externalization

• Process Externalization scenarios utilize Web services to securely expose business services to outside partners.

• For example

• Cell phone service providers and Internet portals frequently use web services to aggregate content

• Customer-facing organizations may use services to build composite offers (such as travel packages that include airfare and rental cars).


Enterprise Service Bus

• The term Enterprise Service Bus (ESB) is a family of products used in implementing the messaging capabilities of a service oriented infrastructure.

• The messaging capabilities required in a service oriented infrastructure extend the functions of traditional• Enterprise Application Integration (EAI)

• Message Oriented Middleware (MOM)

• Support for Web Service standards

• Integration with other service infrastructure components such as

• policy management• metadata registry• operational and business monitoring frameworks


How can your organization get started with SOA?

• Make sure that you have sound business drivers

• Top-down approaches do not work in the real world.

• Bottom-up approaches are not manageable either.

• In contrast, organizations that are successful with SOA often adopt a middle-out approach.

• Demonstrate value in rapid iterations. Time-to-value is a critical, healthy metric(The “trust-me” approach is not a healthy model for successfully leveraging SOA).


Reference

• Service Oriented Architecture (SOA) in the Real World - Microsoft Cooperation

Documents

Copyright ©2004 Virtusa Corporation | CONFIDENTIAL Service Oriented Architecture Ruwan Wijesinghe