Agenda 05/21/

Transcription

1 DNP3 Protocol AGA/GTI SCADA Security Meeting August 19, 2002 / Washington, DC Presented By: Mr. Jim Coats, President Triangle MicroWorks, Inc. Raleigh, North Carolina 05/21/97 1

2 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/97 2 5

3 Credentials Vice President of DNP3 Users Group Lead US member for IEC TC 57 WG 03 Past member of DNP3 Technical Committee Eight years experience developing/supporting products for DNP3 through Triangle MicroWorks Source Code Libraries Test Harness OPC Server and Protocol Gateway 05/21/97 3

4 Purpose of a Communication Protocol Replicate database from one device to another 05/21/97 4

5 Objectives of a Communication Protocol Minimize protocol overhead to avoid extra cost of high bandwidth media Ensure reliable data transfer (CRC or checksum) Provide necessary features such as time stamps or freeze operations Provide data quality flags Since September 11 th, prevent unauthorized use or monitoring of data 05/21/97 5

6 Report by Exception (RBE) Protocols like Modbus transmit all the data each time a device is polled RBE only transmits changes, so fewer data points Timestamps allow creation of Sequence of Events (SOE) log on Master Station RBE can be polled or unsolicited 05/21/97 6

7 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/97 7 5

8 History of DNP3 Distributed Network Protocol Developed by GE (previously Harris, Westronics) Based on early parts of IEC Turned over to Users Group in 1993 DNP and IEC have been specified in IEEE P1379 Recommended Practice for Data Communications Between Intelligent Electronic Devices and Remote Terminal Unit 05/21/97 8 6

9 Newton-Evans Research 1. DNP3 protocol is now the most popular protocol in use by global electric utilities. 2. Also the DNP LAN implementation led the way for planned use by both North American and international utilities. Taken from The World Market for Substation Automation and Integration Programs in Electric Utilities: August /21/97 9

10 DNP Today Vendor Products >100 vendors, +250 DNP products and services Utilities/Industrials used by >300 utilities and industrials worldwide Countries used in over 32 countries Total Industry $250 Million / year of DNP products and services Industries Electric, Oil & Gas, Water and Industrial 05/21/97 10

11 DNP3 Topology Master Station Relay Engineer Terminal RS-232 Serial Substation RTU Modem Modem Phone Line Relay Relay Relay 05/21/97 11

12 DNP3 Users Group Basic membership cost is $200 per year Members from: Vendors - System Integrators Utilities - Software developers Volunteers staff the following committees to manage the protocol: Steering Committee Technical Committee Conformance Committee Marketing Committee Liaison Liaison Committee 05/21/97 12

13 DNP3 Technical Committee Technical Committee Chairman: Andrew West, Invensys (Foxboro Australia) Secretary: Grant Gilchrist, GE Energy Systems Meets via conference call once a month Meets in person once per year Daily interaction by Maillist Protocol evolution tracked by year i.e. DNP /21/97 13

14 DNP3 Technical Committee Technical Committee = Managed Evolution Define new features, then update documentation and test procedures Clarify existing documentation when different interpretations exist A Controlled Standard, avoids multiple Vendor specific variations of the protocol 05/21/97 14

15 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/

16 Utility Benefits Select products based on performance, not protocol Reduced training costs to learn only one protocol. Greater availability of support services Able to participate directly in evolution of protocol via participation in User Group Evolving to continue to meet market needs 05/21/97 16

17 Vendor Benefits Avoid NRE charges to add/update new protocols for each new project Well documented, proven protocol Participate in development of common protocol instead of company protocol Large Utility Client Base Greater availability of 3 rd party support services and Test Tools 05/21/97 17

18 Ensure Interoperability DNP3 UG Technical Committee DNP3 Conformance Test Procedures Independent Conformance Testing Company Certificate of Conformance Equipment Vendor Products * The Utility will specify in all RFQs that a Certificate of Conformance is required Utility * 05/21/97 18

19 Interoperability Documents The following documents are used to interface DNP3 Devices: DNP3 Device Profile Document DNP3 Implementation Table DNP3 Points List 05/21/97 19

20 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/

21 Core Specification Documents DNP V3.0 Basic 4 Document Set DNP V3.0 Data Link Layer DNP V3.0 Transport Functions DNP V3.0 Application Layer Specification DNP V3.0 Data Object Library DNP V3.0 Subset Definitions Document (Level 1, 2, & 3) Conformance Test Procedures Technical Bulletins All of these documents are available for download by DNP User Group members from the DNP web site. 05/21/

22 OSI 7-Layer Model Compliance DNP3 uses a simplified 3 layer version of the OSI 7 Layer model called EPA (Enhanced Performance Architecture) 7 - Application 6 - Presentation 5 - Session 4 -Transport 3 - Network 2 - Link 1 - Physical DNP adds a Transport layer to permit messages larger than a data link frame 05/21/

23 DNP Message Buildup Application message = unlimited size Transport fragment = 2048 bytes (max) Data Link frame = 292 bytes (max) Physical byte = 8 bits Receive goes up the stack, transmit goes down the stack. Size of data transmitted/received may fit into one data link frame. So do not require multi-frame fragments or multi-fragment messages. A single DNP application function is usually sent as a single application layer message, which can consist of many data link frames. 05/21/

