There is quite a lot of confusion about the Enterprise Service Bus because the leading ESB-providing companies, like Gartner, Sonic and IBM made different definitions of the term.
When we compare all the different ESB solutions we can define a common set of characteristics that apply to an ESB:
- Brokered Communication
The basic function of a ESB is to send data between processes on a single or multiple computers. The brokered communication is offered by the use of a software intermediary between the sender and the receiver.
Based on a predefined set of criteria ESBs are capable of routing messages to subscribers
- Endpoint Metadata
ESBs normally maintain metadata that describe the service interfaces and message schemas.
- Basic Web Services
An ESB supports basic Web service standards like SOAP, WSDL and foundational standards like TCP/IP and XML to communicate.
A lot of venders try to position their ESB as the single solution that solves all integration needs, but an ESB product can rarely do this as it misses features like business activity monitoring and business rules.
Does Microsoft deliver an ESB? No they do not. Of course you can build an ESB with the toolset from Microsoft, but they believe in delivering a broader set of important integration requirements that go beyond the ESB. Microsoft offers message validation and transformation, BAM, Business rules management and business process orchestration & management.