Q: When is SOA not a good idea?

A: Complexity is the prime prerequisite for SOA. Small companies that are consolidated on a single infrastructure (like Microsoft) and don’t have complex application integration requirements are not candidates for SOA. Larger companies whose application infrastructure comes mostly from a single vendor (60 percent or more, according to experts we spoke to) will want to think carefully about whether building their own SOA is necessary or wise.

Then comes speed, and the need for it. If processes don’t need to change quickly, then transforming IT in order to be able to change them more quickly is pointless.

At Owens Corning, 75 percent of its software applications come from SAP. Owens Corning’s products are manufactured and sold in similar ways around the globe, which means CIO Johns has long driven a strategy of business process integration through SAP’s applications. "SAP is the integration strategy," Johns says. His goal is to unify all of the company’s worldwide divisions on a single version, or "instance," of SAP running on a single database. He is also monitoring SAP’s strategy of service-enabling its applications to create a ready-made SOA for its customers. (See "If You Can’t Beat ’Em, Integrate ’Em," Page 58.)

Global manufacturer Whirlpool has also placed a big bet on SAP and global process integration, which, to Esat Sezer, the company’s corporate VP and CIO, makes more sense than application integration. "I’m not dealing with that anymore," he says. "I have outsourced that to SAP. I look forward to SAP handling integration requirements that I used to have to handle myself."

Q: Creating a service requires more planning and design than traditional application development and integration. How much extra does service-enablement cost?

A: Forrester’s Heffner estimates that the extra work involved in service-oriented development can range from 30 percent to 100 percent more at the design stage, which makes up 10 percent or less of the overall cost of an application project. The extra effort is necessary to create a service that can be used in many areas of the business, each with their own particular needs. Transamerica’s Gleason says that, for example, services that deal with insurance premium payments from customers generally need to accommodate multiple delivery channels—say, a website, a bank wire transfer or a call center—depending on the process for each business unit. Understanding the ways each unit wants to consume the services is part of the design work and is critical to getting units to agree to use the same service.