Developing Security, Privacy, and Cybersecurity Supply Chain Risk Management Plans for Systems
Jeremy Miller2, Julie Snyder > Environment of Operation Diagrams

Environment of Operation Diagrams

Discussion: Provide visual representations of key internal boundaries, critical
components, subsystems, primary and secondary data stores, virtual components,
information exchanges, and services from third-party providers to demonstrate how
resilience and redundancy are addressed in the system architecture. Supporting
topology narratives may be included.
Diagrams may identify the usage of API implementations as part of the identification of
external system services as well as connection points and data flow for information
exchanges.
When developing or generating diagrams, certain system architecture information (e.g.,
IP addresses, network routing and access rules) may be redacted commensurate with
organizational system data protection requirements. Additional artifacts associated with
the diagram may detail information about the architecture, such as IP subnets, MAC
addresses, and relevant ports that support communication for key services.
• System/Subsystem Diagrams
Identify the physical and logical locations of active system components in the
authorization boundary inventory. Components are identified based on their roles in
the system, such as application interfaces, information data stores, or development,
test, and production environments. Diagrams account for all system components,
whether they are located on premises, hosted by an external system, virtualized on
system host devices, physically or logically isolated within the authorization
boundary, or physically or virtually hosted by third-party service providers.
Automation may be used to link the components represented in the diagram to the
inventory source data.
Physical and environmental protections are identified, including physical entry
points and the locations of key environmental control systems (e.g., climate control,
fire control, water control and detection) components, such as sensors and shut-off
valves.
• System/Network Architecture Diagrams
Illustrate the physical and logical boundaries for communication between system
components, including:
o Technologies used to define the authorization boundary and to enable
communication between components and services within the boundary or from
third-party providers
o Data routing and traffic controls, including monitoring for suspicious network
activity
o Communication routes for specialized components (e.g., operational technology,
Internet of Things)
o Components involved in the physical and logical protection of other components
o Components that are physically or logically isolated (e.g., air-gapped)
• Data Flow Diagrams
Identify the direction of data exchanges and the components that receive and
transmit data, including:
o Data types (e.g., privacy, CUI) and associated security impact levels
o Where data is created, processed, and delivered (e.g., database servers,
application servers, storage networks, replication services)
o Where data enters and exits key internal boundaries, including any data loss
protection mechanisms and flow control mechanisms based on data labels or
data classification
o The flow of information that results from information exchanges with external
organization systems, including any data movement constraints due to laws,
regulations, policies, or agreement limitations
Related plan elements: System Type, System Information Types, Authorization
Boundary Description, System Component Inventory