This probably should have been my 2nd post after the "Intro" post but its never too late to create a post on introduction to wireless.
Quick overview of what you will learn:
*
What is
Wireless?
*
WPAN/WLAN/WMAN/WWAN
*
Standalone AP
and Controller based AP
*
802.11a/b/g/n
and 802.11a/c
*
2.4 GHz
*
5.0 GHz
*
Interference
*
Why Wireless
Skills Matter
*
Different Types
of Cisco Access Points
Lets define wireless:
Wireless is: Not
using wires to send and receive electronic signals: sending and receiving
electronic signals by using radio waves.
Lets define Radio Waves:
Radio Waves are: An electromagnetic wave that is used for sending signals through the air without using wires.
4 Common Types of Wireless Networks you will hear about:
*
WPAN –
Wireless Personal Area Network
•
Works in a
very small area (5 to 10 meters)
•
Mice,
keyboards, headsets that connect to your computer
•
Think of
Bluetooth
*
WLAN
(Wireless Local Area Network)
•
Works
typically around an area of under 100 meters
•
Think of the
wireless network you have at your house or office
*
WMAN
-Wireless Metro Area Network
•
Low budget,
bridging network.
•
Alternative
to T1 or 3 point to point leased lines.
*
WWAN
(Wireless Wide Area Network)
•
Cellular
service providers – Example: AT&T nationwide GSM cellular Network.
2 types of access point modes you will hear about:
v Access Point in:
•
Standalone Mode – No WLC
•
Router (layer
3)
•
Switch (layer
2)
•
Wireless
Access Point standalone
•
End Devices
(Wireless phone, ipad, laptop, etc)
•
Access Point
– Lightweight Access Points –
(LWAPP/CAPWAP – Controller Mode)
(LWAPP/CAPWAP – Controller Mode)
•
Router (layer
3)
•
Switch (layer
2)
•
Wireless
Access Point (LAP)
•
Wireless LAN
Controller
•
End Devices
(Wireless phone, ipad, laptop, etc)
We still need the wireless NIC on the client side for everything to complete the list of component
for a wireless network.
Be familiar with the following terms:
Now lets go over 802.11a/b/g/n:
Its always a good idea to understand the basics above. Don't worry too much about the modulation
techniques just yet!
Now lets take a look at 5.0Ghz
2 terms that you should understand are:
Now lets talk about types of interference's that can weaken or disrupt your wireless signal:
So what happens when there is interference? Well, the wireless signal range is degraded,
data throughput decreases and you may end up having complete signal drops or intermittent signal
drops.
Why do wireless skills matter?
Wireless as grown tremendously over the years. Not many people know how to properly design,
configure and manage a wireless infrastructure. It is an advantage to be not only good but great
with managing a wireless network. As more and more wireless devices come into a network, it
will be up to you as a wireless engineer to train, maintain, support your staff with ease if you
take the time to learn and understand the art of wireless!
I highly recommend going with Cisco because when it comes to wireless deployments because
Cisco gets the job done! Feel free to correct any mistakes I've made or ask me any questions.
Please check out my twitter and instagram! Most images are courtesy of Cisco, Apple, Wiki,
Ciscolive. I strongly encourage you to visit and register for free at www.ciscolive.com if you
want to learn more. The site offers free resources from industry experts like myself.
Thank you for visiting!!!
Cisco 3700 Access Points (802.11ac)
Cisco 3600 Access points (support for 802.11AC with module)
Cisco 2700 Access points (3x4, 802.11ac)
Cisco 1600 Acces points (entry-level)
for a wireless network.
Be familiar with the following terms:
v IBSS (Independent Basic Service Set) – Ad
Hoc
•
Wireless NICs
and other devices can communicate directly without the need for an AP.
•
Peer to Peer
v BSS (Basic Service Set) – The area/cell
defined by the wireless signal served by the AP.
•
It might be
referred to as BSA.
