As a part of the Certified Architect course we where required to write an IT-related paper to get our exam. Inspired by Udi Dahans article on autonomous services I decided to write a paper on how the choice of messaging patterns between services in an Service Oriented Architecture (SOA) highly affects key quality attributes such as Performance, Scalability and Availability. I also examined how the choice of communication affects the possible use of features offered by an Enterprise Service Bus (ESB).

The conclusion was that asynchronous messaging in general and specifically publish/subscribe had the best affect on the examined quality attributes. Further more I concluded that that main reason to implement an ESB should be to support asynchronous communication.

The latter might be stating the obvious but I have on numerous occasions spoken to people that believed that buying an ESB would automatically give them a SOA. An ESB is definitely not a silver bullet that without effort will transform your old applications to a successful SOA.   

The paper can be downloaded from here (unfortunately only in Swedish)