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SECTION A: Networking
1. Solve the following subnetting problems a. Identify the network and host ID for each of the following IP addresses and subnet masks. i. 116.27.123.32 ii. 168.174.9.63 iii. 147.125.177.12
255.255.0.0
255.255.128.0
255.240.0.0
(6 marks) b. Divide the address range 172.72.64.0 /19 into 3 equally sized subnets. i. What will the new subnet mask be? ii. How many usable host addresses will be on each subnet? iii. What will the network addresses be? iv. What will the broadcast addresses be?
(7 marks) c. A new and exciting startup company from Barnsley named “Magic Balloons inc” requires a new network. It is going to use the address range
123.123.12.192 /26 to provide for the following:
● 12 PCs for management
● 27 PCs for sales
● 5 PCs for clowns and unicyclists
Outline a plan to subnet the network, giving the network address, broadcast address, subnet mask and number of usable addresses
(including the default gateway) for each subnet.
(8 marks) d. Should they use switches or hubs to connect the devices together? Justify your answer.
(4 marks)

2. Answer the following a. Discuss the differences between crossover and straight-through cables in
Ethernet networks. When should each be used?
(5 marks) b. What hardware would you need to configure VLANs on a network. Describe how you would go about configuring the hardware to support VLANS
(9 marks) c. What are the two different kinds of addresses used by devices on an Ethernet network? Describe the purpose and structure of both types of address and explain why two different kinds are needed
(8 marks) d. Name the 7 layers of the OSI model and state where the two address types from part c may be found.
(3 marks)

SECTION B: Computer Architecture
3. Number systems and data representation a. Perform the following conversions, showing clearly your methods for each i. Convert the binary number 10011011 to decimal ii. Convert the decimal number 43 to binary iii. Convert the binary number 01101101101 to hexadecimal
(6 marks) b. Perform the following calculations and conversions, again show your working for each i. Add the binary numbers 101110 and 10110 ii. Compute the 8bit two’s complement for decimal -36 iii.
Subtract 10101 from 110011, by addition of two’s complement iv. Use the ‘shift and add’ technique to multiply 101 by 10010
(8 marks) c. A binary number is given in the form 111 x 10 -100 , please answer the following and show your working in each case. (note that the base 10 is equivalent to decimal 2 as the number is in binary) i. Identify the mantissa and the exponent values for the number ii. Give the value of this number in binary iii. Give the decimal value for the number (4 marks) d. Convert the decimal number 9 2 /
3
into binary and express it in the form a x
10 b , where a has a single 1 to the left of the binary point. (note that the base
(3 marks) 10 is equivalent to decimal 2 as the number is in binary) e. Explain what is meant by the term executable code and briefly describe its format, as well as how it differs from high level source code. (4 marks)

4. Logic gates and circuits a. Give the truth table for the following circuit (4 marks) b. Can you produce a simpler circuit (i.e. one with fewer gates in it) with the same functionality? Please use only AND, OR and NOT gates in your answer.
(7 marks) c. Can you recreate the previous circuit using only NAND gates? Show how
(2 marks) d. Is the circuit you have built an example of a sequential or a combinational circuit? Explain your answer.
(5 marks) e. Please provide an example of a sequential circuit. This should be different from circuits provided in the question so far. Describe how it works and what it might be used for? (7 marks)
END OF PAPER