MQTT
MQTT is a publish-subscribe messaging protocol that runs on top of TCP/IP. It was first developed to transmit data from field devices on remote locations over unreliable satellite links with limited bandwidth. This initial use case has shaped the protocol to offer a limited number of features and only adds a small overhead to the data to be transmitted. This resource constrained protocol has proved useful when pushing data (e.g. diagnostics) from devices to IT systems. All devices that produce or consume data are clients. The clients connect to a common broker device to either publish data, subscribe for data or both. The MQTT message flow is shown in the figure below.
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Data is tagged with a topic string. The topic is used as a unique identifier to route the publications to its subscribers when they are published by a certain device to the broker.
See also....
Network Configuration Object (04h) (Anybus Module Object)
MQTT Host Object (E2h) (Host Application Object)
Application Object (FFh), command Get_Data_Notification (13h) in Anybus CompactCom 40 Software Design Guide