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COMP41580 VoIP and Wireless Investigations > Introduction to Wireless Networking > Flashcards

Introduction to Wireless Networking Flashcards

1
Q

Advantages of wireless networking

A
  • Convenience
  • Mobility
  • Productivity
  • Easy setup
  • Expandability
  • Security
  • Reduced cost
  • Reliability
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2
Q

Disadvantages of wireless networking

A
  • Interference
  • Signal Strength
  • Security
  • Health & Welfare
  • Transmission speeds
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3
Q

The two Wi-Fi Frequencies

A

2.4 GHz, 5 GHz

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4
Q

Characteristics of 2.4 GHz

A
  • Slow Data Transmission
  • Covers Long Distance
  • 14 Channels
  • Overlapping Channels
  • IEEE 802.11b, g, ax
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5
Q

Characteristics of 5 GHz

A
  • Fast Data Transmission
  • Covers Short Distance
  • 23 Channels
  • No Overlapping Channels
  • IEEE 802.11a, n, ac, ax
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6
Q

IEEE 802.11a

A

This original amendment added support for the 5 GHz band, allowing transmission up to 54 megabits of data per second. The 802.11a standard makes use of orthogonal frequency-division multiplexing (OFDM). It splits the radio signal into sub-signals before they get to a receiver. 802.11a is an older standard and has been largely replaced by newer technology.

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7
Q

IEEE 802.11b

A

802.11b added faster rates in the 2.4GHz band to the original standard. It can pass up to 11 megabits of data in a second. It uses complementary code keying (CCK) modulation to achieve better speeds. 802.11b is an older standard and has been largely replaced by newer technology.

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8
Q

IEEE 802.11g

A

802.11g standardized the use of OFDM technology used in 802.11a in the 2.4GHz band. It was backwards compatible with both 802.11a and 802.11b. 802.11g is an older standard and has been largely replaced by newer technology.

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9
Q

IEEE 802.11n

A

Once the most popular standard 802.11n was the first time a unified specification covered both the 2.4GHz and 5GHz bands. This protocol offers better speed when compared to those that came before it by leveraging the idea of transmitting using multiple antennas simultaneously (usually called Multiple In Multiple Out or MIMO technology). 802.11n is an older standard, but some older devices may still be found in use.

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10
Q

IEEE 802.11ac

A

802.11ac was only specified for the 5GHz band. It built upon the mechanisms introduced in 802.11n. While not as revolutionary as 802.11n was, it still extended speeds and capabilities in the 5GHz band. Most devices currently out in the wild are likely 802.11ac devices.

802.11ac technology was released in two main groups, usually called ‘waves’. The primary difference is that Wave 2 devices have a few more technical capabilities when compared to Wave 1, but it is all interoperable.

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11
Q

IEEE 802.11ax

A

802.11ax (much like 802.11n) unified the specification across all applicable frequency bands. In the name of simplicity, the industry has started to refer to it as Wi-Fi 6. Wi-Fi 6 has expanded the technologies used for modulation to include OFDMA, which allows a certain amount of parallelism to the transmission of packets within the system, making more efficient use of the available spectrum and improving the overall network throughput. Wi-Fi 6 is the latest technology and is what most new devices are shipping with.

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12
Q

Quadrature Amplitude Modulation (QAM)

A

QAM (quadrature amplitude modulation) is a method of combining two amplitude modulation (AM) signals into a single channel. This approach helps double its effective bandwidth. QAM is also used with pulse AM (PAM) in digital systems, like wireless applications.

A QAM modulator works like a translator, helping to translate digital packets into an analog signal to transfer data seamlessly.

QAM is used to achieve high levels of spectrum usage efficiency.

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13
Q

Orthogonal frequency-division multiple access (OFDMA)

A

Orthogonal frequency-division multiple access (OFDMA) is a feature of Wi-Fi 6 (802.11ax) that allows access points to serve multiple clients at the same time. OFDMA follows a set of rules created for the transmission of data between more than one terminal (any device at the end of a transmission channel, such as a computer or phone) over a transmission medium (such as a wireless network).

