English
A go-back-n sender has sent :math:`2^n` data frames. All the frames have been received correctly and in-order by the receiver, but all the returned acknowledgments have been lost. Show by using a time sequence diagram (e.g. by considering a window of four frames) what happens in this case. Can you fix the problem on the go-back-n sender ?
Same question as above, but assume now that both the sender and the receiver implement selective repeat. Note that the answer can be different from the above question.