Sliding Window with Relay. Suppose that host A is connected to host B via an intermediate router R. The link between A and R is instantaneous, but the link between R and B transmits only one packet each second, one at a time. All links are full-duplex so that the two directions transmit independently. Hosts A and B run an ARQ protocol to control the exchange of packets between them. Assume A sends to B using the sliding window protocol with SWS=4. (a) For time equal to 0,1,2,3, and 4 , state what packets arrive at and are sent from A and B. Hint: no packets are lost in this problem because the relay has plenty of queueing space. To get started, notice that with the SWS of 4 , host A sends the first 4 packets at time t=0. Because the link from A to R is so fast, the relay immediately starts to transmit the first packet. The second, third, and fourth packets are stored in a queue at the relay. To check your work, verify that at time t=4, host A sends its seventh packet. (b) Notice that an instant after time t=0, the relay node is transmitting the first packet and has queued the second, third, and fourth packets. So, at this time, there are three packets stored in host R 's queue. What is the largest number of packets that are ever queued by host R (call this the peak queue size requirement)? 2 (c) Starting at time t=2, you should notice that protocol settles into a pattern that repeats as long as host A has packets available to send. After time t=2, what is the largest number of packets that are ever queued