Myth-busting: always entertaining.

A good read!

(This same feedback also posted to another WSJ article about ESBs)

I agree in that the ESB concept is over-hyped. For me, a SOA makes sense if it is viewed as a constellation of web services interacting among them. For this, something like a UDDI server is required for each service locating each other.

For me, all this (i.e. services + directory) is just enough if only synchronous communications are used. If asynchronous communications are needed, then you need also publish/subscribe and store-and-forward, i.e. roughly what a MOM does. You can call it an ESB if you want, although I think this concept in the market encompasses several roles:
1. Publish/subscribe to messages
2. Store-and-forward messages
3. Route messages
4. Transform messages

An interesting thing to note is to implement points 1. and 2. you do *not* need business logic, while to implement 3. and 4. you do.

As I said, I see roles 1 and 2 required in SOAs with asynchronous interactions.

Roles 3 and 4 are also needed in many cases, mainly for integrating disparate systems. However, my main point against an ESB is that, in order to perform these roles, you do *NOT* need of a new, special concept like the ESB. *Any* service in the constellation of services can perform both routing and transformation. It can range from being a single component like an ESB (which I think is a bad idea), or it can just be a set of services (e.g. a different service performing specific adaptation for a system being integrated).

For me, using a single ESB for 3. and 4. breaks the beauty of the SOA idea. You are supposed to made all your data and business logic of your organization available as services in order to be reused, and suddenly you put on top an ESB in which you put *more* business logic (routing and transformation). So my point is that this should be implemented just by means of regular services, and not by specific, central-piece new components called ESBs.

Now, if for implementing routing and transformation you want to use Tibco, WebSphere or whatever, fine - however, the logic created by these products should be at the same level as the other services in the SOA, and not above.

So I am not saying that orchestrating tools are not useful. They are. Only, they are not *imprescindible*; and at any rate they should be viewed just as more services in the SOA. However, this does not fit the marketing strategy of ESB vendors which show its ESB as an *enabler* of a SOA, instead of just one more *component* of it.

We (Sonic Software) didn't re-lable our product to support the ESB wave, we actually invented the concept. We then worked with the analyst and journalist community to help create industry awareness of the new concepts that are introduced by ESB, which has resulted in a whole new product category.

I would agree with you that there is a great deal of hype right now due to lack of understanding of what ESB is, which is compounded by the number of traditional middleware and EAI vendors who have clamoured to get ESB in their marketing literature without having a full understanding of what it means to have an ESB. Your comment about middleware with new clothes is well taken. You might get that impression depending on where you learned about what an ESB is. That is exactly what I am trying to point out with myth #1 in this article.

A certain amount of hype is expected when a technology category begins to take hold and gain traction within serious IT projects. This can be disruptive to the industry as a whole. This is also the primary reason why I wrote the OReilly book on the subject of ESB--to act as the definitive guide to help educate and provide clarity on what makes up an ESB. Please don't shoot the concept of ESB down until you have had a chance to understand it.
Dave

Not surprising that the representative of a company who over-hyped ESB in the first place, and relabeled their own product ESB to catch the service wave, should now try to claim that anyone who saw through the hype is guilty of spreading myths.
ESB is just the middleware emporor's new clothes.