Chapter 6- Wireless Networking

IBSS

(Independent Basic Service Set)- uses an ad hoc topology. Small # of nodes closely positioned transmit directly to each other w/o an intervening connectivity device

MIMO

(Multiple Input Multiple Output) - multiple access point and client device antennas may issue signal to one or more receiver. MIMO increase range and throughput

MU-MIMO

(Multiuser MIMO) - newer tech that allows multiple antennas to service multiple clients simultaneously

RTS/CTS

(Request to send/clear to send) protocol ensures packets are not inhibited by other transmissions

SSID?

(service set identifier) the name of an access point.

WLANs work at OSI layer?

1 & 2 They support TCP/IP

Notable Wifi standards

1. 802.11b, 802.11a, 802.11g, 802.11n, 802.11ac, and 802.11ax 2. 802.11n

Two techniques networks can use for combining multiple frames into one larger frame

1. A-MSDU (aggregated max service data unit) 2. A-MPDU (Aggregated Mac protocol data unit)

Additional security options

1. AP/ antenna placement 2. geofencing 3. guest network 4. wireless client isolation 5. captive portal 6. Iot Access consideration

Most wireless devices implement two techs:

1. FHSS (Frequency hopping spread spectrum) 2. DSSS ( Direct sequence spread spectrum)

List of capabilities common to wireless testing tools:

1. Identify transmitting access points, stations, and channels Measure signal strength from an AP 2. Indicate the effects of attenuation, signal loss, and noise 3. Interpret signal strength information 4. Ensure proper association and reassociation between APs 5. Capture and interpret traffic 6. Measure throughput and assess data transmission errors 7. Analyze characteristics of each channel

TKIP accomplished what improvments?

1. MSG integrity 2. key distribution 3. encryption

The most secure communication is made possible by combining what?

1. Radius server with WPA/WPA2 known as WPA-Enterprise/ WPA2-Enterprise

No wifi connection

1. Wrong SSID 2. Encyprtion protocol mismatch 3. Incorrect passphrase 4. static channel utilization 5. mismatch RF band 6. mistmatch standards 7. long AP association time

Ap variables set during installation?

1. admin password 2. SSID & if SSID is broadcast 3. Security 4. If DHCP is used or not

SSID contains?

1. beacon frame info 2. is configured in the AP config utility and is recommended that it be changed from default setting

What to consider when installing AP?

1. distance 2. type & number of obstacles 3. coverage 3. interference

Slow wifi connection

1. insufficient wireless coverage 2. RF attentuation/signal loss 3. interference 4. channel overlap 5. wireless standard specification 6. simultanous wire and wireless connection 7. problmes with firmware 8. incorrect antenna type 9. mismatch antenna polorization 10. client saturation or overcapcity 11. client disassociation

3 frame types that 802.11 specifies a max sublayer frame?

1. management frame- association/reassociation 2. Control- medium acess & data delivery 3. data - carry data sent between stations

What happens when obstacles are in a signals way?

1. pass through the object 2. be absorbed by the object

IR sensors collect info on:

1. presence/level of fluid 2. bloodflow 3.proximity to device 4. commands from control device

MU-MIMO characteristics

1. reduces congestion & contributes to faster data transmission 2. is avaibale with WAVE 2 802.11ac products

Z wave two basic functions?

1. signaling to manage wireless connections 2. control to transmit data/ commands between devices

Wifi, bluetooth, and zigbee use ? (FHSS OR DSSS)

1. wifi-DSSS 2. Bluetooth- FHSS 3. ZigBee- DSSS

TKIP

802.11i encryption key generation & management scheme to improve security for legacy WEP-based devices

Wireless spectrum spans frequency ranges or bands between?

9 KHz & 300 GHz

z wave

A smart home protocol

encryption uses what?

AES (adv. encryption standard) better encryption

BSS identifier?

BSSID ( basic service identifier)

What ensures data confidentiality with both encryptions and packet authentication

CCMP (counter mode) with CBC (cipher block chaining) MAc protocol

802.11 standard specify the use of what procedures to access a shared medium?

CSMA/CA (Carrier sense multiple access with collision)

radius server is used in cooperation with an authentication mechanism called

EAP

Interference

EM waves interfere with wireless communication.

ESS identifier?`

ESSID

How do antennas and electrical signals work?

Electrical signals travels from the transmitter to an antenna, which then emits the signal as a series of electromagnetic waves into the atmosphere. At the destination, another antenna accepts the signal and a receiver converts it back to current.

