Term-End Examination JUNE, 2007 ( CS-09 )

Term-End Examination JUNE, 2007

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) Draw the waveforms of (i) ASK, (ii) FSK and (iii) PSK for the data 110101100. [ 6 ]

(b) What is the prupose of multiplexing? Differentiate between time division multiplexing and frequency division multiplexing. [ 4 ]

(c) Compare Ethernet, token ring and FDDI on following parameters : [ 4 ]
(i) access method
(ii) Signalling
(iii) Data rate
(iv) Error control

(d) Discuss the functioning of Internet Control Message Protocol. [ 4 ]

(e) Explain distance vector routing algorithm with the help of suitable examble. [ 4 ]

(f) For what purpose is leaky bucket algorithm used? Explain any other algorithm used for the same purpose. [ 4 ]

(g) 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? [ 4 ]


2.(a) Differentiate between Baseband Signal and Broadband Signal. [ 5 ]

(b) Explain the following terms with respect to TCP : [ 10 ]
(i) stream data transfer
(ii) Reliable service
(iii) Window size
(iv) Urgent pointer
(v) Checksum


3.(a) At what layer is sliding window protocol used? Explain the protocol and also discuss the issues which are considered while deciding the window size. [ 9 ]

(b) Construct a systematic (7,4) cyclic code using generator polynomial
g(x)=x^3 + x^2 + 1
consider the data vector d=1010. [ 6 ]

4.(a) Enlist the parameters to measure the efficiency of the network and explain in brief. [ 4 ]

(b). What are various signal encoding techniques, used at physical layer of LAN? [ 4 ]

(c). Calculate the number of networks that can exist in class A, B, C IP addresses. Also calculate the number of hosts a network in each class can have. [ 7 ]


5.(a) Explain using diagrams, how the process of formation and pruning of a spanning tree takes place in multicast routing. [ 5 ]

(b). What is the application of Network Address Translation Box? Also explain its operation. [ 5 ]

(c). If signal to noise ration is 7 dB and bandwidth is 10 kHz, find [ 5 ]
(i). the capacity of a channel.
(ii). What should the signal to noise ratio be in dB to increase the capacity by 20% f calculated capacity.