Week 1 - Intro to Wireless Networking

Question 1

What is Wireless Networking

Answer 1

Communication can be done via Wired or Wireless

Wired = Guided Signal via Cable or Wire

Wireless = Unguided Signal via Antennae

Electromagnetic Waves = Electric and Magnetic Fields that for Sinusoidal Waves

Question 2

Describe Electromagnetic Waves

Answer 2

1897 - Guglielmo Marconi first demonstrated Wireless Telegraphy using EM waves

1900 - Marconi used Radio Transmission to send messages using Morse Code

Advantages = Cost. Mobility. Ease of Installation. Reliability

Disadvantages = Interference. Signal Strength (Repeaters to boost signal strength through thick walls.
Security = MITM and Wireshark
Health and Welfare = EM Radiation (EMR) and suspected use of a sonic attack in Cuba ( US embassy employees complaining of neurological symptoms

Question 3

Describe different types of Wireless Technologies

Answer 3

RFID ( Radio Frequency Identification)
Near Field Communication (NFC)
Wi-Fi ( Wireless Fidelity)
Microwave
GSM (Global System for Mobile Communications)
Infrared
Bluetooth
GPS (Global Positioning System)
RF ( Radio Frequency)

Question 4

Describe the different types of Wireless Transmissions

Answer 4

2.4GHz Frequencies and Channels
14 Channels (1 - 14) - Operates @ 2.412 - 2.484GHz
Each channel is 5MHz apart - Some overlap (Interference)
To avoid overlap - routers (in USA) operate on Channel 1(2.412), 6 (2.437) and 11 (2.462)

5GHz Frequencies and Channels
200 Channels
Numerous Non-overlapping Channels
Some channels are restricted
US routers commonly utilise 36,40,44 and 48

Question 5

Describe the Wireless LAN Technologies - 802.11a and 802.11b

Answer 5

802.11a and 802.11b
Ratified in 1999
802.11a better than 11mbps of 802.11b but cost of associated hardware was expensive.
802.11a - Theoretical bandwidth of 54 mbps
a+b operate on diff frequencies…
a = business and b = homes

Question 6

Describe 802.11g

Answer 6

WLAN standard - 3rd Protocol
Operated over a short distance
54 Mbps
2.4GHz - 2.4835GHz
Jan 2003 - Quickly adopted
Higher speed and lower maintenance cost

Question 7

Describe 802.11n and 802.11ac

Answer 7

IEEE 802.11n = 2009
MIMO (Multiple Input and Multiple Output)
Fast throughput
600Mbps

IEEE 802.11ac - Approved Jan 2014
5GHz band
WiFi 5
1Gbps
Excellent for Video Streaming

Question 8

Describe WiFi 6 - 802.11ax

Answer 8

Released in Sep ‘19
4 x throughput of 802.11ac
1148Mbps on 2.4GHz - 4804Mbps on 5GHz
Peak total bandwidth of 6000Mbps
Support explosion of IoT devices
Improve public WiFi in spaces such as train and bus stations
QAM Modulation ( More data per packet) Broader channels broken into sub channels
Multi User, Multi Input, Multi Output (MU-MIMO)
Beamforming Tech - More pronounced beam to antennae

Question 9

Describe WiFi 6

Answer 9

Developed by WiFi Alliance to enable WiFi access to growing no. of devices.(2020 - 12.3bn mobile devices/21bn IoT)
Pressure on public networks
4K video
Operates on 2.4 and 5GHz
Theoretical max throughput of 10.53Gbps
30% increase in speed
Quadrature Amplitude Modulation (QAM)

Question 10

Explain QAM ( Quadrature Amplitude Modulation )

Answer 10

QAM is a modulation scheme in digital telecommunication. It uses modulated radio waves to push through more bits per transmission.
Wifi 6 is 1024 QAM and can transmit 10 bits at a time (2 bits more than WiFi 5)
WiFi 6 routers can deliver up to 12 simultaneous WiFi streams which reduces latency.
Companies such as Netgear are making WiFi6 routers
ISPs still need to catch up with latest tech
OFDMA (Orthogonal Frequency-Division Multiple Access) tech enables 802.11ax router to send and receive data to multiple devices simultaneously by splitting transmission channels into sub channels
WiFi 7 is under development

