So we have 2 flavors of a service bus, namely the ALSB en OESB which is now repackaged and relincensed into OSB = Oracle Service Bus.
If we have a look at both products we could briefly summarise the big differences in focus of both products. Which actually means, looking back into the past, when BEA and Oracle were separate vendors.
So let’s compare both products, in a really, really short summary ;o)
AL SB = stand-alone pipelining mechanism which supports messaging, other adapters and pipelining of actions (a little bit of a sequential approach)
OESB = dragging-and-dropping of different services based on webservices (SOAP Services) or adapters (file, MQ, JMS, DB, …) + focus on transformation and routing
With the 11g release we don’t talk about the ESB or Service Bus anymore but about the Mediator. The SCA Mediator, which actually is the Oracle Service Bus.
The OSB (Oracle Service Bus) = ALSB + OSB = Best of both products = Best of breed