An Azure Service Bus queue provides unidirectional message communications across distributed applications in a loosely coupled messaging pattern. This method of communication between a client and Service Bus instance can be done with either the Azure SDK, HTTPS, or by following the AMQP protocol.

The main advantage of using queues is that it provides load balancing across client-server applications by default. With a queue acting as a middleware client application, reading the message from the queue can be done at a leisurely pace rather than there being any throttling going on with a high number of concurrent requests. In cases where the rate of publishing messages in the queue is greater than the subscriber subscribing the message, an enterprise can always add additional subscriber applications to perform load balancing and to limit the queue depth.

If you are using multiple subscribers to subscribe to messages from the queue, then you should consider various lock types to suit the solution.

This type of distributed design has various advantages, some of which are listed here:

• Offline/online message processing: This is one of the greatest advantages of using Service Bus queues. The publishing and subscribing systems do not need to be online at the same time, as Service Bus queues will act as message brokers between distributed systems.
• Hybrid integration: With cloud adoption, most enterprises will move some or more of their workload to the cloud while keeping resources available on premises. Azure Service Bus queues will allow connecting on-premises resources to cloud-hosted services or applications in a secure manner.
• Loosely coupled applications: Using Service Bus queues as brokers, an enterprise can achieve a loosely coupled design where each system works independently without affecting the processing of other connecting systems.