Computer Networks 1 - Dec 2011

Computer Science Engg. (Semester 5)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) What is data communication?Explain the functional characterstic on which effectiveness of data communication.(6 marks) 1 (b) Differentive between LAN ,Wan and MAN.(4 marks) 1 (c) Explain the OSI reference model for computer netwaorks.(10 marks) 2 (a) What are the factors on which data rate depends in data communication ?(4 marks) 2 (b) Explain the different causes for transmission impairments during signal trasmiission through media(4 marks) 2 (c) Explain with a neat diagram,the components of a PCM encoder(6 marks) 3 (a) With the help of a neat diagram,explain the ASK,FSK and PSK.Discuss the bandwidth requirements in each case(10 marks) 3 (b) What a spread spectrum? Explain the following techniques for spread spectrum:FHSS and DSSS(10 marks) 4 (a) Explain the principle of optical fiber communication. Disscuss the advantages and disadvantages of optical fiber.(6 marks) 4 (b) Obtain the CRC code word using geneator polynominal g(x)=x³+x+1, for the data[100]. Give the hardware reliazation of CRC divisor(8 marks) 4 (c) With the help of an example ,expalin the computation of internet chcksum.Explain how the error detection is done ,using internet checksum.(6 marks) 5 (a) Explain with the help of example ,the concepts of bit stuffing and byte stuffing (6 marks) 5 (b) Explain step and wait ARQ protocol,With the help of a neat diagram(8 marks) 5 (c) Explain the frame formats and control fields for different types of HDLC frames(6 marks) 6 (a) An ALOHA networks transmit 200 bit frame on a shread channel of 20kbs.If the system produces 1000 frames per second,obtain the throughout(6 marks) 6 (b) What is CSMA? Explain the different persistance method of CSMA.(6 marks) 6 (c) Explain the 802.3 MAC frame format(8 marks) 7 (a ) Explain the different persistance method in IEEE 802.11(10 marks) 7 (b) Write a short note on :
TDD TDMA
irtual LAN(10 marks) 8 (a) Explain w.r.t SONET ,the following :
SONET layers
Sonet frame formate
STS multiplexing(12 marks) 8 (b) Explain w.r.t Atm,the following:-
ATM network architecture
ATM frame formats(8 marks)