Industrial Protocols Flashcards
(6 cards)
MODBUS
1 - Serial Communication protocol published initially in 1979 by Modicon (Schneider Electric)
2 - Open Source Scada protocol.
3 - Widely used
4 - Variants exist
5 - Single Client/Server - RS232/485
6 - Client/Server Daisy Chain - RS485
Modbus Variants
1 - Modbus (serial) – Layers 1, 2 & 7 of OSI
2 - Modbus plus – Layers 1,2 and 7 of OSI
3 - Modbus TCP – Layers 1, 2, 3,4 & 7 of OSI
- Modbus TCP operated on Port 502
OPC
1 - Open Platform Communication.
2 - Initially, object linking and embedding (OLE) is used for process control.
3 - Communication Standard developed in 1996 by the Industrial Automation industry task force.
4 - Based on Microsoft OLE, COM, and DCOM technologies.
5 - Maintain the standard.
6 - Specifies the communication of real-time plant data between control devices from different manufacturers.
Why OPC Classic is difficult to firewall?
1 - OPC classic uses DCOM. DCOM is free to use any port between 1024 to 65535. It is “IT firewall unfriendly”.
Features of OPC UA
1 - Not using DCOM anymore just regular sockets using one single port.
2- Browsable namespace with folders, classes, Objects, and Methods.
3 - Designed from ground-up to be secure
OPC UA security Features
1 - Session Encryption – Messages are transmitted securely using 128 or 256-bit encryption levels.
2 - Message Signing – messages are received exactly as they were sent
3 - Sequenced packets – exposure to packet replay attack is eliminated by sequencing.
4 - Authentication – Each UA client and server is identified through x.509v3 certificates, providing control over which applications and systems are permitted to connect with each other.
5 - User Control – Applications can require users to authenticate (Credentials, certificates, etc.) and can further restrict or enhance their capabilities with access rights and address-space “views.”
6 - Auditing – activities by users/system are logged, providing access to the audit trail.
