Chapter 6

802.11a,b,g,n bands and max throughput

802.11a: The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5-GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. 802.11b: The IEEE standard for a wireless networking technique that uses DSSS (direct-sequence spread spectrum) signaling in the 2.4-GHz frequency range and provides a theoretical maximum throughput of 11 Mbps. 802.11g: The IEEE standard for a wireless networking technique designed to be compatible with 802.11b in the 2.4-GHz frequency range while using different data modulation techniques that allow it to reach a theoretical maximum capacity of 54 Mbps. 802.11n: The IEEE standard for a wireless networking technique that may issue signals in the 2.4-GHz or 5-GHz band and can achieve actual data throughput between 65 Mbps and 600 Mbps. 802.11ac: The IEEE standard for a wireless networking technique that exceeds benchmarks set by earlier standards by increasing its useful bandwidth and amplitude. 802.11ac is the first Wi-Fi standard to approach Gigabit Ethernet capabilities.

WLAN

A LAN that uses wireless connections for some or all of its transmissions.

NFC

A form of radio communication that transfers data wirelessly over very short distances (usually 10 cm or less).

Bluetooth

A low-power wireless technology that provides close-range communication between devices such as PCs, smartphones, tablets, and accessories.

On-boarding and off-boarding

on-boarding: A process of configuring clients for wireless access to a network. off-boarding: The reverse process of on-boarding, involving the removal of programs that gave a device special permissions on the network.

MAC filtering

A security measure that prevents an AP or a switch from authenticating any device whose MAC address is not listed by the network administrator as an approved device.

SSID

A unique character string used to identify an access point on an 802.11 network.

IR

A wireless technology that uses a bandwidth just below the spectrum that is visible to the human eye, with longer wavelengths than red light.

RFID

A wireless technology that uses electromagnetic fields to store data on a small chip in a tag, which includes an antenna that can both transmit and receive, and possibly a battery.

Bluejacking and bluesnarfing

Bluejacking: a connection is used to send unsolicited data Bluesnarfing: a connection is used to download data without permission

Diffraction, reflection, scattering, refraction

Diffraction: In the context of wireless signal propagation, the phenomenon that occurs when an electromagnetic wave encounters an obstruction and splits into secondary waves. Reflection: In the context of wireless signaling, the phenomenon that occurs when an electromagnetic wave encounters an obstacle and bounces back toward its source. Scattering: The diffusion, or the reflection in multiple directions, of a wireless signal that results from hitting an object with a rough surface or small dimensions compared to the signal's wavelength. Refraction: In the context of wireless signaling, the way in which a wave alters its direction, speed, and wavelength when it travels through different transmission mediums.

Encryption, authentication

Encryption: The use of an algorithm to scramble data into a format that can be read only by reversing the algorithm—that is, by decrypting the data—to keep the information private. Authentication: The process of comparing and matching a client's credentials with the credentials in a client database to enable the client to log on to the network.

What is a site survey?

In the context of wireless networking, an assessment of client requirements, facility characteristics, and coverage areas to determine an access point arrangement that will ensure reliable wireless connectivity within a given area.

IoT, THAN, PAN

IoT: Any device connected to the Internet. THAN: PAN: Personal Area Network

WPA, WPA2

WPA: A wireless security method that dynamically assigns every transmission its own key. WPA2: A wireless security method that improves upon WPA by using a stronger encryption protocol called AES.

Evil twin, war chalking, war driving

evil twin: An exploit in which a rogue access point masquerades as a legitimate access point, using the same SSID and potentially other identical settings. war chalking: Once hackers discover vulnerable access points, they make this information public by drawing symbols with chalk on the sidewalk or wall within range of a wireless network. The symbols, patterned after marks that hobos devised to indicate hospitable places for food or rest, indicate the access point's SSID and whether it's secured. Alternatively, many websites offer maps of these open networks, as reported by war drivers. war driving: The act of driving around an area while running a laptop configured to detect and capture wireless data transmissions.

Mesh, infrastructure, and ad hoc technologies

mesh: A wireless network in which multiple APs work as peer devices on the same network, thereby providing more fault-tolerant network access to clients. infrastructure: A type of wireless network in which stations communicate through an access point and not directly with each other. ad hoc: A type of wireless LAN in which stations communicate directly with each other (rather than using an access point).

Wireless USB

mimic wired USB 2.0 connections with similar speeds, security, ease of use, and compatibility.

What types of software tools can be used to determine wireless signals

spectrum analyzer: A device that can assess the quality of a wireless signal. Spectrum analysis is useful, for example, to ascertain where interference is greatest. wifi analyzer: Software that can evaluate Wi-Fi network availability as well as help optimize Wi-Fi signal settings or help identify Wi-Fi security threats. Identifying the wireless channels being used nearby helps you optimize the wireless channel utilization in your vicinity.

Types of antenna that are used

unidirectional antenna: A type of antenna that issues wireless signals along a single direction, or path. Also called a directional antenna omnidirectional antenna: A type of antenna that issues and receives wireless signals with equal strength and clarity in all directions.