Configuration

Enabled

If true, the application will attempt to connect to the configured MQTT brokers. When false, the application will stay idle, and no connections will be made.

Host ID

A unique identifier for this Sparkplug Host Application within its configured group.

This Host ID is used for STATE notifications and is a key part of the MQTT topic namespace.

Important:

• The Host ID must be unique among all other Sparkplug Host IDs in the infrastructure.

• As part of the MQTT topic, the Host ID cannot contain reserved characters such as + , / , or # .

Reorder Timeout

Time in milliseconds to wait for missing sequence numbers before reordering messages. In the Sparkplug specification, messages from an Edge node are expected to arrive in order based on their sequence number. If the host receives a message out of order, it will hold the newer message in a buffer,

waiting for the expected message to arrive. If this timeout expires before the missing message is received, the host will request a new birth sequence to the Edge node.

The default value is 5000 ms.

Rebirh Debounce Delay

Time in milliseconds to wait before sending another rebirth request to an Edge node to avoid unnecessary rebirth storms.

The default value is 5000 ms.

Compression

Compression algorithm used for Sparkplug payloads sent to the EdgeNodes:

• None: No compression is applied to the message payload.

• Gzip: Messages are compressed using the Gzip algorithm.

• Deflate: Messages are compressed using the Deflate algorithm.

Enabled

Enables or disables this specific broker connection.

The Sparkplug Host Application can connect to an MQTT broker cluster for redundancy. When enabled, this

broker will be used. When disabled, this connection will not be used.

Protocol

Protocol used to connect to the MQTT broker.

• MQTT: Uses a standard, unencrypted connection.

• MQTTS: Uses an encrypted connection with TLS (Transport Layer Security) for enhanced security.

Broker URL

Specifies the URL or IP address of the MQTT broker to connect to. The protocol prefix (e.g., mqtt:// or

mqtts:// ) should not be included here.

The Sparkplug Host Application can connect to an MQTT broker cluster for redundancy.

Examples:

Good: localhost or test.mosquitto.org
Bad: mqtt://localhost or mqtts://test.mosquitto.org

Port

The network port number of the MQTT broker. The standard ports are 1883 for an unencrypted MQTT connection and 8883 for an encrypted MQTTS connection.

The valid range is 1 to 65535.

Client ID

A unique identifier for this client's connection to the MQTT broker. The broker uses this ID to maintain the client's state, including its subscriptions and unacknowledged messages. A unique, random client ID is

generated automatically, but you can also define your own.

Warning:

If two clients attempt to connect with the same client ID, the broker will disconnect the first client. Each client must have a unique ID to prevent connection instability.

Authentication mode

Specifies the type of authentication used to connect to the MQTT broker.

• None: No authentication is required by the broker.

• Password: Authenticates with the broker using a username and password.

• Certificate: Authenticates with the broker using a digital certificate. This requires a certificate and a private key file to be configured.

• Password - Certificate: Authenticates with the broker using both a username and password, as well as a digital certificate and private key. This is the most secure authentication method.

Username

The username for client authentication.

Password

The password for client authentication.

Certificates

The client's public certificate file, used for authentication when Certificate or Password - Certificate mode is selected.

The file must be in PEM format. This certificate is sent to the broker to prove the client's identity.

Private key

The client's private key file, used for authentication when Certificate or Password - Certificate mode is selected.

The file must be in PEM format. This key works with the public certificate to securely establish the client's identity and encrypt communication.

CA certificate

The Certificate Authority (CA) certificate file in PEM format. This certificate is used by the client to verify that the MQTT broker's certificate is valid and signed by a trusted authority when connecting over TLS.

This is an optional setting:

• Not required if the broker uses a publicly trusted certificate (e.g., signed by a well-known CA).

• Required when the broker uses a self-signed certificate or a certificate signed by a private CA.