CS 4310 Computer Networks Quiz
48 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of an authoritative name server in DNS?

  • It provides a definitive answer to a query within its domain. (correct)
  • It caches name-to-IP address translation pairs for quick access.
  • It generates resource records for local servers.
  • It forwards queries to TLD servers for resolution.

    • What is the formula to calculate the transmission delay of a packet?

  • Length of packet (in bits) / Transmission rate (in Mbps) (correct)
  • Length of packet (in bits) / Transmission rate (in Kbps)
  • Length of packet (in bytes) / Transmission rate (in Kbps)
  • Length of packet (in bytes) / Transmission rate (in Mbps)

    • Which of the following statements about DNS name resolution is incorrect?

  • Hierarchical name resolution is only needed when a name is not found locally.
  • A DNS query can contain multiple questions and receive a single resource record in response. (correct)
  • DNS contains billions of resource records distributed among millions of name servers.
  • Recursive queries impose more load on contacted name servers than iterative queries do.

    • Which caching method can benefit from requests made by other users in addition to its own?

    <p>HTTP web cache</p> Signup and view all the answers

    What is the primary factor that contributes to queuing delay in a router?

    <p>Number of packets waiting to be transmitted</p> Signup and view all the answers

    What information does an 'NS' resource record contain?

    <p>A domain name and the name of its authoritative name server.</p> Signup and view all the answers

    Given a packet arrival rate of 100 packets per second and a link transmission rate of 1 Mbps, what is most likely the state of the queue?

    <p>The queue size varies between 10 and 20 packets on a constant basis</p> Signup and view all the answers

    Which statement about the BitTorrent protocol is false?

    <p>Once a peer obtains the complete file, it continues to share.</p> Signup and view all the answers

    What is a digital signature primarily used for?

    <p>Authenticating the identity of the sender</p> Signup and view all the answers

    Which statement regarding local DNS caching is correct?

    <p>It speeds up query responses by holding recent record lookups.</p> Signup and view all the answers

    Which layer of the Internet protocol is responsible for routing datagrams from source to destination?

    <p>Network layer</p> Signup and view all the answers

    What is the maximum achievable throughput for a client-to-server pair where the shared link capacity is limited to 50 Mbps?

    <p>50 Mbps</p> Signup and view all the answers

    Which is NOT a characteristic of hierarchical name resolution in DNS?

    <p>It uses a flat structure for record retrieval.</p> Signup and view all the answers

    Which type of DNS server provides definitive answers for queries in its domain?

    <p>Authoritative name server</p> Signup and view all the answers

    What is the utilization of a shared link if the transmission capacity is 90 Mbps and packets are sent at a total rate of 72 Mbps?

    <p>0.80</p> Signup and view all the answers

    Which of the following best describes the term 'encapsulation' in networking?

    <p>Wrapping packets with headers from different protocols</p> Signup and view all the answers

    Which of the following is NOT an advantage of using a web cache?

    <p>Web caching creates a slower page load time at the clients on average.</p> Signup and view all the answers

    Which piece of information will NOT appear in an HTTP response message?

    <p>The web server's IP address</p> Signup and view all the answers

    Which of the following is NOT a correct statement regarding HTTP/2 enhancements over HTTP 1.1?

    <p>HTTP/2 has many more status codes than HTTP 1.1.</p> Signup and view all the answers

    Comparing HTTP and SMTP, which of the following statements is NOT correct?

    <p>HTTP only uses persistent TCP connections, while SMTP uses non-persistent TCP connections.</p> Signup and view all the answers

    Which of the following statements about email components and protocols is NOT correct?

    <p>All emails to be sent are directly sent to the recipient SMTP server.</p> Signup and view all the answers

    What is the purpose of web caching?

    <p>To store frequently accessed web objects locally.</p> Signup and view all the answers

    Which feature of HTTP/2 helps to mitigate the problem of Head-of-Line (HOL) blocking?

    <p>Transmission of objects divided into smaller frames.</p> Signup and view all the answers

    What is the primary function of the User Agent in email systems?

    <p>To compose, edit, and read email messages.</p> Signup and view all the answers

    Which of the following statements about TCP flow control is NOT true?

    <p>The value of rwnd never changes throughout the duration of a connection.</p> Signup and view all the answers

    When two senders are competing at a bottleneck link, what fraction of the packets transmitted at the sender are retransmissions if the throughput to the application layer is equal to 0.8 * λin' when λin' is close to R/2?

    <p>20%</p> Signup and view all the answers

    Which action signals congestion in network-assisted congestion control?

    <p>A router sends an explicit message to a host telling it to slow down its sending rate.</p> Signup and view all the answers

    Which of the following statements about the TCP Additive-Increase-Multiplicative-Decrease (AIMD) algorithm is NOT true?

