Imagine hundreds of people gathering online to debate one of the most contentious topics in the SOA community, led by ZapThink's high-octane analysts, Ron Schmelzer and Jason Bloomberg. At issue during what could turn out to be a landmark web event is the thorny question of ESB and whether it really is a worthy foundation for SOA. Sonic Software's Gordon van Huizen the man who coined the term will be defending ESB. Blue Titan's Matt Mihic will be putting the case for the alternative concept of SOA fabric.
The word 'mob' implies a seething mass of humanity, and that's certainly what the ZapThink team have in mind for this webcast, the second in their new monthly ZapForum series. Interactive participation by a well-informed audience is the core of the formula for the ZapForum webinars. Instead of passively listening to what the analysts and guest speakers have to say, attendees are going to be encouraged to add their own observations and questions. Given the calibre of participant this and other events in the series are likely to attract, there's probably going to be as much good material coming in from the attendees as there is from those leading the discussion. There's every possibility of sparky exchanges, unexpected insights and perhaps even spontaneous consensus on certain points. That would certainly merit the name 'mobcast', even if I've appropriated a term previously used when inviting mobile phone postings to a shared podcast location (for which I feel the more langorous spelling 'mobecast' would better convey both the meaning and the delayed immediacy).
Is it really possible in a single one-hour webinar to finally nail the truth about ESB? I made my own views on the topic clear last November. But the concept has some staunch defenders in Sonic's Gordon van Huizen and his colleague Dave Chappell. Dave penned a robust and detailed rejoinder to ESB's critics for Web Services Journal last month: ESB Myth Busters: 10 Enterprise Service Bus Myths Debunked. It's certainly well worth reading and it gives a great insight into how Sonic positions the ESB term.
Personally, I still can't bring myself to agree with Dave that it's helpful to think of ESB either as a) a product or b) a bus. I think what Dave describes in his article is a highly distributed, policy-driven architecture that uses XSL transformations and other XML standards to implement policy in a loosely coupled, flexibly reconfigurable way. Sometimes it might be convenient to have that capability delivered as a product, but it should always be considered something that's extensible beyond the boundaries of an individual product implementatation or messaging bus, for that matter.
I'm a fabric man, through and through. I wrote in my last posting about various layers of SOA. There's so much going on above the message handling that fabric is just a much more expressive word. It's notable also how the threads of that fabric are extending out to weave themselves into every aspect of enterprise IT infrastructure. Sonic's announcement last week that it had added database services to its ESB product suite was a useful acknowledgement that SOA needs to embrace all of the infrastructure, not just the web services-enabled subset. In fact, I detected in Sonic's marketing last week of extensions to its "ESB-based SOA infrastructure line" a tacit admission that ESB is indeed just a part of the SOA fabric. So perhaps I'm already winning this argument. It certainly seems that several of the leading SOA specialist vendors, including Blue Titan, Actional and SOA Software, are leaning towards the 'fabric' term.
From talking to early adopters, mastering the emerging SOA infrastructure is the most pressing concern, however you define it. When I started out planning the lead feature for this month's Loosely Coupled monthly digest, I was going to make it a "bus or fabric?" article. But as I got into it, it became evident that getting started with SOA means thinking about where you're headed, and selecting the right tools for the job. (We've just published a short excerpt from the article as a website feature, Laying the foundations for SOA). In some cases your chosen roadmap will lead you to adopt an ESB as your starting point, in other cases you'll find it more helpful to visualize the infrastructure as a fabric. But in either case, your main concern will be staying in command as the whole edifice develops. Coincidentally, that's the theme of the first event in the ZapForum program, on April 7th. So if you're serious about embarking on an SOA project, you should certainly sign up for that one. If you have any interest at all in the field, I would recommend joining in the second event on May 4th, The Great Debate: ESBs, Fabrics, or Something Else?, and help to make this a memorable mobcast. I look forward to joining you there.