Access Control (CSMA/CD)
Network Fundamentals
Overview
CSMA/CD belongs to shared, half-duplex Ethernet. A station senses carrier, transmits when idle, detects a collision and retries after binary exponential backoff. Modern switched full-duplex Ethernet has separate transmit/receive paths and does not use collision detection.
Protocol stages
- 1Carrier sense
- 2Transmit
- 3Collision detection
- 4Jam / backoff
- 5Retry
Interactive exercise
Knowledge check
Two stations start transmitting on an old half-duplex shared segment at the same time. What happens next?
Educational model — not real hardware, traffic or official certification.