Network+ Exam Objective Review: The 802 standards
By Brian K. Arrowood, A+, Network+, Project+, ITIL V3 Foundation, PRINCE2 Foundation
Crazy Eights: Associating 802 standards and terms for CompTIA’s Network+ certification exam
Navigating through the different 802 standards in the Network+ exam’s objectives can seem more like playing Crazy Eights rather than learning about networking. What are all these 802s? Where is each applied in networking contexts? More important, how do they relate to one another? Being able to quickly associate and connect 802 standards by linking them to their applications along with other objective areas can make the difference between passing and failing the exam.
Undoubtedly, people reading this article are at different preparation levels. There may be candidates with five years of networking experience, while others might have none. They’re always those that might have just passed the A+ and now want a higher tier credential. No matter what your knowledge level is, this article will help you. We’re going to summarize the 802 standards, identify their place within the objectives, briefly mention what they do, and in some cases, draw added associations to other objective domains. After all, the key to passing the Network+ exam is being familiar with the objectives, right?
The Institute of Electrical Engineering – IEEE
You might be saying to yourself, where did all of these 802s come from? That’s a good question. It’s always important to know why we have something, why it’s in place, and why we are learning about it. The Institute of Electrical and Electronics Engineers (IEEE) is an entity that determines all kinds of standards not just the 802s. In terms of networking environments, they are responsible for frequency ranges, cable speeds/types, connections, and just about any other kind of framework that you’d expect. Just know that anytime you see the letters IEEE, we are talking about the guys that have our best interest at heart. I’d encourage you to visit their website, read a little more about them and their history, and even refresh yourself on the benefits of having standards.
The three main 802s – 802.11, 802.3, and 802.1
On to the topics at hand … The three main categories of 802s you need to know are 802.11, 802.3, and 802.1. You have to see them in this wider perspective before looking at them later once the sub-classifications are added on—that is, attached alphabetical letters like d, w, q, af, or at.
The Wireless standard
First and foremost, your mastery of objective 5.3 Given a scenario, deploy the appropriate wireless standard must be second nature. Your recognition of 802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac wireless standards should be automatic. Listing out specifications for each of these wireless types in terms of speed limitations, channel settings, or frequency compatibilities, is beyond our discussion but for those of you that are curious enough, here is a table:
I simply want to engrain that knowing immediately that 802.11 is associated with wireless networks and 802.3 is associated with Ethernet networks provide two of our three main building blocks for digging into other 802 sublayers. What’s so great is that once you can easily distinguish between 802.11 and 802.3 by immediately thinking of them as either wireless or wired networks, you’ll also be better able to draw clearer lines of association to other exam objectives. For instance, take a look at objective 5.2 Explain the basics of network theory and concepts. We know that Carrier sense multiple access with collision detection (CSMA/CD) applies in 802.3 Ethernet networks and that Carrier sense multiple access with collision avoidance (CSMA/CA) applies in 802.11 wireless networks. All we’re doing is linking access methods to associated 802 standards. It really just makes sense. For example, in an Ethernet setting, detecting collisions should be easier and explains why it is called CD (collision detection), whereas in a wireless setting, numerous wireless devices attempting to transmit all at once simply makes avoiding collisions about all you can ask for—hence, the name. To briefly recap, immediately think 802.3 when you see Ethernet, and wireless scenarios should be popping into your mind when you see 802.11.
802.1: network bridging & management
The other main category that you need to be able to recognize deals with network bridging/management and is the 802.1. Important note: anytime you see the word bridge, you should automatically be thinking layer-2 devices and switch configurations. In fact, the first domain objective in the Network+ exam that directly mentions any 802 is 2.6 Given a scenario, configure a switch using proper features and pertains to 802.1 and switches. Here we find 802.1d and 802.1w, each of which describes either Spanning Tree or Rapid Spanning Tree Protocols. Both deal with avoiding switching loops on the network. Now, the term switching loops just doesn’t sound good does it? Well, it’s not. We certainly don’t want information to be continually being passed around in a loop because our network will become inoperable. Just remember that w comes after d in the alphabet so 802.1d is STP and that STP was a predecessor to 802.1w, or RSTP. Don’t forget that both help us to avoid those bad things called switching loops on our networks.
