Download Exam # 1 paper - Computer Networks | CSE 422 and more Exams Computer Systems Networking and Telecommunications in PDF only on Docsity! CSE 422 Exam #1 Fall 2006 October 24, 2006 Name: Score: /100 You must show all your work! For problems involving calculations, a correct numerical answer without the accompanying calculations will count only one point. Please write clearly. 1. (5 pts.) In class, we used an analogy of adding layers to an onion as data proceeds down a protocol stack toward the physical network. Suppose you have a network analyzer and can “watch” packets on an Ethernet LAN. Within the packet, which of the following packet headers is placed closest to the data: IP header, TCP header, Ethernet header? 2. (10 pts.) Consider a noise-free channel with a bandwidth of 32,000 Hz. What is the maximum data rate achievable, when using a signaling technique with 128 different signal elements? Show your work. 3. (10 pts.) Consider a channel with a bandwidth of 32,000 Hz with a measured signal to noise level of 30 decibels. What is the maximum data rate achievable, when using a signaling technique with 128 different signal elements? Show your work. 1 4. (19 pts.) Consider the following switching strategies: circuit switching (CS), datagram packet switching (DPS), virtual circuit packet switching (VCPS): (a) (9 pts) Which type of switching is used by each of the following: • Asynchronous Transfer Mode • the Internet Protocol (IP) • a voice connection over a T1 line (b) (5 pts) Which one(s) of these switching strategies is connection-oriented? Circle one or more. CS DPS VCPS (c) (5 pts) Which one(s) of these switching strategies uses the arrival time of data in determining where the data is switched? Circle one or more. CS DPS VCPS 5. (6 pts.) Many socket programs invoke the gethostbyname() system call. What piece of information is usually being sought by the process when it invokes the gethostbyname() call? Circle one. port number IP address hostname subnet mask 2