    <p>AIMD cuts the congestion window size, cwnd, to 1 whenever a timeout occurs.</p> Signup and view all the answers

    Which of the following statements about TCP Slow Start and Congestion Avoidance is NOT true?

    <p>TCP Congestion Avoidance never falls back to Slow Start.</p> Signup and view all the answers

    What is the consequence of a packet loss detected by a triple duplicate ACK in the AIMD algorithm?

    <p>Cwnd is reduced in half.</p> Signup and view all the answers

    In TCP Slow Start, how does the congestion window (cwnd) change when packets are successfully acknowledged?

    <p>Cwnd increases exponentially for each acknowledgment.</p> Signup and view all the answers

    What happens to the sending rate of TCP if the receiver's buffer is full?

    <p>The sender holds packets until the buffer has space.</p> Signup and view all the answers

    Which statement about reliable data transfer mechanisms is NOT true?

    <p>Negative acknowledge lets the sender know that a packet was received correctly at the receiver.</p> Signup and view all the answers

    Which statement about TCP is NOT true?

    <p>TCP supports 'multicasting' which means the transfer of data from one sender to many receivers in a single send operation.</p> Signup and view all the answers

    Which of the following statements about the Seq and ACK fields of segment 3 is correct?

    <p>Segment 3: Seq = 47, ACK = 80</p> Signup and view all the answers

    What timer-related action does the TCP sender take upon receipt of ACK 120?

    <p>Cancels any running timers.</p> Signup and view all the answers

    Which statement regarding 'TCP fast retransmit' is true?

    <p>It is an approach used by TCP to retransmit a segment after receiving 3 duplicate ACKs before that segment's timer expires.</p> Signup and view all the answers

    In TCP, how does the protocol handle out-of-sequence packets?

    <p>It keeps the out-of-sequence packets until the in-order packet is received.</p> Signup and view all the answers

    What is the purpose of the checksum in TCP?

    <p>It detects and aids in recovery of bit errors in transmitted data.</p> Signup and view all the answers

    What happens when a packet or its ACK is lost in the channel?

    <p>The sender will resend the lost packet and possibly other packets with higher sequence numbers.</p> Signup and view all the answers

    Which description best corresponds to a 'services' view of the Internet?

    <p>An infrastructure for building network applications.</p> Signup and view all the answers

    Which physical media technology offers the highest transmission rate and lowest bit error rate?

    <p>Fiber optic cable</p> Signup and view all the answers

    What characteristic is associated with the packet-switching technique?

    <p>It experiences congestion loss and variable delays.</p> Signup and view all the answers

    Given a network with 4 routers, what is the maximum number of connections that can exist at one time?

    <p>29</p> Signup and view all the answers

    If each connection requires 2 consecutive circuits, what is the maximum number of connections at a time?

    <p>32</p> Signup and view all the answers

    When each connection requires 3 consecutive circuits, what is the maximum possible number of connections?

    <p>17</p> Signup and view all the answers

    Which description correctly relates to circuit-switching networks?

    <p>It reserves specific resources for each call between source and destination.</p> Signup and view all the answers

    Which of the following statements about the Internet architecture is true?

    <p>It includes protocols for message format and transmission.</p> Signup and view all the answers

