Intelligent Enterprise

BUILD A FOUNDATION

It's a simple matter to expose functionality and applications using Web services, but standards such as UDDI and WSDL will only go so far in ensuring interoperability. Behind those API-level mashups, a great deal of work needs to be done in the enterprise to develop the SOA and settle on the models, security provisions and governance regimes (see "SOA Metamodel" diagram, right).

"Even if you have great SOA environments on both sides, you need to have agreement on the data, the definitions and protocols used when going back and forth," Desisto says. "Without agreement, SOA is a good technology, but it's not going to get you where you want to be on integration."

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The key to building reliable infrastructure is good governance, good service management and good security. And when bringing in services from outside the firewall, "test to make sure they live up to expectations," Linthicum says. "Make sure they're not too fine-grained or course-grained, that they're reliable, and that they work and play well in composites."

Even among enterprises that have wholeheartedly embraced the trend, few SOAs have the kind of maturity required to deploy, manage and govern composite apps--let alone ones invoking mixes of internal and external services. Among more conservative organizations, just the idea of working with a single SaaS vendor may be controversial, as it requires that you share data outside the firewall and depend on that vendor's uptime performance.

Despite the headline-making service outages Salesforce.com suffered in early 2006, SaaS advocates argue that these vendors offer reliability and security that far exceeds that of most conventional IT shops. "In response to those incidents, Salesforce beefed up its redundancy and started publishing its outages on its Web site," points out Vincent of Accenture (an integration partner with Salesforce.com). "How many IT organizations do you know of that have that kind of transparency? I work with a lot of IT organizations and few can claim to have very satisfied customers. If you take a look at the SaaS vendor satisfaction scores, you'll see they have a lot of happy customers."

If the predictions come true and 25 percent of business software is actually delivered SaaS style by 2011, it will be because the issues will have been resolved, and that will require solid SOA on both sides of the service. "If enterprises have their SOA right and they select the right services, then security, scalability and customizability shouldn't be issues," Linthicum says.

In other words, as Sinatra would put it, "the best is yet to come, and babe, won't it be fine." In this model of a services-oriented architecture, data sources and legacy apps (bottom tier) are wrapped in services and exposed along with original, new services. The data abstraction layer ensures consistent, virtual access to any data source. The enterprise services bus addresses data services/ messaging. SaaS and more granular Internet-based services join the services layer and may be orchestrated as part of larger composite apps.