What is DNP3?
DNP3 refers to Distributed Network Protocol and is a system of protocols used commonly by utility companies for electricity and water in their process automation systems. This system is designed to allow communication between SCADA devices and IED’s. SCADA refers to Site Control and Data Acquisition systems while IED’s are Intelligent Electronic Devices.
The DNP3 protocol was developed in 1993 by GE-Harris Canada to create some form of standard for communications between SCADA components and the electric grid. Prior to the development of this protocol, communication between SCADA devices and IED’s from different manufacturers were not possible. With IEC 60870-5, there is now a medium for communication for electronic devices that come from various manufacturers. This meant that all system components of a SCADA stem were now able to interact and communicate with each other, resulting to more efficiency and interoperability.
The DNP3 protocol is said to be a very efficient and robust in its networking and communications possibilities, especially when compared with older protocol versions. Not only does it feature multiplexing capabilities, it also allows for link control and data fragmentation. It also has error checking, prioritization systems, and layer 2 type of addressing services for common user data. This protocol also allows for time synchronization support with an RTU or Remote Terminal Unit. It even provides time stamping on data objects, so there will be enough data in reconstructing events in between polls, even if RTU polling is not constant.
But since this protocol was designed for implementation “on-site”, security features are not integrated on the system at first. But to address buyer concerns, these security features were integrated later and may be done through proprietary implementation. So with the security feature now integrated, the DNP3 protocol has proven to be a very efficient protocol for SCADA system devices and intelligent electronic devices.