Consider a simple protocol for transferring files over a link. After some initial negotiation, A sends data packets of size 1 KB to B; B the replies with an acknowledgement. A always waits for each ACK before sending the next data packet; this is known as stop and wait. Packets that are overdue are presumed lost and are retransmitted. a) In the absence of packet losses or duplications, explain why it is not necessary to include sequence number data in the packet header. b) Suppose that the link can lose occasional packets, but that the packets that do arrive always arrive in the order sent. Is a 2-bit sequence number (that is, N mod 4) enough for A and B to detect and resend any lost packets? Is a 1 bit sequence number enough? c) Now suppose that the link can deliver out of order and that sometimes a packet can be delivered as much as 1 minute after subsequent packets. How does this change the sequence number requirements?