Network layer 3 notes
a dev diary update
frames
mac address for each device
address specific piece of hardware
network interface controller
mac address should be globally unique
Purely layer 1 bad because there's no media access control
Corrupts both.
Controlled
Part 2 Data layer
Now we are layer 2, frame 1
[[architecture-1-data-link.excalidraw]]
there's now a stream of "frames" where we're constantly telling physical layer what to do
ENCAPSULATION
Putting data inside a frame.
Payloads EXTRACTED from the frame ![[architecture-1-data-link.excalidraw]]
OSI MODEL REVIEW
Data link layer only knows connection between the TWO MAC ADDRESSES
CD == Collision Detection
Same concept as detecting race conditions probably...??a
Mac address table
| MAC ADDRESS | PORT | | --------------- | ---- | | e93eu812u9e8u12 | 1234 | | 1981e2ue9812ue | 1235 | | 1902ei9102ie | 1236 | | e01982ue8192eu | 1237 | | | |
- Identifiable devices
- Media access control
- Collision DETECTION
- Unicast
- Broadcast 1:n (1 to all)
- Switches - like Hubs with "super powers"
Device to device communication
So ![[data-link-layer 2024-12-20 19.06.30.excalidraw]]
I'll start with what the situation was at the company and go from there. So there's a problem that happens when layer 2 is across the united states. We need to follow the same protocols or have a really long ethernet chord.
I need to connect the two layers together. I need to be able to know how to transmit across the country in lowest cost possible.
Engineers (over decades) shall create internet (inter -connected network) to create abstraction layers?
now can have access to the data layer 2
![[data-link-layer 2024-12-20 19.13.20.excalidraw]]