Service Bus Messaging
The Microsoft Azure Service Bus provides a communication and integration platform for networking distributed Web services. Simple and complex message streams can be implemented regardless of where the individual communication partners are executed (in the cloud or in the customer's data center). Support is provided for point-to-point connections (unidirectional and bidirectional), queues for caching exchanged messages, as well as publish-subscribe patterns about topics where multiple senders can dispatch messages to multiple recipients.
Service Bus Learning Path
Azure Queues and Service Bus queues - compared and contrasted
Microsoft Virtual Academy (MVA)