Correct Answer - Option 4 : The exponential back-off mechanism reduces the probability of collision on retransmissions.
Ethernet is a way of connecting computers together in a local area network (LAN). Ethernet operates in two layers of OSI model, physical and data link layer. In order to handle the collision in Ethernet, access control mechanism used is CSMA/CD.
1) A station stops to sense the channel once it starts transmitting a frame.
In Ethernet, a station need not stop sensing the channel once it starts transmitting a frame. So, it is false
2) The purpose of the jamming signal is to pad the frames that are smaller than the minimum frame size.
Jamming signal in Ethernet is signal that carries 32-bit binary pattern sent by a data station to inform other stations of the collision. It is not true that the purpose of jamming signal is to pad the frames that are smaller than the minimum frame size.
3) A station continues to transmit the packet even after the collision is detected. Once the collision has occurred, jam signal will be sent and after that station will stop transmitting the packet. So, it is incorrect.
4) The exponential back-off mechanism reduces the probability of collision on retransmissions.
Exponential back off algorithm is used to space out repeated retransmissions of the same block of data to avoid network congestion. It is a collision resolution mechanism which is used in random access MAC protocols. So, it is correct.