    Study Notes

    Multiple Choice Questions - CS 4310 Computer Networks

    • Question 1: The "services" view of the internet describes it as a network of networks, comprising hardware and software components that manage communication protocols and actions related to message exchange between entities.
    • Question 2: Fiber optic cable offers the highest transmission rate and lowest bit error rate among the options listed (coaxial cable, 802.11 WiFi Channel, 4G/5G cellular, and Fiber optic cable).
    • Question 3: Packet switching is associated with congestion loss and variable end-to-end delays.
    • Question 4: Transmission delay calculation depends on packet length and link transmission rate. In this case, a packet length of 1200 bytes at a 100 Mbps transmission rate results in 0.00096 seconds of transmission delay.
    • Question 5: In a packet queuing situation with a high arrival rate (100 packets/second), a low transmission rate (1 Mbps), and moderate packet length (20 kilobits) the queue size will likely become extremely large.
    • Question 6: Maximum achievable end-to-end throughput is 50 Mbps per client-server pair.
    • Question 7: The utilization of the shared middle link is 0.67
    • Question 8: Digital signatures are used for effectively detecting message content tampering.
    • Question 9: The network layer is responsible for routing datagrams from source to destination.
    • Question 10: Encapsulation is the process of adding header fields to data from an upper layer and placing it within the payload of a lower layer packet.
    • Question 11: Characteristics of a Client-Server approach include a server with a known IP address that processes requests from clients.
    • Question 12: Applications that can tolerate some data loss but require low delay are interactive games and streaming video.
    • Question 13: Flow control, congestion control, and throughput guarantee are functions provided by the transport layer. Reliable data transfer is not provided by the transport layer.
    • Question 14: One key difference between non-persistent and persistent HTTP is that persistent HTTP maintains a connection, while non-persistent HTTP closes the connection after each communication. Persistent connection in HTTP is 'stateless'.
    • Question 15: HTTP cookies are used to store information about a client's previous interactions with a particular website or web server, which are associated with a user.
    • Question 16: If-Modified-Since' in a HTTP GET request informs a web server whether a cached copy should be used rather than fetching the same data again.
    • Question 17: Web caches can improve speed of client access by using already cached data on servers which improves web client performance by reducing network traffic.
    • Question 18: HTTP response messages will include the status code, status phrase, content type. The IP address of the web server is not included in the HTTP response.
    • Question 19: The correct statement for HTTP/2 is that it allows transmission ordering of requested objects based on client-specified priority and divides objects into frames and transmits in an interleaved fashion to mitigate HOL blocking.
    • Question 20: HTTP is a client-pull protocol, while SMTP is a client-push.
    • Question 21: Different components and protocols of E-mail systems were discussed.
    • Question 22: An authoritative name server in a DNS provides definitive answers for requests within its domain.
    • Question 23: DNS name resolution involves distributing resource records amongst many name servers to ensure a hierarchical structure.
    • Question 24: HTTP web caching and local DNS server caching greatly benefit from leveraging results of cached data from previous user requests and can be compared to collaborative caching.
    • Question 25: NS records in DNS hold the name of the authoritative name server for a specific domain.
    • Question 26: BitTorrent p2p file sharing methodology uses chunking to share across multiple peers. Rarest first prioritizes missing chunks for requests.
    • Question 27: DASH (Dynamic Adaptive Streaming over HTTP) is used to allow video streams to adapt to dynamic bandwidth available at any time for playback.
    • Question 28: A manifest file in multimedia streaming helps organize video segments for efficient retrieval and playback by clients.
    • Question 29: Transport-layer demultiplexing involves extracting the payload, determining the destination IP addresses, and then routing the segment to the correct socket.
    • Question 30: Multiplexing and demultiplexing in TCP/UDP allow data transmission between different clients and servers on their respective ports.
    • Question 31: Destination IP address, Destination port, and Length of UDP segment are all included in a UDP segment header.
    • Question 32: A cumulative acknowledgment (ACK(n)) signifies that packets up to and including sequence number 'n' have been successfully received and acknowledged.
    • Question 33: Pipelining facilitates network efficiency by allowing multiple packets to be transmitted consecutively.
    • Question 34: Out-of-sequence packets are often discarded in congestion control schemes and sender is forced to retransmit the lost packets because buffer space for out of order segments is limited.
    • Question 35: Reliable data transfer mechanisms rely on timers for retansmission, sequence numbers for duplicate avoidance, and checksums for data integrity.
    • Question 36: Data transfer in TCP is considered to be bi-directional.
    • Question 37: Segment 2 has a Seq(80) and ACK(45). Segment 3 has a Seq(47) and ACK(80).
    • Question 38: On receiving ACK 120, TCP sender will restart the timer associated with segment that had a sequence number 92 and initiate new timers/processes for other segments accordingly.
    • Question 39: Retransmission in TCP involves retransmitting a segment after encountering 3 duplicate ACKs, before the corresponding timer has expired.
    • Question 40: TCP flow control aims to regulate data flow from sender to receiver, preventing receiver buffer overflow, and is controlled by TCP receiver window size.
    • Question 41: The application layer throughput is 80% when receiver throughput rate (as a proportion of sender rate) is near half of the shared bottleneck line rate.
    • Question 42: Network assisted congestion control uses explicit messages sent by routers to hosts to signal slower transmission rate.
    • Question 43: The correct actions of AIMD algorithm in TCP congestion control are that it decreases cwnd to half its value after experiencing a loss as detected by triple duplicate ACK and increase the congestion window by 1 every RTT.
    • Question 44: TCP Slow Start and Congestion Avoidance use different rate increase strategies.
    • Question 45: Delay-based TCP congestion control attempts to maintain a low delay and optimize throughput while reducing the sender's window size linearly by a factor of the amount of currently measured throughout divided by the bandwidth based on the minimal delay.
    • Question 46: QUIC is a transport layer protocol that differs from TCP in several aspects; it allows multiplexed stream, uses a single handshake, and can update its code rapidly.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    CS 4310 Computer Networks Fall 2024 Midterm Exam PDF

    Description

    Test your knowledge of computer networks with this quiz designed for CS 4310. It covers topics such as internet architecture, transmission methods, packet switching, and delay calculations. Prepare for your exams and enhance your understanding of network communications.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser