What is SOA

Former Member · ‎10-20-2006

For a quite while, I am trying to understand what is SOA?

-Naveen.

HarshC · ‎10-21-2006

Hi Naveen,

Here is one perspective:

Webservices are capable of exposing any existing functionality in a platform independent way. But how do you decide what functionlity needs to be exposed and what should be kept blackboxed? This is where SOA comes in. SOA/Service Oriented Architecture is the science of deciding the granularity of (web)services.

Let me give you an example of granularity:

Lets take the case of an application that calculates your age based on your date of birth. Now internaly this application needs to find out the current date, maybe it even has a separate method called getCurrentDate to do this.

Now if I decide to expose this applications functionality using webservices. I may chose to expose the age calculation functionality through a webservice call, but I may not see any reason to expose the internally getCurrentDate method! This is deciding the granularity.

From SAP's perspective: If they have a business process, that internally has 100 different steps. How do they expose this. Do they give you control/interfaces to all the hundred steps? Maybe that is an overkill, it might be enough to break the process into 12 logical modules instead of a hundred. This is a call made at the SOA level.

As it must be obvious, these decisions are application specific, and in SAP's case very business process oriented. This level of architecture is termed ESA/Enterprise Service Architecture by SAP.

Hope this helps,

Harsh

PS: This is another good definition of SOA:

A service-oriented architecture is a collection of services that communicate with each other. The services are self-contained and do not depend on the context or state of the other service. They work within a distributed systems architecture.

moorthy · ‎10-20-2006

Hi,

Very simpler words, it is Service Oriented Architecture - towards openworld.

It is in SAP NetWeaver world , Enterprise Service Architecture (ESA) and now it is ESOA - Enterprise SOA.

http://help.sap.com/saphelp_nw2004s/helpdata/en/be/dcb6412fb5449f9c97abb566f19c57/content.htm

Thread-

Regards,

Moorthy

Former Member · ‎10-20-2006

Naveen,

Service-oriented architecture expresses a perspective of software architecture that defines the use of loosely coupled software services to support the requirements of the business processes and software users. In an SOA environment, resources on a network are made available as independent services that can be accessed without knowledge of their underlying platform implementation. A service-oriented architecture is not tied to a specific technology and may be implemented using a wide range of interoperability standards including RPC, DCOM, ORB or WSDL.

For more information you have to browse through this links:

http://en.wikipedia.org/wiki/Service-oriented_architecture

http://www.xml.com/pub/a/ws/2003/09/30/soa.html

http://www.service-architecture.com/web-services/articles/service-oriented_architecture_soa_definiti...

ftp://ftp.software.ibm.com/software/soa/pdf/soaagenda.pdf

http://www-306.ibm.com/software/solutions/soa/?ca=google_soa

Hope this helps......

---Satish