For SAP, enterprise SOA is a reality and customers are catching on quickly. Whatever business you are in, it's about speed. When change occurs, companies need to know which business partners will best help them to adapt. The span from 1990 to 2000 saw the era of business process reengineering enabled by ERP. The time from 2000 to present and in to the future will see business network transformation enabled by enterprise SOA. Due to the evolution of new business models, companies need to act and react quickly to a constantly changing business environment. The solution from SAP is eSOA. Let's take the journey from Web Services to enterprise SOA.
What is a Web Service ?
Webservice is a standardized service encapsulating the functions of an application so that other applications can identify and access the service. They are SELF CONTAINED and SELF DESCRIBING APPLICATION FUNCTIONALITIES that can be PROCESSED through OPEN INTERNET STANDARDS like XML and WSDL.
Nature of Services
The semantics of a service is the behaviour expected when interacting with the service. The semantics expresses a contract between the provider entity and the requester entity. It expresses the effect of invoking the service. The callable entities are clearly described by Service Interface.
A Service Interface is the abstract boundary that a service exposes. It defines the type of messages and the message exchange patterns that are involved in interacting with the service with Endpoint Information. It is provided by autonomous components meant to interact with other components, encapsulating certain functionality or a set of functionalities. Thereby achieving the benefits of Flexibility in processes, Re-usability, Quality and leverage existing investments.
Principles of SOA
The main principle of Service Orientation is services are loosely coupled, services are reusable, services share a formal contract, services are autonomous, services are stateless and should be discoverable.
SOA is not just an architecture of services seen from a technology perspective, but the policies, practices and frameworks by which it is ensured that the right services are provided and consumed.
Advantages of Service Oriented Architecture
Service Oriented Architectures offer the following benefits over traditional client/server architectures:
Greater agility and flexibility
The ability to add Business Process Management capabilities
Ability to recompose process into composite applications
Out-of-the-box system integration
Reusability
Easier business-to-business process execution
Efficient development
Incremental adoption
Easy to adapt to changing standards
SAP's eSOA the GREAT
The evolution of business models has put new requirements on business applications that can't be met with existing architectures. Change must be easy and cost neutral. Companies demand integration across heterogeneous systems. They prefer Productized delivery. eSOA and BPP (Business Process Platform) is the result of this evolution. SAP leverages this platform to develop highly efficient and flexible solutions for various industries which can be easily extended by customers and partners.
What is eSOA ?
enterprise Services + SOA = eSOA
enterprise SOA is a business-driven software architecture that allows you to share and reuse services within your company and with strategic partners.
With eSOA - Business functionality is represented through reusable enterprise services. With eSOA, complex processes can be broken down into smaller process steps, which are represented in software as reusable enterprise services. This enables your IT organization to support business change with increased adaptability, flexibility, and cost efficiency.
What are enterprise Services ?
We know that a Web service is a standardized service encapsulating the functions of an application so that other applications can identify and access the service. Whereas an Enterprise Service is a highly integrated web services combined with business logic and semantics that can be accessed and repeatedly used to support a particular business process.
For example take the case of a Sales Order creation. As we already have pre-existing RFCs and BAPIs for creating Sales Order, they can be easily converted to a web service and this web service can be registered in a directory or a UDDI so that external parties can access and make use of it.
Whereas think of a situation where a company wants to implement Order Management business process completely as service enabled. This is were the challenge is all about. If you have to manually build the business process, one has to identify each and every BAPI or RFC and convert it into a web service and then link each one of them as a workflow to make a complete business process. It's time consuming as it has to be done from the scratch.
Whereas the same company when decides to go for SAP's eSOA, they get the advantage of leveraging the Enterprise Services. Enterprise Services are full fledged best practice web services which are pre-delivered, pre-packaged, orchestrated and end-to-end tested and proven. These Enterprise Services are bundles of combined webservices which has linkage to all intermediary webservices. So they are much better. Enterprise services provide business processes that can be used to compose business scenarios while ensuring business integrity and ease of reuse.
Where does Enterprise Service come from ?
Technically the Enterprise services come from SAP but the services that run on the Netweaver platform that leverages the Global Data Types can come from Customers and Partners as well.
SAP delivers Enterprise Services as ES Bundles through the Enhancement Packages.
What does Enterprise Services contain ?
Enterprise Services technically includes :-
Service Interfaces
Also known as XI Content
Resides in the Enterprise Services Repository
Glue Code
Also known as XI proxies
Resides in SAP backend systems
Generated from Service Definition from the Repository
Service Implementation
Also known as Application code
Resides in the SAP backend systems
Where can one get more information about the ES Bundles ?
Explore ES bundles in the Enterprise Service Workplace.
http://www.sdn.sap.com/ --> Enterprise SOA
In the collaboration wiki, find:-
How to use guides
Enterprise Services Packages Description
Enterprise Services Packages Catalog
Where can I test the Enterprise Services ?
Test and use Enterprise Services using the Discovery System for Enteprise SOA. Discovery System is a fully configured SAP Landscape delivered on a physical server with ready to run Enterprise Services and composite applications.
Summary
enterprise SOA is a services oriented architecture (eSOA) that merges SAP's enterprise application content (enterprise services) with the open composition platform - SAP Netweaver, to enable flexible business processes by SAP, partners and customers. I hope this help you understand the basics of Web Services to Enterprise Service.
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