Consider a full-duplex 512 kbps link with length 36,000Km connecting two hosts. The data frames carry a useful payload of size 6000 bits. Assume that both ACK and data frames have 400 bits of header information, and that ACK frames carry no data. The propagation speed along this link is 3108 m/sec. a) What is the RTT on this link? b) What is the effective useful data throughput, in kbps, when using Stop-and-Wait?