Random Access Protocols - Variations
no carrier sensing - cannot see if line is in use
- transmit any time
- detect collisions via traditional error detection schemes (eg Nacks, timeouts)
- eg, ALOHA, SLOTTED ALOHA
carrier sense multiple access - CSMA
- sense if channel is busy, send if idle
- collisions if 2 stations send at same time
CSMA / CD: with Collision Detection
- sense if channel is busy or a collision occurs
- stops sending if a collision is noticed
- eg, IEEE 802.3