Network + Ch. 6 Terms

In 2009, IEEE ratified the this standard. it was in development for years before that. wireless standard that provided much higher effective throughput than the earlier 802.11 standards. boasts a maximum throughput of 600 Mbps. backward compatible with the 802.11a, b, and g standards because uses both the 2.4-GHz and the 5.0-GHz frequency bands.

802.11n

An active reader interacts with a batterypowered tag.

ARAT (Active Reader Active Tag

As a signal runs into various obstacles, its energy will gradually fade, which causes the strength of the signal that reaches the receiver to be lower than the transmitted signal's strength. Excessive fading can cause dropped connections or slow data transmission.

fading

describes the relative strength over a three-dimensional area of all the electromagnetic energy the antenna sends or receives.

radiation pattern

As a wave travels into and through a different transmission medium, such as when traveling through glass or other solids, the wave's direction, speed, and wavelength are altered, or refracted.

refraction

an even newer technology implemented by 802.11ac Wave 2 products that allows multiple antennas to service multiple clients simultaneously.

MU-MIMO (multiuser MIMO)

The most popular OSI Physical and Data Link layer standards used by WLANs

Wi-Fi

released after 802.11b. The higher throughput of it, as compared with 802.11b, is attributable to its use of higher frequencies, its unique method of modulating data, and more available bandwidth. require a greater density of access points to cover the same distance that 802.11b networks

802.11a

Officially approved in early 2014, operates on the 5-GHz band. first Wi-Fi standard to approach Gigabit Ethernet capabilities, providing better support for more wireless clients at a time.

802.11ac

designed to be just as affordable as 802.11b while increasing its maximum theoretical throughput with different data modulation techniques. compatible with 802.11b networks.

802.11g

which is the central connectivity device for Wi-Fi clients on a network, is manually configured to use a selected group of channels.

AP (access point)

Cisco's newer wireless protocol.

CAPWAP (Control and Provisioning of Wireless Access Points)

refers to the way in which a wave travels from one point to another.

Propagation

The proportion of noise to the strength of a signal

SNR or S/N (signal-to-noise ratio)

Based on the UWB (Ultra-Wideband) radio platform, Certified products mimic wired USB 2.0 connections with similar speeds, security, ease of use, and compatibility. UWB radios transmit in the range between 3.1 and 10.6 GHz, a relatively uncrowded band that is also commonly used for wireless media streaming.

Wireless USB

Based on the 802.15.4 standard, is a low-powered, batteryconserving wireless technology. It is designed to handle small amounts of data and is therefore ideal for use in ISM (industrial, scientific, and medical) sensors

ZigBee

A wireless-enabled computer listens on all channels within its frequency range for a special signal, known as this

beacon frame

The reverse procedure involves removing the agent.

off-boarding

The computer transmits a special frame, known as this, on all available channels within its frequency range.

probe

A hacker searches for unprotected wireless networks by driving around with a laptop or smartphone configured to receive and capture wireless data transmissions.

war driving

a mini-version of a LAN is a PAN (personal area network), and the purely wireless version is this.

WPAN (wireless PAN)

unique character string used to identify an access point.

SSID (service set identifier)

In 1999, the IEEE released its this standard, which separates the 2.4-GHz band into 22-MHz channels. Among all the 802.11 standards, it was the first to take hold. It is also the least expensive of all the 802.11 WLAN technologies.

802.11b

based on the ANT protocol, which is an ad-hoc wireless protocol operating at about 2.4 GHz. gathers and tracks information from sensors that are typically embedded in heart rate monitors, GPS devices, and other activity monitoring devices

ANT+

When prompted by an active reader, a passive tag pulls power from the reader's radio waves to power its transmission. These tags only work within a few centimeters of the reader.

ARPT (Active Reader Passive Tag)

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.

Authentication

A group of nodes that share an access point.

