CSMA/CD Collision Handling
CSMA/CD Collision Handling
- Collision Signal is generated by Physical layer.
- Jam signal (collision enforcement): To make sure that all stations involved in the collision will detect collision. A pattern of 32 bits.
- Collision backoff and retransmission method (Truncated Binary Exponential Backoff Algorithm, BEBA):
- n : number of collisions experienced (n <= 16)
- k : Min (n,10) -- Truncation
- r : Random delay time (unit: slot time) between 0 <= r < 2k
- Slot time = 51.2 us.
- Disadvantage of BEBA:
- Last-in-First-out effect: Stations with no or few collisions will have a better chance to transmit before stations that have waited longer.
Notes: