Q$2$: Suppose that we use Selective Repeat protocol for reliable data transfer in transport layer. Consider that host A wants to send a file to host B$.$ The file is decomposed into $7$ parts, so we have pkt$0,$ pkt$1,$ pkt$2,....,$ pkt$6$ to be sent. Assume that the sequence numbers start from $0$ and we have infinite sequence number space $(0,1,2,3,...),$ so we don$$t reuse sequence numbers. Also, assume window of size $4.$ Suppose that the second packet $($i$.$e$.,$ pkt$1)$ is lost and the ack for the third packets is lost as well $($i$.$e$,$ ack$2).$ All other packets and acks are sent and received correctly and without any delay. Because of these two losses, the sender doesn$$t receive the acknowledgement for pkt$1$ and pkt$2$ and their timers expire one after the other just after the ack$3$ arrives in the sender and before arrival of ack$4.$ We assume no loss and delay for any retransmission and its ack. Draw the timing diagram for the file transmission. Mention clearly sequence numbers of data and ack packets, as well as the window at sender side. You don$$t need to show the window at receiver side. You MUST specify the window status $($at sender$)$ whenever a packet is sent or an ack is received in the diagram$).$ Also, mention the actions that happen in sender and receiver upon receiving a packet or ack or timeout. The example actions for packets or acks with sequence number x are $$send pck x$,$receive pck x$,$send ack x$,$receive ack x$,$deliver$,$record ack x arrived$,$buffer$.$ Please see lecture slides related to $$Selective Repeat$$ topic for an example of the timing diagram that is expected for this question.