CompNetExamFall10

CompNetExamFall10 - Computer Networks - Final exam Prof....

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

View Full Document Right Arrow Icon
Computer Networks - Final exam Prof. J.-P. Hubaux and Dr. M. H. Manshaei December 21, 2010 Duration: 3:00 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 60. This document contains 18 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)
Background image of page 1

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

View Full DocumentRight Arrow Icon
1 Short questions (10 points) For each question, please circle a single best answer . 1. WikiLeaks has recently faced DDoS (Distributed DoS) attacks. These attacks: (a) make use of Trojan horses to infect a specific host. (b) use botnets with thousands of compromised hosts. CORRECT (c) install malware that corrupts and deletes sensitive files. (d) allow the attacker to reveal identities of people submitting documents to different servers. 2. Consider an HTTP client that wants to retrieve a Web document at a given URL. Assuming that the IP address of the HTTP server is initially unknown, what transport and application-layer protocols besides HTTP are needed? (a) UDP (b) TCP (c) DNS (d) all of the above CORRECT 3. Among the following applications, which one is not suitable for P2P architecture: (a) file sharing (b) electronic banking CORRECT (c) video streaming (d) instant messaging 4. A Web cache: (a) can help prevent DoS attacks. (b) is a network entity that guarantees anonymity of Internet traffic. (c) responds to HTTP requests on the behalf of a Web server. CORRECT (d) makes use of cookies to reduce the response time for a client request. 5. In TCP, the timeout interval is a function of: (a) estimated RTT at the transmitter. CORRECT (b) maximum segment size (MSS) and the overhead of a datagram. (c) the size of buffer at the receiver. (d) both (b) and (c). 2
Background image of page 2
6. Which of the following is correct about the flow control service in TCP? (a) The sender selects the maximum segment size (MSS). (b) The receiver increases its application data rate. (c) The sender does not overflow the receiver’s buffer by transmitting too many segments. COR- RECT (d) The receiver increases its buffer size. 7. A TCP transmitter has received an acknowledgment with the sequence number equal to 80 . This means that: (a) the receiver has received segment 80 . (b) the receiver has received the segment preceding segment 80 . CORRECT (c) the receiver can accept 80 bytes without overflow in its buffer. (d) the transmitter should sent
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 18

CompNetExamFall10 - Computer Networks - Final exam 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