Connectivity Framework
7: Connectivity Standards
For more details and to determine the suitability of CoAP for a specific set of system requirements, please refer to the assessment template( see chapter 6) in Annex E.
7.2.3 MQTT( FORMERLY MQ TELEMETRY TRANSPORT)
MQTT is an open connectivity transport standard, maintained by OASIS. It requires the TCP transport.
MQTT is generally used in the information domain( Figure 1-1). It targets device data collection. As the name indicates, the main purpose is telemetry or remote monitoring. Its goal is to collect data from many devices and transport that data to the IT infrastructure. It targets large networks of small devices that need to be monitored or controlled from the cloud.
MQTT implements a hub-and-spoke architecture. Typically, all the devices connect to a data concentrator server. The protocol generally works on top of TCP, which provides a simple, reliable stream. Since the IT infrastructure uses the data, the entire system is designed to transport data easily into enterprise technologies. MQTT has also been adapted for UDP in a separate protocol called MQTT-SN.
MQTT is suited for many-to-one data collection. It is not commonly used for device-to-device transfer or for one-to-many data distribution. MQTT is a simple protocol with few control options. Most applications don’ t need to be particularly fast; latency specifications are often measured in seconds.
MQTT targets applications such as monitoring an oil pipeline for leaks or vandalism, that require message feeds from thousands of sensors to be concentrated into a single location for analysis. When the system finds a problem, it can take action to correct that problem. Other applications for MQTT include power usage monitoring, lighting control and even intelligent gardening and agriculture. They share a need for collecting data from many sources and making them available to the IT infrastructure.
For more details and to determine the suitability of MQTT for a specific set of system requirements, please refer to the assessment template( see chapter 6) in Annex F.
7.3 FIELDBUS TECHNOLOGIES
Fieldbus ecosystems are well developed and extensively deployed in many industries. Most originated with special-purpose hardware and protocols. Well-known fieldbuses include Profibus( Profinet), EtherNet / IP, Modbus & Modbus / TCP, HART & HART wireless, and the Foundation Fieldbus family. Each has developed extensive ecosystems of vendors and customers.
The industrial internet will bring benefits of common connectivity standards based on the Internet Protocol( IP). This is a significant transition; today’ s industrial ecosystems use a wide variety of communication and connectivity standards.
Interoperability between fieldbus variants is, in general, poor. Many of these have been adopting IP-based networking models and Ethernet transports. This is improving technical interoperability. Syntactic or higher levels of interoperability are only available with special point solutions.
IIC: PUB: G5: V1.0: PB: 20170228- 53-