Retransmission − The sender always maintains a clock and sets a timeout period. Negative ACK − Whenever the receiver receives a damaged frame or a duplicate frame, it sends a NACK back to the sender and sender must retransmit the correct frame. Positive ACK − Whenever a receiver receives a correct frame, it should acknowledge it. There are some requirements for error control mechanisms and they are as follows −Įrror detection − The sender and receiver, or any must ascertain that there is some error in the transit.
Generally, there are three types of techniques which control the errors by Automatic Repeat Request (ARQ) they are − Selective-repeat Automatic Repeat Request (ARQ) is one of the techniques where a data link layer may deploy to control errors.