•
Single AP
v ESS (Extended Service Set) –
•
Most common
in a corporate environment
•
All access
points to the same SSID
•
Roaming
ability takes place
v SSID (Service Set Identifier ) – Unique
32-character identifier
Now lets go over 802.11a/b/g/n:
*
Narrow band
and spread spectrum are the two main ways of sending a signal
*
802.11a
operate at:
*
5.0GHz band
*
Uses OFDM
with modulation formats that are available: BPSK, QPSK, 16-QAM, 64-QAM
*
802.11b
operate at:
*
2.4GHz band
*
Uses DSS
(Direct-sequence spread spectrum) with CCK or PBCC modulation formats.
*
802.11g
operate at:
*
2.4GHz band
*
Uses either
OFDM or DSS and the modulation formats are set according to the data rate.
*
802.11n
operate at:
*
Can operate
at both 2.4GHz and 5.0GHz band
*
Uses DSSS but
prefers OFDM (Orthogonal frequency division multiplexing)
*
MIMO + OFDM
*
802.11a/c
operate at:
*
5.0GHz band
with support for backwards compatibility with other 802.11n technologies
operating in the same band. MIMO + OFDM
*
802.11ac AP
Support up to 8 data streams (Each stream at 433Mbps)
*
Max speed
1.3Gbps
*
Samsung
Galaxy S4 chipset only supports 1 single stream (up to 433Mbps in speed)
Its always a good idea to understand the basics above. Don't worry too much about the modulation
techniques just yet!
Now lets take a look at 5.0Ghz
2 terms that you should understand are:
v RSSI – Received signal strength indicator
•
The measure
of signal strength that arrives at the receiving device.
•
The lower the
number to 0dBm would indicate a stronger signal
•
Grade value
from 0 to 255 with each grade value is an equivalent dBm (decibels to a
milliwatt) value.
•
The scale
will be different from one card vendor to another.
•
Anything
above SNR of -72dBm would mean the client is far away or signal is weaker
v SNR – Signal to Noise Ratio
•
Comparison of
the amount of signal as compared to the surrounding noise.
•
The higher
the SNR the better. (Anything between 25dB to 40dB SNR is very good signal)
Now lets talk about types of interference's that can weaken or disrupt your wireless signal:
*
Types of
signal interference:
•
Physical
interference – Easier to see.
•
A cordless
phone sitting next to an AP.
•
Plants and
Trees
•
Microwave
ovens
•
Hidden
physical interference – difficult to mitigate. Think about: What is inside
those walls?
•
An Exterior
wall that consists of brick and thick insulation can cause interference and its
not easy to see.
•
Lead paint
•
Bulletproof
glass (you might think nothing of it but the degree of attenuation is high )
•
Channel
interference – Other wireless devices on an overlapping channel.
•
Neighbor APs
using channels that is interfering with the AP channel that ones own is on.
So what happens when there is interference? Well, the wireless signal range is degraded,
data throughput decreases and you may end up having complete signal drops or intermittent signal
drops.
Why do wireless skills matter?
Wireless as grown tremendously over the years. Not many people know how to properly design,
configure and manage a wireless infrastructure. It is an advantage to be not only good but great
with managing a wireless network. As more and more wireless devices come into a network, it
will be up to you as a wireless engineer to train, maintain, support your staff with ease if you
take the time to learn and understand the art of wireless!
I highly recommend going with Cisco because when it comes to wireless deployments because
Cisco gets the job done! Feel free to correct any mistakes I've made or ask me any questions.
Please check out my twitter and instagram! Most images are courtesy of Cisco, Apple, Wiki,
Ciscolive. I strongly encourage you to visit and register for free at www.ciscolive.com if you
want to learn more. The site offers free resources from industry experts like myself.
Thank you for visiting!!!
Cisco 3700 Access Points (802.11ac)
Cisco 3600 Access points (support for 802.11AC with module)
Cisco 2700 Access points (3x4, 802.11ac)
Cisco 1600 Acces points (entry-level)
