CWNA Study Cards

What frequency is better at a longer distance?

2.4 ghz, because the waves are longer and don't fade out as soon in comparison to 5ghz. so 2.4ghz is better at longer distances.

What does a 3x3:2 device mean for spatial multiplexing?

3 transmit, 3 recieves. Can perform 2 spatial streams at a time.

S1G - IOT What are the data rates, bands used and supported technologies?

346.6677 mbps Below 1 ghz 4 spatial streams

What is an Omnidirectional Antenna?

360 degree propagation

how long is a short guard interval? and what is it used for?

400 nanoseconds - this is the space between symbols being transmitted. this is used to eliminate the inter-symbol interference, which is referred to as ISI

how much space is each channel apart in 2.4GHz band?

5 Mhz apart.

High Throughput PHY(HT) What are the data rates, bands used and supported technologies?

600 mbps 5 Ghz & 2 Ghz MIM0-(Multiple Streams) 4 Spatial streams

DMG - Directional Multi-gigabit What are the data rates, bands used and supported technologies?

6756.66 mbps 57-66 Ghz Control modulation, OFDM single carrier modulation

what frequency does 802.11ah support?

700mhz, 860mhz, 902mhz,

Very High Throughput (VHT) What are the data rates, bands used and supported technologies?

800 mbps 5ghz 8 spatial streams

how long is a long guard interval? and what is it used for?

800 nanoseconds - this is the space between symbols being transmitted. this is used to eliminate the inter-symbol interference, which is referred to as ISI

highrate direct sequence spread spectrum(HR/DSS) what are the data rates, bands used, supported technologies and PHY?

802.11b 5.5 - 11 mbps (backward compatible with older phy) 2.4 ghz single spatial stream

what standard is used that prioritizes bridging

802.1D

what standard is used for VLAN tagging?

802.1q

what are the standards for PoE?

802.3af & 802.3at are PoE standards

What is the BSS (Basic Service set)?

A BSS consists of a group of computers and one AP, which links to a wired LAN

What is a VPN?

A virtual private network (VPN) is a communication tunnel that provides point-to-point transmission of both authentication and data traffic over an intermediary network.

how does open system authentication work

Authentication frame is sent from a client to an access point; when the AP receives the frame, it verifies the SSID, and if it's correct the access point sends a verification frame back to the client, allowing the connection to be made PS: Authentication request, Authentication response, Association request, and Association response

What is beamwidth?

Beam Width is the area where most of the power is radiated, which is the peak power.

For site surveying, what can't be done in wireless design software and which should be done to validate the strength or validation of design for your wifi implementation?

Being able to Actually capture signals with the physical space.

What is the minimum ethernet cable required for an AP using PoE?

CAT5 with a maximum length of 100 meters or 328 feet.

what ethernet cable provides the better performance for an AP using PoE than CAT5?

CAT6 with the same constraints at CAT5 - maximum length of 100 meter or 328 feet.

What is modulation?

Carried signal that represents bits

MCS tables are used to determine data rate. what factors are used to determine this?

Modulation, coding, guard interval, channel width, and spatial streams.

What frequency does 802.11a support?

OFDM 5ghz 54 mbps

ERP (extend-rate PHY) What are the data rates, bands used and supported technologies?

OFDM in 2.4ghz (6,9,12,18,24,36,48,54 mbps) 2.4 ghz Backwards compatible with DSSS/HR-DSSS so 1-2,5.5,11 are also supported

orthagonal frequency-division multiple Access (OFDMA)

OFDMA is a multi-user version of OFDM enabling concurrent AP communication (uplink & downlink) with multiple clients by assigning subsets of subcarriers, called Resource Units (RUs) to the individual clients.

What is another Fast Secure roaming method, besides for Fast BSS transition? (FT)

OKC stands for Opportunistic Key Caching and is a non-standard fast roaming technology supported by Microsoft Windows clients and some Android devices

what happens with frames granting authentication?

Once a request to authenticate is sent from the client to the AP. a frame is sent back to the client from the Ap granting Authentication. -No status code is listed

What is PEAP?

PEAP (Protected Extensible Authentication Protocol) is a version of EAP, the authentication protocol used in wireless networks and Point-to-Point connections. PEAP is designed to provide more secure authentication for 802.11 WLANs (wireless local area networks) that support 802.1X port access control. -Provides Dynamic Encryption Keys

What is a panel Antenna?

Panel antennas are common at Ultra high frequency (UHF) frequencies, where they are often used for cellular/mobile base stations or wireless networking due to their size and directional properties.

What encryption solutions are Deprecated?

RC4, SHA1, RC5,TKIP

What is distributed data forwarding?

Data goes from the AP to the Final destination

What is centralized data forwarding?

Data goes to the AP, to the Wireless LAN Controller, and the final destination

what is Absoprtion?

Dense materials absorbing RF energy. This weakens the signal passing and decreases amplitude.

What is DNS used for?

Domain Name System, which provides IP address to name resolution (big host file), and serving as an alternate to Locate WLAN controllers

What is EIRP?

Equivalent Isotropicaly Radiated power This is output power from the intentional radiator. (output power from the transmitter plus any gains or losses leading up to the connection point of the antenna.)

