Though there is active debate over how necessary enterprise service buses are to a service-oriented architecture, a recent Forrester Research Inc. report finds that continued SOA adoption bodes well for the ESB, which it calls "the leading entry point for SOA."
The particulars of the report include the identification of two separate ESB markets, a crowded leaders bracket and price points that make ESBs an attractive option for any company with integration issues. Overall, Forrester, in a survey of 116 companies, reported that 77% of large enterprises, 51% of medium enterprises and 46% of small enterprises will be actively implementing SOA by the end of the year, with an estimate that one-third of "infrastructure decision makers" will be increasing their ESB deployment over the next 12 months.
"Even if they're not quite sure how they're going to build out an entire SOA, people know they've got integration issues, and the ESB is where they're going to address those issues," said Forrester analyst Mike Gilpin.
The report broke the customer market into two separate groups. One it called the "keep it simple" group and the other it called the "I want it all now" group.
The "keep it simple" crowd wants a low-cost point of entry, standards-based Web service orchestration tools and something on top of which a more robust SOA can be built in the future. Gilpin said price in particular had become a major selling point for ESBs, enabling companies to build initial Web services for a relatively small investment as they ramp up on the skills necessary to construct a full SOA.
This is where companies like Cape Clear Software Inc., Sonic Software Corp. and Fiorano Software Inc. have been able to gain traction.
"In fact, the success of ESBs may be responsible for the overall decline in the amount of money spent on integration software," he said. "So they're moving more units, but the cost is less."
The "I want it all now" crowd wants something that can cater to its soup-to-nuts integration issues, more fine-grained control over the service lifecycle and business process management tools.
Gilpin believes those two different market segments will create a demand for two different types of ESB products -- a lightweight entry-level product and a comprehensive SOA integration and governance product. The report indicates that both ESB pioneers and enterprise application integration (EAI) converts have their sights set on the comprehensive market, leaving the door open for lightweight offerings like IBM's soon-to-be-released WebSphere ESB.
Forrester had surprisingly nice things to say about the conversion work of EAI vendors, who often get labeled as legacy middleware by the analyst community, to the ESB format, finding them to be competitive in service mediation and control/change with the Web services infrastructure pure plays. The EAI converts offered up stronger market presence scores according to the report, but only Oracle Corp. and webMethods Inc. were able to gain some measure of competitive footing on price.
The leaders bracket included Cape Clear, Sonic, Fiorano, Iona Technologies Inc., Oracle, webMethods, Tibco Software Inc. and Sun Microsystems Inc., which bought SeeBeyond Inc. this summer. BEA Systems Inc. made the leaderboard twice -- once for its AquaLogic ESB and once for its WebLogic Integration suite. IBM's latest ESB offerings were too new to make the study.
Gilpin does not expect platform vendors like BEA, Oracle and IBM to cause the market to winnow too much because integration issues should not be tightly coupled with where an application runs inside an SOA.
He identified lack of cohesion in the product set as a challenge for the market.
"People are concerned that ESBs are not sufficiently defined by standards," he said. "It's kind of like the application server market before J2EE [Java 2 Enterprise Edition]."
He looked toward initiatives like the Apache Synapse project, which hopes to define standard methods for Web services mediation, as potential ways to solve that problem.
Gilpin identified governance as the biggest unmet need in the ESB market. SOA registry vendors have been staking out that area, and he expects the two areas to come together whether by merger or through teamwork, perhaps with XML networking worked into the equation as well.
"SOA is so big that it's nearly impossible for one vendor, even IBM, to offer it all," he said. "What you're likely to see is groups of vendors working together as teams to form an ecosystem."