Service-oriented architecture (SOA) may no longer be the hot new thing that it was a few years ago, but the Web-based infrastructure remains very popular, according to industry players.
Its roots began over two decades ago, in the early days of software integration, before it evolved into component-based development in the late 1990s. Back then, interfaces such as CORBA (Common Object Request Broker Architecture) were used to enable software components to communicate.
Today, SOA is a methodology that uses open standards such as Web services, which allows organizations to build more flexible IT infrastructures that respond more quickly to changing business needs.
What makes SOA so compelling for organizations?
U.S.-based Gene Phifer, who is Gartner's vice president and distinguished analyst, offered some insights over a phone interview with ZDNet Asia. According to him, SOA still generates the highest level of client enquiries.
Companies are keen on SOA because it is "built as a collection of services", and as such, allows companies to be more responsive to change, Phifer said.
"Organizations can consume these services one at a time and assemble those to [suit] their needs," he said. "[SOA] gives them more agility to respond to changes." He added that these changes can come in the form of mergers, new government regulations, and so on.
On a deeper level, SOA provides companies with the ability to take processes "buried in the bowels of application suites like SAP, Oracle, and homegrown apps", and expose and consume those applications at a very granular level, as well as model those processes very easily, he explained.
"Anything that changes can do that much better if the system is architected in SOA," he said.
Standards and interoperability
Another key aspect of SOA is that because it is built upon Web services, it enables organizations, and their ecosystem of business partners and customers to interoperate freely.
Pointing out that the SOA concept has been around since the 1980s, Phifer attributed its popularity as being ignited by the development of Web services in the early years of this decade. "You can think of it as the spark that lit the fire," he said.
Web services, popularized around 2001, are pieces of software that can communicate with another application over a network by using a specific set of standard protocols. These include Simple Object Access Protocol (SOAP), the Universal Description, Discovery, and Integration (UDDI) framework, and the Web Services Description Language (WSDL).
Peter Murchison, vice president of WebSphere Software at IBM Asia-Pacific, said: "With business processes supported by an SOA foundation, a company can make its previously-siloed data and software applications better interoperate across business units, as well as with third parties."
Echoing what Phifer mentioned earlier, Murchison told ZDNet Asia that "things like mergers, regulations, global competition, outsourcing and partnering have resulted in a massive increase in the number of applications a company may use".
The usual scenario would be that companies built applications with little knowledge of other applications that could be added in the future, and required to share information with existing applications, he said. And as a result, businesses are now struggling to maintain IT systems that co-exist, but are not integrated, he noted. Or if they are integrated, they are rigidly so, he added.
Murchison said: "Now just think about how many duplicate processes are occurring in separate departments and applications--and how much these duplicate processes are costing them."
And that is where SOA comes in, allowing businesses to provide standardized services and business processes, and thus enabling them to run their IT infrastructure more smoothly, he said. He added that this also frees up more energy for organizations to focus on their core businesses.
Tough to get right
But for all the simplification SOA promises to provide, implementing it is not a walk in the park.
The SOA landscape is now littered with middleware vendors such as Oracle, IBM, Microsoft, and application server vendors including BEA Systems and Sun Microsystems.
Traditional enterprise application integration (EAI) vendors such as Tibco and WebMethods also offer SOA products. Smaller pure-play vendors such as SOA Software, have also come into the market.
Gartner's Phifer noted that each of these vendors have different approaches to SOA implementation.
"SOA is something that takes months… It may take years to modify existing apps, it requires new methodologies and a new way of thinking for traditional developers," he said. "For many people, it's a big shift in the way they've been doing development."
Phifer added that these developers would require training, and the organizations need to bring in new tools to build, deploy and reassemble old applications. These tools include business process management (BPM), which allows enterprises to build orchestrated flows between those processes, and enterprise service bus (ESB), which is another software architecture that enables message transport, routing, mediation and orchestration.
What are vendors doing to make implementations less painless, especially since SOA involves the "forklifting" of many legacy applications to standards-based ones, and this can be a lengthy and arduous process?
For IBM, said Murchison, its commitment to the technology is clear. The company invests over US$1 billion annually in SOA, and has built up an extensive SOA team boosted with thousands of SOA consultants, architects and IT specialists.
Big Blue has SOA Design Centers--two in the Asia-Pacific region, China and India--and SOA Centers of Excellence around the world that handle client requirements, Murchison added.
Today, IBM has more than 1,800 SOA customer engagements around the world as well as over 1,200 SOA business partners worldwide. Customers in the region which have adopted IBM's SOA products include Japan's Point Apparel and Singapore's Housing Development Board.
IBM's middleware rival Oracle, however, has other thoughts on the matter.
Oracle believes that the market is far too fragmented, with too many products and too many vendors in the middleware space, said Roland Slee, vice president of Fusion middleware sales at Oracle Asia-Pacific.
The software giant makes sure that its Fusion software has all the functionality to be "hot-pluggable", and can mix-and-match elements of Oracle's middleware with third-party middleware such as those from JBoss or BEA, or Sun directory server, said Slee. He added that Oracle's SOA offerings also complement its integration and business intelligence solutions.
Besides the middleware component, Oracle's SOA approach crosses over into its grid computing, database management and business applications products.
Slee said: "Our database and infrastructure [software] sit underneath the middleware. SOA allows you to combine these elements to create a single, seamless process, and our grid computing architecture allows you to combine those things."
Oracle has also taken its existing Oracle E-Business Suite, J.D. Edwards, Siebel and PeopleSoft business application, exposed their integration points as Web services, to create new composite business applications, he added. "We've blended together their functionality, where people traditionally built point-to-point integration in their applications," he said
Out with EAI, in with SOA
With software integration taking up a big chunk of organizations' concerns, traditional EAI vendors now tout SOA as their core approach to integration.
Tibco for instance, distinguishes itself from the competition by focusing its SOA approach beyond Web services, said Ram Menon, the company's senior vice president of worldwide marketing.
"It's also important to note that because most enterprise-wide SOA initiatives must deal with much more than just pure Web services, a larger part of the SOA equation deals with existing legacy assets that dominate their landscape," said Menon.
Tibco BusinessWorks is the company's third-generation SOA product that was launched in 2001. Menon said that although it was designed "from the ground up" using the latest standards, and not just Web services standards, it provides all the functionality of an ESB. This includes a range of value-added services not typically included in the definition of an ESB such as adapters, support for events, transactions, exception handling, and so on.
He stressed that this range of services was developed in direct response to customer requests as a result of their real-world SOA deployments.
Not only does Tibco products support Web services, they also support all the other integration scenarios that are needed to expose these legacy assets as reusable business services, which can be easily assembled into new composite applications, Menon said.
"Almost all customers we speak to do not envision using Web services for everything, and in many cases, only expect to use SOAP for a smaller part of their SOA initiatives," he said.
Most of Tibco's customers in the Asia-Pacific--which make up about 20 percent of the company's 2,500 customer base worldwide--originally purchased Tibco products to implement the messaging infrastructure needed to support their real-time business, or to execute common EAI scenarios, said Menon.
Some of these customers are now looking to define and execute an SOA strategy, and are rationalizing their infrastructure portfolios to determine which existing technologies can be leveraged, and which additional products must be purchased, he said.