ou are implementing the behaviour corresponding

to the go$-$back$-$N sliding window protocol which is relatively easy, but the receiver needs

to also provide some flexibility regarding the rate at which the correctly received segments

are collected by the layer above. Implement unit tests to show evidence that the following

functions are correctly implemented:

$($a$)($general$)$ Sequence numbers are counted modulo $2$b$,$ where b is the number of bits used

for sequence numbers.

$($b$)($sender$)$ Process acknowledgements; there are at least two cases, sliding window can

advance and the sliding window does not advance.

$($c$)($sender$)$ Obtain new sequence numbers to be added to the sliding window; two cases,

sliding window full and not full.

$($d$)($sender$/$receiver$)$ Examine the content of the sliding window.

$($e$)($receiver$)$ Tell the sequence number that can be sent in an acknowledgement to the

sender$.$

$($f$)($receiver$)$ Advance sliding window as data is consumed by the layer above; two cases $-$

advancement possible and not possible.

$($g$)($receiver$)$ Add to the sliding window a sequence number correctly received from the

sender; two cases $-$ addition possible and not possible.

$($h$)($receiver$)$ Obtain the capacity of the sliding window $($the number of sequences that can

still be added to the sliding window$).$