Problem #$2[25]$: In a communication network using direct link transmissions, stop$-$and$-$wait protocol is used to manage the flow of information packets. Please describe the operation of the following four scenarios for this protocol $($you may use diagrams as necessary$)$:

The ACK for an information packet is received before the timer expires.

The information packet is lost before it is received.

The information packet us received but its ACK for is lost.

The timer expires before the ACK of an information packet is received.