Packet filter, application proxy, and stateful inspection are all recognized types or classes of firewalls in both IT and industrial control environments. A network monitor, on the other hand, is not considered a firewall but rather a tool for observing and analyzing network traffic. It does not provide firewall-like controls for blocking or allowing traffic.
Reference: ISA/IEC 62443-3-3:2013, Section 4.2.3.3 ("Types of firewalls"); ISA/IEC 62443-1-1:2007, Section 3.2.6.

The formula for risk in ISA/IEC 62443 is typically expressed as:
Risk = Threat × Vulnerability × Consequence
This means that risk is a product of the likelihood that a threat will exploit a vulnerability and the impact (consequence) if that event occurs. This formula is consistently used in both the general information security domain and explicitly referenced in the ISA/IEC 62443-3-2 standard in the context of IACS risk assessments.
Reference: ISA/IEC 62443-3-2:2020, Section 5.2 ("Risk is typically calculated as Threat × Vulnerability × Consequence"); ISA/IEC 62443-2-1:2009, Section 5.2.4.

According to the ISA/IEC 62443 Cybersecurity Fundamentals, the risk matrix is a tool used to assess the risk of a particular event. The risk matrix is divided into three categories: likelihood, consequence, and risk. The likelihood is the probability that an event will occur, the consequence is the impact that the event will have, and the risk is the combination of the two. In this case, the risk of a medium likelihood event with high consequence is a high risk, as shown by the red cell in the matrix. References:
ISA/IEC 62443 Cybersecurity Fundamentals
[ISA/IEC 62443 Cybersecurity Certificate Program]
[Cybersecurity Library]
[Using the ISA/IEC 62443 Standard to Secure Your Control Systems]

Authorization security policy is the primary factor that determines access privileges for user accounts. Authorization security policy is the function of specifying access rights or privileges to resources, which is related to general information security and computer security, and to access control in particular1.
Authorization security policy defines who can access what resources, under what conditions, and for what purposes. Authorization security policy should be aligned with the business objectives and security requirements of the organization, and should be enforced by appropriate mechanisms and controls. Authorization security policy should also be reviewed and updated regularly to reflect changes in the environment, threats, and risks2. Authorization security policy is an essential part of the ISA/IEC 62443 standard, which provides a framework for securing industrial automation and control systems (IACS). The standard defines four security levels (SL) that represent the degree of protection against threats, and specifies the security capabilities that should be implemented for each SL. The standard also provides guidance on how to conduct a security risk assessment, how to define security zones and conduits, and how to apply security policies and procedures to the IACS environment34 . References: https://bing.com/search?
q=authorization+security+policy
https://learn.microsoft.com/en-us/aspnet/core/security/authorization/policies?view=aspnetcore-7.0

Foundational Requirement 6 (FR 6), Timely Response to Events (TRE), as described in ISA/IEC 62443-3-3, requires that the system detect and respond to security-relevant events, including notifying the proper authority or personnel about security violations in a timely manner. This enables rapid incident response, containment, and recovery actions, all of which are critical to minimizing damage.
Reference: ISA/IEC 62443-3-3:2013, Section 4.3.3.6 (FR 6: Timely Response to Events).