Receiver silently discards the frame if it founds the frame to be either corrupted or out of order.

Go back N leads to retransmission of entire window if for any frame, no ACK is received by the sender.

This is because receiver window size is 1 and therefore receiver can not accept out of order frames.

All the following frames are also discarded.

If receiver receives a frame whose sequence number is not what the receiver expects, then it silently discards that frame.

Go back N does not accept out of order frames and silently discards them. (like not sending a NACK to the sender to send the correct frame) “Simply rejecting the frame and not taking any action”

The correct frame is retransmitted by the sender after the time out timer expires.

If receiver receives a frame that is corrupted, then it silently discards that frame.

Go back N does not accept the corrupted frames and silently discards them.

Then, Go back N sends the independent acknowledgement for that frame.

Consider after the expiry of acknowledgement timer, there is only one frame left to be acknowledged.

The kind of acknowledgement used depends on the expiry of acknowledgement timer.

Go back N may use independent acknowledgements too if required.

The above point does not mean that Go back N can not use independent acknowledgements.

Go back N may use independent acknowledgements too.

It starts after a new frame is received.

A new acknowledgement timer does not start after the expiry of old acknowledgement timer.

After the timer expires, receiver sends the cumulative acknowledgement for all the frames that are unacknowledged at that moment.

Each time the receiver receives a new frame, it starts a new acknowledgement timer.

Receiver maintains an acknowledgement timer.

Go back N uses cumulative acknowledgements.

Receiver window size is always 1 for any value of N.

Example in Go back 10, sender window size will be 10. In Go back N, sender window size is N and receiver window size is always 1. The features and working of this protocol are explained in the following points.

Go back N protocol is an implementation of a sliding window protocol.

Sliding window protocol java program