Network Administration · Foundational Concepts
A conceptual framework that standardizes how network systems communicate — dividing complex network communication into seven distinct, interoperable layers.
Module 01 — Core Architecture
Click each layer to explore its role, protocols, PDU, hardware, and real-world responsibilities. Layers 7–5 are the upper (host) layers; layers 4–1 are the lower (media/transport) layers.
Module 02 — Data Flow
As data travels down the OSI stack on the sending device, each layer adds its own header (and sometimes trailer). The process is reversed — called de-encapsulation — on the receiving device.
Watch Encapsulation in Action
Step through the process to see how each layer wraps the data with its own header information.
Module 03 — Protocol Suite
Network administrators must know which protocols operate at which layers. Filter by layer group or browse all protocols below.
Module 04 — Model Comparison
While OSI is the conceptual standard used for teaching and troubleshooting, the TCP/IP model is what the internet actually runs on. Network admins must understand both and map between them.
| OSI Layer | TCP/IP Layer | Key Protocols | PDU | Admin Relevance |
|---|
Module 05 — Memory Technique
Network administrators use simple phrases to memorize the seven layers — both top-down (Application → Physical) and bottom-up (Physical → Application).
Module 06 — Knowledge Check
Answer questions covering OSI layer functions, protocols, PDUs, and troubleshooting scenarios — the kind of knowledge tested on CompTIA Network+ and CCNA exams.