Review the various wireless networking standards and examine their relative merits.
- The 802.11 standard's been around now for, well, arguably, a little bit over 20 years, and well, I've been there since the beginning, and I love talking about 802.11. Now, we need to be careful here. I know I called this 802.11 standards, but really there's only one standard, 802.11. But it's a 20-year-old standard, so things have gotten faster, better, more colors, and all that kind of stuff, so what we do is we create extensions to the 802.11 standard, and that's when you hear things like 802.11b or 802.11n, or 802.11ac.
They're just taking the 802.11 standard, and doing stuff to it to make it better, faster, smarter, does more, more colors, whatever, okay? So even though we say the word extensions, the Network Plus will say standards, so if someone says the 802.11g standard to you, don't beat them up, just smile quietly to yourself and go, "It's really an extension, but you probably took a CompTIA course." Anyway, all right, so let's get started. I have in front of me a complete stack of wireless access points that pretty much cover the history of 802.11, and I had to go down into the vaults to find a couple of these guys.
Anyway, what I'm gonna do is use these as a way to describe the different 802.11 standards which you're gonna be seeing on the Network Plus. So let's start with the granddaddy of 'em all, good ol' 802.11b. Now, the 802.11b is arguably the first standard. 802.11b ran at a blistering 11 megabits per second. It ran on the 2.4 gigahertz band, and within that band, so when they say 2.4 gigahertz band, that's not one frequency, it's a range of frequency.
That's why they call it a band. And so, within that band, they knew that there'd be a lot of other SSIDs around, so the idea was to break it up. So the original 802.11b standard defines 14 different channels, which are pieces of that 2.4 gigahertz band. Now, depending on where you lived, you would have more or less channels. Here in the United States, we got 11 channels. Now, there's a problem with these channels, and, oh, by the way, these channels are numbered very creatively, one through 11.
The problem with the channels is that they overlapped, and that's not good, because if you had set one wireless access point to channel one and another one to channel two, they'd interfere with each other, and I mean, it would work, but you'd have problems, so when we talk about 2.4 gigahertz band devices, 802.11b being the best personal first example, is we really only have three channels, one, six or seven, and 11. And those are the only three channels you can have without overlapping, and we'll see as we get into later standards, that we do stuff to get past that.
So this one is good old 802.11b. The next standard I want to talk about, or extension, is arguably the other alternative for the first 802.11 extension, is 802.11a. Now, this is actually a pretty cool old wireless access point. This is Cisco, made out of steel. Anyway, if you actually ever used one of these, send me an email and just say, "Hey, I remember these, Mike." This is a good old Cisco Aironet 1200, and you still see 'em out there every now and then.
But this was a great, robust, this was enterprise level wireless access point, and it's also, in this particular case, an 802.11a device. Now, 802.11a, even though it came out at about the same time as 802.11b, it's very different. First of all, it runs on the five gigahertz range. It also has channels, but the whole channel thing changes a little bit with 802.11a. Trust me when I tell you, we don't really worry about channels when we get into the five gigahertz range.
802.11a ran at 54 megabits per second, so it was a lot faster, and it actually had arguably, a slightly shorter range. These two guys came out at the same time, so when 802.11b came out, it really used a more popular ISM band at 2.4 gigahertz, whereas the one that this guy was using at five gigahertz, while it is also an ISM band, industrial, scientific, and medical, that ISM band wasn't nearly as often populated, so a lot of people would go to 802.11a, even though it tended to be a little bit more expensive, not just because it was a lot faster than 802.11b, but also, you had less chance of interference from all these other types of different devices.
So, this guy is good old 802.11a. We didn't see a lot of it, but boy, did his legacy follow on with later versions. Now the third type of 802.11 standard I want to talk about is the one that, in my opinion, really put wireless on the map. And if you don't recognize this guy, well, you will. (laughs) What I have in front of me here is probably the '57 Chevy of wireless access points.
In fact, this really isn't a wireless access point. It's really a router, if you look, it's a router. This is the infamous Linksys WRT54G. 802.11g changed the game. I mean, there was plenty of wireless around back in the 802.11b and 802.11a days, but 802.11g really did something very clever. First of all, it runs on the 2.4 gigahertz band, just like 802.11b, which means it is pretty much instantaneously backward compatible with 802.11b, but it took the speed functions from 802.11a, so 802.11g runs at 54 megabits per second, which when it came out was smokin' fast.
