Data Link Layer

Unit exchange: Frame

Divides Packet into frames, add headers and trailers.

Pasted image 20240425110739.png

Introduce MAC Address.

Pasted image 20240505152655.png

Preamble: where the frame start
Destination MAC address: which devices to broadcast
Source MAC address: normally the current device address
ET: Which protocol of Layer 3 (Network Layer) is being used to process this frame
Payload: data that the frame carry from source to destination
FCS: trailer for error correction check

A Switch is a layer 2 device