CWNP CWNA – IEEE 802.11

1. IEEE 802.11

So in this module, we’re going to talk about the IEEE standards for wireless communications under 800 and 211. We’ll look at the original standards, and then we’ll see over time how we’ve continued to increase the standards to get better wireless communications and security. So then we’re going to look at the 8211 2007 Amendments, the 8211 2012 Ratified Amendments, and maybe if we get the opportunity, we’ll look at some of those what they call post 2012 Ratified Amendments, meaning we’re not ready. To, you know, do another whole year’s worth of hey, here’s everything new but what’s currently out there and what kind of amendments we might expect to see as they’re coming in. So we’ll look at those after 2012 and the drafts.

2. Original IEEE 802.11 Standard

When we take a look at the original 800 and 211 standards, basically it was a whole category that was designed to talk about the way in which wireless communications would work. And so what they do is in these standards is they define the technologies at the physical layer and at the Mac sub layer. Now remember, the datalink layer in the OSI model has actually two parts arts. And so we’re looking at the Mac sub layer, which is the portion of what is going to talk to the physical layer. Now, when we see these, we’re talking about different methods of being able to transmit data over the air.

One of them that you might have seen in the original standards was the use of infrared technology, which is a light based medium, not a light that’s visible to us, but it was still a method of being able to communicate. And it was something we used actually quite often for a while. In the original days, we’d have infrared connected printers. You’re using infrared when you use your TV remotes. So anyway, it’s just a light based medium and it was for a very short distance that it would work. But believe it or not, it was defined by eight or 211 standards. It is now considered to be obsolete. Another type of definition they gave us was how our communications signals would deliver information. And one of the original ones we saw was called the FHSS, or the frequency hopping spread spectrum technology. What we saw here is that we actually had narrow band signals to spread the information across multiple different channels, but not all at the same time.

So frequency hopping just simply meant and if you looked at the channels that we had back then at the 2. 4 GHz, we had like three channels that we could use in the older days, back in the days when they first started putting computers and police cars, they were using this frequency hopping spread spectrum on the 900 MHz range. And they kind of felt maybe it’s secure, maybe it’s not. The idea is with all those channels, as I would send my data, I would send my data on one channel for a specific amount of time and then I would hop to another channel and continue to send my transmission and then hop again. I guess maybe at some point they thought that might be a little harder to track, but we all could easily figure out what the hopping schedule is. But nonetheless, they called it spread spectrum because it was spreading the communications over many signals. Now an RF signal is considered spread spectrum when the bandwidth is wider than what is required to carry the data. And so that’s another part of that definition of what spread, spread spectrum. Excuse me, those are tough words. I think they picked the worst words in the world to try to say out loud. Another type of spread spectrum technology was the direct sequence spread spectrum or DSS. And it’s again different than frequency hopping. It used fixed channels. But again, going back to that definition is that the bandwidth was wider than what was needed to be able carry the data.

3. IEEE 802.11 -2007 Ratified Amendments

When we look at the 2007 ratified agreements, what we began to see were basically agreement upon the different standards by the IEEE. And so they published it basically in what we would call 2007. And so what they came out with for us is some technologies that you might be familiar with, such as the standard for radio communications that we called eight two dot eleven A. You know, that was the one where they said, hey, we’re going to operate at a 5 GHz range. They actually gave us twelve channels. We’ll see that in a bit as we talk about it. And it had speeds that were much higher than the original 800 and 211 B that everybody was using. 811 B, of course, was the 2. 4 GHz.

We had three channels, and then on those channels we had up to what? Eleven megabits per second at our best speed. It sounds completely slow today when we think about communications, but 1999 is over a decade ago, closing in on almost two decades ago. So do you remember back those days that was high speed 800 and 211 G, which is a 2. 4 GHz as well, and still operated on three channels, but they used a different type of modulation, so they were able to get much higher speeds out of the communications. And then we’ll take a look at the 800 and 211 I, but I’m not focusing on it here because it’s not one that we use to define how our computers were connecting to the wireless network. But so, again, and by the way, there’s many more amendments. I just put some of the ones that are probably better known and that you’d probably want to know more about at some point, but that would be doing research on your own to look at the way in which those standards were set up.

4. 802.11b

Well, as I got through saying eight or 211 B, they called it the high rate, using the direct sequence spread spectrum method of moving the data through the air. And it was based on the 2. 4, what they called the 2. 485 or three 5. That doesn’t sound like a big difference, I realize. But you have to remember that within that that range from 2. 4 to 2. 4835, that there were many channels that we could use that were only 20 GHz in size. And what I mean by that is that within that range, if you did the math, you could divide the difference and be able to find all these little channel spaces that we could use. And I didn’t draw all of the channels that are potentially there.

And one of the things that they chose when they decided, hey, let’s create a channel, is they would actually create a channel using three of these lanes, and we might say that’s channel one, then we might say that’s channel six. And then, of course, I had a channel eleven, I just didn’t draw it on there. And the primary purpose was to transmit here at that frequency, but give you enough overlap so you didn’t have interference from the other channel. Kind of like the idea of when we turn on our FM radio, you might notice that every time you click the tuner just once, that it doesn’t go to the very next station.

