The DNP3 or distributed network protocol is a communication protocol that is used to do the communication between the industrial devices. It is utilized to monitor several industrial data, DNP3 protocol is widely used in the SCADA network. This protocol is widely utilized by several electric and water utilities. It can do critical remote communication in a SCADA network. So the communication between several industrial devices can be easily carried out by utilizing this protocol. It is an open communication protocol and due to this, it is widely used in the industrial sector another reason for its popularity is because of its security features.
DNP3 is based on the object model and this would decrease the bit mapping of the data, which is done by other protocols. This is how DNP3 stands out from other protocols and there won’t be any huge disparity in the status monitoring or control paradigms as you can see in other protocols.
What are the major features of the DNP3 protocol?
- Master slave topology can be utilized
- Multiple masters can be utilized for the communication
- It is an open standard protocol due to this it is supported by several equipment manufacturers
- Remote communication is possible
- It can be utilized anywhere in the SCADA network, like in PLC or other components in the SCADA network
- It can access thousands of devices on a single link
How DNP3 communicates?
As we discussed earlier DNP3 is capable to do master-slave communication. DNP3 communication would be carried out between the masters that are centrally located and the distributed remotes. DNP3 has the feature that a single master can be utilized to do the communication between more than one field station through the Ethernet physical media. More than one master can be connected to single field stations. The Master can give the control commands to the field stations and this field station would provide proper information to the master. DNP3 utilizes three OSI layers to achieve proper communication and they are Datalink, Transport, and Application layer. All these features have made the DNP3 protocol suitable for the SCADA network.
The master would provide the proper interface between the human network and the monitoring system. A proper interface between the physical device and the master can be achieved with the help of the remote. The communication between the master and the remote is carried out by utilizing a library of common objects to transmit the data. DNP3 utilizes several function codes to exchange data between the control system and the field. Master would utilize some of these function codes to receive real-time information from the field. DNP3 has certain predefined objects and this would be useful to create any required object from the existing ones. These predefined objects make the DNP3 protocol suitable for SCADA communication.
What are the major threats that can be handled by the DNP3 communication protocol?
It can prevent spoofing, in the industrial network spoofing could take place by impersonating the user or the device it can be prevented. It can prevent the changing messages in transit, and DNP3 is capable to capture the proper message and retransmit it at the proper time. It would protect the private or secret messages in the transmission.
What are the advantages of having DNP3-based communication?
- Real-timecommunication is possible regarding plant and network operation
- Good quality and consistency in communication
- Data would be transmitted when it changes
- Data reporting is easily done and this would be useful to prevent many accidents in the plant
- Multiple master communication is possible so slaves can transmit data to more than one master
- PLC addressing is extended
- Large message transmission can be easily done
- PLC configuration can be remotely done
- Another advantage of utilizing the DNP3-based communication is that it can be used in media that could be subjected to noisy interferences
What are the disadvantages of the DNP3 communication protocol?
- Messages would be transmitted in clear text in the transmission media and due to this there is less message confidentiality because there is no encryption
- There is no feature to check the integrity of the message, so the errors in the message won’t be properly detected
- All the messages would be transmitted or communicated without proper authentication