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Making the Case for SOA

Software & IT

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A Service Oriented Architecture (SOA) is a computing environment in which applications are composed, rather than developed, through a set of standard interfaces. A SOA takes advantage of networking capabilities to compose applications through the coupling of services in a way that is independent of architecture, programming language, development platform and vendor.

SOA creates an environment in which the logistics of deploying business applications is separated from the applications themselves. A SOA consists of various layers of capability, separating those capabilities common to all applications – security, data handling, transaction processing, etc. – from those applications that implement the rules specific to a business’ core competency. Once a SOA infrastructure is in place, applications can be composed using services that implement the business rules. This loose coupling of the business logic simplifies making changes to these processes because the infrastructure does not need to change. In other words, SOA allows the business to drive changes in Information Technology (IT) rather than having IT limitations constrain the business.

SOA is not really a new concept. It can be thought of as an extension of technologies introduced to automate the Enterprise Architecture (EA). Moving from object orientation to service orientation seems to have moved the focus of EA technology one step further from relying on specific platforms, tools or implementation technologies. This increased degree of abstraction makes it possible to get a greater degree of separation of business rules and the techniques used to implement those rules.

The implementation of SOA within a large organization offers great hope of improved efficiencies, reduced redundancy, tactical agility and federation. Common sense indicates that SOA should offer significant potential benefits for businesses with frequently changing markets, regulations, rules or relationships. As with all IT changes, the transition to SOA is not without costs. Many organizations are currently grappling with the question of whether the benefits they will get from SOA justify the cost to achieve service orientation.

This paper presents research intended to help organizations answer the question of whether SOA is right for them. This research focuses on both the cost and benefit aspects of SOA. The first section of the paper describes what an SOA is and why organizations are considering SOA migrations. After this a detailed discussion is presented focused on the cost issues associated with transition to SOA. This cost discussion will concentrate not only on service development and application composition but also on those activities associated with deploying and maintaining SOA infrastructure. Cost estimation methodologies for these various scenarios will be presented and exemplified. The paper will then address

a framework for identifying and quantifying the expected benefits to the organization. An example business case analysis will be presented to show how the cost and benefit methodologies developed can work together to help organizations make the right decisions with respect to SOA migrations.


Arlene Minkiewicz
Ms. Minkiewicz leads the Cost Research Department as Chief Scientist at PRICE Systems. In this role, she is responsible for the research and analysis necessary to keep the suite of PRICE Estimating products responsive to cu rrent cost trends. She works with industry leaders to collect and maintain cost research data and offers analyses of this data to the cost estimating community through the PRICE products.
Arlene’s most recent accomplishments include the development of a catalog of cost estimating relationships for systems and system of systems projects that will be delivered to the cost estimating community as part of the TruePlanning suite. Her most recent research on software sizing has been slated for publication in the March 2009 issue of Crosstalk.
Arlene frequently publishes articles on estimation and measurement in publications such as Software Development Magazine and Crosstalk. She speaks frequently on these topics at conference such as STC, ISPA, SCEA, IEEE Aerospace Conference, SEPG, and many others. Her ‘The Real Costs of COTS-Based Software Systems’ paper was recognized in 2004 by ISPA and SCEA as Best Paper in the Software Track. Her paper “A Case Study and Assessment of a COTS Upgrade for a Satellite Ground System”, co-authored with Marilee Wheaton of the Aerospace Corporation, received Best Paper in Software Track in 2006 by SCEA and her paper “The Evolution of Hardware Estimating” received Best Paper in the Hardware and EVM Track at the 2007 ISPA/SCEA joint conference.