Overview of the DNP3 Protocol
The development of DNP3 was a comprehensive effort to achieve open,
standards-based Interoperability between substation computers, RTUs, IEDs
(Intelligent Electronic Devices) and master stations (except inter-master
station communications) for the electric utility industry. Also important was
the time frame; the need for a solution to meet today's requirements. As
ambitious an undertaking as this was, we reached this objective. And since the
inception of DNP, the protocol has also become widely utilized in adjacent
industries such as water / waste water, transportation and the oil and gas
industry.
DNP3 is based on the standards of the International Electrotechnical
Commission (IEC) Technical Committee 57, Working Group 03 who have been working
on an OSI 3 layer "Enhanced Performance Architecture" (EPA) protocol standard
for telecontrol applications. DNP3 has been designed to be as close to
compliant as possible to the standards as they existed at time of development
with the addition of functionality not identified in Europe but needed for
current and future North American applications (e.g. limited transport layer
functions to support 2K block transfers for IEDs, RF and fiber support). DNP3
has been selected as a Recommended Practice by the IEEE C.2 Task Force; RTU to
IED Communications Protocol.
DNP3 was developed by Harris, Distributed Automation Products. In November
1993, responsibility for defining further DNP3 specifications and ownership of
the DNP3 specifications was turned over to the DNP3 Users Group, a group
composed of utilities and vendors who are utilizing the protocol.
DNP3 is an open and public protocol. In order to ensure interoperability,
longevity and upgradeability of, protocol the DNP3 Users Group has taken
ownership of the protocol and assumes responsibility for its evolution. The
DNP3 Users Group Technical Committee evaluates suggested modifications or
additions to the protocol and then amends the protocol description as directed
by the Users Group members.
Complete, comprehensive documentation of the protocol is available to the
public. The 'Basic 8' documents
detail the protocol specifications,
as well as what is required at the different sublevels, how to implement
secure authentication, how to create XML device profiles, and conformance test procedures.
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