---
title: Generic MQTT Integration Guide (Last Will and Testament)
slug: litmusedge/how-to-guides/integration-guides/generic-mqtt-tcp-lwt
description: Learn how to set up a Generic MQTT-TCP connector with a Last Will and Testament configuration. 
docTags: 
createdAt: 2022-11-24T18:28:04.000Z
---

Review the following guide for setting up an integration between Litmus Edge and an MQTT broker using Last Will and Testament. 

# Overview of MQTT Last Will and Testament

When this type of integration is set up, it includes a notification to other clients that are connected to the MQTT broker when your connection as a client disconnects.

When a client connects to the MQTT broker, it creates a connect packet that is predefined and sent to the MQTT broker.

You can define the message to notify you if the client disconnects.

There are four properties that you can set for the Last Will and Testament.

- LWT Topic: This is the topic that is used by the MQTT broker to send if the client disconnects.
- LWT Payload: This is the payload message that is sent if the client disconnects.
- QoS: This is the quality of service level (0, 1, or 2).
- Retain: This indicates if the message should be retained (true or false).

The MQTT broker sends this message in the following scenarios:

- If the client fails to communicate within the defined *Keep Alive* period
- If the client does not send a disconnect packet before it closes the network connection
- The broker closes the network connection due to a protocol error by the client.

# Before You Begin

You will need access to an MQTT broker. 

# Step 1: Add the Generic MQTT Connector

Follow the steps to [Add a Connector](docId\:ytsWGWeU6H6oEUnHj5hW3) and select the **MQTT - Generic **provider. 

Configure the following parameters.

- **Name**: Enter a name for the connector. 
- **Hostname**: Enter the server address. 
- **Port**: Confirm that the default value **1883** is entered. 
- **Client ID**: Enter the client ID. If it is left blank, a default value will be auto-generated. 
- **Username **(Optional)
- **Password **(Optional)
- **QoS**: The Quality of Service (QoS) level is an agreement between the sender of a message and the receiver of a message that defines the guarantee of delivery for a specific message. Select one of the following:
  - **0**: The message is sent once and delivery isn’t guaranteed.
  - **1**: This method guarantees that the message will be delivered to the broker, but also doesn’t prevent it being received multiple times.
  - **2**: This method guarantees that the message will be delivered to the broker, and the message will be sent exactly once. 
- **Parallel Publish Count**: The number of messages being published simultaneously. Once the defined limit has been reached, subsequent messages are silently dropped. The default value is 100. 
- **Integration Topic**: Enter **testTopic**. 
- **LWT topic**: Enter **lwtTopicName**. 
- **LWT payload**: Enter **Some LWT Payload**. 
- **LWT payload type**: The payload type for MQTT's Last Will and Testament feature. The options are *string *and *base64*. 
- **LWT QoS**: The Quality of Service value for MQTT's Last Will and Testament feature.
- **LWT retained**: Select this checkbox to retain the value for MQTT's Last Will and Testament feature. 
- **Throttling limit**: The maximum number of messages per second to be processed. The default value is zero, which means that there is no limit. 
- **Persistent storage**: When enabled, this will cause messages to undergo a store-and-forward procedure. Messages will be stored within Litmus Edge when cloud providers are online.  
- **Queue Mode**: Select the queue mode as **lifo **(last in first out) or **fifo **(first in first out). Selecting **lifo **means that the last data entry is processed first, and selecting **fifo **means the first data entry is processed first. 

# Step 2: Enable the Connector

After adding the connector, click the toggle in the connector tile to enable it. 

::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/s5Aclay2bU1xicFZQWpMX_mqttgeneric.png" size="60" width="369" height="345" position="center" showCaption="false"}

If you see a *Failed *status, you can review the [Connector Logs](docId\:BEQQ0sSzwsv9v9rIF3rhk) and relevant error messages. 

# Step 3: Verify Connection in Flows Manager

You can verify the connection is successfully set up by creating a flow in Litmus Edge. 

**To create a flow:**

1. In Litmus Edge, navigate to **Flows Manager**. 
2. Click **Add Flow**.
3. Enter **MQTT LWT **in the **Name **field and click **Create Flow**.
4. Click the **Start **icon next to the MQTT LWT flow.
   ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/r97cBIu5zR7UgRGejsEOQ_flowstarticon.png" size="80" width="1170" height="358" caption="Flows Manager Start icon" position="center" showCaption="true"}
5. Click the **Go To Flow Definition** icon. 
   The* Flow canvas *opens in a new browser tab. 
   ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/6PlxhptXn4xZ_4ZdrIAuf_gotoflowdefinition.png" size="80" width="944" height="366" caption="Go To Flow Definition icon" position="center" showCaption="true"}
6. From the node palette, drag the **MQTT In** node (network section) to the canvas. 
   ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/7f0HoqgLntPC_1APyE5Yr_mqttinnode.png" size="80" width="1121" height="637" caption="MQTT In node" position="center" showCaption="true"}
7. Double-click the **MQTT In** node.
   The *Edit MQTT In Node* dialog box appears. 
8. Click the **Edit **icon next to the *Server *field. 
   The *Add new mqtt-broker config node* dialog box appears. 
   ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/h_f4IwachNpeLbdv60Q_q_editservericon.png" size="60" width="505" height="462" caption="Edit server icon" position="center" showCaption="true"}
9. In the *Name *field, enter the name of the broker. 
10. From the Connection tab, configure the following parameters. 
    - **Server**: Enter the server address. 
    - **Port**: Enter **1883**. 
    - **Client ID**: Enter the client ID. 
    - **Keep Alive**: Enter **60**. 
11. Click **Add**. 
12. From the *Edit MQTT In Node* dialog box, enter **lwtTopicName **in the **Topic **field. 
13. Select the desired **QoS **value. 
14. Click **Done**.
15. From the *Node *palette, drag the **Debug **Node to the canvas and connect the two nodes.
16. Click **Deploy**. 
17. Expand the message window beneath the flow and click the **Debug **icon. Verify that messages are displaying. 
    ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/gPJk6NsW3loIyEUdOJWuM_debugicon.png" size="80" width="885" height="365" caption="Debug node messages" position="center" showCaption="true"}