Reference no: EM132210026

Wireless Ethernet and TCP/IP Networking

Q1 View the series VLANs and Trunks for Beginners - Part 1 about VLANs and trunks.

Proceed to explain the following:
a) Differences between an (i) access port and (ii) a trunk. Refer to IEEE 802.1Q VLAN standard.
b) Give a concise description with graphic illustration of an IEEE 802.1Q field added to an Ethernet packet.

Q2 Explain the working of the following layer-2 network devices:
a) CSMA/CD in a scenario with 4 x Network Interface Cards (NICs) connected to a 4-port hub.
b) Why does a full-duplex switch behave similar to the hub above at start-up?
c) How does Auto-negotiation function on a switch port and what is its advantages?

Q3 The concept of "Determinism".
a) Explain the importance of determinism in an industrial LAN and
b) Explain why a lightly loaded Fast- or Gigabit Ethernet, can be construed as deterministic enough for most industrial systems.

Q4 NETID
a) Explain the role that NETID plays in routing an IP packet on the LAN of origin.
b) Furthermore, explain the concept of subnetting within a domain.
c) Why is the amount of available Host ID's on a subnet always 2 less than the maximum?
d) Illustrate this by calculating the amount of Host ID's on a class C subnet

Q5 Subnet mask = 255.255.255.128
a) Is the above subnet mask valid in a class C NetID environment?
b) How many Host ID's can be hosted on the above-mentioned subnet?
c) A host on the subnet mentioned in (e) is preparing to send a packet to a destination host with IP address 192.168.0.132. Will this IP packets be delivered directly or via the default gateway? Explain your answer.

Q6 Static vs dynamic routing tables:
a) Discuss the difference between static and dynamic routing tables
b) Name three advantages of static routing tables.

Q7 Reserved IP addresses
a) Are the series of addresses contained in 192.168.0.x a part of reserved IP addresses? If so, in which class? Explain your answer.
b) Which series of IP addresses are reserved in class B?

Q8 P Routing concepts.
Study: Network address translation and answer the following questions.
a) What was the original use of NAT?
b) Explain the concept of IP masquerading.
c) Explain the concept of port forwarding and DMZ.
d) What is the purpose of route tracing?
e) Which DOS utility can be used for route tracing?

Q9 2.4GHz Wi-Fi
You may read INTERFERENCE OF 802.11B WLAN AND BLUETOOTH: ANALYSIS AND PERFORMANCE EVALUATION

a) How many non-overlapping IEEE 802.11b channels are there in the 2.4 GHz ISM band?
b) How wide (bandwidth in MHz) should each of these non-overlapping channels be?
c) How far are they supposed to be spaced apart (in MHz)?

**You may read additional information on this question.

You have to use two IEEE 802.11b APs in close proximity. The first is set to channel 1.
d) What channels could you use on the second one
e) Why?

Q10 5GHz Wi-Fi

You have two IEEE 802.11a APs, one of them is on channel 42.
a) Is this an indoor or an outdoor frequency in South Africa?
b) What will be the closest channel for United States?
c) What will be the closest channel for Australia?
d) What form of modulation is used on this technology?

Q11 a) ISM bands
a) What was the ISM bands originally intended for?
b) What additional use have they found lately?

Q12 Encoding (other than SS)
In figure 4 the number of bits encoded per symbol (vertical axis) is shown against the signal-to-noise ratio (horizontal axis) required for successful transmission.
a) Does 16 QAM provide a significant advantage over any other encoding scheme on a noisy channel at 5dB SNR? Explain your answer.
b) Does 16QAM hold a significant advantage over 16PSK on a 15dB SNR channel? Explain your answer.
c) What is the minimum SNR required for QPSK to work well?
d) Would you say it can be advantageous to have an encoder which can encode any of the five schemes as well as a monitoring tool for the SNR ratio of the channel? What would you be able to do with such a setup?

Q13 Spread Spectrum (SS) encoding
a) Name four spread spectrum techniques.
b) Which one of them was originally devised against eaves-dropping in the military environment?

Q14 Comprehensively define radio frequency terms
Research and concisely describe the following RF terms:
a) Isotropic antenna
b) Antenna Gain
c) Beam width

Q15 Radio frequency calculations
You have a 20dBm transmitter, running through 35m of coaxial cable with a 18dB/100m loss, to its antenna.

