SKR Engineering College 2006 B.E Computer Science COMPUTER NETWORKS - Question Paper

Subject Name: Computer Networks (CS1302)

Part - A
1.What is meant by IP spoofing? How can a router be used to prevent IP spoofing?
2.Define character – oriented and bit – oriented protocols.
3.What is the need for bit stuffing?
4.What is the use of ARP and RARP, ICMP protocols.
5.The period of the signal is 100ms. What is the frequency in kilohertz?
6.Identify the class and the default subnet mask if the IP address 217.65.10.7
7.Define reflection, refraction and critical angle.
8.Express a period of 100ms in microseconds.
9.What are the functions of presentation layer?
10.Define bit stuffing.

Part- B
11.(a) (i) define the key elements of protocols and the standards.(8)
(ii) discuss in detail the data transmission in OSI reference model.(8)
(OR)
(b) describe OSI. elaborate the layers of OSI? discuss about physical, data link,
network and session layer.

12.(a).Describe 2 approaches by which packet loss is detected in a Go Back-N ARQ protocol and selective repeat protocol.
(OR)
(b). With detail explanation classify guide and unguided media.

13.(a) (i) What is the remainder found by dividing x7+x5+1 by the generator polynomial x­3+1?
(ii) A bit stream 10011101 is transmitted using the standard CRC method. The generator polynomial is x3+1. Show the true bit string transmitted. Suppose the 3rd bit from left is inverted during transmission. Show that this fault is detected at the receiver’s end.
(iii) A bit String 0111101111101111110, needs to be transmitted at the data link layer. What is the string truly transmitted after bit stuffing?
(OR)
(i) discuss CSMA/CD algorithm of Ethernet.
(ii) discuss Token Ring and Token bus in detail.

14.(a) (i) Compare and contrast Link state and Distance Vector algorithms. (8)
(ii) obtain the shortest distance using distance vector routing algorithm. (8)
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(b) discuss about the congestion control in frame Relay and TCP Network.



15.(a) discuss about SMTP, FTP, WWW, HTTP with their uses and state strengths
and weakness of every of them.
(OR)
(b) (i)Explain the role of a DNS on a computer network, including its involvement
in the process of a user accessing a web page.
(ii) define about symmetric- key cryptography.

Earning:   Approval pending.