3.(10pt.) Consider two hosts are linked by a 4Mbps (4x106) channel and RTT is 0.04 sec. Assume the size of each packet is 8000 bits. Answer the following questions for ARQ schemes:

a)Assume that the link is error-free, what is the possible maximum rate of transmission for Stop-and-wait, GBN, and SR, respectively? Why?

b)For GBN and SR, in order to allow sender to continuously send packets without any waiting, what is the minimum window size in terms of the number of packets?

c)For b), what should be the minimum number of bits for the sequence number for GBN and SR, respectively?

d)Suppose that we are continuously transmitting packets end-to-end start from the 3rd packet, and the 7thpacket is lost. Assume there is no other packet lost or ACK lost. For stop-and-wait, GBN, and SR, which packets need to be retransmitted?