CS2302 Computer Networks–Important Question with Keys (2012 1st Edition)

Anna University
Department of Computer Science Engineering

Department : B.E CSE

Semester : V
Year : 3rd yr
Regulation : 2008
Subject Code : CS2302

Subject Name : Computer Networks

Content : CS2302 Computer Networks– Important Questions with Keys – 1st Edition of 2012.


16 MARKS QUESTIONS & KEYS


UNIT I


1. Explain ISO/OSI reference model.

_ Physical layer

_ Data link layer

_ Network layer

_ Transport layer

_ Session layer

_ Presentation layer

_ Application layer


2. Explain the topologies of the network.

_ Mesh topology

_ Star topology

_ Tree topology

_ Bus topology

_ Ring topology


3. Explain the categories of networks.

_ Local Area Network(LAN)

_ Metropolitan Area Network(MAN)

_ Wide Area Network(WAN)


4. Explain coaxial cable & fiber optics.

_ Coaxial cable

_ Coaxial cable standards

_ Coaxial cable connectors

_ Fiber optics

_ Propagation modes

_ Fiber sizes

_ Cable composition

_ Light sources for optical cable

_ Fiber optic connectors

_ Advantages & disadvantages of optical fiber


5. Explain line coding (digital to digital conversion).

_ Unipolar

_ DC component

_ Synchronization

_ Polar

_ Non return to zero(NRZ)

_ NRZ-L

_ NRZ-I

_ Return to zero

_ Biphase

_ Manchester

_ Differential Manchester

_ Bipolar

_ Alternate Mark Inversion(AMI)

_ Bipolar 8-zero substitution(B8ZS)

_ High-Density Bipolar 3(HDB3)


UNIT II


1. Explain error detection and error correction techniques.

_ Types of errors

_ Single bit error

_ Burst error

_ Error detection

_ Vertical redundancy check(VRC)

_ Longitudinal redundancy check(LRC)

_ Cyclic redundancy check(CRC)

_ Checksum

_ Error correction

_ Single-bit error correction

_ Hamming code

_ Burst error correction


2. Explain error control mechanism.

_ Stop and wait ARQ

_ Sliding window ARQ

_ Go back-n

_ Selective-reject


3. Explain the flow control mechanism

_ Stop and wait

_ Sliding window.


4. Explain the timers and time registers in FDDI.

Time registers

_ Synchronous allocation(SA)

_ Target token rotation time(TTRT)

_ Absolute maximum time(AMT)

_ Timers

_ Token rotation timer(TRT)

_ Token holding timer(THT)


5. Explain about Ethernet.

_ Access method :CSMA/CD

_ Addressing

_ Electrical specification

_ Frame format

_ Implementation:

_ 10 base 5 :Thick Ethernet

_ 10 base 2 :Thin Ethernet

_ 10 base T :Twisted-pair Ethernet

_ 1 base 5 :Star LAN


6. Explain the frame format for token ring and token bus.

_ Access method: Token passing

_ Priority and reservation

_ Time limits

_ Monitor stations


7. Explain about HDLC.

_ Station types:

_ Primary station

_ Secondary station

_ Configurations:

_ Unbalanced configuration

_ Symmetrical configuration

_ Balanced configuration

_ Modes of communication:

_ Normal Response Mode(NRM)

_ Asynchronous Response Mode(ARM)

_ Asynchronous Balanced Mode(ABM)

_ Frames :

_ Flag field

_ Address field

_ Control field

_ Information field

_ FCS field


UNIT III


1. Explain the two approaches of packet switching techniques.

_ Datagram approach

_ Virtual circuit approach

_ Switched virtual circuit(SVC)

_ Permanent virtual circuit(PVC)

_ Circuit – switched connection versus virtual – circuit connection

_ Path versus route

_ Dedicated versus shared


2. Explain IP addressing method.

_ Internetwork protocol (IP)

_ Datagram

_ Addressing

_ Classes

_ Dotted decimal notation

_ A sample internet


3. Define routing & explain distance vector routing and link state routing.

_ Distance vector routing

_ Sharing information

_ Routing table

_ Creating the table

_ Updating the table

_ Updating algorithm

_ Link state routing

_ Information sharing

_ Packet cost

_ Link state packet

_ Getting information about neighbors

_ Initialization

_ Link state database


4. Define bridge and explain the type of bridges.

_ Bridges

_ Types of bridges

_ Simple bridge

_ Multiport bridge

_ Transparent bridge


5. Explain subnetting

_ Subnetting

_ Three levels of hierarchy

_ Masking

_ Masks without subnetting

_ Masks with subnetting

_ Finding the subnetwork address

_ Boundary level masking

_ Non-boundary level masking


6. Write short notes about repeaters, routers and gateways.

_ Repeaters

_ Routers

_ Routing concepts

_ Least-cost routing

_ Non adaptive routing

_ Adaptive routing

_ Packet lifetime

_ Gateways


UNIT IV


1. Explain the duties of transport layer.

  • End to end delivery
  • Addressing
  • Reliable delivery Error control Sequence control Loss control Duplication control
  • Flow control
  • Multiplexing


2. Explain socket in detail.

  • Introduction Explanation program


3. Explain UDP & TCP.

_ User Datagram Protocol(UDP)

_ Source port address

_ Destination port address

_ Total length

_ Checksum

_ Transmission Control Protocol(TCP)

_ Source port address

_ Destination port address

_ Sequence number

_ Acknowledgement number

_ Header length

_ Reserved

_ Control

_ Window size

_ Check sum

_ Urgent pointer

_ Options and padding


4. Explain about congestion control.

_ Congestion avoidance

_ BECN

_ FECN

_ Four situations

_ Discarding


5. Explain leaky bucket and token bucket algorithm

_ Leaky bucket algorithm

_ Leaky bucket

_ Switch controlling the output rate

_ Flowchart


UNIT V


1. Explain the functions of SMTP.

System for sending messages to other computer users based on e-mail addresses. SMTP provides mail exchange between users on the same

or different computers.

  • User Agent
  • Mail Transfer Agent
  • Multipurpose Internet Mail Extensions
  • Post Office Protocol


2. Write short notes on FTP.

  • Transfer a file from one system to another.
  • TCP connections
  • Basic model of FTP


3. Explain about HTTP.

  • HTTP transactions
  • HTTP messages
  • URL


4. Explain the WWW in detail.

  • Hypertext & Hypermedia
  • Browser Architecture
  • Categories of Web Documents
  • HTML
  • CGI
  • Java


5. Explain the type of encryption/decryption method.

Conventional Methods:

Character-Level Encryption: Substitutional & Transpositional

Bit-Level Encryption:

Encoding/Decoding, Permutation, Substitution, Product, Exclusive-Or & Rotation

Public key Methods


6. Explain about RSA algorithm.

  • Public key Encryption technique.
  • Encryption algorithm
  • Decryption algorithm
  • Security in RSA

  • 7. Explain about secret key encryption algorithm.
  • Data Encryption Standard
  • Algorithm
  • Sub key generation