Chapter One
Demystifying Wireless Networking Secrets in This Chapter
#1: You Don't Need Much to Go Wireless 4 #2: Multifunction Access Ports 6 #3: Is Wireless Networking Expensive? 8 #4: Are Wireless Networks Insecure? 8 #5: Are Wireless Networks Dangerous? 8 #6: Is Wireless Difficult to Set Up? 9 #7: Is Wireless Slow Compared to Ethernet? 10 #8: Where Do the Standards Come From? 10 #9: Standards on the Horizon 14
In just a few years the marketplace for wireless networking products has exploded, and it continues to grow at an incredible rate. At the same time, the market has consolidated, with fewer competing wireless technologies available. Unfortunately, these changes haven't made wireless networking any less confusing for the average consumer.
Once you know which standards are the key players in the wireless space, you can make an informed decision about the design (or extension) of your own network. Setting up a home or small office/home office (SOHO) wireless network isn't difficult. It requires less effort and cost than a wired local area network (LAN). If you have ever networked computers using Ethernet cable, a wireless network should be an easy upgrade for you. If you haven't worked with Ethernet before, don't worry, you're still in good shape. Read on.
Secret #1: You Don't Need Much to Go Wireless
Wireless-the name says it all: Cut the cord. Wireless networking is cable-free, no-strings-attached networking. Most wireless networks send data through radio waves, broadcasting in all directions.
note
One or two proprietary products use infrared light to send data. Other than infrared links between laptops and PDAs, you will probably never encounter infrared products outside the specialized environments in which they are used, such as for industrial controllers.
If you have never had to run Ethernet cable, then you can rejoice in your good luck and go skipping into the future free of the emotional (and sometimes physical) scars that many of us carry from years of pulling cable through walls or under houses (see Figure 1-1). If, like me, you suffer from Post Traumatic Ethernet Disorder (PTED), then take heart; you have pulled your last Cat5 cable. From this point on your computers are going to be free and untethered, as in the WLAN in Figure 1-2.
Wireless networks operate in the unlicensed band of the radio spectrum, typically 2.4 GHz or 5 GHz.
You need three things to set up your first wireless network:
* At least two computers
* A wireless network interface adapter (one for each computer)
* A wireless access point (at least one)
Wireless Network Interface Adapters
Like the Ethernet card on a wired network, the wireless network interface adapter translates between your computer and the network. The network interface adapter is frequently called a network interface card, or NIC. Your computer and the network speak different languages, called protocols, and the NIC acts as an interpreter.
Wireless network interface cards come as PC cards, USB adapters, compact flash cards, or PCI/ISA cards. Each computer on your wireless network needs an adapter.
Wireless Access Points
A wireless access point (AP) connects wireless devices on your network to each other. Every wireless local area network (WLAN) needs at least one AP. An AP is usually the most expensive piece of hardware in a WLAN (other than the PCs, of course). Prices on wireless products have been coming down, with APs currently ranging in price from $80.00 for a bare-bones AP to over $300.00 for an AP with advanced features.
Secret #2: Multifunction Access Ports
You can save money and improve performance by purchasing an AP that provides additional network services. Here are some of the features you should look for:
* Print server-Connects your printers directly to the WLAN and prints wirelessly without hooking your printer up to a PC
* Dynamic host configuration protocol (DHCP) server-Assigns addresses to each computer on the network
* Network router-Connects to your broadband Internet connection and routes traffic to and from your computers, allowing them all to share a single Internet connection
* Network switch-Connects PCs to the network using Ethernet cables and allows for faster communication between client PCs
You'll learn more about each of these features later in the book.
Why Go Wireless?
