CS 4310 Computer Networks Quiz

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.

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.