# Setup tab

In the **Setup** tab, define the connection to the MQTT server, the topics for publishing, **Quality of Service** level, and the **Message field**:

| Option                       | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Connection**               | Specify the address of the MQTT server to which this step will connect for sending or receiving messages.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| **Client ID**                | Specify a unique ID for the MQTT client. The MQTT server uses this **Client ID** to recognize each distinct client and that client's current state.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| **Topic**                    | <p>Specify the <strong>Topic</strong> name using one of the following methods:</p><ul><li>Select <strong>Specify topic</strong> to enter a specific Topic name. Then, in the <strong>Topic name</strong> field, enter the name of the MQTT topic to which you want to publish streaming data (messages). Each MQTT Producer step will start a single thread for publishing.</li><li>Select <strong>Get data from field</strong> to specify a <strong>Topic</strong> name based on a field from another step which is generating rows in the same transformation stream. Using the dropdown list, then select the name of the field you want to use. You can use this option to dynamically control setting the value for the <strong>Topic</strong> name. Each individual message will still have only one topic, but each row coming into the MQTT Producer step will generate a new message with a potentially different topic.</li></ul> |
| **Quality of Service (QoS)** | <p><strong>Quality of Service (QoS)</strong> is a level of guarantee for message delivery. Select one of the following options.</p><ul><li>At most once (0), which is the default value</li><li>At least once (<strong>1</strong>)</li><li>Exactly once (<strong>2</strong>)</li></ul>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Message Field**            | Select the individual record contained in a topic that you want to send.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |


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