Suppose , a sender sends a packet and it does not receive an acknowledgement . The timer at the sender side runs out . In which cases the sender resends the packets and in which cases it does not ?
I know this : If the sender does not receive acknowledgement frame the sender will resend the frames and it will add congestion .
But in a book I read that : In acknowledgement policy , if the receiver does not acknowledge every packet , then it may reduce congestion . How is it possible ? How will the sender come to know that the packet is successfully delivered ?