Besides the obvious advantage of not having to install or invest in Ethernet cables, a WLAN offers many advantages over a wired network. While the initial cost may be higher, in many instances it is cheaper to expand a WLAN than an Ethernet network. A WLAN is also easier to modify, and you can move computers anywhere in range of your WLAN's signal and remain connected. Sharing resources among users on a WLAN is just as easy as it would be on a wired LAN, only more flexible. You can easily share printers, files, and an Internet connection among many computers without running cables through walls, ceilings or under floors. With a WLAN you can remain connected but not attached. Try to do that with an Ethernet connection!
Wireless technology also can be used to expand an existing Ethernet network. Perhaps you already have a network but you would like the freedom to move around with a notebook or tablet computer. You can add an AP to the network and a wireless NIC to the notebook and be able to move around with your notebook while sharing resources and an Internet connection with PCs on your wired LAN (see Figure 1-3).
There are many myths about wireless networking, from health risks and security concerns to the expense of equipment and installation difficulty. Most are inaccurate, but some have a small kernel of truth in them. The following secrets combat some of the most common myths used as arguments against going wireless.
Secret #3: Is Wireless Networking Expensive?
Setting up a WLAN costs a little more than a wired network, but expensive is a relative term. While the initial cost for wireless equipment is more, the time invested in installing is far less. In addition, being mobile instead of tethered to an Ethernet cable makes up for a lot of the cost.
Over the next year, high quality equipment based on older wireless standards will drop in price significantly as newer equipment hits store shelves. Already some multifunction APs have dropped in price by almost 40 percent. There are already opportunities to acquire some excellent equipment on the cheap, if you do your research and shop around. The benefits of mobility, flexibility, and aesthetics alone make scrapping your Ethernet cables and going wireless worth the small price difference.
Secret #4: Are Wireless Networks Insecure?
Wireless networks broadcast data in every direction. It is possible for a hacker with a wireless NIC and a laptop to receive the signal from your WLAN and gain access. Don't panic; we can prevent this. With my background in security, I spend a lot of time looking for insecure networks and systems. I am the last person to defend products with weak or poorly designed security. That said, while WLANs do have some security issues, they are no more severe than those present in wired LANs.
Security firms, antivirus makers, and firewall vendors all like to exaggerate the threat from hackers, viruses, worms, and now terrorists. The threat is real to some extent, but hardly as grave as people in the industry make it sound. Good security is mostly good planning and common sense. You can sufficiently secure any network, and I will show you how to do just that in Chapter 15.
Secret #5: Are Wireless Networks Dangerous?
People are becoming more concerned about the health risk associated with radio frequency (RF) devices. The scientific jury is still out on this question, but for the time being the general consensus seems to be that there is no health risk associated with low power devices used in WLANs.
Radio waves are a form of radiation. When most of us hear that word we tend to panic, but it helps to understand the difference between different types of radiation and distinguish between what is potentially harmful and what is considered safe. We are surrounded by radio frequency radiation (RFR) at work and at home. Microwave ovens, cordless phones, computers, fax machines, and cell phones all emit some form of RFR.
What raises concern with wireless network devices is that they operate at high frequency (2.4 GHz and above), and at higher frequencies radio waves have shorter wavelengths. Shorter wavelengths (microwaves) have a greater potential for harming living tissues than longer wavelengths.
The difference in the danger level is the power output of the devices. The Federal Communications Commission and other regulatory bodies have set strict limits on RFR emissions. In the U.S., current FCC regulations set the output for 802.11x devices at 1 watt.
Most available 802.11x devices have a power output of less than 100 milliwatts (1 milliwatt is equal to 1 thousandth of a watt); the majority produce around 30 milliwatts. This is far below the safety limit set by the FCC, and considerably lower than the power produced by a microwave oven. A microwave oven can emit up to 1100 watts, not milliwatts, 1100 times higher than the safety level imposed on 802.11x devices. Although a microwave oven is shielded, even a small leak is far more dangerous than components on a WLAN. Even the handset for a 2.4 GHz cordless phone emits around 5 watts of power. The base stations of many phones emit over 25 watts.
