--- title: MQTT - System Protobuf SSL slug: manufacturing-connect-edge/mqtt-system-protobuf-ssl docTags: createdAt: 2023-12-01T19:35:37.850Z --- ## Overview MQTT - System Protobuf SSL integration enables an Edge System to connect with a System Protobuf broker using SSL authentication. ## Supported Versions Compatible with MQTT Protocol version 3.1.0 and MQTT Protocol version 3.1.1 ## Supported Communication - Outbound (Publish data from Edge to MQTT Broker) - Yes - Inbound (Subscribe data from MQTT Broker to Edge) - Yes ## Configurations | **Variable** | **Detail** | **Required** | | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------ | | Name | Enter a name for the connector | Yes | | Hostname | IP Address or Server FQDN of MQTT broker (Must be reachable from the Edge system) | Yes | | Port | MQTT broker port | No | | CA certificate | CA Certificate for SSL connection | No | | Client id | Unique client identity. If left blank, a default value is auto-generated. | Yes | | Username | User name | Yes | | Password | User password | Yes | | 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.
You can publish several messages simultaneously. When you publish, a larger value allows more throughput but may lead to packages losing messages despite assigning QoS=1.
**Note**: the QoS option depends upon the server configuration. | No | | Parallel publish count | For example, Mosquitto has the following options:
* max\_queued\_messages (100 by default) * max\_queued\_bytes (0 by default) According to the Mosquitto documentation, once this limit has been reached, subsequent messages are silently dropped. You can modify the server configuration or set this value in accordance with the server option. | Yes | | Integration topic | Default topic for publishing or subscribing | Yes | | Throttling limit | Set a limit on the number of outbound messages per second. If sending data to a server that has restrictions on the rate of incoming messages, this ensures that no messages are lost. | No | | Persistent storage | If enabled, messages in the outbound queue are stored on disk. If there are interruptions in connection or power loss, messages will be retained and eventually sent when the connection is restored. | No | | Queue mode | Select the sequence of data transfer: FIFO or LIFO. Selecting FIFO (First In First Out) will send the earliest message first. Selecting LIFO (Last In First Out) will send the latest message first. | No | ## Compatibility Validation This information is just for reference. More products and versions may be supported provided they are compatible with the supported version as mentioned above. | **Product** | **Version** | **Date** | | ------------------------ | ----------- | ------------ | | Mosquitto Message Broker | 1.x | Nov 14, 2019 | | HiveMQ | 2.x | Nov 14, 2019 |