CSD008/COMP3616, Networks & Internet Systems: Problem Set 5 ----------------------------------------------------------- Reminders: There are no marks associated with these problems, and you do not hand in your answers. "Tanenbaum" refers to the 4th Edition. 1. (Tanenbaum, Ch. 5, problem 39) A network on the Internet has a subnet mask of 255.255.240.0. What is the maximum number of hosts it can handle? 2. (a) Suppose a host with IP address 128.96.34.15 has a subnet mask of 255.255.255.128. What is the subnet number of the subnet this host is attached to? (b) The host in part (a) wants to send an IP datagram to a host with IP address 128.96.34.139. Is the destination on the same subnet as the sender or not? 3. (Tanenbaum, Ch. 6, problem 14) Why does UDP exist? Would it not have been enough to just let user processes send raw IP packets in order to communicate? 4. (Tanenbaum, Ch. 6, problem 23) A process on host 1 has been assigned port p, and a process on host 2 has been assigned port q. Is it possible for there to be 2 or more TCP connections between these 2 ports at the same time? 5. (Tanenbaum, Ch. 6, problem 20) Datagram fragmentation and reassembly are handled by IP and are invisible to TCP. Does this mean that TCP does not have to worry about data arriving in the wrong order? 6. (a) (Tanenbaum, Ch. 6, problem 28) Consider the effect of using slow-start on a line with 10 millisec round trip time and no congestion. The receiver's window is 24 kB and the Maximum Segment Size is 2 kB. How long does it take before the first full window can be sent? (b) (Tanenbaum, Ch. 6, problem 29) Suppose that the TCP congestion window is 18 kB and then a timeout occurs. If the Maximum Segment Size is 1 kB, how big will the congestion window be after 4 successful transmission bursts? 7. (Tanenbaum, Ch. 6, problem 31) A TCP machine is sending full windows of 65,535 bytes over a 1 Gbps channel that has a 10 millisec one-way delay. What is the maximum achievable throughput? What is the line efficiency? 8. Mention some of the challenges faced in delivering "continuous media" (e.g. video, voice) over a computer network. Of the two protocols TCP and UDP, which one is usually used to deliver continuous media in the Internet, and why? 9. Briefly describe the steps carried out by a Web client retrieving a Web page, and by the Web server providing that Web page. 10. Briefly describe (with the aid of diagrams) the "hidden" and "exposed" station problems in IEEE 802.11 Wireless LANs.