It was fantastic, 802.11g changed the game. Now, granted, it's still on the 2.4 gigahertz band, so it has the channel limitations. You can only have three channels and all that, but the cool part was, is that it was completely backwardly compatible with 802.11b. It came with a lot of high speed, and Linksys made a lot of money with this guy. So that is good old 802.11g. Now, everybody's going to have versions of 802.11 that they like, and others that they dislike.
My personal dislike is the next guy right here. This is 802.11n. 802.11n came out as a way to increase the speed beyond 54 megabits per second, and to start moving into the five megahertz range, so when we talk about 802.11n, first of all, they're always gonna have more than two antennas. This one has exposed antennas. Sometimes you'll see them, they don't have any antennas at all. Trust me, they have more than two in there.
802.11n runs at both the 2.4 gigahertz and the five gigahertz band, that's number one. Number two, this guy can run as slow as 108 megabits per second, but it can run a lot faster, usually around 300 megabits per second. The reason I'm being a little wishy-washy on speed is because 802.11n introduced the idea of what we call channels, and literally, you can keep plugging more and more antennas into this guy, and you can increase throughput up to some maximums, which I'm not even gonna say on camera because they're pretty high.
Nobody really got to them though. The other really cool thing about 802.11n is that it introduced something called MIMO. MIMO allowed you to use multiple channels to talk to different devices, so if I had two devices, and if I had enough, literally enough send and receive antennas, I could almost make an own little personal conversation to one device at a time, unfortunately, but it could make for a higher speed. 802.11n, for all of its improvements, really brought some stuff into the game that made life challenging, at least for me, trying to configure this stuff.
For example, one of the things that 802.11n invented was a different kind of packet that it would send out, so in order for it to be backwardly compatible with different devices, it would have to go into these different types of legacy modes, and it would be difficult to configure access points to do it the right way, in particular, if you didn't have the right kind of network card. See back then, you would upgrade to an 802.11n type network, and you thought you had 802.11n network cards in your devices, but all of a sudden you couldn't get with the real high speeds, and the reason is, is either the WAP didn't have the right type of configuration.
They had a mode called Greenfield mode, which means we're all in 802.11n, and everything's running great. And it was a bit of a challenge. You'd end up having to go back to your network cards in your laptops or whatever it is, and you'd have to do these firmware updates or something to get those cards to know what was taking place, so there was a lot of tweaking with 802.11n, and in my opinion, even with its improvements in speed and such, it was a little bit of a challenge. It's gonna take the next version of 802.11 to get this right. My favorite version of 802.11 is 802.11ac.
I've got an ac wireless access point right here. So this nice, pretty guy, which I literally just pulled out of my house, I installed this fairly recently, is 802.11ac. 802.11ac, in my opinion, took everything that was bad about 802.11n and fixed it, and made stuff faster all the same. 802.11ac runs in the five gigahertz band. Now, it can also run in the 2.4 gigahertz band, but not for 802.11ac. This wireless access point right here has three antennas for n, and three antennas for ac, so it's really three antennas for the five gigahertz band and three antennas for the 2.4 gigahertz band.
So I shouldn't even say n. This guy could even do 802.11b. Why anyone would do that, but you could. So, it has the ability of backward compatibility, but simply by making a better access point, not because 802.11ac itself does it, so be sure you're comfortable with that difference. This guy runs at incredibly high speeds. For the Network Plus, we're just gonna say that it runs around one gigabit per second, but it's actually a lot more flexible than that. With 802.11ac, you have channels, and the more channels you add, the more speed you get.
In fact, it's really limited by how good the network cards are in your client, so it can go up in the higher and higher speeds, but again, for Network Plus, just think about one gigabit per second. So 802.11ac has a lot of power to it, and it's really something that I love and I use it all the time. The last thing I want to mention with 802.11ac is that it builds on the 802.11n MIMO concept and now has something called MU-MIMO, multi-user MIMO, so basically it's MIMO, just like we saw in 802.11n, but it's multi-user, so as many channels as you add, you can provide MIMO to multiple users at one time, and it really increases throughput dramatically.
I love 802.11ac. So these are the 802.11 extensions, or standards, or whatever you want to use. On the Network Plus, keep in mind that the questions you're gonna be seeing about standards aren't gonna be too many questions like what speed did 802.11b run at? I mean, they may throw that at you, but what they're gonna do instead is they're gonna create scenario-type questions, where it's like their wireless network is running too slow. What version would you recommend them to come up to? Or they're having problems with channels.
What do you think they could do about that? And so, a lot of stuff is gonna be moving from 2.4 to five, or moving from an earlier version to a later version. Just takes some common sense, you'll knock those question out no problem.
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- Implementing wireless security
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