1. In each of the following scenarios there is a relationship to work life in the IT industry. With each of the following question, ensure that your answer includes the explanation of how it would be applied to workplace situations. Write short notes after investigating the following scenarios: [2+2+4=8 marks]
a) 802.11a supports different modulation techniques, each allowing for different data rates. This adds complexity and cost to the radio, so your boss suggests 802.11zzz should only support one modulation technique, namely the maximum data rate possible. Do you support this idea? Why or why not?
b) Your company wants to provide wireless networking services in public places, such as in an airport lounge, where a wireless networking device detects multiple wireless networks with different SSIDs. What is the use of employing an SSID mechanism, state two reasons as to why it is necessary?
c) You company provides wireless networking services. One of your customers complains about the downloading performance being poor. After investigation, you find that the customer’s 802.11 wireless network is interfering with his neighbour’s wireless transfers. You want to improve performance, but you do not have any control over the neighbour’s wireless connection (The only thing under your control is your customer’s wireless router). Discuss the suitability of the following strategies in achieving better performance, e.g., under what conditions could it help, and when may it not be effective.
i. Frequency Assignment – Assigning a different channel to the user’s wireless router.
ii. Power Control — Lowering the transmit power of the user’s wireless router.
iii. Enable RTS/CTS
2. Suppose a large office building has ESS WLAN for the office users. As a network engineer, you are asked to identify the drawbacks of the ESS WLAN with respect to roaming users. What would you recommend as a remedy to this drawback, if there any? [3+3=6 marks]
3. Explain how the CSMA/CA in DCF handle media contention. [5 marks]
4. Suppose your company is going to provide services on broadband wireless access networks. For this reason you are asked to perform a comparative study on different technologies of wireless broadband networks. You need to complete the following table based on your study (please replace Technology T with an appropriate technology similar to WiMAX and Wi-Fi, also add few additional features in place of Feature x, y and z): [6 marks]
Feature
WiMAX
Wi-Fi
Technology T
Frequency band
Channel bandwidth
Radio Technology
Half/Full Duplex
Modulation technique
Bandwidth Efficiency
Access protocol
Feature x
Feature y
Feature z
5. Define ‘throughput’ in regards to wireless network. Use a practical method (e.g., using an software) to measure throughput of a wireless network? You should provide any appropriate screenshots.[5 marks
