Wireless Communications

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9 hours 49 minutes
Video Transcription
Let's continue moving forward.
Our next section is on wireless communications
when we talk about wireless, one of the first things to mention is the frequency in which our wireless devices operate.
Originally, there was five G H C, then 2.4 GHz.
Then there was a combination of both choices.
A couple of things about each of these, with 2.4 GHz. This gives us a much better range. Inside,
the signal is more capable of permeating through walls and some of the other obstacles. That's why 2.4 was preferred for a long time
because it is such a preferred frequency. A lot of other devices like I P cameras and mobile phones, baby monitors and things like that also use this frequency. So it's the chance of interference.
A lot of times you can move to a different channel. There are only three channels that can be used in the 2.4 range. 16 and 11.
This is definitely something that may come up on the test, so make sure you know it.
In the 2.4 arrange, all you can use is 16 and 11. You have more flexibility and more channels supported with five GHz range. But you can't get as great of a distance.
You don't get the capability to wander, but you're more likely to have less interference. So pros and cons to each
now 802.11 is a standard specified by the I triple E for carrier sense multiple access with collision avoidance. And that's what wireless communication uses for media access
for wireless devices. Unlike Ethernet, instead of putting their signal out, they send an intent to signal.
So it's carrier sense multiple access, but with collision avoidance.
We went into that idea earlier in the network infrastructure information so you can go back and take another look at collisions.
Throughout the years we've seen these different standards evolve. We had ratification back in 1997 and from 99 we got 802.11 A and B 802 11. A started out with good speech, gave speed of 54 megabits per second. But it operated in that five GHz range,
which meant that we were not going to see the same distance or capability of roaming
eight oh 2.11 b came out, operated in the 2.4 range but dropped speeds down to 11 megabits per second. Eight oh 2.11 g really became the de facto standard because it operated in the 2.4 range at 54 megabits per second. So we got the speed in the right range.
Then we went over to 802.11 n much faster data rates, good capability of roaming and a wide support for the different channel types.
I will mention that eight oh 2.11, even though it's not really on. This chart never really made it to market, because by that time it was ready eight oh, 2.11 and was ready to be ratified.
It was actually the first wireless standard that required W P A. To to be used for security.
Everything prior to that just had to support Wet
obviously eight oh, 2.11 n and eight oh, 2.11 a C. Both support W P. A. Two and WP A three is here, so we continue to evolve
to review some of the highlights. Here we have eight oh, 2.11 a five GHz range
Then in the 2.4 range, we had eight oh, 2.11 B, and that made it to market, whereas a really didn't. But when we went to 802.11 b, it had widespread usage at 11 megabits per second and was very popular.
That is, until the real answer we were looking for came along, and that was eight. Oh, 2.11 G because it provided good speed of 54 megabits per second, gave us operation in the 2.4 range, and it was backwards compatible with eight oh 2.11 b, which is very helpful as we have varying devices.
You don't want to go out and spend a lot of money on a router and then in two months have to change that.
Here's what I was mentioning about 802.11 I I never made it to market, but it was the first standard to require W P. A two
eight oh 2.11 and what we just talked about can have a great distance to transmit, supports eight antennas and can use multiple channels through something called bonding. It's almost like multiplexing
There are few other types of wireless technology we should talk about Z Wave and a N T plus or two that are becoming very, very, very popular today.
Z Wave. Think about your home automation like your doorbell, your lights and your thermostat and all those things in our homes now that can be connected to the Internet if you ever configured them the challenges they need to join my home network. But how do I configure them to join my home network before they're set on my network?
They used the wave technology, which allows a very quick, basic low end network protocol could take an act.
you can configure the device like an Alexa or something like that, and then you're able to have it joined the network, and that's how you access it. From that point forward,
the Z wave is a technology usually used for setting up these automated devices.
A and T Plus is being used more and more for health devices. If you've got a Fitbit that tracks your pulse rate or steps that you walk that's using the anti technology,
we're seeing more health care taken care of through the use of wireless technologies.
I have a friend who's diabetic, and she has to tap the monitors. Her blood sugar if her blood sugar gets elevated, sends a message to her cell phone.
We're getting to a point in time where we're really taking advantage of some of this technology for health and home automation.
Bluetooth. Here's a quiz. What's the best way to secure a Bluetooth device?
Wait for it. Turn off. Bluetooth security is really an oxymoron. Bluetooth isn't something that's designed to be secure. It's designed for ease of use.
It's set up with the auto Discover auto pair and a pen.
certainly you can configure the pen, but for the longest time, the default pin for all Bluetooth devices was 0000 Obviously not a real big challenge for an attacker, and they're very vulnerable to attacks. There's blue snarfing and blue jacking blue jacking the spamming, a Bluetooth device going back.
There's blue snarfing and blue jacking.
Blue jacking is spamming, a Bluetooth device. Blue snarfing is stealing information through a Bluetooth connection with Bluetooth data transmits about 10 m. But I'll tell you, you'd be surprised with the right tools. How far away you can actually be and still siphon information off of Bluetooth device.
If you want some fun reading, look up cantina like antenna. Um, but with a C, and you can see the work that people have done with Pringles cans and Bluetooth. It's kind of cool.
Other wireless technology R F I d
with R F I D. More and more devices are being fitted, whether it's these devices that you have in your EZ Pass as you go through toll booths or the chips in the back of the dog's neck in case they get lost. Credit cards, passports, R F I. D. S are everywhere. They're designed so that there are very passive chip until they get carried by a transponder.
When that Kerry happens, then the chip sort of comes to life and transmits its information.
For that reason, this could be a security vulnerability. So we have to make sure our devices that do come with these R F I D chips are kept somewhere that's secure.
A lot of laws today come with mesh, so that signal doesn't leak.
It's certainly something to keep track of or something to think about.
a type of R F. I. D chip is called NFC Near field communication,
your NFC devices or devices that have to be very, very close to the reader.
If you have some of the newer hotel keys rather than having to swipe the key, you just have to hold it up to the lock. That's an NFC chip.
Those have all sorts of uses. They're easy to scan components. I think the Net Plus Exam might put forth that this would be a good idea to keep inventories of systems.
When I come to the shop and I check out a laptop, I just have to scan it with the reader, and that's good for inventory management. There are all sorts of uses for NFC,
of course, there's infrared communication. Infrared is used for remote controls and other sorts of devices used to see them with the personal data assistant, but not so much anymore,
certainly in for airports can also be used to sync information. We have all types of different wireless technology, and this is just a field that's going to continue to evolve, especially with the Internet of things evolving the way that it is this is going to explode over the next few years.
antennas when we're talking about signals and antenna, of course, is going to be used to transmit and boost the signal. Some antennas are omnidirectional.
In many cases, if you look at your home device or your home wireless router, you have an Omni directional antenna going back.
in many cases, if you look at your home device or your home wireless router, you have an Omni directional antenna. You've got radiation and the signal going equally in all directions.
There are certain antennas, like the one on the right, a Yagi antenna that's used for single direction from building to building. You might have a Yagi antenna. It's very focused on one specific direction.
They like to ask about antenna types on the exam, So take note.
Wrapping up wireless connection. We talked about the 802.11 standards, the different frequencies in which these devices can operate the pros and cons of operating at five GHz versus 2.4 GHz. We talked a little bit about the various channels that we can use, and then we wrapped up by talking about types of antennas,
multidirectional or uni directional,
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