What IEEE standard is 802.3?

Ethernet use in WLAN

what are Extended Inter-frame Space (EIFS)?

Extended inter-frame spacing is an additional waiting period used in addition to the mandatory DIFS in case of corrupted frames. (Delayed, retry on error frames)

What is FHSS (Frequency-Hopping Spread Spectrum?

FHSS is used to avoid interference, to prevent eavesdropping, and to enable code-division multiple access (CDMA) communications. The available frequency band is divided into smaller sub-bands. ... FHSS signals are highly resistant to narrowband interference because the signal hops to a different frequency band.

what is DSSS (Direct-sequence spread spectrum)?

Fdirect-sequence spread spectrum is a spread-spectrum modulation technique primarily used to reduce overall signal interference. The direct-sequence modulation makes the transmitted signal wider in bandwidth than the information bandwidth

what frequency does 802.11ax support (Wi-Fi 6 - HE)

HE 2.4 and 5 Ghz 8 data strams 9.6 Gbps

what frequency does 802.11n support? (Wi-Fi 4 - HT )

HT 2.4ghz and 5ghz max rate of 600 mbps

What is HTTPS and what does it do?

HTTP over SSL (port 443) that encrypts communication channels (session) in web browsers.

What is a protocol analyzer?

Hardware or software that captures packets to decode and analyze their contents. also shows statistics, and reports.

What is amplitude?

Height of an RF wave

What two layers describe the 802.11-2016 standard and amendments?

Layer 2 - datalink layer, and layer Layer 1 - physical layer

What is the reccomend VoIP latency time for good performance.

Less than 150ms latency

What is QUAM modulation? what these quams 16,64,256,102?

QAM is a modulation scheme that transmits data by changing the amplitude, or power level, of two signals: first in-phase with the incoming data and the second 90 degrees out of phase. QAM relates to the number of bits of information encoded in each time period. (16 quam bits. each symbol is 4 ,64 quam bits. each symbol is 8 256 quam bits. each symbole is 16 1024 quam bits. each symbol is 32

What is QPSK?(Quadrature Phase Shift Keying)

QPSK is a modulation that modulates 2 bits informational bits per symbol

What does MAN mean?

Metropolitan Area Network

What is reflection?

Reflection occurs when an RF signal bounces off a smooth, non-absorptive surface. changing direction of the signal.

what is Return loss?

Return loss looks at the amount of power absorbed by a load when power from a source is sent to it. The return loss being the difference between the incident power, and the power reflected back down.

What is a lightweight AP?

The Access points are all managed by a Wireless LAN Controller.

What is an BSSID?

The BSSID is the MAC address of the AP the client device is currently connected to. This can help determine exactly which access point the client device is connected to. Keep in mind that each access point has a range of MAC addresses assigned to it

What is the data plane used for?

The Data Plane is the layer that has infrastructure to carry network traffic.

What does the IETF do?

The IETF works to standardize Internet technologies and protocols especially the Internet Protocol Suite (TCP/IP)

What is a mesh gate?

The Mesh Gates allow for connections between the mesh BSS and other mesh BSSs

the physical layer is split into which two sub layer?

The Physical layer Convergence protocol sublayer, and the Physical Medium dependent (PMD) sublayer. we have an MPDU passed down from the data link layer, gets passed down to the Physical Layer Convergence Protocol sub layer (PLCP), which puts a PLCP header on it and makes is a PSDU. The PSDU then gets sent down to physical medium dependent (PMD), where it will be attached with a preamble or training field and transmitted as a PPDU. Then modulates on to the network medium through, OFDM, QUAM or whatever modulation is specified.

What is the Wifi Alliance?

The Wi-Fi Alliance grants certifications to tested equipment validating interoperability and performance related to security, QoS, power management, VoIP, and connectivity

What is the FCC?

Set boundaries of the IEEE standards may function in.

What is Shared Key Authentication?

Shared Key Authentication (SKA) is a process by which a computer can gain access to a wireless network that uses the Wired Equivalent Privacy (WEP) protocol. With SKA, a computer equipped with a wireless modem can fully access any WEP network and exchange encrypted or unencrypted data.

What are Short Inter-frame Space (SIFS)?

Short Inter-frame Spacing is the time interval required by a wireless device in between receiving a frame and responding to the frame. PS: Delay before "Ack" frames or any other frames that need high priority.

What happens with data rates when an older security technology is used in 802.11 network?

Since these are older deprecated security measures (TKIP/RC4) newer devices must fall back to older phy speeds. (54 mbps for example)

Equivalent Isotropically Radiated Power (EIRP)

System output power after antenna gain

in the Frame Control field, what is the "type" subfield used for?

That says it's either a control, data, Management frame

What is a requirement for most WLAN implementations that include RTLS? (Real-time location system)

That the APs/Sensors are placed on the perimeter of the facility to be covered. in order to accomplish the triangulation process.

What is Network Access Control (NAC)?

The set of standards defined by the network for clients attempting to access it. Usually, NAC requires that clients be virus free and adhere to specified policies before allowing them on the network.