BSS (basic service set)

The identifier for this group of nodes that share an Access Point

BSSID (basic service set identifier)

unites separate entities. To be precise, it unites mobile devices, PCs, and accessories under a single communications standard. operates in the radio band of 2.4 GHz to 2.4835 GHz. require close proximity to form a connection, with the exact distance requirements depending on the class.

Bluetooth

Wireless devices are not designed to transmit and receive simultaneously and so cannot prevent collisions. Instead, 802.11 standards specify the use of this to access a shared medium,

CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)

Data streams are divided and encoded into small chunks, called chips, which are spread over all available frequencies within one of three, wide channels, all at the same time.

DSSS (direct sequence spread spectrum)

A group of access points connected to the same LAN.

ESS (extended service set)

BSSes that belong to the same ESS share a special identifier

ESSID (extended service set identifier)

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.

Encryption

Short bursts of data are transmitted on a particular frequency within the band and the next burst goes to the next frequency in the sequence.

FHSS (frequency hopping spread spectrum)

can happen hundreds of times a second.

Frequency hopping

exists just below the spectrum that is visible to the human eye, with longer wavelengths than red light. An LED in a device creates the invisible radiation, which is then detected by a sensor's semiconductor material that converts the signals into electrical current.

IR (Infrared

is made up of any device that can be connected to the Internet—that is, any sensor, computer, or wearable device that talks to other devices over a network.

IoT (Internet of Things)

this sublayer is primarily concerned with multiplexing, flow and error control, and reliability.

LLC sublayer

Ideally, a wireless signal would travel directly in a straight line from its transmitter to its intended receiver. This type of propagation, known as this, maximizes distance for the amount of energy used and results in reception of the clearest possible signal.

LOS (line of sight)

Centralized wireless management is made possible by a lightweight wireless protocol, such as Cisco's proprietary protocol

LWAPP (Lightweight Access Point Protocol)

The authentication process can be somewhat strengthened by using this, which prevents the AP from authenticating any device whose MAC address is not listed by the network administrator.

MAC filtering

lower portion of the Data Link layer that is specifically involved with managing MAC addresses in message frames

MAC sublayer

First available in 802.11n, multiple antennas on the access point and on a client device process incoming or outgoing data simultaneously.

MIMO (multiple input-multiple output)

is a form of RFID and transfers data wirelessly over very short distances (usually 10 cm or less).

NFC (near-field communication)

A battery-powered tag actively transmits its credentials at regular time intervals. Battery-powered tags don't require such close proximity to function—the most sophisticated devices work up to 200 m away.

PRAT (Passive Reader Active Tag)

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. The tag holds 1 to 8 KB of data, such as a serial number, credit card information, or medical data, which it can transmit to a nearby reader.

RFID (Radio Frequency Identification)

way to ensure that packets are not inhibited by other transmissions is to reserve the medium for one node's use.

RTS/CTS (Request to Send/Clear to Send)

802.11 allows for optional encryption using this standard. You establish a character string that is required to associate with the AP, also known as the network key. User must provide the correct key to gain access to network via the AP. This standard uses keys both to authenticate network clients and to encrypt data in transit.

WEP (Wired Equivalent Privacy)

LANs that transmit signals through the air via RF (radio frequency) waves

WLANs (wireless local area networks)

Standards that replaced WEP, dynamically assigns every transmission its own key.

WPA (Wi-Fi Protected Access or Wireless Protected Access)

The encryption protocol used in WPA was replaced by a stronger encryption protocol for the updated version.

WPA2

—Software that can evaluate Wi-Fi network availability as well as help optimize Wi-Fi signal settings or help identify Wi-Fi security threats.

Wi-Fi analyzer

Similar to ZigBee, it is a smart home protocol that provides two basic types of functions: signaling, to manage wireless connections, and control, to transmit data and commands between devices.

