What is fast retransmit

Question

What is meant by the term fast retransmit?

Answer 1

In the TCP, receiver transmits the acknowledgements only if it obtain any packets from the sender. Hence receiving the acknowledgements from a receiver exhibits additionally that receiver constantly receives something from sender. Thus, the gap within the packet stream is not because of the severe congestion, however a simple packet loss because of the transmission error. Sender may now resend the missing packets before timer get expires. This behaviour is termed as fast retransmit.