NOTE: There are 11 Questions in all.
· Question 1 is compulsory and carries 16 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.
· Answer any THREE Questions each from Part I and Part II. Each of these questions carries 14 marks.
· Any required data not explicitly given, may be suitably assumed and stated.
Q.1 Choose the correct or best alternative in the following: (2x8)
a. When data and acknowledgement are sent on the same frame, this is called _________.
(A) Back packing. (B) Piggy packing.
(C) Piggy backing. (D) none of the above.
b. B-PSK usually requires _______________ FSK for the same data rate.
(A) more bandwidth than (B) less bandwidth than
(C) same bandwidth as (D) an order of magnitude more
bandwidth than
c. Uni-polar, bi-polar and polar encoding are examples of _________ modulation.
(A) digital-to-analog (B) digital-to-digital
(C) analog-to-digital (D) analog-to-analog
d. Decryption and encryption of data are the responsibility of the _________ layer.
(A) physical (B) data link
(C) presentation (D) session
e. Virtual circuit switching is a form of
(A) Datagram switching. (B) Message switching.
(C) Packet switching. (D) Circuit switching.
f. X.25 provides data link control using one of the following bit oriented protocol
(A) LAP (B) LAP B
(C) LAP C (D) HDLC
g. A protocol that is concerned with file transfer, management, and access is _________.
(A) MHS. (B) FTAM.
(C) DS. (D) CMIP.
h. In which OSI layer does the FDDI protocol operate.
(A) physical (B) data link
(C) network (D) (A) and (B)
Answer any THREE Questions. Each question carries 14 marks.
Q.2 a. Why are standards important in data communication? Discuss attributes of a good standard. (6)
b. With a neat block diagram give the architecture of data communication path and explain the relevance of modems. (8)
Q.3 a. With neat diagrams give an account of OSI layering with emphasis on the transport layer and its services to above layers. (7)
b. Compare various transmission media (both wired and wireless). (7)
Q.4 a. Write a note on error detection and correction methods. (7)
b. With neat diagrams discuss TCP segment format and IP data gram. (7)
Q.5 a. What is ISDN? Explain the data link protocols used in ISDN. (6)
b. Compare the mechanism of a space division switch to the mechanism of a time division switch. Compare a TSI to a TDM bus. (8)
Q.6 a. Describe the line configuration, transmission mode, flow and error control methods used in BSC transmission. (9)
b. Name and discuss briefly the bits in the HDLC control field. (5)
Answer any THREE Questions. Each question carries 14 marks.
Q.7 a. What is routing? Discuss distance vector routing with the help of a subnet topology. Discuss what are different matrices used in the algorithm. (7)
b. Explain the terms TDM, STDM. Discuss methods used for Frame synchronization. (7)
Q.8 a. Compare the sliding window protocol of data link layer and transport layer. (7)
b. Discuss the short comings of transmission of data through telephone lines. How this problem is solved using optical fibers. (7)
Q.9 a. Explain QPSK system by means of a block diagram. Explain its operation and draw the constellation diagram. (7)
b. For a QPSK modulator construct the truth table for inputs Q=0 and I=0. (7)
Q.10 a. Discuss the concept of line configurations and various transmission modes used in data communication. (5)
b. What is LCU? Draw the block diagram of UART transmitter and explain its operation. Discuss the concept of line configurations and various transmission modes used in data communication. (9)
(i) Describe the format of ATM cell. (5)
(ii) Advantages of frame relay over X.25. (4)
(iii) Mobile IP protocols. (5)