Z-Wave

A small number of nodes closely positioned transmit directly to each other without an intervening connectivity device

ad hoc

involves a number of packet exchanges between a access point and your computer. is another function of the MAC sublayer described in the 802.11 standard.

association

As defined by the FCC (Federal Communications Commission), which controls its use, the wireless spectrum spans frequency ranges or this between 9 kHz and 300 GHz.

bands

simply trying numerous possible character combinations to find the correct combination.

brute force attack

This is the first page a new client sees in the browser when connecting to the guest network, and usually requires the user to agree to a set of terms and conditions before gaining further access to the guest network.

captive portal

In 802.11n, two adjacent 20-MHz channels can be combined, or bonded, to make a 40-MHz channel

channel bonding

A wireless signal is diffracted, or split into secondary waves, when it encounters an obstruction.

diffraction

Clients running Linux, macOS, or a modern version of Windows will first attempt to associate with a known access point. This feature can result in network devices connecting to rogue access points, or access points installed without the authorization of the network administrator. One type of rogue access point, called this, can be used to trick a device into connecting to the wrong network.

evil twin

Distance, type and number of obstacles, coverage and interference.

factors when deciding where to install a WLAN's access point

create a separate guest network through their Wi-Fi router/access point. This is a smart security precaution, as it gives guests access to Internet service through an open network without opening the doors to the entire LAN on that router.

guest network

An intervening connectivity device, a WAP (wireless access point) or AP (access point), accepts wireless signals from multiple nodes and retransmits them to the rest of the network. To cover its intended range, an access point must have sufficient power and be strategically placed so that all connected nodes can communicate with it.

infrastructure

Electromagnetic waves in the atmosphere can interfere with wireless communications similar to how EMI (electromagnetic interference) affects wired transmissions.

interference

a command-line utility for viewing and setting wireless interface parameters, is common to nearly all versions of Linux and UNIX.

iwconfig

Several access points work as peer devices on the same network

mesh

Issues and receives wireless signals with equal strength and clarity in all directions. This type is used when many different receivers must be able to pick up the signal in many directions, or when the receiver's location is highly mobile.

omnidirectional antenna

Users or network technicians install a specific app, called an agent, on a user's device, whether the device is a smartphone, laptop, or tablet. This gives the device trusted access to certain portions of the network.

on-boarding

Before you can connect two Bluetooth devices, they must do this

paired

The geographical area that an antenna or wireless system can reach is known as this

range

As devices are moved between BSSes within a single ESS, connecting to a different AP requires this. This is an automatic process

reassociation

The wave encounters an obstacle and reflects, or bounces back, toward its source.

reflection

For security purposes, network administrators need a feature that allows them to do this remotely, in case a device is lost or stolen. This feature, called this, clears a device of all important information, permissions, and apps without having physical access to the device. It might even allow you to completely disable the device, making any network or data access impossible.

remote wipe

unauthorized APs

rogue access points

As long as a wireless node is on and has its wireless protocols running, it periodically surveys its surroundings for evidence of an access point

scanning

When a wireless signal encounters an object that has small dimensions compared with the signal's wavelength, it's diffused or scattered in multiple directions.

scattering

assesses client requirements, facility characteristics, and coverage areas to determine an AP arrangement that will ensure reliable wireless connectivity within a given area.

site survey

A device that can assess the quality of a wireless signal.

spectrum analyzer

issues wireless signals along a single direction. This type is used when the source needs to communicate with one destination, as in a point-to-point link, or in a specific area.

unidirectional antenna

Consider whether Wi-Fi access points will be used as this to extend wired access to remote areas of the network. The throughput demands of this can be significantly higher than typical Wi-Fi clients.

wireless bridges

used only initially to configure the APs, or the APs might remain connected to this for continued management. might be a physical device installed locally, or it might be cloud-based, VM-based, or embedded in one of the APs.

wireless controller

wireless signals can be amplified by increasing the power of the transmission or extended by repeating the signal from a closer broadcast point

wireless range extender

commonly called the airwaves, is the frequency range of electromagnetic waves used for data and voice communication.

wireless spectrum