This mechanism is called Selective Repeat ARQ.

Selective repeat protocol, also called Selective Repeat ARQ (Automatic Repeat reQuest), is a data link layer protocol that uses sliding window method for reliable delivery of data frames. When local area networks (LAN) have noisy environments, Selective Repeat ARQ is … Here, only the erroneous or lost frames are retransmitted, while the good frames are received and buffered. An alternative strategy, the selective repeat protocol, is to allow the receiver to accept and buffer the frames following a damaged or lost one. You'll get subjects, question papers, their solution, syllabus - All in one app. Engineering in your pocket.

Selective Repeat ARQ/Selective Reject ARQis a specific instance of the automatic repeat-request(ARQ) protocol used to solve sequence number dilemma in communications. Selective Repeat attempts to retransmit only those packets that are actually lost (due to errors) : Receiver must be able to accept packets out of order. If TCP uses Selective Acknowledgement (SACK), Selective Repeat ARQ is used.

It is more efficient for noisy links, but the processing at the receiver is more complex.

However, here only the erroneous or lost frames are retransmitted, while the good frames are received and buffered. Download our mobile app and study on-the-go. For noisy links, there is another mechanism that does not resend N frames when just one frame is damaged; only the damaged frame is resent. Selective Repeat ARQ − This protocol also provides for sending multiple frames before receiving the acknowledgement for the first frame.