CS-602 Computer Networks - May 2022 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain the OSI model stating its importance in network architectures.
   How to answer

   • Define OSI model with 7 layers listed in order
   • Brief function of each layer
   • Importance: standardization, interoperability, modular design
   • Role in network architectures with example
2. 7 Marks
   bWhat is the principal difference between connectionless and connection oriented communication?
   How to answer

   • Define connectionless communication with features
   • Define connection-oriented communication with features
   • Compare on reliability, ordering, overhead, examples
   • Conclude with use cases TCP vs UDP/IP
3. 7 Marks
   aExplain data link layer address with examples.
   How to answer

   • Define data link layer address / MAC address
   • Format: 48-bit, hexadecimal representation
   • Uniqueness, flat addressing vs IP
   • Examples of MAC address and its use in LAN
4. 7 Marks
   bA radio station is using 14.44 kbps channel for message transmission and the sending message packets are 100 bits long. Calculate the maximum throughput for the channel using slotted aloha.
   How to answer

   • Recall slotted ALOHA max efficiency $1/e \approx 0.368$
   • Compute frame time from 100 bits / 14.44 kbps
   • Apply throughput formula $S_{max} = 0.368 \times$ channel rate
   • Calculate maximum throughput value in kbps
5. 7 Marks
   aDescribe the stop and wait flow control technique.
   How to answer

   • Define flow control and stop-and-wait principle
   • Describe sender waits for ACK before next frame
   • Explain timeout, sequence numbers 0/1
   • Diagram of exchange and efficiency limitation
6. 7 Marks
   bWhat is subnet mask? Explain different classes of IP address.
   How to answer

   • Define subnet mask and its purpose
   • Explain dotted-decimal mask and prefix notation
   • Describe Classes A, B, C, D, E with ranges
   • Give example of mask for each class
7. 7 Marks
   aDescribe Go Back N and Selective Repeat protocol.
   How to answer

   • Define sliding window concept with window size N
   • Explain Go-Back-N retransmission on error
   • Explain Selective Repeat with selective retransmission
   • Compare efficiency, buffering and complexity
8. 7 Marks
   bWhat is bit and byte stuffing? Explain with example.
   How to answer

   • Define framing need for stuffing
   • Explain bit stuffing with 01111110 flag example
   • Explain byte stuffing with ESC flag example
   • Show stuffed / destuffed bit sequence
9. 7 Marks
   aExplain the connection establishment and connection release in Transport protocols.
   How to answer

   • Define connection establishment with three-way handshake
   • Explain SYN, SYN-ACK, ACK exchange
   • Describe graceful connection release / FIN handshake
   • Diagram of state transitions
10. 7 Marks
    bDescribe the Frame Relay Protocol Architecture and explain the functions of each one.
    How to answer

    • Define Frame Relay and its protocol layers
    • Describe architecture: physical and frame relay layers
    • Explain functions: multiplexing, congestion control, DLCI
    • Give use case example
11. 7 Marks
    aDiscuss Internet services standards for TCP/IP and the process of standardization for RFCS and TCP/IP.
    How to answer

    • Define TCP/IP standards and RFC process
    • Explain RFC standardization stages
    • List key Internet services standards
    • Example RFC numbers
12. 7 Marks
    bExplain Distance Vector routing with example.
    How to answer

    • Define distance vector concept with Bellman-Ford
    • Show distance table exchange between neighbours
    • Worked example with small topology
    • Mention count-to-infinity and split horizon
13. 7 Marks
    aExplain routing and congestion control.
    How to answer

    • Define routing vs congestion control
    • Explain routing algorithms goals
    • Explain congestion causes and control methods
    • Compare open-loop vs closed-loop techniques
14. 7 Marks
    bDifferentiate various broadband network local loop technologies stating their properties.
    How to answer

    • List broadband local loop technologies: DSL, cable, FTTH
    • Describe properties: bandwidth, medium, distance
    • Differentiate on speed, cost, deployment
    • Tabular comparison
15. 14 Marks
    Explain the following terms with example:

    1. i)FDDI
    2. ii)ARP
    3. iii)ICMP
    4. iv)UDP
    How to answer

    • Define FDDI, ARP, ICMP, UDP each briefly
    • Give function and layer for each protocol
    • Provide one example / use case per term
    • Mention packet / frame format key field