Wireless spectrum

Electromagnetic frequencies used for data/voice communication

Range

Geographical area that an antenna can reach

Examples of IoT devices that are part of a home?

Health monitor, smart speaker, smart thermostat, smart cameras

RFID used commonly for?

Inventory

What is ZigBee used for?

IoT devices such as fleet management, building automation, HVAC control

Omnidirectional antenna

Issues and receives wireless signals with equal strength and clarity in all directions.

Directional (unidirectional ) antenna

Issues wireless signals along a single direction.

LOS

Line of sight- when signal travels in a straight line directly from transmitter to receiver

NFC

Near field communication- Transfer data over short distance

OFDMA

Orthogonal Frequency Division Multiple Access- supports more efficient multiuser functionality for 802.11 ax devices

Signal- to -noise ratio

Portion of noise to the strength of signal noise/stregth= Signal-to-noise ration

RFID?

Radio Frequency Identification- electromagnetic fields to store data

RADIUS

Remote Authentication Dial-in User service an open source authentication and authorization service

Fixed frequency?

Single frequency for that band

WPA

Wifi protected access- dynamically assigns every transmission its own key

Multipath

Wireless signals follow different paths to destination

remote wipe

admin having a feature to allow off boarding remotely

z wave is also called a what? and what are some examples of it?

also called a hub and smart lighting, smart sensors, smart plugs etc

ANT+

an ad-hoc wireless protocol operating at 2.4 GHz

passive scanning

ap take initiative. wireless devices listen for a beacon frame

Site survey?

asses client requirement, facility characteristics, coverage area

BSS

basic service set- USES AN INFRASTRUCTURE TOPOLOGY. group of stations share an access point

Frame aggreation

combines multiple frames into one larger frame

RTS/CTS decreases what?

decreases network efficiency but can be efficient for large transmission packet

Spectrum analyzer

device that can access quality of wireless signal

ESS

extended service set. uses mesh topology. several access points are connected to same LAN network

EAP

extensible authentication protocol- framework for authentication clients and servers

How does an NFC tag collect power?

from phones or other device by magnetic induction

war chalking

hacker draw symbols near vulnerable ap

War driving

hacker searches for unprotected wireless network by driving around with a laptop configured to receive & caputre wireless data transmission

examples of ANT+

heart rate monitors, gps, smartwatch, bicycle computer, fitness equipment

Bluetooth does what to reduce interfence?

hops between frequencies within that band

Whats a wireless range extender?

how a wireless signal can be amplified by increasing the power of the transmission or extended by repeating the signal

WPS attack

involved cracking a PIN in order to access AP setting

On- boarding

involved installing a specific program/app onto a device to give trusted access to certain portions of netwrok

WPA attck

involves interception of the network keys communicated between stations and APs also called WPA cracking

is IR visible?

just below the spectrum visible to eye

Wired/wireless signals share which layer?

layer 3 and up

ZigBee

low power wireless technology. Holds small amounts of data

Off-boarding

opposite of on boarding

Msg integrity ensures what?

packet is coming from declared source

Mac filtering

prevents ap from authenticating any device whose MAc addy isnt listed

Association

process where packets are exchanged between computer and an access point in order to gain internet access

evil twin

rogue AP planted in a network geographical area to pose as an authorize ap

encryption algorithms

scramble data into a format that cannot easily be interpreted if the signal is intercepted

Fading

signal runs into obstacles, energy is gradually faded

wireless analyzer (wifi analyzer)

software that can 1. evaluate wifi network availability 2. optimize wifi signal setting 3. help identify wifi security threats

Ap devices combine what at home?

switching, routing, and other network function

Antennas radiation pattern describe what?

the relative strength over a 3 dimensional area of all electromagnetic energy that antenna sends/ receives

Active scanning

the wireless client takes the initiative by transmitting a special frame known as a probe

Channel bonding

two adjacent 20-MHz channels can be bonded to make 40-MHz channel

802.11 standard uses ack packets to what?

verify every transmission & requires more overhead than 802.3

How do WLAN transmit signals?

via RF waves

reflection

wave encounters obstacles and bounces back

Refraction

wave travels through objects the wave direction, speed, and wavelength are altered (refracted)

Propagation

way in which a wave travels from one point to another

Scanning

when a wireless devices surveys its surrounding for an access point

scattering`

wireless signal encounters object and signal is diffused or scattered in multiple directions

Diffraction

wireless signal is split into secondary waves when it encounters an obstruction