BPSK (Binary Phase Shift Keying)

The simplest form of PSK; there are two phase shifts (0 degrees or 180 degrees) for data transmission, depending on whether a binary 1 or 0 is to be transmitted.

What are gounding rods/wires?

These ensure a safe pattern for lightning to travel to ground.

What do Access points do?

They give you access to the network?

What is RTS/CTS?

This is (Request to Send / Clear to Send). This is the optional mechanism used by the 802.11 wireless networking protocol to reduce frame collisions introduced by the hidden node problem.

what is MU-MIMO?

This is Multi-user Multiple-input Multiple-output. This allows an AP to transmit to many 802.11ac clients simultaneously.

When talking about POE - what is a PSE?

This is a Power Sourcing device. - which has the ability to supply power to a device. Ex: PoE switch ports

What happens with an authentication frame?

This is a frame requesting authentication sent from the client to the AP.

What is Mobile Device Management?

This is used for manage mobile device that are on your business facility. this allows you to manage what resouces/application they have access to, and the way the device functions.

what are lightning arrestors?

This is used to redirect or shunt electrical current from lightning strikes near by.

What is the Fresnel zone?

This is very important in bridge links because this is the space needed to be seen inside of a the connection. 60% is required, however 80% is recommended for 802.11 bridge links.

What is layer 1 roaming?

This is when a computer/station moves from a 2.4ghz BSS to a 5ghz BSS. switching the radio operation from 2.4ghz to 5ghz. EX: This is also know as Band roaming since you are switching bands

What is Clear channel Assessment? (CCA)

This is where computers/stations check the wireless medium to detect use? to avoid data collision and start processing data to be sent of the wireless medium CS - Detects and measures the signal strength of 802.11 frames ED - Measures the power of ALL RF energy in channel including non 802.11 RF signals

What does 3x3:3 device mean for spatial multiplexing?

This means the device can transmit and recieve on 3 radio chains. and that it can send and recieve three spatial streams for multiplexing.

What is RF attenuation?

This means the reduction of strength of the signal during transmission.

DBPSK (Differential Binary Phase Shift Keying)

This modulation technique utilizes two phase shifts, one that represents a 0 chip and one that represents a 1 chip. This is used with the Barker code coding technique to provide 1 Mbps data rates in DSSS transmissions.

What does a PLCP header contain?

This provides information about the data rate used to transmit the actual MAC frame and other details

in the Frame Control field, what is the "subtype" subfield used for?

This says the specific type of control, data, Management frame. EX: Type may say "data" , subtype might say "QOS"

What are RADIUS servers used for?

This server uses, AAA - Authentication, Authoriziation, Accounting. Authentication: Authentication username and password Authorization: authorize the identity Accounting: Monitor Account activity

What does an "ACK" frame do?

This simply Acknowledges, ONE frame.

What is SNMPv3

This stands for System Network Management Protocol. which allows you to manage you devices on the network.

What is WIPS?

This stands for Wireless intrusion Prevention system. this system is used to detect any anaomalys, patterns, and odd behavior on your Wi-Fi network. this can either be an overlay 3rd party software, or it can be built in to a Wi-Fi system.

what can a Wireless Network Management System do?

This system can manage AP and wireless LAN controller(that may also manage AP's) configuration, and Monitor the APs as part of its overall network management solution. EX: however, MAC operation do not take place in a WNMS based solution

What is a power budget?

This term is used to define the total power required of PDs, or the total power availabe in a PSE to be used.

How does WPA2 Enterprise work?

This uses 802.1x /Eap Authentication for with the following procedure: a master session key is generated, from the MSK you get a pairwise master key, the PMK is used in the 4-way handshake to generate the PTK.

What is spatial-Multiplexing?

This uses advanced data algorithms to create seperate data streams for each antenna.

What is inter-controller roaming?

This would be connecting to different AP's on the same controller while moving.

what is intra-controller roaming?

This would be connection to different AP's on different controllers while moving.

USB devices can cause RF interference on what band of RF communication?

USB devices can create significant RF interference in the 2.4GHz band

What is DHCP used for?

Used for an Internet host/client to obtain configuration parameters such as network address, subnet mask, gateway & DNS

what are AIFS?

Used for sending QOS data frames

what are DCF Inter-frame Space (DIFS)?

Used for sending any non Quality of service data frames

What IEEE standard is 802.1x?

Used port based Authentication used in enterprise WLAN

what frequency does 802.11ac support? (Wi-Fi 5 - VHT)

VHT 5ghz at max rate of 800mbs

What are VLANs used for?

VLANs are used to segregate network access for different computers. which allows controlled network access as an Admin.

What is WMM? (WiFi Multimedia)

WMM maintains the priority of audio, video and voice, over other application which are less time critical. (QOS) - ensure applictions that need better throughput and performance are inserted in queues with higher priority. EX: Based on ECDA and still used the 4 access categories.

who uses CTS-to-self protection mechanism?

When a station using CTS-to-Self wants to transmit data, it performs a NAV distribution by sending a CTS frame. This CTS notifies all other stations that they must wait until the DATA and ACK have been transmitted. Any station that hears the CTS will set their NAV to the value provided. -CTS-to-Self is better suited for use by an AP.

What is refraction?

