Ref: https://learn.cantrill.io/courses/2022818/lectures/45700383
YouTube: https://www.youtube.com/watch?v=6hPMdpk9qA4
Computer Networking
- Local networking, e.g. Ethernet cables → data traffic between devices in a local NW
- Routing → data traffic across interconnected NWs
- Some concepts
- Segmenting: chopping up data into smaller units
- Port: number assigned to a connection
- Session: awareness of a connection
- Applications: SW programs, may communicate over a NW
OSI 7-Layer Model - Overview
- 💡 OSI = Open Systems Interconnection
- Networking Stack = all 7 layers of the OSI-model
- Layers 1-3 = Media layers (deal with data moving from A→B)
- Layers 4-7 = Host layers (deal with segmenting and recoupling data)
- 💡 Every device that accesses a NW has (conceptually) this stack → Data moves from top layer down to physical layer, is transmitted over the physical medium, then moves up from physical layer up to top layer of receiver
- ‼️ OSI-Model is conceptual! Not all networking SW is implemented exactly like this!
- 💡 But makes NWing much easier to understand
- Mnemonics (choose one to help memorize the 7 layers in order)
- APSTNDP
- All People Seem To Need Data Processing
- PDNTSPA
- Please Do Not Take Sales Person Advice
- Please Do Not Transmit Secret Passwords Anywhere
- People Don’t Need To See People Always
- Another Diagram of the OSI 7-layer model, with extra details: