 My name is Ken Mayer and I'm going to be your instructor for this course on CWNA, the Certified Wireless Network Associate. Over the last 30 years, I've had an opportunity to work with a lot of different technologies. I won't focus on many of the equipment that I work with through the routing, switching, and the infrastructure, but rather the work that I have done so far with companies like Cisco, with NetScreen, which is now part of Juniper, and Aruba Networks, which is about the wireless communications. I've been involved with those technologies, at least the last 15 of the 30 years that I've been in this business, and I hope to be able to take some of that information and be able to give it to you, things I've seen with the deployments for large companies, for small companies, and all those things in between. Now in this module, we're going to talk about some of the history of wireless communications. We'll look at some of the different standards, some of the regulatory agencies like the FCC, the ITUR, IETF, the ISOC hierarchy, the Wi-Fi Alliance, the IEEE, the ISO, and however many other acronyms you think I can put out there for you. We'll also talk a bit about the hierarchical model of our networks, and where the wireless access points fit into there. We'll look at some of the differences about carrier signals, and again some of the fundamentals of communications. So wireless communications, believe it or not, have been worked with since the 19th century. I know that seems like a long time ago, because it was, but we had a lot of scientists that were out there, people like Tesla and some others, who were experimenting with wireless communications, and they were successful at doing some of those types of communications, but it really wasn't, well as it evolved, it wasn't until about the 70s that the state of Hawaii actually had wireless communications that they were using to be able to transmit information between the islands. Now the medium that they used, they called it aloha, that makes sense, it was Hawaii, and it operated at 400 megahertz, which is certainly not the frequency range we're using today. In the 1990s, this is again moving forward in our history, we saw commercial wireless starting to take place, operating at the 900 megahertz range, basically things like cordless telephones, if you even remember the day when we actually had telephones that were attached somewhere to a jack in the wall of our house, but that and some other kids toys, wireless toys, began in the 90s and that was the common range that was being used. Now the International Telecommunications Union, radio communication sector, big name for them, the ITUR, and other local entities like the Federal Communications Commission started setting the rules for what a user can or can't do with a radio transmitter. Now these organizations manage and regulate the frequencies that we can use, whether licensed or unlicensed, the power levels of the transmissions, and the types of transmissions or the methods that we use for sending information. They're also working together to help us guide the growth and the expansion of what's being used with today's wireless users. So it's really kind of a big area. There's a lot of companies, a lot of government agencies, and not just in the United States, but also in most of the countries around the world. And you'll see that there are some differences. If you were to travel, you might see a different number of channels being used at different frequencies. Maybe a different power level is allowed. So it's important for vendors to be able to work with these different agencies to figure out how to build and create their products for the countries in which they're selling this information or the actual equipment, not the information. Now the IEEE, the Institute of Electrical and Electronic Engineers, is the one that's creating the standards for compatibility and coexistence between networking equipment. Now this group of people is, you know, several hundred people in this organization. And the idea is that they're not building the actual equipment, but they're creating the guidelines of how these different pieces of equipment from different vendors should work, so that if you, say, have an access point from one location or one company and you bought a laptop that has a wireless card built by another organization, how do we know that they're supposed to work together? And so that's what the IEEE standards are designed to do, is to be able to make that type of compatibility work. But it still has to fall inside the guidelines set by the FCC. The Internet Engineering Task Force, IETF, are the ones that create internet standards. Again, they create standards that are not creating the actual product. These standards are designed to be integrated into the wireless networking and security protocols and standards that we use for Wi-Fi communications. Another group, the Wi-Fi Alliance, is the one that's going to perform certification testing to make sure that the actual equipment by the vendors, whatever wireless networking equipment they use, is conforming to the IEEE standards of 802.11 when it comes to the different types of communication guidelines for wireless local area networks. Now the International Standards Organization designed what they called the OSI model, the Open System Interconnect. And it was again guidelines of a way to help us know how technologies can talk to each other. So when we're taking a look at the OSI model, we have to remember that we still are going to have, more than likely, when we're creating these wireless networks, have to be involved with the IP protocol for the network layer and the different types of transport protocols, because we are facilitating