Azure Service Bus Overview
Service
Bus Evolution
The first CTP of Azure Service Bus was released in 2007
under the name of BizTalk Services and featured the relay service
functionality, basic workflow hosting capabilities and basic Access Control
functionality. The release was controversial for a couple of reasons. Firstly
it was a service that would be hosted by Microsoft. You could not download and
install it on-premise, instead you consumed the service from on-premise applications.
When the technology was would pay for the service based on the resources you
consumed. Today, with the rise in popularity of cloud computing, the concept of
resource based billing for cloud services is more widely understood, but in
2007 it was very new, after all this was a year before Microsoft announced
Windows Azure.
The second reason for controversy was the choice of name for
the technology. “BizTalk Services” was very similar to “BizTalk Server”,
Microsoft’s integration platform, and many BizTalk developers were concerned
about the release and the implications it had on the future of BizTalk Sever.

When Microsoft announce the release of Windows Azure at PDC
in 2008 BizTalk Services has been re-branded to “.NET Services”. The relay
service and Access Control Service were present in this release; however the
workflow hosting capabilities had been removed.
In 2010 the technologies were re-branded to “Windows Azure
AppFabric Service Bus”, again this caused some controversy as AppFabric was also
used in “Windows Server AppFabric”, a technology that seemed to have little to
do with “Windows Azure AppFabric”. The reasoning for this was that AppFabric
would be the branding used for Microsoft’s middle-ware platform, and in future
releases the cloud-based and on-premise versions would share common
functionality.
2011 saw the release of brokered messaging capabilities,
providing queues, topics and subscriptions and durable messaging. Shortly after
these released it was re-branded again to “Windows Azure Service Bus”. 2011
also saw the release of a CTP version of integration capabilities, allowing
integration between enterprise applications and the exchange of EDI messages.