In the first part of this two-part feature, I explained that past research told me that enterprise services buses (ESBs), the 21st century form of message-oriented middleware (MOM), were not being used as technology for technology's sake as would be expected. For example, few users seemed to just be replacing enterprise application integration software or even adopting ESBs in service oriented architectures (SOAs). I believe this was true because of an adoption moderation effect caused by the open source software (OSS) ESB/MOM ecosystem. Quietly, multiple OSS ESB projects started up in the 2003-2004 timeframe, just as the ESB concept was emerging. Users were waiting to see what the OSS community brought to the party, maybe for the first time in a major software category. Now the wraps are off. This second part of the article covers the ESB service and support offerings market that is growing up around the OSS ESB/MOM ecosystem and the response of the established ESB/MOM suppliers, which in some cases involves their getting the OSS religion themselves. Traditional mid-stack software suppliers tend to offer ESBs as part of an integrated framework (although most have begun to offer them a la carte as well) while up-and-coming OSS ESB suppliers tend to offer them a la carte. Is there an advantage of one approach over the other? Maybe but I found that the separate domains are converging.
