Merge pull request #4174 from TomasEkeli/patch-1

The Azure ServiceBus Queue -name must match the Dapr pubsub topic

Author: hhunter-ms

daprdocs/content/en/reference/components-reference/supported-pubsub/setup-azure-servicebus-queues.md

@@ -181,6 +181,23 @@ When subscribing to a topic, you can configure `bulkSubscribe` options. Refer to
 
 Follow the instructions [here](https://learn.microsoft.com/azure/service-bus-messaging/service-bus-quickstart-portal) on setting up Azure Service Bus Queues.
 
+{{% alert title="Note" color="primary" %}}
+Your queue must have the same name as the topic you are publishing to with Dapr. For example, if you are publishing to the pub/sub `"myPubsub"` on the topic `"orders"`, your queue must be named `"orders"`.
+If you are using a shared access policy to connect to the queue, that policy must be able to "manage" the queue. To work with a dead-letter queue, the policy must live on the Service Bus Namespace that contains both the main queue and the dead-letter queue.
+{{% /alert %}}
+
+### Retry policy and dead-letter queues
+
+By default, an Azure Service Bus Queue has a dead-letter queue. The messages are retried the amount given for `maxDeliveryCount`. The default `maxDeliveryCount` value defaults to 10, but can be set up to 2000. These retries happen very rapidly and the message is put in the dead-letter queue if no success is returned.
+
+Dapr Pub/sub offers its own dead-letter queue concept that lets you control the retry policy and subscribe to the dead-letter queue through Dapr. 
+1. Set up a separate queue as that dead-letter queue in the Azure Service Bus namespace, and a resilience policy that defines how to retry. 
+1. Subscribe to the topic to get the failed messages and deal with them. 
+
+For example, setting up a dead-letter queue `orders-dlq` in the subscription and a resiliency policy lets you subscribe to the topic `orders-dlq` to handle failed messages.
+
+For more details on setting up dead-letter queues, see the [dead-letter article]({{< ref pubsub-deadletter >}}).
+
 ## Related links
 
 - [Basic schema for a Dapr component]({{< ref component-schema >}})