I NEED HELP WITH D PORTION. THE END-END DELAY FOR EACH INDIVIDUAL PACKET SHOULD BE CALCULATED. I GOT 39 ms, 47 ms, 23 ms FOR PACKET 1, PACKET 2, PACKET 3 RESPECTIVELY in the STORE AND FORWARD CASE. I GOT 23 ms, 31 ms and 39 ms for CUT THROUGH CASE. PLEASE VERIFY MY ANSWER AT THE EARLIEST.

Consider figure 1, where the sender transmits one packet of size L = 1 KB

(kilobytes). The link speed are R1 = R2 = R3 = 1 Mbps (megabits per second). The length of each link is

100 Km. Compute the end-to-end delay for the following situations. We assume that the propagation

speed of the packet is 20,000 Km/s, and that the processing time of the packet at each router is 5 s.

(a) Both routers are store-and-forward routers.

(b) Both routers are cut-through routers. Note that a cut-through router does not wait for the entire

packet to arrive before it starts the transmission of the packet. (Remark: In reality, there are cut-

through switches instead of cut-through routers. But, for this problem, we assume there are cut-

through routers.)

(c) Suppose R1 = R2 = R3 = 1 Gbps (gigabits per second). Repeat part (a) and (b).

(d) Again repeat part (a) and (b). However, now, R1 = R2 = 2 Mbps, and R3 = 1 Mbps. Three packets

of the same length, each with L = 1KB, are transmitted at the sender. What is the end-to-end

delay of each packet? For simplicity, you may neglect the processing time, which is small

compare with other delays. Also, you need not count packets waiting time at the sender.

(e) For the situation in (d), draw a timing diagram by completing figure 2 and identify the queueing

delay of each packet. Again, you may neglect the processing time.

L RI R2 R3 Sender Router1 Router 2 Receiver Figure 1 2 2 packet 4 6 6 packet 2 6 & 10 8 10 10 10 time (ms) Figure 2. Timing diagram