24 Balanced Link Layer Master [P] Request Message (User Data, Confirm Expected) Slave (Acknowledgment) [S] Response Message (User Data, Confirm Expected) [P] [S] (Acknowledgment) [P] = Primary Frame [S] = Secondary Frame 05/21/

25 Balanced Link Layer At the link layer, all devices are equal Collision avoidance by one of the following: Full duplex point to point connection (RS232 or four wire RS485) Designated master polls rest of slaves on network Physical layer (CSMA/CD) 05/21/

26 Device Addressing DNP3 Link contains both Source and Destination address Both are always 16 bits Application layer does not contain address The provision of a source and destination address simplifies message routing in certain network topologies. A DNP link address is a device s logical address. A single physical device is permitted to respond to multiple addresses (contain multiple logical devices). Each device will appear to the master as a completely separate device. 05/21/

27 Application Layer Features: Time Synchronization Time-stamped events Freeze/Clear Counters Select before operate Polled report by exception Unsolicited Responses Data groups/classes 05/21/

28 Application Layer 05/21/

29 Means of Retrieving Data Master/Slave Network Polled Static Polled Report by Exception Point to Point (or MAC) Unsolicited Report by Exception Quiescent Operation Master/Slave Network - Slaves do not speak unless spoken to MAC = Media Access Control - CSMA/CD Polled Static - Class 0 or specific data request message sent to each device Polled Report by Exception - Class 1, 2, 3 request message sent to each device with occasional integrity (class 0) data poll. Unsolicited Report by Exception - most communication is unsolicited, but the Master occasionally sends integrity polls for class 0 Data to verify its database. Quiescent Operation - master never polls slave Last two modes are useful when communication medium is dial-up modem. 05/21/

30 DNP3 LAN-WAN Features Puts entire DNP3 Stack on top of TCP/IP Became part of Standard in Nov 1998 Makes use of widely available and inexpensive third-party products Specification also allows for use of UDP (connectionless) service 05/21/97 30

31 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/

32 What s Next for DNP3? Major revision to DNP3 Basic 4 Document set Address Security Issues DNP3 Master Conformance Test Procedures Double-Bit Status Output Event Objects Self Description XML file approach Define new protocol functionality 05/21/97 32

33 Security in DNP3 Threat until recently was noise on the wire CRC bytes were actually called Security bytes in many protocol analyzers Most security provided by Physical isolation of network and lack of common knowledge about systems Since moving toward more network solutions, security has now become a priority 05/21/97 33

34 DNP3 User Group Plan for Security Form a Working Group within the DNP3 Technical Committee Will hire consultant to write Technical Bulletins Discussion so far has been on 2 solutions: Encryption/decryption device placed at each end of the wire Security Enhancements directly in the protocol 05/21/97 34

35 Self Description Using XML XML is an excellent standard that is naturally suited for these types of applications Primary benefit is Plug & Play, for faster and more accurate device install or replacement One data file contains information normally found in the DNP3 interoperability documents: Device Profile Document Implementation Table Points List, including scaling and units information DNP3 Solution will build on existing models developed by IEC TC 57 Working Group 14 and/or UCA2 Online or offline transfer of XML file to DNP3 Master 05/21/97 35

36 Offline Option DNP3 Communicatons DNP3 IED DNP3 Master DNP3 Slave DNP3 XML Device Profile 05/21/97 36

37 Benefits of using XML Files Offline Can be applied to existing devices placed in operation years ago Does not interfere with real time communications Good for small devices that may not support DNP3 file transfer Requires no changes to DNP3 Embedded code All XML files can be stored in centralized network location 05/21/97 37

38 Online Option DNP3 XML Device Profile DNP3 File Transfer during first startup sequence DNP3 Communicatons DNP3 Slave DNP3 Master DNP3 XML Device Profile Transfer to device during configuration IED Config Software 05/21/97 38

39 Benefits of using XML Files Online XML file is contained in device, always know where to find it Requires no changes to DNP3 Embedded code if already supports File Transfer Nominal affect on real time communications IED only transferring a file, does not need to know details of file or XML Can evolve without affecting Embedded code 05/21/97 39

40 Agenda Purpose of a Communication Protocol History of DNP3 Benefits of Industry Standard Protocols Overview of Protocol Features What s Next for DNP3? Demonstration of Test Harness 05/21/

41 Test Harness Demonstration Manual Commands Periodic Commands Toggle binary input to create unsolicited response TCL/TK Script for conformance testing A full 21-day evaluation of the Test Harness may be downloaded from 05/21/97 41

42 Summary DNP3 is: Well established in the Electrical Utiltiy Industry Has an active users group that is eager to enhance the protocol to meet new requirements 05/21/

43 DNP3 Users Group Web site All protocol documentation and meeting minutes posted on web site List of equipment supporting the protocol Join DNP3 maillist Next General meeting - February 2003 in Las Vegas 05/21/

44 More Information on DNP3 IEEE P SCADA Mailing List - Contact me, Jim Coats at: jcoats@trianglemicroworks.com (919) /21/