MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport. It is useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium.
In computer networking, a transport layer provides end-to-end or host-to-host communication services for applications within a layered architecture of network components and protocols. The transport layer provides services such as connection-oriented data stream support, reliability, flow control, and multiplexing.
Mosquitto is an open source message broker that implements the MQTT (MQ Telemetry Transport) protocol v3.1.
The User Datagram Protocol ( UDP) is one of the core members of the Internet protocol suite. The protocol was designed by David P. Reed in 1980 and formally defined in RFC 768. UDP uses a simple connectionless transmission model with a minimum of protocol mechanism.
OpenDDS is an open source C++ implementation of the Object Management Group (OMG) Data Distribution Service (DDS). OpenDDS also supports Java bindings through JNI and can be included with JBoss (ESB) frameworks by means of a JMS wrapper. OpenDDS leverages the ADAPTIVE Communication Environment (ACE) to provide a cross platform environment.