It goes usually two. Right. Example, you might start at one, one, three, and then the next channel you hear is 101 five. And the reason for that, again, the same as it was with this purposing of the channels, is to leave a little bit of leeway between the two channels so they didn’t step on each other. And so, likewise, we did that with the 811.

5. 802.11a Part1

Eight or 211. A, amazingly enough, was a better technology for high speed communications, but it wasn’t used very often because it was in the 5 GHz range. All right, why not? Well, 2. 4 and 5 GHz are both, ism right, industrial, scientific and medical bands that can be used, which means they’re unlicensed. And, and, and the reason it wasn’t so popular is that 2. 4 was a very popular method of communicating. I mean, we had, you know, kids remote control cars running on that, we had other communications and so everybody had those radios and it was considered maybe too new or maybe it was considered too expensive to move in getting a radio that could do some transmissions at the 5 GHz.

So now originally, they were going to make that transmission in these hundred megahertz channel ranges. And again, just like I talked about, when we look at the start and stop of those channels, we had these channels that they were going to make 100 MHz each, but again, we made them small. And the reason we did that is so that we would have the ability to create multiple channels, which is working and just works just fine.

But also because of the way in which they did the types of modulation, they improved on the DSS with this orthogonal frequency division multiplexing. And that technology allowed us to send more data over the same channels, so we got higher speeds. So I liked the idea that A was high speed. I liked that it had up to twelve channels in that frequency range, even though we’re only using eleven of them in Japan, as an example, they use all twelve, but it’s a matter of what the FCC has us do. But anyway, it was just better. But I think maybe it was an expense because it was a radio, or I should say, a frequency that we just weren’t used to using.

6. 802.11a Part2

In the 8211 a realm. The bands that we used in the communications again is Unlicensed and we call it the Unlicensed National Information Infrastructure or we use call them the Uni bands. And when we take those total of twelve channels you would see that maybe channels 1223, right just some of them would be in a classification of a uni one category and then we’d be able so we can break them up into the categories. I don’t necessarily think you need to know all of the differences of these categories and what they were available for, but it’s certainly something you can look up. But the purpose of that division of the channels was to describe information about the data rates and the communications that we would use and how we would use those.

7. 802.11g

8211 G brought us back to the 2. 4 GHz range, but gave us the high speeds up to 54 megabits per second. It was using a technology called the Extended Rate Physical, or ERP, but again, it worked on the same band or same frequency as 8211 B. Again, it was still an Ism frequency band. And we had these data rates of 6912 18, all the way up to 54. Where do those data rates come from? The data rates are what are negotiated based on your distance and the strength of the received signal. Right. The further out you were, then the less data rate you would get because the signal wouldn’t be as strong.

But the IEEE required that the data rates of 612 and 24 had to be available. In other words, when we’re programming our access point, we can actually say, if I have a client that can’t do more than six megabits per second, I’m not going to let them join. And that’s fair. I mean, you could choose the speeds that you think are suitable.

But the reason they wanted to have things like six is that if somebody came in let’s say this is a wireless receiver that can work on 800 and 211 G, but if I still had people in my network that were on B, then we would have data rates that would support the backward compatibility. By the way, I need to tell you this, that if you have an 800 and 211 G network and you still allow an 800 and 211 B receiver or client to associate, then the entire network is going to slow down to B.

The access point is not going to do half one way, half another. And the reason for it is because it’s a different method of encoding data. When we’re sending out management frames, the management frame has to be on a language that all of the clients can hear. So, yeah, you want to slow your network down? Bring an 800 and 211 B laptop enabled device into to your eight or 211 G network.

8. 802.11 Review

In the 8211 a realm. The bands that we used in the communications again is Unlicensed and we call it the Unlicensed National Information Infrastructure or we use call them the Uni bands. And when we take those total of twelve channels you would see that maybe channels 1223, right just some of them would be in a classification of a uni one category and then we’d be able so we can break them up into the categories. I don’t necessarily think you need to know all of the differences of these categories and what they were available for, but it’s certainly something you can look up. But the purpose of that division of the channels was to describe information about the data rates and the communications that we would use and how we would use those.

9. 802.11i Part1

8211 G brought us back to the 2. 4 GHz range, but gave us the high speeds up to 54 megabits per second. It was using a technology called the Extended Rate Physical, or ERP, but again, it worked on the same band or same frequency as 8211 B. Again, it was still an Ism frequency band. And we had these data rates of 6912 18, all the way up to 54. Where do those data rates come from?

The data rates are what are negotiated based on your distance and the strength of the received signal. Right. The further out you were, then the less data rate you would get because the signal wouldn’t be as strong. But the IEEE required that the data rates of 612 and 24 had to be available. In other words, when we’re programming our access point, we can actually say, if I have a client that can’t do more than six megabits per second, I’m not going to let them join. And that’s fair.

