In our next section we're going to talk about the violence local area networks.
And let's start with the light wireless local area network overview so why we need wireless networks
into these companies wireless networks are a powerful tool for boosting productivity and encouraging
information sharing with untethered to access to documents e-mails applications and other network resources.
Employers can roam where they need to and have constant access to the tools required to do their jobs.
That is the main reason that explains the need for the wireless networks and let's go ahead with the
advantages of the wireless.
The first advantage anchor is mobility and collaboration.
Employees who use your wireless LAN can roam around your office or two different floors without losing
their connection.
Imagine everyone in a team meeting or in small conferences having access to up to the minute communications
and all documents and applications on your network.
The second advantage is the improved responsiveness.
Customers want quick response to queries and concerns guys and a wireless network can improve customer
service by connecting staff to the information they need.
For example a doctor in a small medical office can access online patient files while moving between
exam rooms or a retail sales person can check on available inventory necessary to write up orders on
the showroom floor.
The third advantage is better access to the information.
Wireless lines allow a business to bring network access to areas that would be difficult to connect
to a wired network.
For example adding wireless access points to a warehouse can make it easier to check and manage inventory.
Providing the company with accurate inventory figures in the real time and the fourth advantage is the
easier network expansion.
Companies that need to add employees or reconfigure offices for a complete will immediately benefit
from the flexibility wireless lines provide desks can be moved and new employees can be added to the
network without the effort and the costs recur to run cables and the wires.
The most common wireless technologies used today are Wi-Fi Bluetooth why Max cellular broadband and
the satellite broadband
let's go with I Tripoli 800 and to that eleven by five standards eight unders and to that eleven refers
to a family of specifications developed by the eye Tripoli for wireless LAN technology.
These specifications.
This standard specifies and all the air interface between a wireless client and a base station or between
two wireless clients.
In this chart you can see the history and the enhancements of the standard.
The first standard is a standard and two that eleven as you can see and the maximum death rate is two
megabits per second just.
But the less than that which is eight under then two that on a C is supporting up to seven gigabit per
second and you can see the bands that the standard are using and the benefits they support and the modulation
type and advanced antenna technologies.
Let's go ahead we then worse again.
This chart explains some differences between wireless local area network and the wired LAN physical
layer component of wireless local area network is radio frequency and the physical Lear component of
the Internet is cable as you know.
Availability of the wireless LAN is everybody in the range of the access point while you need a cable
connection on the internet look we're a network to reach the network and we can face with the signal
interference for wireless local area network but it is inconsequential for the Internet local area network
and let's go ahead with the wireless network interface cards a wireless network interface controller
is a network interface controller which connects through a wireless radio based computer network rather
than a wire network such as Internet.
This card uses an antenna to communicate via microwave radiation and let's go ahead with the wireless.
More than a wireless modem is a device that provides wireless broadband connections such as DSL for
home users over the Wi-Fi.
Most of us use modem in our houses and connect to Internet by using more them or wireless.
Let's go ahead with the business wireless solutions.
When 800 to that eleven networking began all access points were autonomous mode which means that each
AP access point worked as a standalone unit with no knowledge of the or interaction among other access
points autonomous mode was fine in the beginning when wireless networking was often limited to providing
network access in common areas or broad boardrooms and continuous streaming was not a requirement.
Rather than using autonomous access points you can use lightweight access points to if you have a network
component that offers wireless local area network controller services.
In this scenario the access points all have their configuration managed but the wireless controller
you can set a single policy on that wireless controller and that configuration setting can be deployed
to all managed access points reducing the workload of managing hundreds of afternoons access points.
Let's go ahead with the wireless antennas and antenna.
Use the wireless system three fundamental properties gain direction and the polarization and we have
three types of antennas and they're only directional directional and the Yagi directional antennas are
designed to be pointed to or focus in a single direction somewhat like our flashlight only antennas
collect and broadcast signal in a 360 degree pattern similar to how a light bulb throws light in all
directions and the antenna is a directional antenna consisting of multiple parallel elements in a line
and let's go ahead with the.
