Lesson 3 Flashcards
Topic A
Topic A
Wireless communication is possible through the use of
Electromagnetic waves such as radio waves or micro waves
Light pulses
Wireless should be used when
When it is difficult or impossible to connect using wire (hazardous areas, long distances or inside historic buildings)
Wireless connections are
point to point
multipoint
broadcasts
Point to point in used when
Cellular communications
linking distant buildings CAN MAN or WAN
Multipoint is use when
connections to many nodes are needed like wireless networks
Broadcast communications are need when
data goes from a source node to all other nods on the network
What is the standard for wireless communications
802.11
802.11 defines
CSMA/CA
Spread spectrum reliability
802.11b specifies
multichannel roaming and automatic rate selection
802.11 ac defines
faster wireless communications, better range, improved reliability and Improved power consumption
What is latency
time taken for a packet to reach its destination
Latency includes what
Checking the data
Correcting errors
resending the packet lost in transit
MIMO does what
increase wireless network range and bandwidth
Name the networking standards
802.11
Speed Freq Range Srm
A 54 5 20 1
AC 433 5 35 8
B 11 2.4 100 1
G 54 2.4 100 1
N 150 2.4/5 70 4Name the wireless channels with no overlap
1
6
11
What can impact RF transmissions
power lines
Metal structures
Atmospheric conditions
Broadcast Radio
Single Frequency
High and low frequency versions
Does not travel very far
Easy to install
Inexpensive
High power can travel farther
Spread spectrum
Form of radio transmission
Uses more than one frequency
Difficult to eaves drop and capture signals
difficult to distinguish from background noise
Signal Distrobution methods
Frequency hopping
direct sequencing
OFDM
Uses multiple frequencies simultaneously to send data
DSSS
pg 98
Infrared transmission
Signals are sent as pulses of IR
300-300,000 Ghz
Just below visible light
Need unobstructed view of receivers
Signal can reflect off hard surfaces
IrDA is the governing body
Used in legacy systems and security sensors
Bluetooth 4.1
Short range communications between devices to create a WPAN
Up to eight devices can be connected
Range is 30m; Max is 100 between two devices
Uses RF based media and no need for line of sight
Used with NF communications for POS purchases
Microwave Transmissions
Point to Point transmissions
1-300 GHZ
Need unobstructed view
Environment can impact signal
Can be reflected of satelites
Used with WANs and MANs
Often used as backhaul comms
Connects core networks with regional networks
Used by WISPs for rural area comm
wireless Internet Service Providers
WISPs
Topic B
Topic B
WAP or AP
Access to the network
SSID
32 bit alpha numeric string that identifies the WAP
Many systems come with a default SSID
True
SSID mismatch
occurs when a device receives a packet that contains different SSID than its own.
Devices must have the same SSID as the WAP in order to work
True
SSID mismatches are rare because
They are done automatically
SSID mismatches are rare because
They are done automatically
What provides LAN mgmt
Wireless Controllers for the multiple access points
How do you control multiple access points
Wireless LAN Controllers
Wireless LAN controllers are used in conjunction with what to controller
LWAPP
Lightweight Access Control Protocol to manage lightweight access points
It can be hardware or software
Wireless Bridge
Used to connect two wired bridges using wireless technologies
Name the wireless antenna types
Directional
Omni Directional
Wireless Antenna Performance Factors
Pg 117
WLAN
Spans a small area, building, floor or room
Name some wireless LAN components
Station Access Point Service Sets BSS or BSSID ESSID IBSS Distribution System
Distributed Coordination Function
A collision avoidance method that controls access to the physical medium.
What are two modes for 802.11
Infrastructure and ad-hoc modes
Infrastructure mode
utilizes one or more WAPs to connect workstations to the cable backbone
Uses BSS or ESS
Uses hub and spoke topologies
Ad-Hoc
Also called IBSS
Utilizes peer to peer configurations which each workstation talks directly to other workstations
Uses mesh topologies
SSID broadcasts
Continuous announcements by a WAP that transmits its name or SSID
Name some mobile devices
Mobile Phone Laptop Tablet Gaming Device Media Device
Guidelines for implementing a wireless network
Pg 121
MUMIMO
Multi-User MIMO
MIMO
Multiple Input Multiple Output
What is a WPAN
Wireless Personal Area Network
Bluetooth freq range and Mbps
2.4 Ghz
24 Mbps
An increase in the amplitude of a radio wave is called what
Gain
Types of wireless technology
Infrared
Radio
Microwave
DCF
Distributed Coordination Function
Collision avoidance method that controls access to the physical medium
Each station checks the status of the wireless medium before beginning the transmission
What are some factors when deciding on the placement of WAPs
Building Layout
Coverage Area
Clients
Obstacles
Interference
Completed
Completed
