Enterprise service buses hit the road

See correction at end of article

EAI (enterprise application integration) has come a long way since our early ancestors fashioned the first custom connectors out of wood, shell, and stone. Back then, the goals were modest, the work was difficult, and the results were brittle. They were also costly to maintain. Change required starting over from scratch.

Today we know that IT systems must adapt more quickly to business needs, and there’s no shortage of middleware vendors promising to make that happen. The magic ingredients are SOA (service-oriented architecture) -- an integration paradigm that prescribes open standards and lightweight, distributed components -- and the ESB (enterprise service bus), a newfangled integration platform designed to support the SOA paradigm and tie into legacy assets.

The golden dream behind the ESB is to replace proprietary integration brokers with open communication layers through which distributed services and business processes are readily exposed and easily managed. The immediate reality, however, is that it may be too soon to leave the old messaging subsystems behind.

Regardless of the underlying messaging core, an ESB must somehow -- through open standards or by proprietary means -- create a foundation for reliable messaging. Until WS-* specifications for reliable messaging fall into place, that reliability continues to come from the likes of JMS (Java Message Service), homegrown messaging engines, proprietary MOM (message-oriented middleware), and J2EE servers.

Among the seven ESB packages in this roundup, all but two incorporate an old-school messaging subsystem; Fiorano Software and Sonic Software are based on proprietary messaging middleware. Iona Technologies extends its legacy EAI architecture. PolarLake and FusionWare take a server-centric, connector-based approach. Only Cape Clear Software and Cordys use a truly open and distributed SOA.

What else must an ESB suite provide? It should have tools that streamline development, a data-transformation engine, intelligent message routing, and a management interface supporting real-time monitoring and exception handling, as well as deployment and management of actual services. Most of the products reviewed here meet all of these requirements to varying degrees.

Additional features may include process orchestration and management, BAM (business activity monitoring) and QoS capabilities, support for enterprise management systems such as HP OpenView and IBM Tivoli, and the inclusion of ready-made adapters for quick integration of enterprise apps, data sources, application servers, alternative transports, etc. These were all key differentiators among the products tested. Further, not all of these suites support service discovery and re-use, accelerate XML processing, or offer content-based message routing. In short, each of the products offers a distinct set of strengths. Not all of them, however, would meet the challenges of large, complex integration projects.

Cape Clear 6.1
Born from members of team Iona, Cape Clear made its name as an early pioneer in Web-services platform infrastructure. Cape Clear 6 is a well-equipped Java-based ESB suite that combines Web-services messaging with content-based routing and data-transformation capabilities, BPEL (Business Process Execution Language)-driven orchestration and workflow, and a battery of wizard-driven helpers and administrative tools for monitoring and managing system health.