AD-602 Computer Networks - May 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
   aWhat is a computer network and what are its primary goals? Identify and explain the key components of a computer network including hardware and software elements.
   How to answer

   • Define computer network and its primary goals - resource sharing, communication, reliability, scalability
   • List hardware components - hosts, NIC, hub, switch, router, modem, transmission media
   • List software elements - protocols, NOS, network services and applications
   • Explain role of each component with examples
2. 7 Marks
   bDescribe each of the seven layers of the ISO/OSI model. For each layer explain its function and provide examples of protocols and devices associated with it.
   How to answer

   • List seven layers of ISO/OSI model from Physical to Application
   • Explain function of each layer in brief
   • Give example protocols for each layer
   • Give example devices associated where applicable
3. 7 Marks
   aExplain the concept of data rate in the context of the physical layer. How is data rate related to the bandwidth of a communication channel? Explain.
   How to answer

   • Define data rate - bits per second at physical layer
   • Define bandwidth - range of frequencies / capacity of channel
   • Explain Nyquist and Shannon capacity formulas relating data rate and bandwidth
   • Explain effect of noise, signal levels on maximum data rate
4. 7 Marks
   bWhy is error control necessary in data communication? Describe the methods used for error detection and correction in the Data Link Layer.
   How to answer

   • Explain need for error control - noise, attenuation causes errors
   • Distinguish error detection vs correction and ARQ
   • Describe parity, CRC, checksum, Hamming code
   • Explain role of Data Link Layer in framing and retransmission
5. 7 Marks
   aWhat are the key characteristics of the elementary protocol? Explain the operation of the 1-bit sliding window protocol in the Data Link Layer.
   How to answer

   • Define elementary / utopian protocols and their assumptions
   • List key characteristics - simplex, stop-and-wait, no errors
   • Explain 1-bit sliding window - sequence numbers 0/1, ACK, piggybacking
   • Explain stop-and-wait operation with sender-receiver scenario
6. 7 Marks
   bExplain the basic operation of Carrier Sense Multiple Access with Collision Detection (CSMA/CD) contention protocol and what measures are taken to manage collisions?
   How to answer

   • Define CSMA/CD and where it is used - Ethernet
   • Explain steps - carrier sense, transmit, collision detect, jam signal, backoff
   • Explain binary exponential backoff for collision management
   • Mention limitations and efficiency considerations
7. 7 Marks
   aDescribe the basic idea behind Dijkstra's Algorithm for finding the shortest path in a graph with suitable example.
   How to answer

   • Explain shortest path problem and greedy principle of Dijkstra
   • Outline steps - initialize distances, select minimum, relax edges
   • Illustrate with small weighted graph example with iterations
   • Mention complexity and limitation to non-negative weights
8. 7 Marks
   bDescribe the operation of IP fragmentation and reassembly. Discuss the conditions under which IP fragmentation occurs and its impact on network performance.
   How to answer

   • Define MTU and need for fragmentation and reassembly
   • Explain IP fragmentation fields - identification, flags, offset
   • Discuss conditions - datagram larger than MTU, path MTU
   • Explain impact - overhead, loss, reordering, performance degradation
9. 7 Marks
   aWhy is the Network Layer necessary in computer networking? Discuss its role and importance and also explain the key services provided by the Network Layer.
   How to answer

   • Explain need for Network Layer - routing across multiple networks
   • Discuss role - logical addressing, routing, forwarding
   • List key services - packet switching, congestion control, internetworking
   • Give examples - IP, ICMP, routing protocols
10. 7 Marks
    bDescribe the header format of UDP. What are its main fields and discuss the purpose of each field.
    How to answer

    • Draw UDP header with 4 fields - source port, dest port, length, checksum
    • State size of each field - 16 bits each, 8 byte header
    • Explain purpose of each field
    • Mention UDP characteristics - connectionless, unreliable
11. 7 Marks
    aDescribe the three-way handshake process used in TCP connection establishment. What is the purpose of each step?
    How to answer

    • Define TCP connection establishment and SYN, SYN-ACK, ACK exchange
    • Explain purpose of each step - sync sequence numbers, confirm
    • Mention flags and initial sequence numbers
    • Explain how connection parameters are negotiated
12. 7 Marks
    bWhat is TCP Flow Control and why is it necessary in data transmission? Explain any challenges or limitations associated with TCP Flow Control.
    How to answer

    • Define TCP flow control using sliding window and advertised window
    • Explain necessity - avoid overwhelming receiver, reliability
    • Explain challenges - silly window syndrome, deadlock, overhead
    • Mention solutions - Nagle, Clark, window scaling
13. 7 Marks
    aWhat is the Domain Name System (DNS) and what role does it play in computer networking? Explain how DNS translates domain names to IP addresses and vice versa.
    How to answer

    • Define DNS as hierarchical distributed naming system
    • Explain role - name to IP resolution for usability
    • Explain forward and reverse lookup with resolver, root, TLD, authoritative servers
    • Give example resolution steps and record types
14. 7 Marks
    bDefine modern ciphers and explain their advantages over traditional ciphers.
    How to answer

    • Define modern ciphers - block and stream ciphers using binary
    • Give examples - DES, AES, RSA
    • Compare with traditional substitution/transposition on security, key, speed
    • List advantages - larger key space, diffusion, suitable for computers
15. 14 Marks
    Write a short note on any two :

    1. a)Connection Oriented and Connection less services
    2. b)Hybrid ARQ
    3. c)ICMP
    4. d)SNMP
    How to answer

    • Select any two topics from the four options
    • Define each with key principles and operation
    • Give examples / header / use-case where applicable
    • Mention advantages and applications