CS-602 Computer Networks - Dec 2024 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
   aGive the comparative analysis of OSI and TCP/IP Model.
   How to answer

   • List layers of OSI (7) and TCP/IP (4/5) with functions
   • Compare on basis of layers, model type, reliability, approach
   • Merits/demerits of each model
   • Diagram of layered architectures side by side
2. 7 Marks
   bGive the difference between connection oriented and connection less services.
   How to answer

   • Define connection-oriented service with connection setup phase
   • Define connectionless service with datagram approach
   • Compare reliability, ordering, overhead, applications
   • Give examples: TCP vs UDP/IP
3. 7 Marks
   aExplain in detail about the error and flow control mechanisms employed at data link layer.
   How to answer

   • Define error control vs flow control at data link layer
   • Explain error control: ARQ, CRC, checksum, Hamming
   • Explain flow control: stop-and-wait, sliding window
   • Role in reliable delivery over noisy channel
4. 7 Marks
   bExplain the working principle of Go-Back-N and Selective repeat protocols.
   How to answer

   • Explain sliding window concept and sender/receiver windows
   • Go-Back-N: cumulative ACK, retransmit all from error
   • Selective Repeat: individual ACK, retransmit only lost frame
   • Compare efficiency, buffer requirement with diagram
5. 7 Marks
   aWe measure the performance of a line ($4 \text{ kHz}$ of Bandwidth) when the signal is $20V$, the noise is $6mV$. Calculate the Maximum data rate supported by this line.
   How to answer

   • Compute SNR from signal 20V and noise 6mV
   • Apply Shannon capacity $C = B \log_2(1+SNR)$
   • Substitute $B=4\,kHz$ and calculate
   • State maximum data rate in bps
6. 7 Marks
   bExplain the working of ARP and RARP.
   How to answer

   • Define ARP: IP to MAC resolution need
   • Explain ARP request/reply broadcast steps
   • Define RARP: MAC to IP resolution for diskless hosts
   • Explain RARP operation and limitations
7. 7 Marks
   aExplain Binary Exponential Back-off (BEB) with suitable example.
   How to answer

   • State need for backoff after collision in CSMA/CD
   • Explain binary exponential algorithm: random wait $0$ to $2^k-1$ slots
   • Illustrate with example of successive collisions
   • Mention max retries and stabilization effect
8. 7 Marks
   bExplain briefly about the Persistent and Non-persistent CSMA protocols.
   How to answer

   • Define CSMA persistence concept
   • Explain 1-persistent, non-persistent behaviour flow
   • Compare delay, collision probability
   • Suitability for different loads
9. 7 Marks
   aDescribe the working principle of Bellman Ford algorithm using suitable example.
   How to answer

   • State Bellman-Ford purpose: single-source shortest path with negative weights
   • Explain relaxation for V-1 iterations and negative cycle detection
   • Work out suitable graph example step by step
   • Give complexity and comparison with Dijkstra
10. 7 Marks
    bExplain the Fragmentation and reassembly using suitable example.
    How to answer

    • Define MTU and need for fragmentation
    • Explain fields: identification, offset, MF flag
    • Illustrate fragmentation of datagram into pieces
    • Explain reassembly at destination
11. 7 Marks
    aWhat do you understand by collision free protocol? Explain the Binary Count Down Protocol with suitable example.
    How to answer

    • Define collision-free protocol and reservation concept
    • Explain binary countdown: station addresses and bitwise OR contention
    • Work out example with competing stations
    • Advantages over contention protocols
12. 7 Marks
    bGive the basic difference between broad cast and multicast routing.
    How to answer

    • Define broadcast: to all nodes in network
    • Define multicast: to specific group of nodes
    • Compare addressing, tree construction, bandwidth use
    • Give routing protocol examples
13. 7 Marks
    aDraw and explain the header format of a User Datagram Protocol (UDP).
    How to answer

    • Draw 8-byte UDP header with 4 fields
    • Explain source/destination port, length, checksum
    • Mention connectionless, unreliable features
    • Use in DNS, streaming applications
14. 7 Marks
    bExplain Simple Network Management Protocol (SNMP) and its functions.
    How to answer

    • Define SNMP for managing IP networks
    • Explain manager, agent, MIB architecture
    • Describe Get, Set, Trap operations
    • List functions: monitoring, configuration, fault management
15. 14 Marks
    Write a short note on any two :

    1. a)TCP Congestion Control
    2. b)Aloha and Slotted Aloha
    3. c)Finite State Machine
    4. d)MLMA
    How to answer

    • Select any two topics from a-d
    • Give definition, working/diagram and key features for each
    • Mention advantages/applications
    • Conclude with significance in networks