Pairing OPC UA with a Good IIoT Protocol, a leading online publisher of automation-related content, recently ran an article on the value of pairing OPC UA with a good IIoT protocol like DHTP. The article discusses how OPC UA was initially expected to serve as an IIoT protocol, but more recently the trend seems to be towards using OPC UA at the plant level only. Other protocols, such as MQTT and AMQP are being offered as candidates for connecting outside the plant, but they are not ideally suited to IIoT. This article explains why, and introduces 9 criteria for good IIoT data communication.