Computer Networks 1 - Dec 2014

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 are the communication system? Explain in brief.(5 marks) 1(b) With a neat diagram, explain the interaction between layers in the OSL model.(10 marks) 1(c) What is the difference between a physical and logical address? Explain with example.(5 marks) 2(a) Distinguish between low pass channel and a pass channel.(6 marks) 2(b) A network with bandwidth of 10Mbps can pass only an average of 18,000 frames per minute with each frame carrying an average of 10,000 bits. What is the throughput of this network?(4 marks) 2(c) Compare and contrast between PCM and DM.(6 marks) 2(d Explain polar bi phase Manchester and differential Manchester encoding schemes with example.(4 marks) 3(a) Explain following modulation techniques :
i) Amplitude modulation.
Frequency modulation.(6 marks) 3(b) A multiplexer combines four 100k bps channels using a time slot of 2 bits.Show the output with four arbitrary inputs. What is the frame rate? What is the frame duration? What is the bit rate? What is the bit duration?(4 marks) 3(c) with relevant diagrams, explain the data transfer phase in virtual circuit network(10 marks) 4(a) Explain CRC error detection method with an example.(6 marks) 4(b) Explain the structure of encoder and decoder for a Hamming code.(4 marks) 4(c) What is internet checksum? If a sender need to send four data items 0 X 3456,0 X ABCC,0 X 02BC and 0 X EEEE,answer the following:
i) Find the checksum at sender site.
ii) Find the checksum at receiver's site if there is no error.(10 marks) 5(a) Explain GO-BLCK-N ARQ. List the differences between them.(10 marks) 5(b) Explain the different frame types in HDLC.(6 marks) 5(c) Write a short note on piggybacking.(4 marks) 6(a) With a flow diagram, explain the working of CSMA/CD(10 marks) 6(b) Explain the following channelization techniques : i) TDMA ii) CDMA .(10 marks) 7(a) What do you mean by hidden and exposed station in IEEE 802.11 protocol. Explain in detail.(6 marks) 7(b) With neat diagram,explain the architecture of Piconet and Scatternet Blue tooth networks.(6 marks) 7(C) Explain the working of global system for mobile (GSM) in detail.(8 marks) 8(a) Explain IPV header format with its extension headers.(10 marks) 8(b) Write short note for following :
i) Token Passing
ii) Gigabit Ethernet
iii) Polling
iv) FHSS(10 marks)