Azure Service Bus offers four distinct types of messaging communication patterns:

• Service Bus queues: Service Bus queues offer unidirectional asynchronous messaging for an enterprise. This messaging is durable and follows the First-In-First-Out (FIFO) pattern.
• Topic/subscription: Service Bus topics provide the publish-subscribe type of message exchange pattern. There can be many publishers along with a number of message listeners.
• Event hubs: This is used to store and route event type messages on a massive scale, such as telemetry data.
• Relay: Service Bus relays provide bidirectional communication and allow an enterprise to expose an endpoint in the cloud. With relay services, clients can securely expose services sitting behind a corporate firewall to the outside world.

As this chapter is all about messaging, we will concentrate on Azure Service Bus queues and topics, and provide you with the basic foundational knowledge to get started with the Azure Service Bus messaging platform.