Network Models and IP Addressing
Key Takeaways
Subdomain 4.1 names the OSI model, the TCP/IP model, IPv4, and IPv6.
Each model describes how network functions are layered; an IP address identifies a host on a network.
IPv4 and IPv6 are the two IP versions named in the outline.
Source: ISC2 CC Exam Outline effective September 1, 2026, subdomain 4.1, checked 2026-10-22.
The Models
Subdomain 4.1, Understand network security, names the Open Systems Interconnection (OSI) model, the Transmission Control Protocol/Internet Protocol (TCP/IP) model, Internet Protocol version 4 (IPv4), and Internet Protocol version 6 (IPv6). The models describe how functions are layered. Use them to place a symptom at a layer when a scenario describes one.
Source: ISC2 CC Exam Outline effective September 1, 2026 (v01/2026), subdomain 4.1, https://www.isc2.org/certifications/cc/cc-certification-exam-outline, checked 2026-10-22.
Addresses
IPv4 and IPv6 are the two IP versions in the outline. A scenario that names an address should be read by version and by whether it identifies a host on the local network or on the wider network. The outline does not require subnet calculation, so focus on the concepts.
What the Outline Lists for This Section
The outline names these items. Be able to explain each one in plain language and apply it to a short scenario:
- 4.1: Concepts (OSI model, TCP/IP model, IPv4, IPv6, VPN)
- 4.1: Firewalls (e.g., ports, applications)
- 4.1: Wireless (e.g., Wi-Fi, Bluetooth)
- 4.1: Embedded systems (e.g., Industrial Control System), Internet of Things (IoT)
Common Traps
A common trap is confusing a model with a protocol or device. The OSI and TCP/IP models describe layers; firewalls, wireless, and IP versions are the concepts the outline names.
Which two IP versions does subdomain 4.1 name?
IPv4 and IPv6
IPv2 and IPv5
TCP and UDP
OSI and TCP/IP
Sections you finish are checked off in the contents.