An example of how OFDMA works is when two phones send data over the same phone line. A time-interval may be assigned to each phone, and they will take turns sending their signal over the line at each assigned interval.

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14
Q

Ad Hoc topology

A

Ad hoc mode is also referred to as peer-to-peer mode because it does not involve an access point, but is instead made up of multiple client devices. The devices, acting as “peers” within the network, connect to each other directly. Has a range of approx. 100m

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15
Q

Infrastructure topology

A

Infrastructure mode is the most common style of Wi-Fi, and it is the one people think of when they connect at home or the office. With infrastructure mode, you need an access point that serves as the primary connection device for clients. All other clients in the network (computer, printer, mobile phone, tablet, or other device) connect to an access point to gain access to a wider network.

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16
Q

Wi-Fi Direct Topology

A

Wi-Fi Direct is a form of Ad Hoc, but with some additional features and capabilities. Wireless connectivity is provided to compatible devices that need to connect without the use of an access point. Televisions are frequently Wi-Fi Direct compatible, allowing users to send music or images straight from a mobile device to their TV.

17
Q

Wi-Fi Hotspot Topology

A

The term “Wi-Fi hotspot” usually refers to wireless networks placed in public areas, like coffee shops, to allow people to connect to the internet without having to have special credentials. While some are free, others require a fee, particularly those administered by companies that specialize in the provision of hotspots in places like airports or bus terminals.

Many cell phones are hotspot-enabled, and users can turn on the feature by contacting their cell service provider. With a hotspot turned on, the user can share their internet connection with someone else, providing them with a password for more secure access.

18
Q

Bridge Topology

A

Bridge joins two networks so that the networks can communicate with each other and serve as a single network. Bridges make internetwork connections possible. This wireless bridging technology consists of hardware as well as network protocol support.

19
Q

LAN connection

A

A local-area network is a computer network that exists at a single site, such as an office building. It can be used to connect a variety of components, such as computers, printers, and data storage devices. LANs consist of components like switches, access points, routers, firewalls, and Ethernet cables to tie it all together. Wi-Fi is the most commonly known wireless LAN.

20
Q

PAN connection

A

A personal-area network consists of a network centralized around the devices of a single person in a single location. A PAN could have computers, phones, video game consoles, or other peripheral devices. They are common inside homes and small office buildings. Bluetooth is the most commonly known wireless PAN.

21
Q

MAN connection

A

A metropolitan-area network is a computer network that spans across a city, small geographical area, or business or college campus. One feature that differentiates a MAN from a LAN is its size. A LAN usually consists of a solitary building or area. A MAN can cover several square miles, depending on the needs of the organization.

Large companies, for example, may use a MAN if they have a spacious campus and need to manage key components, such as HVAC and electrical systems.

22
Q

WAN connection

A

A wide-area network covers a very large area, like an entire city, state, or country. In fact, the internet is a WAN. Like the internet, a WAN can contain smaller networks, including LANs or MANs. Cellular services are the most commonly known wireless WANs.

23
Q

Rogue Access Point

A

A rogue access point is a wireless access point that has been installed on a secure network without explicit authorization from a local network administrator, whether added by a well-meaning employee or by a malicious attacker.

24
Q

Security Concerns Wireless networking

A
  • Packets can be intercepted
  • These packets can then be decrypted
  • Once packets are encrypted they can access encryption keys
  • Mitigate the risk by hiding the SSID (Access Point name)
  • Another means of mitigating risk is MAC Address Filtering i.e. only allowing devices with certain MAC addresses to access the network.
  • Hackers can also monitor Beacons & Probes as they gather reconnaissance about a network.

COMP41580 VoIP and Wireless Investigations (11 decks)

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