Azure Service Bus provides a robust and scalable messaging infrastructure. It provides the framework to connect on-premise and cloud-based applications/services together.

Using Topics with the Service Bus provides the framework to build scalable publish/subscribe messaging exchange patterns.

There are basically two types of authentication mechanisms used to secure Service Bus entities, SAS and ACS. Also, both Service Queues and Relay Services provide accessibility rights for Listening, Sending, and Managing Service Bus entities and Relay Service endpoints. Exposing on-premise WCF services can be easily achieved using Relay Services. The SBWS is an option for on-premises deployments when cloud deployments are not allowed.

In the next chapter we will further build on what we have learned so far about loosely coupled messaging and dive into the world of Service Oriented Architecture (SOA) and how it applies to BizTalk.