lOMoAR cPSD| 63316909
•
WGU D315 Network and Security Foundations
Study Guide: Key Concepts and Practices | New
Update 2026/27 | Graded A
D315 - Network and Security Foundations - Study Guide
1. Introduction to Networking Concepts
1.1 Networking Components
Networks connect devices—enabling communication, collaboration, entertainment, and access
to services.
• End Devices: Computers, smartphones, printers, and servers use the network to
communicate.
• Networking Devices:
• Switch: Forwards data within a LAN using MAC addresses.
• Router: Directs traffic between networks using IP addresses.
• Firewall: Filters traffic based on rules; can be hardware or software.
• Access Point: Connects wireless devices to wired networks.
• Range Extender: Expands wireless reach.
• Modem: Connects local network to the ISP, translating signals.
Network Services & Applications: DHCP (automatic IP assignment), DNS (name-to-IP
resolution), file sharing, authentication.
Practice:
What’s the difference between an end device and a networking device? Can
you name two examples of each?
1.2 Network Types
• PAN (Personal Area Network): Short-range, connects personal devices
(Bluetooth, wearables).
, lOMoAR cPSD| 63316909
•
• LAN (Local Area Network): Covers small areas like homes/offices. WLAN (Wi-
Fi): Wireless variant.
• CAN (Campus Area Network): Connects multiple LANs across a campus.
• MAN (Metropolitan Area Network): Spans a city/town.
WAN (Wide Area Network): Connects LANs over large distances (the internet is a WAN).
• SAN (Storage Area Network): Dedicated to storage devices/data transfer.
Review:
Describe a scenario for each type. Where would a MAN be found?
1.3 Network Topologies
• Bus: Single cable; simple but single point of failure.
• Ring: Devices in a loop; takes data in one direction; also has a single point of
failure.
• Star: Devices connect to a central switch or hub; most common now—
scalable and fault-tolerant.
• Mesh: Every device connects to every other; used for redundancy in larger
networks.
• Hybrid: Mixes styles for flexibility.
Wireless Topologies:
• Infrastructure: Devices connect through a central access point.
• Ad Hoc: Devices connect directly to each other.
Quiz:
Why is the star topology most common in modern networks?
1.4 Network Architecture
• Client-Server: Central server provides resources (web, file, print) to clients.
• Peer-to-Peer: Devices share resources directly, no central server.
• Centralized: Single location manages all configs/resources.
•
WGU D315 Network and Security Foundations
Study Guide: Key Concepts and Practices | New
Update 2026/27 | Graded A
D315 - Network and Security Foundations - Study Guide
1. Introduction to Networking Concepts
1.1 Networking Components
Networks connect devices—enabling communication, collaboration, entertainment, and access
to services.
• End Devices: Computers, smartphones, printers, and servers use the network to
communicate.
• Networking Devices:
• Switch: Forwards data within a LAN using MAC addresses.
• Router: Directs traffic between networks using IP addresses.
• Firewall: Filters traffic based on rules; can be hardware or software.
• Access Point: Connects wireless devices to wired networks.
• Range Extender: Expands wireless reach.
• Modem: Connects local network to the ISP, translating signals.
Network Services & Applications: DHCP (automatic IP assignment), DNS (name-to-IP
resolution), file sharing, authentication.
Practice:
What’s the difference between an end device and a networking device? Can
you name two examples of each?
1.2 Network Types
• PAN (Personal Area Network): Short-range, connects personal devices
(Bluetooth, wearables).
, lOMoAR cPSD| 63316909
•
• LAN (Local Area Network): Covers small areas like homes/offices. WLAN (Wi-
Fi): Wireless variant.
• CAN (Campus Area Network): Connects multiple LANs across a campus.
• MAN (Metropolitan Area Network): Spans a city/town.
WAN (Wide Area Network): Connects LANs over large distances (the internet is a WAN).
• SAN (Storage Area Network): Dedicated to storage devices/data transfer.
Review:
Describe a scenario for each type. Where would a MAN be found?
1.3 Network Topologies
• Bus: Single cable; simple but single point of failure.
• Ring: Devices in a loop; takes data in one direction; also has a single point of
failure.
• Star: Devices connect to a central switch or hub; most common now—
scalable and fault-tolerant.
• Mesh: Every device connects to every other; used for redundancy in larger
networks.
• Hybrid: Mixes styles for flexibility.
Wireless Topologies:
• Infrastructure: Devices connect through a central access point.
• Ad Hoc: Devices connect directly to each other.
Quiz:
Why is the star topology most common in modern networks?
1.4 Network Architecture
• Client-Server: Central server provides resources (web, file, print) to clients.
• Peer-to-Peer: Devices share resources directly, no central server.
• Centralized: Single location manages all configs/resources.
