Wireless Networking Flashcards
The Wireless Standard is :
802.11
802.11 uses _______ ________ to transmit data between wireless nodes
radio waves
wireless networks start with a ___________ ____________ ______________
wireless access point ( WAP )
the cornerstone of what makes 802.11 work is a:
Service Set Identifier ( SSID )
If you are using 802.11 you are in:
Infrastructure mode
In windows you can create a wireless connection using and in:
Ad hoc mode
If you have a single WAP and a Single SSID, you have what is known as a :
Basic Service Set Identifier ( BSSID )
When you have multiple WAPs that are all working together is called:
Extended Service Set Identifier ( ESSID )
All 802.11 networks are designed to work / run within the industrial and scientific medical band ( or range of frequencies )
2.4 and 5 GHz
Wireless networks, specifically the 802.11 user ________ to communicate between the WAP and the wireless client ( laptop or computer )
CSMA/CA or ( Carrier-sense multiple access with collision avoidance
The actual data is transferred form the WAP to the wireless client via 2 ways:
Direct-sequence spread-spectrum ( DSSS ) - original - spread signal across
Orthogonal frequency-driven multiplexing ( OFDM ) - todays standard -
this 802.11 standard is the first / original, it ran at 11 mbps, was on the 2.4 ghz ( limited Channels ) band, and used DSSS to transfer data.
802.11b
this 802.11 standard it ran at 54 mbps, was on 5 ghz and used OFDM to transmit data
802.11a
this 802.11 standard really changed things was the first widely used. It ran at 54 mbps but was only on a 2.4 ghz ( limited Channels ) band. It also used OFDM to transmit data
802.11g
this 802.11 runs from 108-300 mbps, ran on both 2.4 and 5.0 ghz, introduced M1MO, used OFDM, had what was called Greenfield mode, created a lot of tweaking Current standard**
802.11n
this 802.11 standard, took everything that was bad and made them better, backward compatible, it ran 1 gbps, was on 5 ghz band, works off of the M1MO concept called MU-M1MO (multi-user) Current standard**
802.11ac
this is a 802.3 standard, that allows certain switches push power through the ethernet cables to supply power to a wireless access point thats capable
Power over Ethernet ( POE )
this is used when you don’t have a switch to produce POE
POE injector
The original POE standard was called:
802.3af, ran on 15.4 watts
The latest POE standard is called:
PoE+ 802.3at, runs on 30 watts
This type of antennae is a metal pole/rod that goes straight up and produces radiation pattern shaped like a sphere.
Omni
this type of antennae is used a lot / most common, with 802.11 where the antennae’s actually go in opposite direction of each other. Produce a Flat donut shaped pattern
Dipole
this type of antennae is used a lot in enterprise environments, sends out a half sphere of radiation, more one directional and are regularly used on exterior walls.
Patch
this type of antennae produces a football / funnel lens shaped radiation field,
Directional like a Yagi or Parobolic ( stongest, shoots a signal for like 8 miles )
a standard antennae connector type is called a :
SubMiniature version A ( SMA ) connector
Antennae / radio wave gains are measured in:
dBI (decibals)
Because the 802.11i was slow to release, a new wireless standard that utilizes a Temporal Key Integrity Protocol (TKIP) was created and is called:
Wi-Fi Protected Access (WPA)
The latest wireless standard / one used today, that utilizes a Advanced Encryption Standard (AES) along with Counter Mode with Cipher Block Chaining Message Authentication Code Protocol ( CCMP ) is called:
WPA2
this wireless standard allow you to use a shared-key for authentication, you could give to users for access
WPA-PSK ( WPA with pre-shared key )
this wireless standard uses “Radius” where you have to put in a Server IP and must know the Radius password for authentication.
WPA/WPA2-Enterprise
Other features that you could use to better secure your wireless network are:
Disable SSID broadcast
Use MAC filtering
Limit the number of DHCP-issued addresses
Unauthorized Access Points, like when someone plugs say a SOHO router into a LAN drop in your network to attempt to access the network is called:
Rogue access point
This is used to help block signals from a wireless access point that has say an “Evil” twin on the network and is federally illegal in the US
802.11 jammer
This is also used to prevent a “Evil” twin authentication attack where the rogue access point sends out a broadcast to all the machines on the wireless network telling them to get off of their current network and login in to it is called a:
De-authentication attack
this is used to help configure all of our WAP’s in or at one location. It can be a switch, software ( aka Unifi ) on a server. Allow you to monitor traffic, setup various zones, or access areas.
Wireless controller
The ________ _____________ are used on both SOHO and Enterprise routers
802.11 standards
Problems or environmental issues that could hinder the radio wave of a WAP reaching it’s clients and vice versa are but not limited to:
interference
Reflection
Refraction - or bends the radio wave
absorption - like concrete wall can really suck the radio waves
attenuation - or the distance can be to long from the WAP to client
A tool to help survey your signal in a planned wireless project, to help you find good and bad spots. When using this tool to help set up your network, pay attention to the bandwidths and use channels with the least amount of congestion
Wireless Analyzer
This wireless tool is a relative gauge of strength that shows the signal you are receiving. The stronger the signal the more or higher the negative the value.
Signal-to-noise ratio
these are used to help with the Signal-to-noise ratio, acts like a repeater, creates bridges between the broadcasted SSID to the wireless repeater
Wireless extenders
this is a newer wireless network, that uses multiple WAP’s where they talk to each other to help propagate signal
mesh
Sources of wireless interference can included:
other WAPs
microwaves
wireless mice and keyboards
Remove sources of ___________ or change the ________ ____________ to avoid channel interference
interference
WAP’s frequency
Too many users on the network, not enough WAP’s. Try spinning up more SSID’s. Also Jitter can cause this on a wireless network especially with downloads like watching video’s, so you must increase capacity like adding or moving WAP’s arounds. Also,
use more ( the latest ) 802.11 standard devices to help with:
Slow capacity
Incorrect antennae types - using a dipole instead of a directional or vice versa
incorrect location of antennae - test and retest to make them work the best
**remember to used antennae’s with short cables****
Antennae problems