these packets to be able to go from one host to another host over a combination of wireless and wired networks. So as the administrator, you need to have some familiarity with these layers three and four, where when you think about what we're doing, and this is my picture of an access point, when we think about the actual wireless radio frequency, that's pointing us here at the physical layer. That's instead of a copper wire or a fiber cable, we are sending radio frequencies to represent the medium that we're transmitting at. And also we have to have a way of doing communications that we'll talk more about at layer two with the data link layer. Now what's important about the OSI model is that the whole goal was to be able to say, hey look, we have to be able to have what they call these PDUs, the ability for one layer to talk to the layer above it and the layer below it. Meaning that it doesn't matter what we use in the physical realm as long as whatever technology is capable of working at the data link layer and whatever's at the data link layer can work at the network layer. In fact, it was designed again as a model that we could just rip any one of these layers out and replace it with a new layer. As an example, in the network layer, we've been focusing on IP version four for a very long time and then suddenly we ripped that out and now put in IP version six. No problem at all with IP version six as long as it can talk to the transport layer and talk to the data link layer. And that was the beauty of having this type of an open model rather than having companies create their own protocols that are basically proprietary to them. This was designed for open standards for any vendor creating this type of equipment. Now the FCC was established by the Communications Act of 1934. Now think about what's really happening back in 1934. We did a lot with radio, obviously a lot of radio shows, families watching or listening to the radio in the night times. So the FCC obviously has grown since then with what they are responsible for and they are responsible for regulating any interstate and international communications that are done by radio or by television, over a wire, by satellite, by cable, I mean any type of electronic communication. They also regulate the licensed spectrum and the unlicensed spectrum. Now when I say licensed spectrum, if you think about your AM and FM radio channels, I mean obviously those are licensed to companies that are broadcasting on those stations and part of the reason for the licensing is to make sure that we don't have different radio stations trying to compete on the same band and cause interference. So there's a big reason why there needs to be a license for that. The unlicensed spectrums are those that you don't have to use a license for but the downside is that since nobody has to get a license to use that medium that we can have a lot of different products that can interfere. As an example, if you're in your office, you have Wi-Fi, what you're going to notice is that as you get close to let's say the kitchen or the cafeteria that things like the microwave are going to cause interference because they're using some of those same frequencies and that becomes a bit of a problem. So we do have the issue and we'll talk more about it when we get into these communications of having other devices or other types of technology basically stepping on your data signal within your location and so that's probably the downside when it comes to using an unlicensed medium. Now when we talk about any of the communications, any of the frequencies licensed or unlicensed, the FCC still has regulations that we have to abide by. Now I know I just said unlicensed, anybody can use it but we still have to deal with the FCC rules such as the frequency that we're using, the bandwidth information, something we're going to talk a lot about and force you do a little bit of math which is the maximum power of the intentional radiator, well basically the antenna or the equipment but we'll get into those, and the maximum what they call EIRP or the equivalent isotropically radiated power. So yes believe it or not with your, let's say your access points, there is only so much power that we're allowed to use total for the communications and you know technically we could communicate if we had enough power over many many miles, you know hundreds of miles or more just like you see with things again like radio stations so but we don't do that in our office environment again because of other regulations from the FCC and we'll talk more still about the power calculation and of course they also regulate the use whether equipment is ready for indoor use or outdoor use and also as I just talked about with these radio stations as an example the spectrum sharing rules so all of that is licensed or regulated by the FCC. Now the ITUR basically as I said before the international telecommunications union radio communications sector, big name for a company or a foreign organization, anyway the United Nations has tasked that organization the ITUR with global spectrum management. Now in saying that the types of areas as I said before are very important to us because each region of the world will have some of their own regulations and so this group's trying to work with those. As an example they have region A which is the Americas and we would look at something like the Inter-American Telecommunications Commission which they call the CITL as the organization that works with and remember there's more in the Americas than just the United States I mean just in North America you have Canada you have Mexico and you know other countries as you go further south. Western Europe they have Region B anyway and they