Biju Patnaik University of Technology 2010 B.Tech Computer Science and Engineering PCCS4302/ DATA COMMUNICATION AND COMPUTER NETWORKS - Question Paper

1.Answer all the question:

a)Why are protocol and standards needed ?

b)Define carrier signal and its role in analog transmission .

c)Name the advantages of optical fiber over twisted pair and coaxial cable.

d)Can the value of a checksum be all 0s(in binary)? Defend your ans.

e)With a neat diagram mention the frame format of IP datagram ?

f)Define piggybacking and its usefulness .

g)Why was there a need for Dynamic DNS ?

h)In electronic mail,what are the tasks of a user agent ?

i)What is a proxy server and how is it related to HTTP?

j)How does the Ethernet address 1A:3B:4C:6D:2E:1F appear on the line in binary ?

2(a)Compare ranging from secret key and public key cryptographic system.

(b)Differentiate ranging from IPv4 and IPv6.

3(a)What is the drawback of PSK versus FSK modulation ?

(b)How does the frame relay differ from ATM?

4 Write short on any two:

(a) Bluetooth

(b) UDP Protocol

(c) fault detecting codes.

5(a)Show the NRZ and NRZI encoding for 1011 1111 0010 0001.

(b)Suppose we want to transmit the message 1011 0010 0100 1010 and protect it from fault using the
CRC-8 polynomial X^4 + X^2 + X^1 +1 .What is the outcome of the receiver CRC computation if the
leftmost bit of the message is inverted due to the noise on transmission link ? How does the
receiver know that an fault occurred?

6(a)Explain the mechanism of stop-and-wait ARQ.Justify which ARQ can be used to improve upon
stop-and-wait ARQ?How ?

(b)Differentiate ranging from token bus and token ring LAN standards?

7(a)What are the functions of DTE and DTC?

(b)List various methods used to convert digital signal to analog signal and discuss any 1 of
them.

8(a)Differentiate ranging from circuit switching and packet switching .

(b)Explain how space division switch differs from time division switch.

Earning:   Approval pending.