Assume:
- 6dBi antenna the transmitter
- 21dBi antenna at receiver
- loss through free space is 108.4dB

a) Draw a system block diagram with every point of calculation numbered
b) Calculate the launch level at the transmitter's antenna
c) Calculate the receive level at the receiver's input

Q16 Insight in RF systems
Would a perforated high-gain dish antenna be suitable for use as the antenna at the base station in a PtMP (Point to Multi-Point) setup, yes or no? Fully describe why you chose the answer you did.

Q17 Wi-Fi setup, variants and terms
a) Describe the typical steps to install & set up a new Wi-Fi AP.
b) Compare various Wi-Fi technologies by completing table 1
c) Explain the significance, and give an example each of:
(i) BSSID
(ii) SSID
d) Briefly explain the concepts of (Layer2) bridging
e) Briefly explain the concepts of (Layer2) roaming

Q18 Medium Access Control Algorithms
a) Expand the acronyms and describe the basic difference in the operation between IEEE 802.3 (CSMA/CD) and IEEE 802.11 (CSMA/CA) Medium Access Control methods.
b) Now expand on the concept of CSMA/CA as used in Wi-Fi.

Q19 Wi-Fi sign-on, authentication and security issues
a) With reference to Wi-Fi, expand the acronyms AES and RADIUS explain what it is and how it is used in authentication.
b) How does the WPA (or WPA2) authentication implementation differ for:
(i) Home users (WPA-Personal)?
(ii) Corporate (WPA-Enterprise) users?
(iii) How does PSK fit into the above?

Q20 Wi-Fi site surveys
a) List the steps involved in performing a site survey for Wi-Fi.
b) Name 4 measurements taken during an active Wi-Fi site survey.

Q21 Industrial RF technologies
a) Give a brief technical description on Wireless HART
b) Point out at least 4 differences between Wireless HART and ISA100.11a
c) What is ISA 100.11a?
d) Why was the ISA100 committee formed?

Q22 Which 802.11 standard has the best performing parameters in terms of data rate, range, channel separation issues and interoperability?
a) 802.11n
b) 802.11b
c) 802.11g
d) d. 802.11a

Q23 WPA2 uses IEEE 802.X with the Extensible Authentication Protocol (EAP) to perform mutual authentication, either via a ............... server or by means of a changing key generated on the basis of a shared secret pass-phrase.
a) AES
b) RADIUS
c) WEP
d) Common

Q24 At the MAC level, 802.11 LANs involve the use of ______ for medium access control.
a) CSMA/CD
b) CSMA/CA
c) BSSIDs and SSIDs
d) d. Bridging and Roaming

Q25 Which two answers are true?
a) Auto negotiation is mandatory for a 1000BASE-T LAN
b) The IP Masquerade server acts as a router
c) NAT is an acronym for Network Address Token
d) Port forwarding is referred to as tunnelling
e) Determinism has no pre-determined or fixed timing
f) The default gateway performs bridging functions

Q26 How many hosts are possible on each subnet of a class B network if the subnet mask is 255.255.224.0? What are the total number of subnets on this class B network?
a) 8190 and 6
b) 62 and 16
c) 30 and 14
d) 8192 and 8

Q27 Which two answers are TRUE for Ethernet (IEEE802.3) Frames?
a) The Source and Destination Address fields carry 6 bytes in total
b) The payload data field is a variable length field and depend on the data carried
c) No CRC is used as the frames are inherently reliable
d) The Preamble and SFD fields contain 8 bytes each
e) The Source and Destination Address fields carry 6 bytes each

Q28 Which two answers are TRUE for the setup of new AP's in a new building?
a) It is not required to plan ahead where AP's are to be installed in a new building
b) There is no reason for IT professionals and architects to consult about building design when as building layout doesn't influence Wi-Fi coverage at all
c) A large of amount of work goes into planning the positions of AP's in new buildings
d) Architects and IT professionals should team up when planning AP's in new buildings as little design changes can have a profound influence on coverage
e) Radius servers are not required in corporate Wi-Fi systems

Q29 Which three answers are TRUE for Wi-Fi?
a) Roaming is best carried out by giving each AP its own SSID
b) An AP can either be a bridge or an AP, never both simultaneously
c) The BSSID of AP's are often taken from the MAC address of the radio
d) Corporate roaming requires a RADIUS server to invisibly hand users over between stations
e) When AP's are used in bridge + AP mode, they easily become bottlenecks as load increases