AMIETE – CS/IT (OLD SCHEME)

Code: AC12 / AT10                               Subject: DATA COMMUNICATION & NETWORKS

Time: 3 Hours                                                                                                     Max. Marks: 100

NOTE: There are 9 Questions in all.

· Question 1 is compulsory and carries 20 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.

· Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.

· Any required data not explicitly given, may be suitably assumed and stated.

Q.1       Choose the correct or the best alternative in the following:                                 (2 10)

a. Interconnected networks need communication processors such as switches, routers, hubs, and gateways. Select the best option:

(A)  TCP/IP                                        (B)  protocol

(C)   open systems                               (D)  internetwork processor

b. Coaxial cable, microwave, and fiber optics are  all examples of:

(A) enterprise collaboration                 (B)  electronic commerce

(C)  telecommunication channels          (D)  telecommunication media

             c.   A communication medium that uses pulses of laser lights in glass fibers is ……

(A) fiber optic cables                          (B)  cellular phone systems

(C)  telecom processors                       (D) telecom software

             d.   A tree toplogy is a variation of a ………….. topology.

(A) mesh                                            (B)  star

(C) Unipolar                                       (D)  Manchester

             e.   Node to Node delivery of data unit is the responsibility of ….. layer.

(A)  physical                                        (B)  data link

(C)  transport                                      (D)  network

             f.    Which layer offers mail services and directory services to user in network?

(A) data link                                       (B)  session

(C)  transport                                      (D)  application

             g.   ISDN is acronym for……………

(A) Information services for digital network          

(B) Internetwork system for data networks

(C)  Integrated services digital network     

(D)  Integrated signals digital network

h.   Which following transmission medium can be used  by ATM?

(A) twisted pair cable                         (B)  coaxial cable

(C)  fiber optic cable                            (D)  All of the above

             i.    What is the maximum number of wires required for sending data over a  serial communications link?

(A) 2                                                  (B)  1

(C)  4                                                  (D)  3

             j.    Which of the following transmission media has the largest terrestrial range without the use of repeaters or other devices?

(A)  hardwiring                                    (B)  microwave

(C)  satellite                                         (D)  laser

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

Q.2     a.   Explain essential services provided by networks to the users.  How are they implemented in internet?                                                                     (8)

             b.   A communication system is required to handle signals from a spacecraft to the ground station.  It must handle two 6- MHz video signals, ten 200 kHz data signals from sensors on the equipment and astronauts, and five 3 kHz voice channels.

                   (i)   If all channels were evenly spaced at the width of the widest bandwidth channel, what total bandwidth will be needed?

                   (ii)  If uneven spacing is used, how much total bandwidth is needed, assuming there are no guard bands?

                   (iii) Sketch a frequency domain graph of the signals, with uneven spacing, when the FDM process is used to combine the signals for a signal link.     

(3+3+2 = 8)

Q.3     a.   Explain with block diagram, the working of TCP/IP, when it acts as a pipe between HTTP client and HTTP server.                                                 (8)

             b.   Explain Session Initiation Protocol.  Draw necessary diagrams also.                    (8)

Q.4     a.   Define channel capacity.  How is it related to bandwidth?  Calculate the missing values in the table :-                                                                      (8)

Signal power	Noise power	Bandwidth	Capacity
100 100 10 10	1 2 10 50	3 kHz ? 10 kHz ?	? 20 kbits/s ? 10 bits/s

b.   Explain TCP/IP network architecture, and various protocols available in this.                      (8)

Q.5     a.   Explain with the help of diagram hierarchical routing algorithm.                            (8)

     b.   What types of signals need to be digitized and points to keep in mind for digitization? What circuit element does this and show its operation?         (8)

  Q.6     a. How is mobile communications ordinarily achieved? What range is typically supported by typical base station?                                                (8)

             b.   A cellular system is using 20 base stations to replace a single large base station. The single base station has 200 user frequencies within the spectrum. In theory, what is the maximum no. of users that the cellular system can support? What if 20 percent of increase cannot be used because of overlap in cell coverage?                                                               (8)

Q.7     a.   Explain FDDI and its frame structure by making a block diagram.                       (8)

b.   Explain the sliding window flow control peer-to-peer protocol.                           (8)

Q.8     a.   Why at present it is not possible to have wireless Ethernet and only CSMA-CA is used?                (8)

             b.   Describe the various framing methods.  (8)

Q.9     a.   Write an algorithm/procedure to make a spanning tree algorithm to remove loops in the networks.                                                              (8)

             b.   What is Broadband ISDN?  Briefly explain.                                                        (8)