Question 11

WLAN Topologies Ad Hoc Mode

Answer 11

Ad - Hoc Mode
1 comp internet access and 1 comp no internet
No access point - Less risk of failure to connect
Wireless Ad Hoc Network (WANET) - Beneficial for sharing files
Proximity = 100 Metres
Share your wireless connection

Ad-Hoc Network
Mobile Ad-Hoc Network (Manet)
Vehicular Ad-Hoc Network (Vanet)
Smartphone Ad-Hoc Network (Span)
Wireless Mesh Network
Army Tactical MENT
Wireless Sensor Network
Disaster Rescue Ad Hoc Network

Question 12

Describe Infrastructure Mode

Answer 12

A wireless network framework that has a central WLAN access point/router at the heart of the network.
Wireless devices then communicate with each other via this access point

In this mode, routing and security functions are centralised.
When using an access point, there are a number of security verifications that take place including:
MAC address verification, Encryption and SSID checking
MAC address verification involves verifying that the MAC address of a device that wishes to connect to an access point is allowed to connect to a network.
A Service Set Identifier (SSID) is the name associated with the network.
An access point or router can be associated with an SSID.
Thus a device must have a trusted SSID that is associated with the router’s SSID
WEP (Wired Equivalent Privacy) - This means that the access point is encrypted with an encryption key. A device can therefore only connect to that router or network if it possesses the encryption key. However a number of security vulnerabilities have been exposed this way.
Therefore, the preferred encryption protocol for routers is WPA.
Broadband routers often contain a wireless LAN access point which can possess unsecure access to the internet.
Infrastructure mode also applies to public WiFi access.

Question 13

What is Wigle.net and how is it beneficial for SSIDs

Answer 13

If you pull a list of SSIDs from a smartphone that you are investigating and you want to know the location for a SSID, this website is ideal

Question 14

Explain Bridge Mode

Answer 14

We can connect 2 different parts of a network wirelessly.
No cables
Low cost as no cabling and scalability
This type of topology can be used in homes or small offices
E.g, a wireless network in a conference room could be wirelessly connected to an office network

Question 15

WLAN Security Issues

Answer 15

A rogue access point could be set up by an employee who wishes to access certain websites that are blocked by the corporate network
Similarly, an access point could be created by a hacker who wishes to sniff traffic on your wireless network
Look at the Hack5 website and search for the pineapple ( can get devices to connect to it as a rogue access point and then sniff the user traffic)
Your device will believe it is connecting to an access point with the strongest signal

Question 16

Explain WiFi Scanning Modes

Answer 16

2 ways - Active and Passive

Active Scan - Device searches for a wireless network by transmitting probes and listens for a response from access points that are within range.
A probe request can be broadcast to a number of access points or sent directly to an access point.
With a broadcast probe request, the request by the client will include SSID = Null. The access point will then respond with the name of the access point in terms of its SSID
A direct probe request will include the name of the SSID that the network adapter wishes to connect to. The response indicates the configuration and capability of the wireless network managed by the access point.

Passive Scan - A client device listens for beacons that are specific frames transmitted by the access point.
While scanning the device or application can determine the SSID
WiFi scanning is a means by which a device discovers wireless networks that are within range of the WiFi adapter.
They define the device and determine the information about the network
which can include the channel, signal strength and security configuration.
This info is then used to determine which wireless networks a device may join or connect to.

Question 17

Active Probe Request (Direct)

Answer 17

In this scenario, the client sends a direct request to connect to an access point on the network with the SSID of UCD.
That access point in turn responds to the request.
Authentication can then occur.

Question 18

Active Probe Request (Broadcast)

Answer 18

In this scenario, the client sends a broadcast probe request to connect to access points within range of the clients network adapter.
Both access points respond to the request.
Once a probe request has been completed, then an authentication request response can be made

Question 19

Security Concerns of Wireless Networks

Answer 19

Packets can be intercepted during transmission
Traffic and data can be decrypted
Once packets are decrypted a hacker can access encryption keys
One way to mitigate the risk is to hide the SSID which is the access point name
MAC address filtering is another means of mitigating risk whereby only certain devices with a specific MAC address will be allowed access on a network.
Hackers can also monitor beacons and probes as they gather reconnaisance about a wireless network