ESB

1、An enterprise service bus(ESB) is the infrastructure of SOA.

2、Its purpose is to provide interoperability (connectivity, data mapping,and routing) combined with some additional services such as security,monitoring, and so on.

3、An ESB　can be heterogeneous (and often is ).

4、Whether the ESB is protocal-driven or API-driven is a fundamental decision.

5、A protocol-driven ESB defines a protocol that providers and cosumers have to match,but it is up to the providers and cosumers how to match that protocol. The ESB and connected systems are decoupled in such a way that they do not share any code, so that ESB does not have to deploy libraries for the systems.The drawback is that any protocol changes force the providers and cosumers to make corresponding updates.

6、An API-Driven ESB　provides an API for providers and cosumers to use to implement and/or call services.This allows protocal details to be transpant,but requires some way for the ESB to deploy generate code ,and/or libraries to the providers and consumers.

7、There are different value-added services that an ESB might provide.The most improtant is the ability for distributed  debugging.

8、Bussiness activity monotoring(BAM) allows you to monitor the ESB, so you can learn about your bussiness in real time and react accordingly. This might create some bussiness opportunities and market advvantages.