Under this same objective, but listed below a subheading called interface configuration, we find trunking and 802.1Q. The letter Q really does give this one away because you should be thinking quality immediately when you see it. Of course, QoS is Quality of Service, and both the terms trunking and 802.1Q, then, pertain to making networks run more efficiently by prioritizing and tagging frames sent through the trunk switch and/or port. If you were looking at the exam objectives, you probably didn’t even see QoS under 2.6, but take a look at 1.10 Identify the basics elements of unified communication technologies. Now you’ve tied together two more objectives!
Power over Ethernet – PoE
Everything needs power, right? Well, numerous networking devices, such as a switch or phone, can be powered through the use of an Ethernet cable. We call this PoE and PoE+. But you’ve probably guessed by now that we can’t just call these PoE or PoE+. We have to associate an 802 standard with them. Back under objective 2.6 Given a scenario, configure a switch using proper features is where we find listed 802.3af and 802.3at as the standards coinciding with PoE and PoE+, respectively. Remember how we said that 802.3 deals with Ethernet? How appropriate, then, that each of the PoE versions is also given an 802.3 prefix. Just use the same alphabet order for knowing which one comes before the other. F comes before t, so we derive that PoE (802.3af) came before PoE+ (802.3at). The only other important distinction you need to be aware of is differing voltage between the two. PoE yields 15.4 watts and PoE+ can give you well over 25.5. For the exam, it’s highly likely that you’ll have to know which one is being used in a scenario simply by voltage.
ht – High Transfer (rate)
Taking a look at our next relevant objective, 2.7 Install and configure wireless LAN infrastructure and implement the appropriate technologies in support of wireless capable devices, we find that some of those previously mentioned 802.11s are brought back. Actually, the 802.11a-ht and 802.11g-ht are really just improvements upon the basic versions of wireless classifications that go by the same names (i.e. 802.11a and 802.11g). All the “ht” means is that the speed has been increased to be more competitive with N-class networks. However, we already recognized that these were wireless related standards because we knew that 802.11a and 802.11g were different forms of wireless types and that both a Wireless-A network and a Wireless-G network each runs slower than an N-class network—that is, when without the “ht.”
802.1x and Security
It’s no secret that safety and security lies at the heart of many modern-day concerns not just those directly related to IT or networking. However, you can imagine how when information is being passed around in networks, whether texts are in the clear or not, hackers are somewhere lurking—eager, willing, and ready to seize opportunities for gaining unauthorized access to confidential data. It should come as no surprise, then, that we have an 802 for security and authentication: the 802.1x. Objective 3.3 Given a scenario, implement network hardening techniques lists it as a network security item. It’s seen again under objective 3.6 Explain the purpose of various network access control models. 802.1x is a little unusual compared with the others because not only does it have security and authentication applications for wireless but also wired environments. In either case, Extensible Authentication Protocol (EAP) works to enable authentications. Notably, there are a few terms you’ll often hear in relation to 802.1x. In wired settings, you’ll find that port-based network access control is a phrase frequently used. For wireless ones, you’ll often see it described as a predecessor in networking paths permitting connections to RADIUS servers. In all actuality, a variety of other security protocols can be associated with the 802.1x other than its mere authentication capabilities. These are just some easy-to-grasp concepts. All the while, we keep making connections to other objectives! For instance, RADIUS servers are listed under objective 1.2 Compare and contrast the use of networking services and applications, and EAP is right there at 3.3. You can see how once you understand a single concept, connecting the dots to other ones is a piece of cake!
Without question, the 802s are important networking standards. The 802.11 deals with wireless, the 802.3 with Ethernet networks, and the 802.1 with bridging/switch management. Within each of these main areas, CompTIA asks you to know about STP (802.1d) and RSTP (802.1w), 802.1Q and trunking, 802.3af (PoE) and 802.3at (PoE+), and 802.1x. Don’t forget the 802.11a, b, g, n, ac, a-ht, and g-ht. More important, take your time, and don’t get overwhelmed by all the jargon. Think through the figures like we have in this article. Let their associating terms sink in. Before you know it, you’ll be a master at 802 standards, and the game of Crazy Eights, found within the Network+ certification exam!
Recap of the 802s in the CompTIA Network+ Exam Objectives
1.2 Compare and contrast the use of networking services and applications
1.10 Identify the basics elements of unified communication technologies.
2.7 Install and configure wireless LAN infrastructure and implement the appropriate technologies in support of wireless capable devices
3.3 Given a scenario, implement network hardening techniques
5.3 Given a scenario, deploy the appropriate wireless standard
Any opinions? Anything you want to add/share? Post your comments below we’d love to hear from you.