use the Western Europe European Confidence or Conference of Postal and Telecommunications Administrations they call CEPT and again different countries. Region C is Eastern Europe and I won't go through and tell you all of the different names you can certainly look at that as you go through this course. Region D the African area which is interesting because I did some work recently about six months I lived down in Kenya and so I got to see a little bit more about how the regulations and laws are a little bit different there than they are in other regions of the world and then of course the Asia Pacific which would include Asia and Australia telecommunications what they call the APT so we have the United Nations has an organization they're working with that is breaking down the different regions of the world and trying to work with how wireless communications should be used in those different parts of the world. The Internet Engineering Task Force IETF is one of five main groups that are a part of what we call the ISOC or the Internet Society and you'll see a little breakdown chart here in just a bit to better explain the hierarchy of where IETF fits into the Internet Society but what they're doing is basically the IETF is the one that does a lot of the designs creates a lot of what we call the request for comments that eventually become standards that we use in different types of internet communication so in the ISOC by the way besides IETF they have the Internet Architecture Board they also have the you know group that assigns names and IP addresses they call it ICANN or the Internet Corporation for Assigned Names and Numbers and even in that organization is broken down by different regions of the world they have the Internet Engineering Steering Group and the Internet Research Task Force now for those of you seeking certifications you don't really need to know about all of the different pieces of ISOC but when you're out there and you're working in the production world it is important that you understand what some of these regulations are and how they're changing because we have to work with them so the goal here is to let you know about these different organizations that you will hopefully in your life of working with wireless continue to stay up to date with things as they change now one of the RFCs I was just talking about the request for comments these you know start off as ideas that get published and then other groups can add their thoughts to these RFCs and if everybody likes this new thought then you know it's basically gets an update but as it gets updated it gets a different number and so you can trace back many of the RFCs to you know almost generationally through the ways in which they have evolved but anyway RFC 3935 is designed to give us the purpose of what IETF is supposed to do and what they're supposed to do in their part of ISOC is to give us high quality relevant technical and engineering documents that influence the way people design use and manage the Internet and in such a way to make the Internet work better now the documents will include protocol standards they'll talk about the best current practices and including some informational documents of different kinds basically around how we do communications now I know I said about the Internet but a lot of what the IETF does and designs are going to be standards that we use inside of our networks I mean just as an example the way in which we use IP addresses and we're going to use those inside of our network as well as getting out into the Internet and so that's where we see a lot of the work that the IETF has done for us so again at the top level we have the Internet Society ISOC and from there you'll see that we branch down to the names and numbers with ICANN and that's pretty much where we stop there they're the ones that would again approve new domain names if you wanted to use those or the types of address IP addresses you use and then on the design of right the new updates and what we can do better with our communications we'll start through the internet architecture board and from there they're going to have a research task force working underneath them as well as the internet engineering steering group I get really again like I said you don't have to memorize all of this for those of you seeking certifications in this particular course but it's just information I think that is crucial for you to understand so that you know where all this stuff comes from anyway the internet engineering steering group is the ones that are basically in this hierarchy over the IETF and so what are the does the IETF do I said well in essence they're trying to make the internet better so you know that might be with applications general protocols operations management different types of routing protocols I mean IETF well we're the ones that helped us with designing the OSPF routing protocol transport layer information again internet standards best practices security information real-time applications such as voice over IP and the type of infrastructure to support that and as they put all of these different ideas together that as I said eventually become our standards you're going to see them published as these request for comments the Wi-Fi Alliance is a non-profit organization of about 550 different vendors that is devoted to improving the equipment that we use with wireless communications the goal of the Wi-Fi Alliance is to examine the different vendors equipments and make sure that they work together work at the way the standard was set and that it would interoperate with any other vendor and so when they test that equipment you'll often see the little Wi-Fi certified logo which basically tells you that it's going to