Service Bus is a software model, a middleware, that is mainly used with WCF or SOA to handle and loosens all the coupled messaging between all the applications required. There are 2 types of Service Bus, the one running on Windows Azure and the one that can run on the local servers which we call Enterprise Service Bus.
To clarify more what Service Bus can do, it can work with different applications, reach them and interact with them regardless of the different mechanism they work with.
Here is a video from Channel 9 that clarifies more the concept of EAI and What Service Bus can do.
For the Windows Azure Service Bus, it provides REST, relayed and brokered messaging capabilities for the Messaging, connecting the applications running on premises with the ones running on Windows Azure and finally works also for the mobile devices push notifications.
For more information about the Windows Azure Service Bus Relayed Messaging you can go to the following link and for more information about the Windows Azure Service Bus Brokered Messaging you can find it in the following link.
So why people use the Service Bus?
- It can be used for delivering messages to multiple connectors or endpoints.
- Simplify the integration between multiple applications as each one of them is using different connector with different way of integration.
- Ensure the delivery of the messaging to the applications.