Everybody, welcome back. My name is Tyler McMinn with Aruba, and this is the Aruba Mobilities Essentials Part 2, where we're jumping in on Terminology, wireless terminology. So without further ado, let's jump in and see what we got to cover. [MUSIC] So when you're looking at wireless LAN components, it is a good idea to understand some of these basic acronyms that might be tossed around when troubleshooting or when designing a network here. And one of the first ones is this BSS here, this basic service set. Now the BSS is officially an AP, or an access point, with one or more clients connected to it. So it stands for a cell of coverage, if you will, or a basic service area of coverage that this one access point will use. If you take a look here, we got a couple of clients, we got a couple of APs, and we've got these basic service sets that are going to be set up, one essentially per AP. So these are being broadcasted out and identified based on their MAC address, by the burned-in MAC address on the radio and tied to the SSID to establish this basic service area of coverage, or this BSA of coverage. The area of coverage around an access point where a client is capable of connecting to and communicating with the AP. So this client, this client is within range of this access point. Now they're purposely kind of left a little space here to indicate that these are not extended. So there's no real roaming between these APs. And so you just have these kind of solitary service areas like you would have at your house or your small business next to another house or another small business that was separating these two together, so two basic service areas. It may be that your beacons would reach over here, but there may not be enough signal strength for this client to be able to join across. Or more possibly, you've encrypted this service set so that other clients can't join even if they were within range. So basic service set, which extends a basic service area around it. This basic service area kind of illustrates these stations getting their access. And I've tossed around this term station many times in the last series of videos. Where any type of device like a wireless phone, or a laptop, or anything like that, that's considered a station on the network. And any kind of 802.11 wireless device would qualify as a station. And we usually just abbreviate the word station as STA. So it refers to a client device. APs are technically stations too because they also have radios with burned in MAC addresses, in much the same way that your Ethernet ports would have a burned in MAC address. But APs are usually not call stations since they do more than just transmit and receive radio frequency data. APs, their job is to act as a bridge. So anyway, STA, stations, kind of makes sense. We got a couple more here. So there are your station, the little iPhones that are popping in there. And then if we were to connect these access points to the same distribution system, in this case, a 48 port switch, then your APs could not only receive power over the Ethernet cable in many cases. But they're being bridged to have the same access to the rest of the network here. So this local area network on the wired side is shared between these two devices. Now it's a little less common that they would be separated like this. Normally you'd want these two APs to kind of overlap so you had continuous coverage. But I digress. We still are keeping these as basic service sets, rather than extending them across. Another option that you could use instead of a wire connection if the APs were owned by the same organization but you didn't have an available wire, like this was on one building and this was on the edge of another building. You could use a wireless connection to bridge these between each other. So often we'll refer to this as a backhaul, and kind of lame in wireless terms. You're backhauling the wire connection from your switch on this building, and you're bridging that across rather than extending a wire between your switches in between these two buildings. You could connect them each to access points and then bridge those across. Bonus points, can you remember the Aruba access point that has a 60 gigahertz radio that does this? It is the 387 series that does this backhaul on a 60 gig. Pretty cool to be able to extend this up to a quarter of a mile if you wanted to. So I'm just imagining setting up all my neighbors in my [LAUGH] neighborhood with some really high end gear. I don't know if my neighbors deserve that quality of connection. Okay, so back to the service set identifier. The basic service set could be your service set here with your service set identifier as the name of your network, your SSID. Now a lot of you guys have probably already heard of SSIDs. We set these up in our homes to broadcast our wireless, and I think you can see these pretty easily. I demonstrated this earlier. So if you remember the example from previous videos, this is a SSID that's being broadcasted on this remote lab equipment. And if you open up programs like Insider, where you can list off details about these different service set identifiers, these different SSIDs that are being broadcasted out. So that is your SSID name. You could choose not to advertise the SSID, just leave it null. But you are still announcing what the SSID is from the client side. It's just the actual broadcast of the name doesn't come from the access point. So the clients themselves would still advertise Myhouse, which means that you're probably still going to be able to figure that out. If a hacker is walking around, they'll be able to grab that information pretty easily. So