When the direction of an RF signal changes going through a medium.

What is co-channel interference?

When two devices are configured to use the same channel, so they are speaking over one another.

what are Access Control List (ACLs)?

Which IP networks can communicate with what other IP networks, which TCP port can get through

What is data rate?

Rate at which bits are sent out over a transmission medium

What is distribution system? (DS)

a DS is the interconnecting system that allows for the creation of an ESS on a LAN or across LANS. The DSS inside of this system allows for communications among devices on the Wireless media, including between BSS's, and within a BSS.

What is link budget?

a link budged is a calculation of all gains and losses that a communication signal experiences in a RF signal. This will equal the Recieved power in dB.

What is CSMA/CD?

a method used to avoid data collisions in the 802.3 ethernet Standard

the Elevation chart represnts a view of an antennas radiation pattern from which direction?

above, infront, below, behind.

What does IEEE do?

an organization that promotes new technologies and creates standards and protocols that govern these new technologies

we know security is important, in what way can an AP security be spoofed?

by MAC filtering, you can spoof a valid MAC address to communicate on the network if there are certain MAC addresses Whitelisted.

What 2.4 GHz Wi-Fi channels are available in all regulatory domains?

channels 1-11

Name 3 relative power units for RF:

dB (decibel), dBi - Decibel relative to isotropic radiator, dbd - decibels relative to a dipole antenna

What is a Frame Check Sequence?

data generated against the remaining frame information to ensure accurate delivery.

What is the User data payload?

data including IP headers, TCP headers, and application data

in RF math what does a loss of 10dB do to any absolute power?

divide power by 1/10

In RF math what does a loss of 3dB do to any absolute Units?

divide power by 1/2

What is the process of a standard?

draft to amendment to standard.

What is an Autonomous AP?

each Access point is a standalone device and administered individually.

What is Per-user PSK? (PPSK)?

each user has their own pre-shared key, this method is considered more secure than PSK. allows for fast/secure roamig.

using point to point bridge links, what kind of antenna would you use?

either highly directional or directional antennas depending on the distance.

What is a good way to segregate AP's for better control of Access to resources on the local LAN.

for each SSID you can configure VLANS for those devices to communicate on, to access resource on the LAN.

What is a preamble used for?

he radio preamble (sometimes called a header) is a section of data at the head of a packet that contains information that the wireless device and client devices need when sending and receiving packets

Space Time Block Coding (STBC)

improves signal to noise ratio

observing the 802.3af-2003 PoE standard. how many watts are use for a PSE, and how many are used for a PD.?

in the 802.3af-2003 PoE standard a Power sourcing device (PSE) uses - 15.4 wats a Powered device (PD) use - 12.95

observing the 802.3at-2009 PoE standard. how many watts are use for a PSE, and how many are used for a PD.?

in the 802.3at-2009 PoE standard a Power sourcing device (PSE) uses - 30 watts a Powered device (PD) use - 25.5 watts

What is a Cloud based wireless Model

in this model AP management and control is in the cloud. EX: Monitoring and statistics are also available in the cloud. -cloud failure does not equal WLAN failure, as the AP's will keep their last pulled configuration.

what is a Controller-less wireless model?

in this model AP's are directly configured, the management plane is located in the AP or Wireless Management Network System.

in an 802.11 Frame what is the "802.11 information" frame header?

information that allows data to be properly received by the target 802.11 Station/computer.

orthagonal frequency-division multiplexing (OFDM) What are the data rates, bands used and supported technologies?

is a digital multi-carrier modulation scheme that extends the concept of single subcarrier modulation by using multiple subcarriers within the same single channel 6,9,12,18,24,36,48,54 mbps 5 ghz one spatial stream with enhanced modulation

What is a DTIM? (Delivery traffic indication message)

is a kind of TIM which informs the clients/station about the presence of buffered multicast/broadcast information stored on the access point.

what are dbm?

is an ABSOLUTE measure of power (dbm)

what can a WWNA link do?

it can allow aggregation of multiple channels of communication (multiplex). And allows them to pass across a WAN link

how wide is a 2.4GHz channel? Where does the first channel start at?

it is 20Mhz. 2412

What is Dynamic Frequency Selection? (DFS)

s a channel allocation scheme specified for wireless LAN, commonly known as Wi-Fi. It is designed to prevent electromagnetic interference with other usages of the C band frequency band that had predated Wi-Fi, such as military radar, satellite communication, and weather radar.

What are some weak security options to implement on a WLAN?

some of the options include: -SSID hiding - can see the network in beacon frames -MAC filtering - can be easily spoofed. -Wi-Fi Protected Setup (WPS) -Open System Authentication - intentional public network are the only exception.

What is interference?

the combination of two or more waves that results in a single wave.

What is a wavelength?

the distance between corresponding points on adjacent RF waves

What is the Management plane user for?

the management plane of a networking device is the element of a system that configures, monitors, and provides management, monitoring and configuration services to, all layers of the network stack and other parts of the system

What is port density?

the number of ports on a PSE that may be used to provide power.

What is a single channel architecture?

the single channel architecture uses: -Single channel throughout -centralized control of Ap transmissions -Multiple channel layers may be used.

