CompNetMidtermFall10

CompNetMidtermFall10 - Computer Networks - Midterm Prof....

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Computer Networks - Midterm Prof. J.-P. Hubaux and Dr. M. H. Manshaei November 9, 2010 Duration: 1:45 hours, closed book. Please write your answers on these sheets in a readable way. Poorly written answers will not be corrected. Use extra sheets if necessary (put your name on them). You may write your answers in English or in French. The total number of points is 40. This document contains 14 pages. First Name (Pr´enom): Last Name (Nom de famille): SCIPER No: Division: 2 Communication Systems 2 Computer Science 2 Other (mention it): . . . . . . . . . Year: 2 Bachelor Year 2 2 Bachelor Year 3 2 Other (mention it): . . . . . . . . . (answers to the questions are shown in italic and blue) 1 Short questions (5 points) For each question, please circle a single best answer . 1. Statistical multiplexing is: (a) a mechanism providing circuit-like behavior in packet-switched networks (b) a method to optimally share files in a peer-to-peer system (c) an algorithm that divides up the frequency spectrum of a link (d) an on-demand form of sharing a transmission link CORRECT 2. The end-to-end delay depends on: (a) the congestion of the network (b) the number of hops between source and destination (c) the application-layer protocols (d) the processing delay in the routers (e) all of the above (f) (a), (b) and (d) CORRECT 3. A tier-2 ISP: (a) is a provider of one or more tier-1 ISPs (b) is connected to only one tier-1 ISP (c) can be connected to other tier-2 ISPs CORRECT (d) Both (b) and (c) 4. HTTP with persistent connections (a) requires 2 RTTs per object (b) requires the server to open a new TCP connection to send a response (c) provides higher security against Denial of Service (DoS) attacks (d) none of the above CORRECT 5. Cookies enable (a) a Web server to infect a user’s machine with malware (b) a Web server to track a user’s activity at its own Web site CORRECT (c) a Web server to know all previous Web pages visited by the user (d) a Web server to learn your full name, e-mail address and credit card information 2 6. IMAP (a) is built on top of POP3 (b) is stateless across sessions (c) allows users to create remote folders CORRECT (d) is not compatible with SMTP 7. In a reliable data transfer protocol, duplicate ACK (a) is a technique to increase the probability of successful ACK transmission. (b) is used to decrease the congestion window at the sender. (c) can be used instead of NAK packets. (d) is used to detect packet loss before the timeout. (e) both (c) and (d) CORRECT 8. By replacing a stop-and-wait protocol with a pipeline protocol, a sender increases its link uti- lization by a factor of k . How many packets does the sender allow to transmit without receiving acknowledgements?...
View Full Document

This note was uploaded on 01/09/2012 for the course CS cs464 at Bilkent University.

Page1 / 14

CompNetMidtermFall10 - Computer Networks - Midterm Prof....

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online