ISA/IEC 62443 Cybersecurity Fundamentals Specialist — Question 21

Which layer specifies the rules for Modbus Application Protoco1 (MBAP)?

Answer options

• A. Data link layer
• B. Session layer
• C. Presentation layer
• D. Application layer

Correct answer: D

Explanation

The Application layer is responsible for defining the rules of protocols like Modbus Application Protocol (MBAP), which deals with data exchange between applications. The Data link, Session, and Presentation layers serve different roles in the OSI model, focusing on data transmission, session management, and data formatting, respectively, and do not define application protocol rules.