What is Airtime fairness?

this is a design feature that is, by design, meant to allow faster clients to have more airtime than slower clients.

What is a sectorized Antenna?

this is a highly directionla antenna that works with other sectorized antennas.

what is IFS (inter-frame-space)?

this is inter-frame space which is the space between packets?

When we talk about scalability and Availability Solutions, what does "N+1" mean?

this means in a infrastructure you have "N" amount of devices with one extra as a backup for availability in case something goes down.

What happens when a signal hits it's peak amplitude?

this means that it sends sends a "1" bit of data.

what frequency does 802.11af support?

this supports frequencies under 1ghz

what are Attenuators used for?

to decrease signal strength.

What is an Amplifier?

used to increase or amplify the RF signal strength. The amplifier needs to match the frequency of signal propagaed.

Random Back-Off Timer

when a station has a frame to transmit, it randomly picks a number from the contention window. the stations begin to count down, from this number as the back off timer. the backoff timer only decrements when the line is idle. once 0 you may transfer data.

What kind of antenna would you install to reduce the lack of coverage to target a host?

you could use either a directional antenna or highly directional antenna to increase transmission and receiving signal in that area.

What values are needed to configure an AP to use a RADIUS Server?

you need the following: -Radius Server IP address, -Radius Server ports -Then the Shared Secret Key

What is Radio Resource Managment (RRM)?

(RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems. These systems can automatically configure the channel and output power settings for APs and it includes extra features such as coverage hole detection (dead spot detection) and mitigation

What're important to factors to check for WLAN bridging?

-Check the distance between the two points if more than 7 miles, you need to put earth bulge into the picture -ensure proper line of site -ensure protected installation are used, encryption of the data as well as physical lockbox for the encluse for the antennas

What is a Distributed wireless model?

-In this model there is cooperative control, AP's cooperate with each other in the control plane. -The data plane is distributed forwarding

when you create hotspots in a business what are some factors you should you look into?

-ensure proper separation from internal network public network, different vlans. -ensure payment processing is confidential

Direct Sequence Spread Spectrum (DSSS). what are the data rates, bands used, and supported technologies?

1 or 2 mbps 2.4ghz band Single spatial stream

Which channels are non-overlapping in 2.4ghz

1,6,11

How many channels are in the 2.4ghz frequency available in the US

1-11

how does power saving work in the 802.11 standard?

1. Before a STA goes into the doze state, it sends a frame, usually null data frame, to the AP indicating that power management is enabled.2. Once STA indicate, that it is in Power Save mode, the AP begins to buffer all frames destined to that station.3. When the station goes into awake state, it sends a frame to the AP in order to begin the data retrieval process.4. When AP has finished sending all buffered data to the station, the station goes back into the doze state.

you have an AP that's being powered by a PoE switch, but no power. list things you should check for.

1.) Check that the port is configured properly 2.) is the PSE on? 3.) Verify the power budget in the switch has not been exhuasted. there may not be enough power left to power the AP

What two factors must be important for transmitting voice and video?

1.) Video would require high throughput but for voice not so much however we want the reliability of being able to get that data safely to the otherside

What are the 8 steps to the Wi-FI troubleshooting method?

1.) identify the problem 2.) Discover the scale of the problem 3.) Define Possible Causes 4.) Narrow to the most likely cause 5.) Create a plane of action or escalate the problem 6.) perform corrective actions 7.) verify the solutions 8.) Document the results

What is a public key infrastructure (PKI)

A PKI certificate allows someone to digitally bind their identity and use the certificate to perform some of these functions: Encrypt and authenticate e-mail messages and documents. Digitally sign e-mail messages and documents.

What is a Spectrum Analyzer used for

A Spectrum Analyzer is used for Non-802.11 signals/analysis. This allows you to locate interferences, view channel RF utilization and historical RF activity.

What is a yagi antenna?

A Yagi antenna, also known as a Yagi-Uda array or simply a Yagi, is a directional antenna commonly used in communications when a frequency is above 10 MHz. This type of antenna is popular among Amateur Radio and Citizens Band radio operators. It is used at some surface installations in satellite communications systems.

what is a Mesh BSS? (MBSS)

A basic service set (BSS) that forms a self-contained network of mesh station/computer (STAs)

how does 802.1X port authentication work?

A client connects to the uncontrolled port with can be used at any time to receive 802.1x eap authentication status. Once validated, the controlled port is then enabled and can Access the LAN.

What is a sine wave?

A pure tone, a sound with one and only one frequency.

What is a captive portal?

A technological solution that forces clients to complete a process before accessing the network. (think hotel wi-fi)

What is an ESS? (Extended Service Set)

An ESS is created when multiple AP's(BSS's) are interconnected. each BSS consists of a single AP together with their client devices.

How do you tell the difference between a standard and an amendment?

An amendment is lowercase While A standard is uppercase.

What is IBSS? (independent of BSS)

An independent BSS (IBSS) is an ad hoc network that contains no access points, which means they cannot connect to any other basic service set.

what is a highly-directional antenna?

Antennas that transmit with a very narrow beam. -Grid -Parabaloic antenna

what is BYOD?

