In Go-Back-N window, when the timer of the packet times out, several packets have to be resent even some may have arrived safe. Whereas in Selective Repeat window, the sender resends ___________

Subject: Computer Networks

Topic: Frame Relay

Options:

1. Option A: Packet which are not lost
2. Option B: Only those packets which are lost or corrupted
3. Option C: Packet from starting
4. Option D: All the packets

Correct Answer:

Option B: Only those packets which are lost or corrupted

Explanation:

In Selective Repeat, the sender side uses a searching algorithm to find the packets which need to be retransmitted based on the negative acknowledgements received and then resends only those packets thus saving bandwidth.