PART A: Short Answer Questions (10 x 5 = 50 Marks)1. Explain the difference between switch, router and a hub. Please justify your answer with appropriate visuals and diagrams. (5 marks)2. Draw, in...

PART A: Short Answer Questions (10 x 5 = 50 Marks)1. Explain the difference between switch, router and a hub. Please justify your answer with appropriate visuals and diagrams. (5 marks)2. Draw, in chart form, the voltage representation of the following bit sequence XXXXXXXXXXusing different digital encoding schemes; NRZ-L, NRZI, Manchester, differential Manchester, and Bipolar AMI. (5 marks) (Note: Please clearly identify the voltage levels for each scheme)3. Multiplexing combines multiple analog and digital signals into one signal to forward data over a shared medium. Moreover, time division multiplexing (TDM) divides the transmission time on a medium among users and comes in two basic forms. Use appropriate diagrams and illustrations to explain different forms of TDM. (5 marks)4. A company has two offices located approximately one (1) mile apart. The company requires data transfer between these two offices at speeds up to 100 Mbps. List as many solutions as possible for interconnecting two offices. Justify the answers by showing understanding of technical, financial, and political feasibilities. (5 marks) 5. Code division multiplexing allows multiple users to share a common set of frequencies by assigning a unique digital code to each user. Let us consider an example of two (2) mobile users A and B who use code division multiplexing. Mobile user A has been assigned a binary code of XXXXXXXXXX, and Mobile user B has been assigned a binary DPIT127 Networks and Communications Final Assessment (Spring Session 2020) Page 2 of 3 code XXXXXXXXXXThe mobile user A transmits a 1, while Mobile user B transmits a 0. Show the sum of products that results and your calculations. (5 marks) 6. Using the flooding technique on the network graph shown in the figure, how many packets will be created if a packet originates at node A and the network hop limit is set to two? The cost of each path in the network is shown in figure below. (5 Marks) 7. System development life cycle is a methodology or a plan for a structured approach for the development of a successful business plan. Explain the different phases of system development life cycle (SDLC) in detail. (5 marks) 8. Explain different types of substitution-based ciphers used for data encryption with the help of diagrams. (5 marks) 9. To protect data from catastrophic disk failure, disk drivers support one of the redundant arrays of independent disks (RAID) techniques. What are some of the more common RAID techniques used to store this information across multiple disks? (5 marks) 10. What are the main characteristics of a circuit switched and packet switched network? Explain the advantages and disadvantages for each network. Justify your answer with appropriate diagrams. (5 marks) PART B: Long Answer Questions (5 x 10 = 50 Marks) 1. When designing or updating a computer network, the selection of one type of media over another is an important issue to justify time, effort and cost invested. Please explain these different media selection criteria. Provide two examples for each type of (wireless/wired) media, using figures to justify your reason of choice. (10 marks) DPIT127 Networks and Communications Final Assessment (Spring Session 2020) Page 3 of 3 2. A company has 230 workstations in their head office and the IT manager would like to assign a subnetwork address for each department. She wants to create 8 subnets using the XXXXXXXXXX/24 block. How will she compute the subnetwork requirement? Clearly identify the network ID, broadcast ID and host IDs for each subnet. (10 marks) 3. In an internet networking environment, TCP/IP protocol suite performs different networking functions using the Open Systems Interconnections (OSI) reference model comprising of 7 different layers. Please explain the functionality of each OSI layer and identifies how the OSI model and the TCP/IP Protocol suite are mapped with each other. (10 marks) 4. Medium access control protocols allow devices to “take turns” at transmitting data. Two major types of medium access control protocols are: contention-based and round robin protocols. Use a diagram/flowchart or otherwise explain how the carrier sense multiple access with collision detection (CSMA/CD) and (CSMA/CA) work and how they differentiate from each other. (10 marks) 5. Wireless communication transmits digital data using electromagnetic waves, where air is the medium. Please discuss in detail the advantages and challenges faced by Wireless Networks.