Bring-your-own-device (BYOD) is a policy that allows employees to bring their own personal mobile devices to work and use those devices to connect to (or through) the company network to business resources and/or the Internet. Although BYOD may improve employee morale and job satisfaction, it increases security risk to the organization.

What is a beacon frame?

Broadcast frames that are transmitted periodically, they serve to announce the presence of a wireless LAN with its information.

How does WPA2 offer increased security?

By implementing the Advanced Encryption Standard (AES).

What is CSMA/CA

Carrier sense multiple access/collision avoidance in the 802.11 standard. It's a standard in which the wireless node listens to see if another node is broadcasting data. If so, it waits a random time and retries.

What is CAPWAP?

Control and Provisioning of Wireless Access Points - a way for control data to be tunneled between Lightweight AP and Centralized controller

what are the gain/loss differences in dBi and dBd.

Conversion for dBi= dBd + 2.14 Conversion for dBd= dBi - 2.14

What is DNS used for in networking?

DNS or (domain name system) is used to resolve domain names to IP addresses. it is also used for WLAN functions, including locating controllers, and resolving AP options from a DHCP server. if the AP doesn't have the correct option compared to the DHCP server, DNS will try and resolve the issue.

What frequency does 802.11b support?

DSSS 2.4ghz max rate at 11 mbps

what is Extensible Authentication Protocol? (EAP)

EAP is a framework for transporting authentication protocols. from a supplicant to an authentication server

what is EAP-TLS?

EAP-TLS uses the TLS public key certificate authentication mechanism within EAP to provide mutual authentication of client to server and server to client. With EAP-TLS, both the client and the server must be assigned a digital certificate signed by a Certificate Authority (CA) that they both trust. -Provides dynamic Encryption keys

What is EAP-TTLS?

EAP-TTLS (Tunneled Transport Layer Security) is designed to provide authentication that is as strong as EAP-TLS, but it does not require that each user be issued a certificate. Instead, only the authentication servers are issued certificates. User authentication is performed by password, but the password credentials are transported in a securely encrypted tunnel established based upon the server certificates. -Provides Dynamic Encryption Keys

what frequency does 802.11g support?

ERP 2.4ghz at 54 mbps

When creating bridge links of over 7 miles, what factor should you start thinking about that will affect the RF signal?

Earth bulge - Increasing height can help with RF signal loss.

What is Fast secure roaming?

Featured snippet from the web Fast roaming, also known as IEEE 802.11r or Fast BSS Transition (FT), allows a client device to roam quickly in environments implementing WPA2 Enterprise security, by ensuring that the client device does not need to re-authenticate to the RADIUS server every time it roams from one access point to another.

What are inter-frame spaces?

Inter − frame spaces (IFS) are waiting periods between transmission of frames operating in the medium access control (MAC) sublayer where carrier-sense multiple access with collision avoidance (CSMA/CA) is used CSMA/CD - is for ethernet CSMA/CA - is for Wi-Fi

How is WPA2 Personal used?

It is used by entering a pass phrase in the AP/Client.

What is patch antenna?

It is widely used in portable wireless devices because of the ease of fabricating it on printed circuit boards. Multiple patch antennas on the same substrate (see image) called microstrip antennas, can be used to make high gain array antennas, and phased arrays in which the beam can be electronically steered.

in RF math what does a gain of 10dB do to an absolute power?

Multiply power by 10

In RF math what does a gain of 3dB do to any absolute power?

Multiply power by 2

Name 3 Absolute power units for RF:

Mw - Milliwants, W - Watts, dbm is Decibels to one milliwatt

what is Network Time protcol (NTP) used for?

NTP is a protocol used to synchronize computer clocks across multiple systems. It supports synchronization over local area networks and the Internet.

what does PAN mean?

Personal Area Network?

What is SSH used for?

SSH or Secure Shell is a cryptographic network protocol for operating network services securely over an unsecured network

What is an SSID? (service set identifier)

SSID stands for Service Set IDentifier and is your network's name

What is Scattering?

Scattering is a type of reflection cause by a UNEVEN surface and increase echo and multipath. This can also be caused by encountering obstacles smaller than the wave length

What are Hertz?

The amount of cycles per second

When we talk about WLAN bridging, what mode does the Authenticator and the supplier have to be in?

The authenticator needs to be in the "Root" bridge mode, and the supplier need to be in the "non-root" bridge mode.

what command in the Linux terminal will show ip addressing information?

The command goes by "iwconfig" which will show you all the addressing information on the terminal in linux.

what is the control plane user for?

The control plane refers to the all functions and processes that determine which path to use to send the packet or frame.

what is the data rate specification in the PHY?

The data rate indicates the rate at which the PSDU (or MPDU if you prefer) will be transmitted

what happens if you have a higher frequency in short distances?

The faster repetitions of frequency in low distances results in higher bandwidth.

how does the 4 way handshake work? and what is it used for?

