Although a node will not transmit until the line is quiet, two or more nodes could
come to that conclusion at the same instant. If more than one transmission is sent
simultaneously, creating a collision, the data from all transmissions will be damaged
and the line will remain unusable while the damaged messages are dissipated. When
the receiving nodes fail to acknowledge receipt of their transmissions, the sending
nodes will know that the messages did not reach their destinations successfully
and both will be retransmitted. The probability of this happening increases if the
nodes are farther apart, making CSMA a less appealing access protocol for large or
complex networks.