COMPUTER NETWORKS 4TH MARCH 2012 Examination Paper Answer ALL questions. Clearly cross out surplus answers. Time: 2 hours Any reference material brought into the examination room must be handed to the invigilator before the start of the examination. ANSWER ALL QUESTIONS Marks QUESTION 1 a) State FOUR (4) principles underpinning the Open Systems Interconnection (OSI) Reference Model. b) Describe the purpose of the physical layer of the OSI Reference Model. c) State THREE (3) elements of network design that relate to the physical layer of the OSI Reference Model. ) Describe the purpose of the data link layer. 4 1 3 2 Total 10 Marks QUESTION 2 a) b) c) d) Define the term a packet as used in computer networks. Briefly describe the THREE (3) key components of a packet. Explain the difference between a LAN, MAN and WAN. Describe how signal reflection could be a problem in an Ethernet LAN and explain how this is prevented. 1 3 3 3 Total 10 Marks QUESTION 3 a) b) c) d) Explain why wireless technology was not initially widely adopted. State THREE (3) advantages to using wireless peripheral devices. Describe what a wireless adapter is.
Describe what an access point is. 3 3 2 2 Total 10 Marks QUESTION 4 a) b) c) d) Explain what physical topology is. Explain what logical topology is. Describe how physical topology and logical topology relate to each other. Describe how point to point networks operate. 2 2 2 4 Total 10 Marks QUESTION 5 a) b) c) J State FIVE (5) factors to consider when choosing physical media for a computer network. State FOUR (4) advantages to using fibre-optic cable as a network medium. State the main disadvantage to using fibre-optic cable as a network medium. 4 1 Total 10 Marks QUESTIONS CONTINUE ON NEXT PAGE Page 2 of 3 Computer Networks March 2012 Formatted/HW © NCC Education Ltd 2012 Marks QUESTION 6 a) b) Explain what a repeater is and briefly describe how it works. Explain what a router is and briefly describe how it works. 6 4 Total 10 Marks QUESTION 7 a) b) c) List FIVE (5) key factors to take into account when locating wireless access points. You have located an access point in the best available place for your wireless network but it is not providing the complete coverage you require.
State THREE (3) options you have to extend the coverage of the wireless network. Your wireless network allows public access via a login page. Describe TWO (2) features that should be included in your login page. 5 3 2 Total 10 Marks QUESTION 8 a) b) c) d) A secure network offers privacy. Explain what privacy is in this context. A secure network offers integrity. Explain what integrity is in this context. A secure network offers availability. Explain what availability is in this context. Describe a man-in-the-middle attack. 2 3 2 3 Total 10 Marks QUESTION 9 a)
Firewall traffic blocking rules can be created for network traffic based upon a number of different properties. State THREE (3) properties that are used to create firewall rules. b) Explain what a router firewall does. c) List FOUR (4) key tasks that are vital for managing a firewall. 3 3 4 Total 10 Marks QUESTION 10 a) b) c) State the THREE (3) main functions of a Network Operating System (NOS). Describe how a redirector works. State THREE (3) network services that a NOS will typically enable. 3 4 3 Total 10 Marks END OF EXAM Page 3 of 3 Computer Networks March 2012 Formatted/HW © NCC Education Ltd 2012