Carrier Sense Networks

• All stations can sense the electrical carrier before sending.
• This is possible because of the use of high speed cables over short distances.

We will be concerned with carrier-sense multiple-access (CSMA) protocols.

Factors Affecting CSMA LANs

1. All frames are of constant (or small, bounded) length.
2. There are no transmission errors, other than those of collisions.
3. There is no capture effect.
4. The random delay after a collision is uniformly distributed and large compared to the frames' transmission time.
5. Frame generation attempts (OLD and NEW) form a Poisson process with mean G frames per time.
6. A station may not transmit and receive simultaneously.
7. Each station can sense the transmission of other stations.
8. Sensing of the channel state can be performed at the same time as transmitting.
9. The propagation delay is small compared to the frames' transmission time, and identical for all stations.