ADCA / MCA (II Yr) Term - End Examination June, 2006 CS - 09: DATA COMMUNICATION AND NETWORKS

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ADCA / MCA (II Yr)

Term
-

End Examination

June, 2006

CS
-

09: DATA COMMUNICATION AND

NETWORKS

Time: 3 hours


Maximum Marks: 75

Note:

Question number

1 is compulsory. Answer any three questions from the rest.

1.

(a)

An analog signal is limited to 4 kHz. It is converted to a PCM signal

using 8 bit / sample. What is
the bit rate on the transmission line?

(3)

(b)

Make a timing diagr
am and show the differences between manchester encoding and differential
manchester encoding for the bit stream 1 0 0 0 1 0 1 1 0 1 1


(4)

(c)

Calculate the number of networks that can exist in Class A, B and C IP addresses. Also, calculate the
number
of hosts a network in each class can have.

(6)

(d)

What happens in a token bus network if a station accepts the token and then crashes immediately?
How does protocol handle this situation?

(6)


(e)

Answer the following questions with respect
to a TCP header


(6)

(i)

Why is the TCP header length required? Explain this.

(ii)

What is the need of a variable size sliding window?


(f)


What is a subnet? How is subnetting implemented? Explain this with the help of an example.

(5)

2.

(a)

Expla
in the TCP connection establishment procedures both in the

normal case and in the call
-
collision case with the help of a

diagram each.

(5)

(b)


Explain two important reasons for having a minimum frame length in CSMA/CD. Explain this
diagrammatically.


(5)

(c)

Derive the throughput expressions for ALOHA and Slotted ALOHA.


(5)

3.

(a)

Sketch a Network Address Translation (NAT) Box, and explain its

operations.


(5)

(b)

Why is there a need for compression? Differentiate between JPEG and MPEG stand
ards.


(4)

(c)

Give at least three functions of a modem.


(3)

(d)

How does UDP handle flow control, error control or retransmission upon receipt of a bad
segment?

(5)

4.

(a)

Explain the operation of an FDDI token ring, with the help of a

diagram.

Also, list the two key
difference between FDDI and IEEE

802'5.

(7)

(b)


Explain the functioning of the HDLC protocol for the following:


(8)

(i)

Busy condition

(ii)

Error recovery using RFJ command

(iii)

Two
-
way data exchange

(iv)

Link setup and disc
onnection


5.

Write any three differences between the following 'pairs' :

(15)

(i)

Circuit switching and Packet switching

(ii)


Connection oriented and Connectionless services

(iii)

ARP and RARP

(iv)

Upward multiplexing and Downward multiplexing

(v)

X'25 and Frame relay