POKHARA UNIVERSITY

Level: Bachelor                                  Semester: Fall                          Year: 2022

Programme: BCIS                                                                               Full marks: 100

Course: Data Communication and Networks                                      Pass Marks: 45

                                                                                                            Time: 3 hrs.

Candidates are required to answer in their own words as far as practicable. The figures in the margin indicate full marks.

                                                                      Section "A"

                                                      Very Short Answer Questions

                     Attempt all questions. [10*2]

 1.  Draw the Bipolar NRz and RZ line coding for message 1010111110.

 2.  Draw Peer to Peer architecture.

 3. Write the name of OSI layer for the following devices: Bridge, Router, Hub, Switch, Repeater, Moderns, Layer-3 Switches, and Wireless.

 4.  Give two examples of guided media and unguided media.

  5. Define Frame Relay. Write down its two features.

  6. Define the networking commands PING, TRACERT and NSLOOKUP.

  7.  Draw IPV4 header format.

  8. What are ports and sockets? What is the range for port addresses?

  9. What do you mean by cloud computing?

  10. Draw the architecture of the Email system..

                                             Section “B”

                                 Descriptive Answer Questions

 Attempt any six questions. [6*10]

      11.  What is line coding? Explain about the transmission impairments.

       12.   What do you mean by connectionless and connection oriented protocol? Differentiate between OSI reference model with TCP/IP model.

       13. Explain Circuit Switching and Packet Switching in detail.

       14.  A 7 bit Hamming code is received as 1011011. Assume even parity and state  whether the received code is correct or wrong, If found wrong, locate and correct the error bit.

        15.  Discuss with real life examples of TCP and UDP protocols. Explain the TCP header in brief.

        16.  What is cryptography? Explain the differences between symmetric and asymmetric cryptography.

         17.  Explain the working principle of DNS.

                                                     Section “C”

                                                 Case Analysis

18. Solve the following cases:

           a)  What is the Network ID,Broadcast Address, First Usable IP, or Last Usable IP on the subnet that the node 202.53.111.15/26 belongs to? [5]

           b) How many subnets and hosts per subnet can you get from the network 202.53.111.0, 255.255.255.224? [5]

            c) You have been asked to create a submit mark for the 172.16.0.0 network. Your organisation requires 1000 subnets, what subnet mask should you use? [5]

            d) Create network for two routers (A and B) connected point to point. Assume IP block 200.200.200.0, use VLSM method. [5]