As long as you use unmodified, FCC-approved equipment, you should not be concerned. I say unmodified because there are many modifications that you can make to WLAN equipment, especially antennas, that can increase the range of a network and the power emitted, increasing the associated risk.
cross ref
I discuss extending the range of a WLAN in Chapter 6.
Secret #6: Is Wireless Difficult to Set Up?
A wireless network is no more difficult to set up than an Ethernet network. In fact, in most cases, it's simpler to do. The initial rollout of the network is far easier than Ethernet because you don't have to run cables to every component. The hardest part is deciding where to locate the AP. Configuring the AP and the wireless NICs is simple; the newest devices are extremely user friendly.
The most common sources of frustration in setting up a WLAN are issues with interference or performance degradation. You can avoid these problems through careful planning, and I will show you how to do that in Chapter 3.
Secret #7: Is Wireless Slow Compared to Ethernet?
It's true: a wireless network will have less capacity than a 100 Mbps Ethernet LAN. However, unless you regularly move huge files around on your WLAN, or back up large disks, you aren't going to notice a difference. Your Internet connection won't be any slower, and gaming, file sharing, and printing won't be either. Depending upon how many users are on your WLAN, you should never notice a speed difference.
If you do move very large files (meaning 100+MB) around your network on a regular basis, you will notice a difference. The trade-off for the freedom and flexibility that a WLAN offers is relatively minor. WLANs are getting faster, and with the newer 802.11g standard equipment now available, the speed difference is becoming even less noticeable.
Navigating the Maze of Standards
Okay, I know, now that you're convinced that wireless is really better, you're ready to run out to your computer superstore, hand over your credit card, and start plugging things in. But before you can get to the "how to do it" part, you need a little more of the "how does it work" stuff. This section helps you understand the layers and standards of networking technology so you'll be a more informed consumer when you hit the Giant Store of Computer Stuff.
Standards are the key to the interoperability of networking products. It would be impossible for equipment from different manufacturers to communicate were it not for accepted industry standards. Standards define the protocols that networked devices use to talk to one another. Although standards are essential, the number of wireless standards and protocols is enough to baffle even the most technically-savvy consumer.
The standards that are of most concern to the average SOHO wireless networker are the 802.11x physical layer standards, particularly 802.11b, 802.11a, and 802.11g.
Secret #8: Where Do the Standards Come From?
Two organizations are responsible for setting and certifying the wireless standards. The Institute of Electrical and Electronics Engineers (sometimes called Eye-triple-E) is an international, nonprofit, technical professional organization. The Wi-Fi (wireless fidelity) alliance is a membership organization founded in 1999 that certifies product compliance to the IEEE 802.11x wireless standards. Over two hundred companies are members of this non-profit organization. While the IEEE exists to define and promote standards among engineers, the Wi-Fi Alliance exists to promote these same standards to the public through product testing, certification, and the use of the consumer-friendly term "Wi-Fi" in place of 802.11x standard numbers.
The IEEE produces standards through consensus-based working groups. When the IEEE approves and publishes a standard, industries use it as a blueprint for developing compatible products, processes, or solutions.
Because of IEEE standards, we have the ability to choose between different vendors for WLAN equipment, or even good old Ethernet equipment (IEEE 802.3x standard). The alternative would be multiple incompatible standards and proprietary technologies. In short, because of IEEE standards, you can shop around for great deals, mix and match equipment (to some extent), and be sure that your IEEE 802.11x WLAN will operate.
The Wi-Fi alliance promotes the use of wireless technology worldwide by encouraging manufacturers to comply with the 802.11x standards when designing their networking products. The Wi-Fi Alliance also promotes 802.11x technology to home, SOHO, and enterprise consumers, has networking products independently tested to ensure that they are compliant with the 802.11x standard, and tests interoperability between certified products.
Continues...
Excerpted from 185 Wireless Secrets by Jack McCullough Excerpted by permission.
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