A jam signal indicates that the collision has cleared and the media is not busy.
X A device listens and waits until the media is not busy before transmitting.
The device with the electronic token is the only one that can transmit after a collision.
X All of the devices on a segment see data that passes on the network medium.
X After detecting a collision, hosts can attempt to resume transmission after a random time delay has expired.
Devices listen to the media and transmit data only when they cannot detect another signal on the media. All devices on the media can hear all communications When a collision occurs, all devices stop transmitting for a randomly generated period of time.
CSMA/CD: Carrier Sense Multiple Access / Collision Detection.
The acronym CSMA CD stands for Carrier Sense Multiple Access with Collision Detection. CSMA CD is a set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously.
10BaseT
1. Based on the CSMA/CD process 2. Specifies the MAC portion of the data link layer (layer 2)
Because CSMA/CD does not prevent Hidden terminal problem. so it is onlly applicable in Wired networks.
Csma/cd
IP, appletalk, token ring, CSMA/CD, CSMA/CA
The CSMA/CD access method is used to detect collisions Data transmission is via frames, each having a single MAC address
Collisions can decrease network performance.
Data transmissions is via frames, each having a single MAC address. The CSMA/CD access method is used to detect collisions.
*** In CSMA/CD it detects that a collision take place and resend the frame that was send. On a wirless network losing bandwidth along with time to detect that a collision took place was not acceptable , so CSMA/CA was utilized. ** CSMA/CD can achieve above 70% efficiency under heavy loads compared to CSMA/CA that can only achieve up to 30% efficiency under heavy loads. CSMA/CA network: A network in which the medium access control protocol requires carrier sense and where a station always starts transmission by sending a jam signal; if there is no collision with jam signals from other stations, it begins sending data; otherwise, it stops transmission and then tries again later. CSMA/CD network: A bus network in which the medium access control protocol requires carrier sense and in which exception conditions caused by collision are resolved by retransmission