Now, some of the basic terminologies, these are going to be very important for us to understand the
following lectures.
So I just want to make sure that we're on a basically same page.
Right, because you're going to hear these concepts in any resource about Wi-Fi networking and of course,
throughout this course.
Now, if you already know the basic terminology, sure, you can go ahead and skip to the next lecture.
So an access point and AP.
This is a device that serves as a central wireless connection point for a Wi-Fi network.
The service set identifier or ID.
It's the name of the wireless network, it can be contained and the beacons sent out by access points
or it can be hidden so the clients who wish to associate must first know the name of the network first.
So early security guidance was to hide the inside of your network, but modern networking tools can
detect the SS ID simply by watching for a legitimate client association.
Because as as IDs are transmitted in clear text.
Besides basic service, that identifier is a unique address that identifies the access point or hub
that creates the wireless network.
The extended service said identifier or E as as ID, it's the name of the wireless network and is used
by all APIs that provide access to the same infrastructure in an extended service said.
It can be advertised by apps and their beacons or suppressed so that clients must know the SS ID before
associating with an app.
Roaming.
So when a wireless network with multiple apps, a client that is moving from the coverage area provided
by one app to that provided by another, it's called roaming, so it must disassociate from the first
AP before it can associate to the next AP.
A channel, this is the network path for wireless transmissions, each Wi-Fi standard has numerous channels,
each of which is a specific central frequency.
Data rate.
The rate in which data can be transferred at any given moment to and from a device, most times the
incoming and outgoing data transfer rates affect each other adversely.
For example, if you're uploading a video while loading a Web page, the Web page will load slower than
usual due to the upload usage.
A beacon is transmitted by an AP 10 times per second, and it advertises the existence of the app on
a particular channel or channels, it includes information needed by clients to associate as well as
it may include the inside the supported channels, as well as data rates and whether it's open or requires
authentication.
Now, decibels can also be used to describe antenna power levels, decibel is the basic unit of measurement
used in Wi-Fi radio signals.
Deb specifies a difference or ratio between the two signal levels and is used to describe the effect
of system devices on signal strength.
So a DBM is the debe value compared to one milliwatt of power.
For example, if the signal power is 100 milliwatt and the reference is one million, the value of the
decibel becomes 20 relative to a milliwatt make sense to our TP link adapters antenna has for DBI signal
power.
Now, a suffix indicates that the reference value is often appended to the decimal symbol.
The suffix is I because I refers to an isotropic antenna, which is equally sensitive to signals from
all directions.
The gain is a key performance number, and this combines the antenna's directive and electrical efficiency
to win a transmitting antenna, the gain describes how well the antenna converts input power into radio
waves headed in a specific direction.