work with the majority of other networking vendors I mean that's your Cisco's your Juniper's your Aruba's you know it just goes on and on and on with all of the different types of people or companies that are building equipment to know that they interoperate now the IEEE as I've talked about before is the one that comes up with some of the standards remember they are not building equipment they're just coming up with the guidelines and the standards that we should build our equipment to they have about 400,000 members in 160 different countries and as they create these they're just you know how much how else can I say it's just written documents it they're not making equipment but they're describing how the technical processes and equipment should function so we hope that the vendors are following those ideas such as years ago when we got excited about high throughput 802.11n the IEEE really hadn't finished that document before vendors started putting that equipment out and there was a problem in the early days that not everything was compatible as they worked together because we didn't really have a set standard once it was standardized then of course vendors made their equipment work with that standard and the Wi-Fi Alliance would be able to verify that they worked with within those guidelines and worked with other people's equipment so often the company Cisco is talked about with this hierarchical model and you know whether it was Cisco that came up with this idea or it was some other guidelines they're the ones that really promote it but what the idea here is is to talk about the structure and the building of your networks and the three areas they have are the access layer the distribution layer and the core layer so let's talk a little bit about what happens with wireless communications because if you think about it they are in what we would call the access layer so these are little laptops because that's where we access the network anything that is an endpoint an endpoint of communications just simply means that the device is either sending a new communication or it's receiving some communications but nothing is passing through it like a router or a switch would be and so that's the access layer where we access it and if I have these computers that are doing Wi-Fi then they need a device such as the access point to be able to associate with and that means that they're entering the access layer they're accessing your network because obviously at some point you're going to enter into the wired network and so that's one of part of big critical part really of the design but then we have to worry about how do we get from let's say one area of our network to let's say another area of our network that's also an access layer maybe they're not even wireless maybe it's a server farm or you know virtual machines or whatever else that you might have that in that access especially in larger networks has to go through a distribution layer the distribution layer typically we would think of routers so these circles with an X as a as a router or we can even have a switch that does routing based on IP addresses but the distribution layer is our method of being able to get from one point to the other to be distributed our traffic throughout the network it's also one of the classically the first place that we would introduce security but we've done a lot more now to have security types of technology or security methods available even at the access layer security is an important part obviously these days with the number of hacks that we hear about on the news so it's policy based connectivity and then the core was all about high speed switching the goal of the core was to not worry about security we wanted to move things at highest speeds possible we often see today that from the core we would connect to let's say like a private cloud inside of your network and and that could be again a virtualized server farm or something else we see the core as our way to get out to the internet the idea being that on these edge or what we call the edge that we have other security apparatuses that are protecting the core from the traffic gets there but once we get to the core then we want to have like I said the highest speed possible with nothing stopping it so a lot of what we call edge services which are not depicted here in this little picture connect to the core in most of the typical types of designs when we talk about carrier signals we're talking about ways in which we can transmit our data now when it comes down to it all we're sending is a bunch of ones and zeros part of what we call binary communications and those ones and zeros when put together and read by an application or you know whatever it is that we're using for the communications we'll understand what the message is now those ones and zeros could be sent by light to fiber optics it could be sent by electrical current through a copper wire it's just a method of being able we have to have a method or some sort of media to carry the ones and zeros in this case we're going to use radio frequency and and so that means that our transmitters needs to have a way of being able to send the ones and the zeros from one location to another again the idea is that the receiver would understand the pattern of information and would be able to decipher the ones and zeros being sent so we can put that data together now if a signal fluctuates or if it's altered even slightly then the signal hopefully can still be interpreted so that the data can still be properly sent and received and and so this is called the carrier signal and in fact what you're going to see is that sometimes we purposely see fluctuations in that signal to help identify the ones and the zeros