Answer
See explanation
Work Step by Step
We design a window of some particular size and assign a number to each frame of the window. The sender sends the frames of the window without waiting for acknowledgement, The receiver sends the acknowledgement of frames it receives, after sending all frames of window the sender checks received acknowledgements and slides the windows ahead of the frames whose acknowledgement is received and sends the frames of new window again. This modified protocol is called Go-Back-N ARQ protocol.
