Version 4.1 - 1.8 Wireless Part 1
Similar to Routing and Switching, Wireless is a large topic. There is a whole track dedicated to Wireless. In addition, there are specific topics in the blueprint for Wireless Attacks (4.1g) and Wireless Security (6.4). It looks like the purpose of this section is to discuss Wireless technology itself. One of the main tenets about Security is that you have to know how things work - so you can imagine how people would try to break it - and implement measures to make sure it doesn't happen.
Again, since there is a track for this, I don't think they will go into the finer details of Wireless. But you have to know the basic concepts of its functionality. Since it is so widespread, even users are somewhat aware of how wireless works. For this exam, you have to know more than that but less than CCIE Wireless folks.
This TechWise TV video can help you sort things out. It's only about 6 min long. If you understood everything he said - and then some, you probably know Wireless. If you were looking at that and scratching your head, you probably need to read "802.11 Wireless LAN Fundamentals" by Pejman Roshan and Jonathan Leary (and probably more from there).
Let's start with the standards. There are a lot of numbers that will be thrown at you regarding standards. The IEEE 802 Working Group is the one that defines LAN/MAN Standards. If you go to that link above, you will see the various Active (and non-Active) Working Groups listed. Note 802.3 - This is Ethernet. Anything to do with Ethernet standards would be under this group. If you click that link, it brings you to the list of standards being worked on by this group. Scroll down to "Archive information of completed work" and you will see 802.3z (Gigabit Ethernet) and 802.ad (Link Aggregation). This is where those numbers come from (if you didn't know). For Wireless, the standard is 802.11 (Wireless Local Area Networks).
There is a really good Document about 802.11 by Shyam Parekh from Berkeley. If you're not totally spot on with this topic, you should really read it. Note the first diagram putting 802.11 firmly in the Data Link Layer of the OSI model. Then you have the four 802.11 physical standards in the Physical Layer. Note that 802.11a and 802.11b are in the Physical Layer. So do you see the breakdown of the numbers? 802 = a LAN protocol. ".11" is Wireless. The different versions of 802.11 that you hear about are basically determining how the physical layer of the protocol works. The next chart is a list of 802.11 Standards and Spectrum. Below is the updated list:
802.11 Standards
- 802.11a - Wireless network bearer operating in the 5 GHz ISM band with data rate up to 54 Mbps.
- 802.11b - Wireless network bearer operating in the 2.4 GHz ISM band with data rates up to 11 Mbps.
- 802.11e - Quality of service and prioritization
- 802.11f - Handover
- 802.11g - Wireless network bearer operating in 2.4 GHz ISM band with data rates up to 54 Mbps.
- 802.11h - Power control
- 802.11i - Authentication and encryption
- 802.11j - Interworking
- 802.11k - Measurement reporting
- 802.11n - Wireless network bearer operating in the 2.4 and 5 GHz ISM bands with data rates up to 600 Mbps.
- 802.11s - Mesh networking
- 802.11ac - Wireless network bearer operating below 6GHz to provide data rates of at least 1Gbps per second for multi-station operation and 500 Mbps on a single link.
- 802.11ad - Wireless network bearer providing very high throughput at frequencies up to 60GHz. 802.11af - Wi-Fi in TV spectrum white spaces (often called White-Fi).
- 802.11ah - Wi-Fi using unlicensed spectrum below 1 GHz to provide long range communications and support for the Internet of Everything.
If you look at this list, it's quite revealing. Only some of the standards are probably familiar. Those are the network bearer service channels. (The transmission of the signal.) Those would be the "types" of wireless. Note b vs g - both operate at 2.4 GH - but at different speeds. So GH does NOT equal speed. It's a wavelength band of operation. [The same as your cordless phone maybe?] The e, f and h standards are probably not in scope. But look at 802.11i which covers authentication and encryption. That's probably somewhere on the exam. Either the standard number or the material it covers. We will discuss this later in another part.
It would be well worth reviewing the rest of that document (by Shyam Parekh). You don't have to focus on the specifics of Interframe Spacing (or other topics like Contention), but it's a good review to refresh your memory. Remember - anything could be fair game. You've probably learned this stuff at some point - just review and say "oh, yeah" when it reminds you of something you haven't seen in a while. And with that I'm going to end this part and go onto the next.