The four-way handshake is used for generating dynamic keys that will be used for protecting subsequent data transmissions 1.)access point sends EAPOL message with Anonce (random number) to the device to generate PTK 2.)Once the device has created its PTK it sends out SNonce which is needed by the access point to generate PTK as well. The device sends EAPOL to AP message2 with MIC (message integrity check) to make sure when the access point can verify whether this message corrupted or modified. Once SNonce received by the AP it can generate PTK as well for unicast traffic encryption 3.)EAPOL message3 is sent from AP to client device containing GTK. AP creates GTK without the involvement of the client from GMK 4.)Fourth and last EPOL message will be sent from the client to AP just to confirm that Keys have been installed

what happens if you have a higher frequency in long distances?

The higher cycle rate causes the system to fade out quicker resulting in decreased bandwidth

What is the intentional radiator?

The intentional radiator includes everything in the RF transmission system EXCEPT the antenna. EX: The power output of the IR would be measured at the point where it enters the antenna element. The power at the antenna would be the ACTUAL output power.

What is an A-MSDU?

The is an Aggregated MSDU. This is a special MAC frame format with multiple MSDUs inside a single MPDU.

What is the length field in the PHY?

The length field in the PHY PLCP header indicates the length (in octets or bytes) of the current frame

The data link layer is split into which two sub layers?

The logical link control sublayer, and the Media Access Control sublayer. we have LSDU & LPDU's at the logical link control sublayer, which are passed down to the MAC sublayer as an MSDU. The MSDU is prepended with the 802.11 header and appended with the FCS which then makes it an MPDU.

What is a mesh portal?

The mesh portal (MPP) is the gateway between the wireless mesh network and the enterprise wired LAN

What is a multiple channel architecture?

The multiple channel architecture uses: -most common model -staggered channels throughput -channel selection and AP placement important

What is Network Allocation Vector?

The network allocation vector can be considered as a counter that counts down to zero. The maximum NAV duration is the transmission time required by frame, which is the the time for which the channel will be busy. At the start of transmission of a frame, the NAV value is set to its maximum. A non-zero value indicates that the channel is busy, and so no station contends for it. When the NAV value decrements to 0, it indicates that the channel is free and the other stations can contend for it. *Works with Carrier-Sense Mechanism*

What is polarization?

The physical orientation of the Antenna. Horizonal or vertical etc.

Contention Window

The range of values that a wireless station can use to compute a random backoff timer duration.

When an amendment is ratified, what happens to the standard?

The ratified amendment becomes part of the standard, and will eventually rollout it's specifications within updates. but the new standard is available for implementation.

What are training fields used for?

The training fields are used in HT and VHT (as well as OFDM and ERP) PHYs to synchronize the receiver with the incoming signal

What is RF propagation?

The ways in which an Radio Frequency travels

how does EDCA work? (Enhanced distributed Channel Acces)

There are channel Access categories (TXOPS): AC_BK(Background) - 4th priority AC_BE(Best Effort) - 3rd priority AC_VI(Video) - 2nd priority AC_VO(Voice) - 1st priority These access Queues are attached to their own EDCA-F(functions), which have their own AIFSN number values(priority based).

What is a Semi-directional Antenna?

This Focus's most of their energy in a particular direction.

What is interesting about the VHT PLCP Header and PHY Training Fields?

This PHY header allows a combination of higher legacy and VHT devices to be able to be sent information on a Mixed mode architecture. sending VHT-training fields, and Legacy training fields. The device the receiving end will only pick whats necessary for their device.

What is Radio Resource Management (RRM)?

This allows APs to use automatic channel selection, automatic output power selection, and other configuration. This is all done by based on neighboring AP feedbacks, and network diagnostics.

what is hotspot 2.0 / Passpoint

This allows a hotspot to be implemented regardless of SSID, so that users who are subscribed to whatever back end services they offer, can automatically connect and be authenticated and use that network.

What is a Wireless Lan Controller

This allows for central management for all of your lightweight APs, that let clients into you LAN. other functionalities include: -802.1x eap -802.1x PSK -QOS -VLANS -some allow up to 2k AP's

What is Band Steering?

This allows you to push clients to use the 5Ghz if 2.4Ghz, is full of bandwidth.

What does a "Block ACK" frame do?

This can Acknowledge Multiple frames at once. NOTE: there needs to be an established permission between the AP and the client, to be able to process a block acknowledgement

What can wireless monitoring systems be used for?

This can capture Data analytics for your wireless network, traffic, bands used, Qos and much more.

Why can increasing the power output of a device cause lower throughput?

This can cause a mismatch of certain devices. for example, phones, tablets, and other devices produce weak Wifi signals. while increasing the power of the device, mobile devies can receive that strong signal, but the AP cannot receive that weak signla over the power output. EX: like whispering to someone screaming*

What is Maximum Ratio Combining?

This combines the signal of two antennas to increase signal strength at longer distances.

What is SNR (Signal-to-Noise Ratio)?

This compares the currenty environment with RF frequencys already propagating the area; to your wireless signal you are producing.

in the MAC header, what is the "Duration" subfield used for?

This defines how long its going to take to finish, the current frame transaction, after the current frame is completed.

What is EDCA?(enhanced distributed Channel Access)

This is used for Prioritizing QoS Services.

