20 Packet need re-transmission.
Blue Marked - indicate current window packet.
1 2 3 45678 Go Back N in window from last transmitted packet. N = 5 Here
1 2 3 4 5 6 7 8 4 5 6 7 8 9 10 Go Back N in window from last transmitted packet. Here N != 5 , Then Go Back N , where N = current window size
1 2 3 4 5 6 7 8 4 5 6 7 8 9 10 7 8 9 10 Go Back N in window from last transmitted packet. Here N = current window size
1 2 3 4 5 6 7 8 4 5 6 7 8 9 10 7 8 9 10 10 Final Transmitted Packets