WiFoo..The.Secrets.of.Wireless.Hacking [Electronic resources] نسخه متنی

QR

QAM

quadrature amplitude modulation. A method of combining multiple amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth. QAM is used with pulse amplitude modulation (PAM) in digital systems, especially in wireless applications. Variations of QAM include 16QAM, and 64QAM, where the numbers of modulation points increase to 16 or 64 per symbol.

QoS

quality of service. The capability to treat different types of network traffic differently to ensure required levels of reliability and latency according to the type of traffic. Certain kinds of traffic, such as voice and video, are more sensitive to transmission delays and are therefore given priority over data that is less sensitive to delay.

radiation

Electromagnetic energy, such as radio waves, traveling into space from a transmitter.

radio wave

A combination of electric and magnetic fields varying at an RF and traveling through space at the speed of light.

raw data rate

Typically refers to the number of bits per second that can be transmitted, not accounting for overhead associated with error correction and other protocol-related factors.

receive gain

A measure of received signal boost contributed by an amplifier or antenna system, and typically measured in dBi.

receiver sensitivity

The minimum acceptable value of received power needed to achieve an acceptable bit error rate (BER) or performance. It takes into account the thermal noise of the receiver. Generally expressed in dBm using negative numbers. For example, the Cisco 350 series bridge has a receiver sensitivity of 85 dBm at 11 Mbps.

repeater

Any device that regenerates a signal to continue its propagation, usually increasing total distance or coverage area.

RF

radio frequency. Typically a frequency from 20 kHz to 3 GHz. RF is usually referred to whenever a signal is radiated through the air. Literally, any and all frequencies that can be radiated as an electromagnetic wave.

roaming

Typically used to describe a portable communications device moving its network connection from one fixed AP to another.

rogue access point

An unauthorized AP being used on a network. May be implemented by legitimate network users or an intruder attempting to compromise a network.

RPI

received power indicator. A measurement of how much power is being transmitted by wireless devices, which is a critical measurement for radio monitoring.

RP-TNC

Reverse Polarity Threaded Navel Connector. A Threaded Navel Connector with a reversed center connection (when compared to a standard TNC connector). This connector type is unique to certain wireless radios and antennas. Part 15.203 of the FCC rules covering spread-spectrum devices limits the types of antennas that may be used with transmission equipment. In compliance with this rule, WLAN providers equip radios and antennas with a unique connector to prevent attachment of unapproved antennas to radios.

RSSI

receive signal strength indicator. A parameter used in the location estimation of unknown radios.

RTS

request to send. A signal or frame of data indicating that the transmitter has data ready to be sent. In 802.11 WLANs, a device sends an RTS control packet to ask for a clear time to send the packet.

dipole antenna.