MQTT Endpoint Properties

topic (string, required)

Any valid topic name addressing a single data-point

Example: "path/of/endpoint"

qos (integer, enum)

Quality of service (QOS) level for this subscription at the external MQTT broker. Watch out: If the internal message forwarding should continue with the same non-zero QOS level, this must additionally be configured by specifiying the same qos value also in the general Endpoint properties (one level higher in the commissioning file), and in the subscribe and publish side of each involved Mapping, too.

This element must be one of the following enum values:

• 0

• 1

• 2

Default: 0

Example: 1

retain (boolean)

Whether the last message should be retained (last-value-cached) on the broker (default: false)

Default: false

Example: false

burstInterval (integer)

Interval in ms during which incoming data-point values are aggregated (default: 0 = no aggregation)

Default: 0

Example: 1000

nl (boolean)

Controls whether a message should be forwarded to a connection with a ClientID equal to the ClientID of the publishing connection

Default: true

rap (boolean)

Controls whether a message with the retain flag set to true maintains the flag when being forwarded

Default: false

rh (number, enum)

Controls whether retained messages are sent when subscription is established

This element must be one of the following enum values:

• 0

• 1

• 2

Default: 0

properties (object)

MQTT v5 specific properties

Properties of the properties object:

correlationData (string)

The Correlation Data is used by the sender of the Request Message to identify which request the Response Message is for when it is received

contentType (string)

String describing the content of the Application Message

messageExpiryInterval (number)

Lifetime in seconds of the Application Message

payloadFormatIndicator (boolean)

Indicates whether the payload is UTF-8 encoded or not

responseTopic (string)

String which is used as the Topic Name for a response message in a request/response context

subscriptionIdentifier (number)

Represents the identifier of the subscription

topicAlias (number)

A Topic Alias is an integer value that is used to identify the Topic instead of using the Topic Name. This reduces the size of the PUBLISH packet

userProperties (object)

Application specific key value pairs