Continue your lesson
Follow traffic from the endpoint through each device, protocol, and service in the path.
Block 1 of 1Compare Physical layer · Data link layer · Network layer · Transport layer
Current · 15 min
Compare Physical layer · Data link layer · Network layer · Transport layer
Optional concept notes
Physical layer
Carries raw bits through signaling media, connectors, and transceivers.
Data link layer
Moves local frames using MAC addresses and switching.
Network layer
Routes packets between networks using logical addresses.
Transport layer
Uses ports for application delivery; TCP adds reliability, sequencing, and flow control.
Complete one provider lesson, then answer four related questions. That is enough for today; more practice is optional.
Your lesson stays open here while the provider opens in another tab. Choose one source; the notes above are optional.
Practice the reasoning here
Sketch a small network or packet path. Predict the expected state, introduce one fault, and identify the observation that isolates it.
- State the expected result before changing or testing anything.
- Name the observation, command, log, or report that would confirm it.
- Explain why the closest alternative does not fit the same requirement.
Check the whole objective
This unlocks objective 1.1 for recall. The latest checkpoint needs 70% or higher; a lower result puts the lesson back near the front of your timeline.