DipIETE – ET/CS (OLD SCHEME)

 

Code: DE21 / DC11                               Subject: DATA COMMUNICATION & NETWORKS

Flowchart: Alternate Process: DECEMBER 2009Time: 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:                                   (2x10)

       

             a.  TCP/IP protocol has _________ independent layers

 

                  (A) 7 years                                           (B) 3 years

                  (C) 5 years                                           (D) 9 years

 

             b.  In stop-and-wait ARQ, ARQ stands for

 

                  (A) Automatic reply request                  (B) Automatic repeat request

                  (C) Acknowledgement request              (D) Automatic request repeat

 

             c.  Terminator is used in ________ topology

 

                  (A) Mesh                                             (B) Star

                  (C) Ring                                               (D) Bus

 

             d.  Cable television uses

 

                  (A) FDM                                             (B) TDM

                  (C) Synchronous TDM                         (D) Statistical TDM

 

             e.  ATM is also called

 

                  (A) Frame Relay                                   (B) Data Relay

                  (C) Cell Relay                                      (D) Protocol Relay

 

             f.   URL stands for

 

                  (A) Unique Resource locator                (B) Uniform Resource locator

                  (C) Universal Resource locator             (D) Uninterrupted Resource locator

 

             g.  Which of the following is not a modulation technique?

 

                  (A) ASK                                              (B) MSK

                  (C) PSK                                              (D) FSK

 

             h.  Data transmission in either direction, one direction at a time is

 

(A)  Full Duplex                                     (B) Half Duplex

                  (C) Simplex                                          (D) None of the above

 

             i.   DTE stands for

 

                  (A) Data Terminal Equipment                (B) Data Transmission Equipment

                  (C) Digital Terminal Equipment             (D) Digital Transmission Equipment

 

             j.   The optimum frequency range for satellite transmission is

 

                  (A) 2 GHz – 40 GHz                            (B) 1 GHz – 10 GHz

                  (C) 30 MHz – 1 GHz                           (D) 10 GHz – 100 GHz

 

 

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

 

 

  Q.2     a.   What is OSI Reference model? Briefly discuss the various layers in the model.                    (8)

            

             b.   Briefly describe the key elements of a communication model along with a neat diagram.                   (8)

 

  Q.3     a.   With any communication system, the received signal will differ from the transmitted signal due to various transmission impairments. Discuss these impairments in detail.                                             (6)

 

             b.   Discuss the working principle of optical fiber. With the help of a neat sketch. Also discuss its characteristics, which distinguish it from twisted pair and co-axial cable.                                                     (10)

 

  Q.4     a.   Briefly discuss the HDLC frame structure along with a neat diagram.                   (8)

       

             b.   What is a bridge? Briefly discuss the various functions performed by a bridge.                     (8)

 

  Q.5     a.   What are the important requirements specific to the wireless LAN environments?                (8)

 

             b.   Define multiplexing. Also explain FDM along with its characteristics.                   (8)

 

  Q.6     a.   What are the advantages of packet switching over circuit switching?                    (8)

 

             b.   Define the following:

 

                   (i) Thermal Noise.                                (ii)   Impulse Noise.                                 (4)

 

             c.   Briefly explain fixed routing along with its advantages and disadvantages.             (4)

 

  Q.7     a.   What do you mean by IPv6?  What enhancements have been included in IPv6 over IPv4?              (8)

 

             b.   Briefly explain SMTP and MIME. What are the limitations in SMTP, which have been addressed in MIME?                                                           (8)

 

  Q.8     a.   Define the following terms:

 

                   (i)   Proxy                                            (ii)  Gateway  

                   (iii) Crosstalk                                       (iv)  HTTP                                              (8)

 

             b.   Briefly explain the various principles that guided the designing of the OSI layers.                  (8)

            

  Q.9     a.   Briefly explain ATM. Also compare ATM or Cell relay with frame relay.            (8)

 

             b.   Define ISDN and what are the principles of ISDN as defined by ITU-T.             (8)