I mean, you could choose the speeds that you think are suitable. But the reason they wanted to have things like six is that if somebody came in let’s say this is a wireless receiver that can work on 800 and 211 G, but if I still had people in my network that were on B, then we would have data rates that would support the backward compatibility.

By the way, I need to tell you this, that if you have an 800 and 211 G network and you still allow an 800 and 211 B receiver or client to associate, then the entire network is going to slow down to B. The access point is not going to do half one way, half another. And the reason for it is because it’s a different method of encoding data. When we’re sending out management frames, the management frame has to be on a language that all of the clients can hear. So, yeah, you want to slow your network down? Bring an 800 and 211 B laptop enabled device into to your eight or 211 G network.

10. 802.11i Part2

So let’s take a look. Kind of a review of what we used. So I didn’t even mention the legacy. I don’t think we really need to because again, we’re talking almost two decades ago. So 800 and 211 B and G, both of them 2. 4 GHz range. Again, a different type of spread spectrum technology, which is what makes the difference. Difference in the rate in which we can send data rates maxed out at eleven. We could be backward compatible with G if we wanted to, but that’s if we had to.

Otherwise if we got into OFDM, we could get up to the mandatory backward compatible rates and have speeds up to 54 megabits per second. All sounds pretty good. Really. You can see the that it was really new. It was ratified in 2003. Now amazingly enough, we had 54 megabits available to us in 1999. But again, I think it was this change right here that nobody was really ready to change their radios to be able to operate on the 5 GHz range.

11. 802.11i Part3

Now, the 8211 I was really synonymous with the idea of security, and, you know, security in wireless just wasn’t, I guess, maybe a thought in the original design, and it wasn’t really thought about much in the eight to eleven standard. The concepts that we have when it comes to the wireless security, we could draw as a triangle that we’d call the CIA. And in that CIA, we have our data that’s being transmitted, right? We’re just throwing this stuff out in the air. So confidentiality is a part of data privacy. So I’ll put that as the big c, and that means encryption of the data.

The I stands for the integrity, which means that we are trying to protect our data from being modified. And the a sometimes stands for availability, but in this case, it’s the authentication, which means that the person connecting to my access point is somebody I can verify. Now, for up to seven years of time, the only type of method we had for encryption was the use of a. Well, it says 64 bits.

Technically, it was only 56 bits, because eight of those bits were used for parity, which is error correction, and it was called the wired equivalent privacy, or web. It had some weaknesses, and you could probably go to many of your popular social sites like YouTube and the others and see how easy it is to crack web. And when I say how easy, we’re really talking a matter of four or five minutes with technology to be able to break that. So it’s not really security.

12. 802.11r -2008

The 811, I came up with what they called the robust security network. And RSN was designed to come up with major improvements about the authentication, the integrity and the confidentiality of our data and making it almost impossible for other people, hackers, if you would, to be able to break into these things. And so what we saw were protocols like AES encryption, which was great, that was still is today one of the strongest encryption methods we have.

We had ways to do authentication with the extensible authentication protocols and many other things that would happen. So the idea was that when this person, this user would connect to the access point, the access point would send a challenge of who you are and connect to some sort of authentication server, typically a Radius server, to verify your credentials.

And then through these forms of what you’re going to see later about the WPA Two model, the access point had the ability to secretly hand out the encryption keys that were needed by everybody that was connected and could give out different keys to different people. And so, unlike Web, you didn’t all share the same key. So it really made for a great method of securing the transmissions and to authenticate the person that was there.

13. 802.11w

Eight or 211 was part of what they called a task group w eight or 211 W, I should say. And it was designed to provide a way of protecting management frames. So management frames that would be you trying to connect to or basically get associated with an access point or telling access point you’re leaving for the disassociation.

Those types of packets could be sent from somebody hostile in an attempt to deny you service or to spoof the ones that they intercepted from you to try to get service. And so 811 W came up with ways as a part of the robust security network to create what they call robust management frames to prevent those types of attacks.

14. 802.11n

Now eight to eleven N. We have a whole section we’re going to talk about later called high throughput. And it was an amendment, as I talked about before, to have enhancements of the amount of bandwidth that could be supported as much as 600 megabits per second.

15. 802.11ac

And then after that of course came the AC, which another amendment that talks about what’s called very high throughput and so high that it’s only going to work on the higher frequencies, the 5 GHz, even though originally they were trying to think about the 6 GHz range. But anyway, so it’s going to be on the 5 GHz range, they are going to have wider channels and we’re will go from 20 to 40 MHz channels, which basically doubled the data rates. And it brings up the capability of using multiple channels together of either 80 or 160 MHz channels to be able to again increase the amount of data that can go back and forth. Many have called it the first Gigabit wireless service.

16. Section Review

So in this module, we took a look at the 800 and 211 standards from the IEEE. We started with a brief discussion of the original ones. Then we looked at the 2007 amendments, the 2012 amendments, and by the way, we didn’t see all of them. I told you that.

But I talked about the ones that are most going to affect you. And then of course, there are many other amendments that you might be interested in. And certainly I would suggest the better you want to get at the world of wireless to look at some of those.