Sonic Software, an operating company of Progress Software, published what it considers an “Architecture and Lifecycle Definition ” of an enterprise service bus (ESB) yesterday, but anyone seeking a concise definition will be disappointed as Sonic’s view of the technology is encapsulated in a 55-page white paper.
In a shorter introduction to the definition, Sonic said, “An ESB is software infrastructure that simplifies the integration and flexible reuse of business components using a service-oriented architecture. An ESB makes it easy to dynamically connect, mediate and control services and their interactions.”
Lashing out at the large number of rival companies that also claim to offer an ESB, newly-appointed CTO, Hub Vandervoort said, “It’s time for fuzzy thinking about enterprise service buses to be replaced with a precise definition that allows the industry to separate fractional ESBs from the real thing.”
He said the definition, “will help anyone interested in SOA infrastructure by providing a precise vocabulary and structural definition of an ESB that has been field-proven in over 250 live customer deployments”. The short version and full white paper are available from Sonic’s web site.
But if Sonic hoped the industry might adopt its definition of the ESB as some sort of single version of the truth, that hope was dashed as two rivals immediately contradicted Sonic’s definition in interviews with me yesterday.
Iona Software’s CTO Eric Newcomer said that while, “In general we agree with Sonic’s requirements for an ESB, at a technical level when it comes to how to meet those requirements we think they have got it all wrong.”
Newcomer said that Sonic is, “Making a big deal of the fact that they invented the ESB, but just because you invented the term does not mean that you have the best architecture.” Specifically, he said that Iona believes Sonic’s ESB is “overly JMS [Java Message Service] and broker based”.
“Sonic has good JMS messaging, indeed we used to resell it and we still connect our ESB to it if customers want to,” Newcomer continued, “but our objection is that JMS can not be the only solution. You might want a C++ messaging layer, or another sort of messaging layer of your own making, and you don’t want to drag your customers down into the weeds by making them worry about the constraints of JMS.”
Meanwhile, Ronan Bradley, CEO of fellow ESB vendor PolarLake, said it was, “Great to see Sonic Software’s definition converge towards ours. In particular, they are correctly identifying that mediation – a term we have used for quite some time – is the core feature of an ESB.”
However, he said, “Unfortunately, recognition of the role of mediation is of course not sufficient. Right now, Sonic’s product – just like those of Tibco and IBM – provide little actual support for these activities. They propose that simple scripting using XSLT or process orchestration on its own is sufficient – which it quite simply is not.”
“This means that their customers are either limited to using these products in simpler projects or resort to extensive custom coding to fill in the gaps,” Bradley said. “The custom code required to fill in the gaps is expensive and gumming up the SOA. In contrast, PolarLake’s customers are able to solve even the most complex integration and mediation challenges with what comes in the PolarLake box – without any custom coding.”
Another rival, Cape Clear, published what it called an “ESB Truth Test” in June this year, in which it claimed that, “Cape Clear has built the world’s first and only True ESB. It’s built from the ground up around web services, XML and open standards. There is no proprietary EAI server at the core. It doesn’t require a particular application server or message transport to function. It works with all your existing applications and data sources.”
Meanwhile, Gartner kept its definition of an ESB relatively loose, when it said: “Enterprise service buses (ESBs) are a new kind of middleware that combine features from several previous types of middleware into one package. ESBs support web services by implementing Simple Object Access Protocol (SOAP) and leveraging Web Services Description Language (WSDL) and Universal Description, Discovery and Integration (UDDI). Many ESBs also support other communication styles that involve guaranteed delivery and publish-and-subscribe; those that don’t soon will.”
“All ESBs provide some value-added services beyond those found in basic communication middleware, such as message validation, transformation, content-based routing, security, service discovery for a service-oriented architecture (SOA), load balancing, failover and logging,” Gartner continued. “Some services are built into the ESB core, while others run in “plug in” modules. ESBs have a distributed architecture wherein some services are executed near the application programs, rather than in a central hub. ESBs support Extensible Markup Language (XML) and often also support other message formats.”
Meanwhile, Sonic said yesterday that its definition – which employs more than 20 unified modeling language (UML) class and object diagrams to depict the structure and show examples of how the ESB is built and operates – provides a “comprehensive and unambiguous vocabulary in a technology category rife with confusion and conflicting terminology”.
What do I think of Sonic’s definition of an ESB? I think it’s exactly that – Sonic’s definition. Indeed the company concedes that it describes its own view of the technology, rather than trying to create some sort of single version of the truth as to what an ESB is. After all, there are lots of companies claiming to do ESBs, and they all have different takes on the technology.
I believe the ESB sector is not sufficiently mature to agree on a definition that suits everybody just yet. I also don’t believe that Sonic’s claim to have invented the concept of the ESB gives them any more right to define what is and what is not an ESB than any of their rivals, who may well have taken Sonic’s ideas and improved upon them with the benefit of hindsight. I definitely consider Sonic one of the thought leaders in this space, but that doesn’t mean that everyone will dance to their particular tune.