The Enterprise Service Bus (ESB) is a much maligned, scorned, mocked and generally over-vendorised concept which has resulted in it’s value being shrouded in the usual layers of skepticism. As a former Integration Architect within a large scale Enterprise SOA transformation program, I have spent a huge amount of time looking at the optimal formation of hundreds of middleware silo’s as the strategic backplane of the Enterprise SOA service-tier.
My interest in ESB started way before the ESB hit the hype-cycle, whilst deputising for an amazingly talented Integration Architect, and initially we were simply looking for an architectural model that would allow controlled decentralisation of the middleware bottleneck responsible for strangling (whilst bankrupting) the wider mobilisation of SOA implementation across our enterprise. The initial term we used, coming from a hub-centric EAI landscape, was EAI Bus. I am referring to an EAI hub proliferation on a major scale in terms of cost and numbers. The net result was the spreading loss-of-control of the business systems to achieve integration on anything other than a tactical basis.
So the EAI Bus referred to the creation of a standardised inter-hub protocol over MOM infrastructure effectively extending the remit of any domain-hub (be that product-line, business-unit, or whatever….) into forming an component part of a larger, addressable enterprise backplane. The motivations were:
- Establish a common inter-domain integration standard, leveraging existing investment in domain EAI (BEA) and Enterprise MOM (Webpshere MQ, BEA JMS) technologies.
- Extend addressability across the federated hub namespace – effectively defining the common rail across which services (either strategic SOA assets or legacy EAI endpoints) can be located.
- Empower the IT domains at the edges, who are seeking to integrate on a strategic service-basis, but avoid the inter-domain EAI complexities in favour or working through a local integration unit where possible.
The decentralisation of the integration platform infrastructure and it’s dissemination into the service provider/consumer endpoints was the fundmantal goal. This was an evolution from our EAI reality, and I stress this commenced before the ESB band-wagon kicked in. I’ll be posing additional stages of our ESB evolution story.
The key point I can offer here is that WE knew what we were looking for, prior to the ESB arriving so we had a strong vision and strong motivation that allowed us to refactor existing infrastructure as opposed to re-investing in dreams.