CSMA

A Medium Access Control Layer method used to manage how devices share a Network Medium, i.e. in the same Collision Domain

Carrier Sense

Listen to the medium. If it’s idle then transmit.

Collision Detection

CSMA/CD Used in wired Ethernet LAN Networks Manages Collisions after they occur, i.e. collision resolution

1. If the carrier sense doesn’t match the current transmission, that indicates that there is a collision.
2. When there is a collision, abort the transmission and then send a jamming signal to ensure other stations know there’s a collision.
3. Wait for a random length delay before attempting to retransmit

Collision Avoidance

CSMA/CA Used in WLAN Networks Prevents collisions before they occur

1. Optional Handshake.
2. Send frame, await ACK before sending next.
3. If collision, wait for a random length delay before attempting to retransmit