Problem 3 Packet Loss (8 pts): Assume a client connects to a server via a lossy link. When an application is sending PDUs of different sizes to the server over the path, compute the expected number of bytes lost when transmitting an arbitrary PDU. A. (1pt) Assume the client does not have reliable data transfer. The link has packet loss probability of 20\%. Application sends 200-byte fixed-length PDUs at all times. Ans: 2000.2=40 B. (1pt) Assume the client does not have reliable data transfer. The link has packet loss probability of 20\%. Application sends 200-byte PDUs at half of the times, and 400-byte PDUs at the other half. Ans: 80 C. (1pt) Assume the client does not have reliable data transfer. The link has packet loss probability of 20\%. Application sends PDUs following this distribution: 100-byte (10\%), 200-byte (30\%), 400-byte (50\%), 1000-byte (10\%). Ans: D. (2.5pts) Assume that the client transmits 1 million bytes of data to the server. The PDU goes through a 5-layer network stack with 25 bytes of overhead for each layer except the application layer. During the transmission, exactly 1 bit is corrupted during the transmission, and the corresponding packet must be entirely retransmitted to ensure reliable data transfer. How many bytes in total, including both data and overhead, need to be transmitted, if the PDU size is 100, 1000, 2000, 10000, and 200000 bytes? E. (2.5pts) What is the optimal PDU size for the above network scenario in D, i.e., requiring the fewest number of bytes to be transmitted in total? Why