Ethernet

A technology that establishes a frame format and handles media access control, though the latter became less relevant with the introduction of more sophisticated switches.

Frame format

Each frame can encapsulate a 1500 byte payload. The maximum size of a frame can be 1518 byte.

Ethernet II:

1. Destenation Address
2. Source Address
3. Type
4. Data
5. CRC

CSMA/CD

This stands for Carrier Senese Multiple Access / Collision Detection and referes to the process where a host checks if the medium is already in use before sending a data packet. If two hosts try sending a data packet at the same timed, the first one to register the collision will send a jam signal, which triggers a backoff routine.