Questions & Answers

CSMA/CD not implemented in WLANs because collisions are rare in wireless, unlike wired networks. WLANs use CSMA/CA, tailored for wireless environments, addressing hidden node issues by avoiding collisions. CSMA /CD's collision detection adds unnecessary overhead in WLANs, where efficiency is key. + More - Less

In wired networks, the received signal has almost the same energy as the sent signal because either the length of the cable is short or there are repeaters that amplify the energy between the sender and the rec eiver. This means that in a collison the detected energy almost doubles. However, in a wireless network much of the sent energy is lost in transmission. The received signal has very little energy. Therefore a collison may add only 5 to 10 percent additional energy. This is not useful for effective collision detection. Hence CSMA / CD is not used in a wireless network. + More - Less

The physical characteristics of WiFi make it impossible and impractical for the CAMA/CD mechanism to be used. This is due to CSMA/CD’s nature of ‘listening’ if the medium is free before transmitting packe ts. Using CSMA/CD, if a collision is detected on the medium, end-devices would have to wait a random amount of time before they can start the retransmission process. For this reason, CSMA/CD works well for wired networks, however, in wireless networks, there is no way for the sender to detect collisions the same way CSMA/CD does since the sender is only able to transmit and receive packets on the medium but is not able to sense data traversing that medium. Therefore, CSMA/CA is used on wireless networks. + More - Less

This is because the nodes A and C are out of range of each other(and so cannot detect a collision while transmitting). Thus, Carrier sense multiple access with collision detection (CSMA/CD) does not work, and c ollisions occur. The data received by the access point is corrupted due to the collision. + More - Less