generally, we recommend leaving your announcement of your SSIDs enabled. It's not a huge security benefit to try and disable that. So we have two different SSIDs, two different access points. So two different BSSs or basic service sets that are being used here. Connecting these together in the same network would mean that you would have a distribution system that's wired. Connecting these two APs and then broadcasting the SSID across both of these guys. So the same SSID EmployeeNet is great, that works fine. But notice that the BSSs is still different, it's still going to be a different MAC address, effectively, because the radios are different. Even though the name of the SSID is being announced exactly the same. And it is case sensitive, so as long as the SSID is spelled and the case is exactly the same as a neighboring radio that's advertising that same SSID and the security is the same or the security is nonexistent. But as long as it's equal, then your clients can actually roam across these extended service sets. So an ESS, an extended service set, is when two or more APs are connected to the same network, the same distribution system. And the APS are advertising the same SSID with the same authentication and encryption. And now it's pretty much up to the client which one that it wants to connect to. So an extended service set identifier is the logical name of the wireless LAN that's being broadcasted. And the ESSID is the same for each basic service set, meaning that the name you're announcing is the ESSID. But under the hood, the BSS, the basic service set identifier, the MAC address is going to be unique so the clients know which one they're associating to. Is it going to the one over the left with BSS-1, or is it joining the employee network over to the right with BSS-2? It's the same employee network. But now the client can make a determination typically based on received signal strength which one that it prefers to try and associate with. EmployeeNet on both sides, it's up to the client to pick which one it wants to go to. Now you've got this ability of the client to basically choose which BSS identifier, which MAC address, that it wants to hook up with. With multiple radios, it does give us, or multiple ESSIDs on a single radio you can still advertise other SSIDs. In fact, it's very often that we'll design for a corporate employee network connection as well as a guest network connection, and then extend the names of both of those across. The unique radios that this starts from, it starts from a base radio and then each SSID increments that by a bit, so you have a different hexadecimal assignment there. What that really means is you will always have a unique basic service set identifier, the client will see two different ESSIDs. It'll see GuestNet and EmployeeNet because they're spelled differently. Those are two different networks. So each AP typically will have two radios, a 5 gig and a 2.4, which sounds like a complicated thing, but not really. I mean, the 5 gigahertz or the 2.4, it's still the guest network. Those are two different radios, so the BSSIDs are going to be unique. And then you've got the EmployeeNet in the 5 and the 2.4 and, again, repeated on these other radios here. This really just gives your clients a choice on which AP that wants to join, and which band that makes the most sense for it to try and connect to, the 2.4 or the 5. So what you end up having is multiple extended service set identifiers that are available across wider areas of coverage. If you wanted to run without APs, there is a technology that didn't really get adopted very well, but it is out there. It's the IBSS, an independent basic service set. You might know this as an ad hoc connection or a peer-to-peer link, where one of your devices will essentially start advertising the BSSID that you want to advertise, like MyNet or something like that. And you could encrypt it if you wanted to, and then other devices will join your MyNet. If all three have been configured with MyNet ahead of time, then the first one that boots up with it will be essentially the hub or the announcer. And all the other clients that come up and boot up with MyNet will join the initial client. So that's a lot of turns. We have basic service set, the basic service area. So this is the single device that's not really extending any SSIDs, and it generates its own individual coverage or area of coverage there. A station connects those basic service sets. And then if they do have access points that are connected by a distribution system or a wireless distribution system, your SSID that's being advertised can be effectively extended across what we call an extended service set. So an extended service set identifier is the announced name in much the same way that an SSID is just off of basically a single access point. If multiple access points that are typically close enough for it to matter, for you to roam, are extending the SSID, then we call it an extended service set. And then a basic service set identifier is the MAC address announcement for each of the individual access point radios. An independent basic service set is announced without a AP. I hope that explained a lot of the terminology you may have seen here and there. And as we did, we kind of built out a little bit of different options that you have for your networks. In the next video series or the next video in this Part 2 series, we're going to cover roaming. I mentioned it a little bit with the extended service set identifier, so we're going to revisit that. So I thank you very much for your time. I hope you guys enjoyed the video, and I'll see you in the next one.
