## 4.2.13.8.4.2  Queue Subscriptions
Events published through an ABAP environment instance can be consumed at the SAP Event Mesh. Events published to a queue defined in your SAP Event Mesh service instance can also be consumed in ABAP environment. Queues can be used to buffer events until a consumer can process them. For the right events to arrive at a queue, the queue must be subscribed to the corresponding topics. A consumer can then subscribe to the queue.
## Context
Once a queue has been subscribed to the corresponding topic and you have subscribed to the queue, you can view the list of applications and service instances. The SAP Event Mesh dashboard enables you to create queues and bind incoming message topics to such queues.
##  Note
The syntax used to compose topics and the payload for ABAP environment business events supports the standardized CloudEvents format (https:/ /cloudevents.io ).
For more information about the syntax, see also Syntax for Service Descriptor.
Ensure that the pattern of the topic, to which the queue is subscribed, consists of the following three parts:
| Name            | Description                                                                                                                                                                                                                                                                                                                                                                                                          |
|-----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Topic namespace | • Contains three segments: vendor, product information, and a technical identifier. • The topic namespace originates from the namespace of the service key created for the respective SAP Event Mesh instance.  Note When defining the Service Descriptor for the service instance of the SAP Event Mesh service, make sure that the length of the namespace property does not exceed the maximum of 24 characters. |
| Abbreviation    | Value ce for cloud events                                                                                                                                                                                                                                                                                                                                                                                            |
| Event topic     | Value as displayed in the value help in the previous Outbound Topic Binding configuration step.                                                                                                                                                                                                                                                                                                                      |
You can also use wildcards, such as &lt;namespace&gt;/* .
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##  Example
If you want to create a queue-topic subscription for the sap/s4/beh/businesspartner/v1/ BusinessPartner/Changed/v1 event topic, you need to add the topic namespace and the ce abbreviation at the beginning of the topic: &lt;namespace&gt;/ce/sap/s4/beh/businesspartner/v1/ BusinessPartner/Changed/v1 .
## Related Information
Manage Queue Subscriptions Configuration of Event Publishing and Event Consumption Scenarios [page 1143] CloudEvents Context Attributes [page 1120]