That's a lie them topology mounts.
We have basically two topology much for wireless network guys and they are ad hoc mode.
And the infrastructure modes let's start with the ad hoc moment in the ad the much to the wise is connect
each other wirelessly without the aid of an infrastructure do as such as a wireless router on or access
point as you can see in here.
We have leapt up one and leapt up two and they're connected wirelessly to each other without an access
point in the infrastructure mod wireless clients interconnect via a wireless rather or access points
such as in wireless local area not in the infrastructure mode.
Wireless clients interconnect via a wireless rather or access points such as in WI Lance in basic SOS
area.
We have just won access points to connect.
As you can see in here we have a laptop one laptop two again and this guys are this time connected to
each other by the help of an access point and in extended service area.
This time we have two or more access points to connect and our laptop one is in here for example and
our laptop too is on the remote.
And as you can see and they are connected to each other by using two or more access points let's go
into the wireless LAN operations and let's go ahead with the Wi-Fi frame format in the Wi-Fi frame.
We have two birds of frame control field.
We have two points of duration field six bytes of destination and source and the rather MAC address
failed two birds of sequential control bid for but I'm sorry six parts of MAC address of the AP and
we have data payloads and the CRC fields let's go ahead with the CSM ACA carrier since multiple access
collision what the evidence is a protocol for carrier transmission it in a under then to that eleven
networks unlike CSM may see the carrier since multiple access collision that Act which deals with transmissions
after a collision has occured CSM ACA acts to prevent collisions before they happen and let's go ahead.
The declined access points connection the first the client sends air these core AP message to discover
the access point in the network then an authentication message is shared between Klein and the access
point.
Then the associate message is shared also between the client and the access point to connect an access
point.
We have five parameters and their SSI.
These security key security in network mode and the channels setting assess the idea is the short for
service set identifier and basically SSA today is the name for a Wi-Fi network.
Security is the security key is the passport that we are using to connect to wireless access point.
We can also set the security and network modes and channels settings to in wireless network guys three
cancer channels are used for communication between sender and wireless receiver devices.
If channel is used so much by clients it can saturate and to decrease the saturation.
We have different types of techniques and they're the s ss which means direct sequence spreads spectrum
FHA says which means free counseling helping spread its spread spectrum and all of them which means
orthogonal accounts in the Asian multiplex.
And that squares with the violence locally that security.
And let's start with the wireless those attacks this part recent Wi-Fi security advances wireless local
area networks remain wary vulnerable for denial of service attacks worldwide.
Traditional those attacks involve overwhelming air hosts with service requests in wireless networks
limited bandwidth and writhing functionality associated with nodes open up new avenues for launching
the those attacks.
Let's go ahead with the rogue access point term a rogue access point is a wireless access point that
has been installed on a secure network without explicit authorization from a local area network administrator.
Rogue access points can allow a hacker to conduct a man in the middle attack flood the network with
useless data creating a denial of service send for us outside advertising attractive features such as
free internet connectivity and provides a conduit for the theft of company information.
Let's go ahead with the men in the middle attack in the men in the middle attack.
Attackers secretly relays and possibly alters the communication between two parties who believe they
are directly communicating with each other.
An attacker with reception range of an unencrypted Wi-Fi wireless access point can insert himself as
a man in the middle.
Let's go ahead.
The wireless local area network configuration to configure a wireless local area network we should choose
the right network modes society channel with channel and a society broadcast or we can choose the security
application and the administration parameters as well as we can see in a year we are choosing a security
mode and we need to enter the password that we need to use while we are connecting to our wireless device.
And also we should use as security modes and ready so where we can define as ready as or rather as port
as well and we can make wireless mac filtering as you can see in here and just allow these guys to enter
our access points.