MARCH /APRIL-2013 (C-09)

BOARD DIPLOMA EXAMINATION, (C-09)

MARCH /APRIL-2013

DECE.-VI SEMESTER EXAMINATION

Data Communication AND Computer Networks

TIME: 3 Hours]                                                                     [Total Marks :100]

PART   - A

INSTRUCTION:  (1) ANSWER ALL QUESTION AND EACH QUESTION

                                           CARRIES 4 MARKS

                    (2)  ANSWER SHOULD BE BRIEF AND   STRAIGHT      TO  THE POINT AND SHALL NOT EXCEED FIVE SIMPLE SENTENCES

1.       Write a short note on infrared transmission.
2.       Define channel capacity.

3.      List three important differences between circuit switching and packet switching.

4.       Draw the OSI 7-Layer mode.

5.       Write any six applications of WAP.

6.       List the different layers of TCP/IP protocol stack.

7.       Give the subnet masks for class A, class B and class C addresses.

8.       What is a point-to-multipoint network?

9.       What is Web server? List any two web server addresses.

10.   Write a short a note on remote login.

PART-B                                                                                                                                                                 10*5=50

Instructions :    (1) Answer any five questions and each question carries 12 marks.                 

                        (2) The answers should be comprehensive and the criteria for valuation   is the content but           not the length of the answer.

11.   (a) distinguish between analog  transmission and digital transmission. (b) explain serial and parallel communications.

12.   Compare the characteristics of different transmission media

13.   Explain the following network topologies and write the advantages and disadvantages of each topology: (a) Bus (b) star

14.   Describe CSMA protocol.

15.   (a) write a short note on ARPANET. (b) write a short note on WWW.

16.   Describe the concepts of internetworking.

17.   Explain file transfer protocol (FTP) in Web applications.

18.   Explain how email is transferred.

Answers
1.

Infrared Transmission

•          Uses IR signals to transmit data

•          Infrared have longer wave length than visible light and shorter wave length than radio waves

•          Infrared frequencies are higher than microwaves and lower than visible light

•          Used for short range communication

•          Do not pass through solid objects

•          Simple to develop & cost effective

•          Cannot be used outdoor

•          Low speed

•          Used in remote controllers, hand-held devices, laptops etc

•          Modulate non-coherent infrared light

•          Line of sight (or reflection)

•          Blocked by walls

•          IR is used in wireless communications, monitoring and control applications

   

     e.g. 1.  TV remote control

            2.   IRD port

•          Unguided infra-red waves are widely used in short range communication like remote controls of TV sets ,stereos , VCRs, VCDs, DVDs etc

•          They are directional, cheaper and easy to build. But they don’t pass through solid objects like room walls etc

•          They don’t interfere with similar systems in adjacent rooms or buildings

Infra-red communication can connect note book computers, printers and does not require FCC license