What is Voltage Standing Wave Ratio? (VSWR)

This is a measurement of how efficiently radio-frequency power is transmitted from a power source, through a transmission line, into a load. the smaller the VSWR is, the better the antenna is matched to the transmission line and the more power is delivered to the antenna. The minimum VSWR is 1.0. meaning no power is reflected from the antenna, which is ideal. (The bigger the mistmatch, the more power that is reflected back thus, the larger the ration such as 6:1) However depending on the equipment you might still be able to get a usable single

What are decibels?

This is a relative measure meant of Power(dB)

What is Fast Fourier Transform (FFT)?

This is a signal processing technique where FTT time is the time during transmission or reception when signal processing is accomplished.

regulatory domain

This is a site that regulates radio communications for certain regions of the world.

What is an A-MPDU?

This is an Aggregated MPDU This is a special PHY frame format with multiple MPDUs inside a single PPDU.

What is a highly directional antenna?

This is an antenna that is is highly focused in a certain direction. very narrow, for distance.

what happens with association request frames?

This is an association request frame sent from the client to the AP. Then an acknowledgement frame is sent to client from the AP -No status code is listed

what happens with association response frames?

This is an association response frame sent from the client to the AP. then an acknowledgement frame is sent to the client from the AP -Status code on frame becomes successful

What is open system Autentication?

This is an older Wifi network access method that was used with WEP. while WEP has been deprecated, this is still in unse today.

What is Adjacent channel interference?

This is channel overlapping which can happen at two places! 1.) when AP's are too close together even if they are on different channels 2.) having APs without 5 channel width apart

What is the Basic Service set Area? (BSA)

This is defined as where your stations communicate.

When talking about POE - What is a PD?

This is device the receives it's power through the POE capable device. Ex: a VoIP phone, or AP powered on from a POE switch

what is active gain?

This is direct increase of power from the transmitter?

After connecting to a Guest SSID, you have no internet access and you're unable to access internet websites. What could have caused this issue.

This is often caused by DNS issues, and Captive portal failures. EX: a resolution for captive portal may be clearing your cache and cookies on the web browser.

What is a TIM? (Traffice indication MAP)

This is part of the power save management technique: If a station/client is part of a basic service set, it will notify the AP that it isenabling Power Save mode by changing the Power Management fieldto 1.When the AP receives a frame from a station with this bit set to 1, the AP knows that the station is in Power Save mode. If the AP then receives any data that is destined for the station in Power Save mode, the AP will store the information in a buffer.

What does Request for Comment(RFC)?

This is part of the process used to improve wireless standards, through testing.

What is dynamic frequency detection?

This is radar detection /avoidence scheme created for regulatory domains.

What is RSSI?

This is recieved signal strength indicator. This is a vendor neutral classification and should not be used.

What is a mesh client?

This is simply a client that connects to the mesh network

What is transmit beam forming? (TxBF)

This is special Antenna technology used to focus the signal on a specific destination. This is only on 802.11n/AC.

What is LOS?

This is the Line of sight between two Antennas

What is throughput?

This is the amount of data during a time that a flow can send or receive.

what is SOM?

This is the amount of recieved signal strength

What is Diffraction?

This is the change or bend of an RF signal when it passed BY a medium.

What is loss?

This is the decrease of RF signal strength or amplitude

what is a working group?

This is the first stage of a new PHY. The working group will see the change through the draft and ratification phases until the amendment either becomes part of the standard or is dropped without ratification.

What is gain?

This is the increase of RF signal strength or amplitude

What is Free Space Path Loss (FSPL)?

This is the measure of how much signal remains with increasing distance in free space.

what is bandwidth?

This is the number of bits per second that a link can sand or receive.

What is fragmentation?

This is the process of taking mutliple frames and breaking them into smaller frames. which can resolve the following: -intermittent interference -SIFs used between fragmented frames to burst through AP EX: -Fragmentation threshold can be configured on AP's

what is passive gain?

This is the shaping or focusing of the antenna to concentrate the signal

what is radio propagation?

This is the way radio waves move from one to another.

What is end to end QoS?

This is to make sure you have QoS priority from end user to when it leaves your netowrk. This enhances the best reliability.

What is roaming?

This is unassociating and reassociating with an AP when connection is lost.

The azimuth chart represents a view of an antenna's radiation pattern from which direction?

Top view: Front, left, right , and behind

What is Transmit Power Control? (TCS)

Transmit Power Control is a technical mechanism used within some networking devices in order to prevent too much unwanted interference between different wireless networks

What is Receieved sensitivity?

What is the minimum signal strength needed.

what does WAN mean?

Wide Area Network

What IEEE standard is 802.11?

Wireless

what does WLAN mean?

Wireless Local Area Network?

When doing RF math, are dB and dBi the same, regardless of loss or gain?

Yes they are the same value loss or gain wise when doing math.

how could you help reduce the exhaustion of your DHCP pool?

You could decrease the lease durations to a smaller value so that IP's are not leased for days, and maybe a few hours.

in the Frame Control field, what is the "Retry" subfield used for?

its is used to increment the number of times the frame has attempted to send.

in the 802.11 standard, are request and response frames user for authentication?

no they are not, the specification only includes an authentication frame.

Do 5ghz channels overlap?

no they do not.

What is frequency?

number of waves/cycles per second