AiVibe

Industrial IoT & Edge

MQTT

MQTT is a lightweight publish-subscribe messaging protocol in which clients exchange messages through a broker using hierarchical topics, widely used in IoT and IIoT for efficient, decoupled communication over TCP/IP.

In MQTT, clients connect to a broker and publish messages to topics, such as plant/line1/press3/temperature, while other clients subscribe to topics or wildcard patterns to receive them. Publishers and subscribers do not need to know about each other. The protocol has a small header and few packet types, supports three quality-of-service levels, retained messages that give new subscribers the last known value, and a last will message published if a client disconnects unexpectedly.

MQTT was created in 1999 by Andy Stanford-Clark of IBM and Arlen Nipper to monitor oil pipelines over unreliable satellite links. It became an OASIS standard with version 3.1.1, also published as ISO/IEC 20922, and MQTT 5 added features such as reason codes, user properties and shared subscriptions. In IIoT, it carries data from gateways and devices to SCADA, historians, unified namespaces and cloud IoT services, and the Sparkplug specification adds industrial conventions.

MQTT itself does not define payload formats, so systems must agree on encodings such as JSON or Sparkplug B. Security relies on TLS encryption, client authentication and topic-level authorisation configured in the broker, and brokers are critical infrastructure that need high availability. The registered ports are 1883 for unencrypted and 8883 for TLS connections, and unencrypted MQTT should not cross untrusted networks.

Key points

Where AiVibe comes in

AiAmbA IoT, AiVibe's edge protocol layer, lists MQTT among its supported protocols, with driver availability confirmed per installation.

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Related terms

Terms that refer to MQTT

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