Chapter 14. Wireless Networking

Wireless Networking Standards

Wireless Components

When we outlined this chapter, we devoted significant space to standard wired Ethernet networking. After all, we've been running a wired network in our house since about 1985the days of ARCNet on RG-62 coax cableand have about a mile (literally) of cable running through our walls, attic, and basement. But then we realized that people nowadays usually don't want to run network cables throughout their homes.

Wireless networking is where the action is. If we had any doubts, a quick trip to Best Buy quashed them. The shelves were full of wireless networking gear. There were few wired networking components in stock, and those were gathering dust. So we decided to refocus this chapter on wireless networking.

Wireless networking has some key advantages relative to wired networking:

Flexibility

A wireless network is, by definition, flexible. You're not tethered by a cable to the nearest network jack. You can install a new PC in the kids' bedroom without having to drill holes in the walls and run a cable own to your office. You can carry your notebook from your office to the den to the deck, with your network connection active the whole time. You can relocate or add systems without worrying about how to get them connected to the network.

Simplicity

Wireless networks are very simple to install and maintain. Once your wireless network is set up, all you need do is install a wireless network card and enter your passphrase to put that system on the network.

SAF

SAF (Spousal Acceptance Factor) is higher with wireless networking. With wired networking, you may find yourself explaining to your spouse why you can't put his system exactly where he wants it, or what those ugly wires hanging out of the walls are for. With wireless, you never have to apologize or explain.

Neighborhood Area Networking (NAN)

If you have a wired network and your cable modem goes down, you're out of luck until the cable company gets around to fixing the problem. With wireless networking, you can set up a NAN (Neighborhood Area Network). If your cable modem goes down, you just connect to a neighbor's wireless network and share his DSL connection until your cable modem is back up. When his DSL is down, you return the favor. With a NAN, Internet outages are pretty much a thing of the past. (Note that some service providers look askance upon connection sharing, particularly if two or more households share and pay for only one connection.)

Wireless networking also has a couple of disadvantages relative to wired networking:

Throughput

Wired 100BaseT Ethernet has a nominal data rate of 100 megabits/second (Mb/s) and actual throughput of roughly 80 Mb/s, or 10 megabytes/second (MB/s). Gigabit Ethernet (1000BaseT) is theoretically 10 times faster, and is actually 3 to 5 times faster. If you use an Ethernet hub, that bandwidth is shared among all systems connected to the network. If you use a nonblocking Ethernet switch, each system has a dedicated, full-speed communication channel. The wireless networking technologies we describe in this chapter provide either 54 Mb/s or 108 Mb/s nominal bandwidth, with actual throughput of roughly 25 Mb/s or 50 Mb/s respectively, and that bandwidth is always shared among all the systems on the network.

If you are using a network only to share an Internet connection, the lower throughput of wireless is unimportant because even the slowest wireless connection is much faster than most broadband Internet service. However, if you do heavy data transfers across the network, such as backing up files from one PC to another, the lower throughput of wireless may become problematic. Also, because wireless bandwidth is shared among all active wireless clients, doing a heavy data transfer between two clients leaves other clients with very little available bandwidth.

Security

Wired networking is inherently secure, in the sense that outsiders cannot easily gain access to the systems on your network or to internal traffic, assuming, of course, that your Internet connection is properly secured. Wireless networks are by default insecure, because wireless equipment vendors ship their products with security features disabled. Some credible estimates say that nearly 100% of all residential wireless networks run wide open, with no security at all. Fortunately, that's attributable to laziness or ignorance, because modern wireless networking gear can be secured nearly as well as a wired network. But all the security features in the world won't help if you don't use them, so make securing your network a high priority.

WHAT ABOUT COST?

At first glance, wireless networking seems noticeably more expensive than wired networking. After all, most computers already have a free Ethernet port, so all you need to buy is some $10 Ethernet cables and a $30 Ethernet switch. To install wireless networking, you'll probably have to buy a $35 wireless networking adapter for each computer and a $50 wireless access point or wireless router. Wired networking is definitely cheaper, right? Well, maybe.

The putative cost advantage of wired networking assumes that all of your computers and your Internet connection are in one room (or that your spouse doesn't mind Ethernet cables draped over doorways and hanging out of the walls). In a typical household, doing the job right means you're going to need some supplies and equipment. At a minimum, you'll want a spool of Category 6 or better networking cable, modular connectors for both ends of each cable run, modular faceplates to hold the modular connectors, old-work boxes to hold the modular faceplates, drop cables for each end of each cable run, a good wire stripping/crimping tool, a drill and other hand tools, and so on. You may even need a $50 bellhanger bit (a standard 3/8" to 5/8" drill bit on the end of a six-foot flexible rod that you use to drill in inaccessible locations.) By the time you add everything upeven assuming you have or can borrow part of what you needdoing a wired network properly often costs as much or more than using wireless networking instead.

We recommend using wireless networking unless you have a good reason to use wired networking. It makes sense to use wired networking:

• To link systems that transfer large amounts of data, particularly streaming video.

• To connect desktop computers and other devices that are in close proximity to each other and do not require mobility.

• To extend your wireless network to cover areas that are prevented by obstructions or distance from joining your primary wireless network.

• To connect devices, such as network printers or surveillance cameras, that do not support wireless connections (although you can connect such devices to a wireless bridge device that converts them to wireless operation).

Don't overlook alternatives to a permanently installed wired network. For example, if you infrequently need to transfer large files from one system to another, it may be easier to copy those files to a writable DVD or an external USB hard drive and sneakernet them to the other machine.

A temporary wired network can also be useful at times. All recent motherboards include integrated Ethernet, so there's a fallback position when you need wired networking temporarily for a particular task. Keep a long Category 6 Ethernet cross-over cable handy for such times. (We have a 100-footer.) With a cross-over cable, you can connect two systems directly to each other, without using a hub or switch. Do the transfer across the cable, and then roll up the cable and put it back in the closet until next time.

WHAT'S A CROSS-OVER CABLE?

There are two types of Ethernet cable. A standard Ethernet cable is used to connect a network adapter to a hub (or switch). Ethernet adapters send on some wires and receive on others. Hub ports reverse the two, so everything works. The adapters send on the wires that the hub receives on, and vice versa. A standard cable can't be used to connect two standard Ethernet adapters directly, because both adapters send on one set of wires and receive on another. Nobody hears anybody. A cross-over cable swaps the send/receive wires at one end, so the two adapters are able to communicate. (Auto-sensing Ethernet adapters automatically detect which pairs to send and receive on, and so can be used with either type of cable; however, a cross-over cable works with any type of Ethernet adapter, auto-sensing or not.)

If you buy a cross-over cable, pay attention to the category rating. A Category 5 or 5e cable is rated for a 100 Mb/s 100BaseT connection. If your systems have Gigabit Ethernetwhich you should always choose if you have the optionyou'll need a Category 6 or better cable. (Actually, Gigabit Ethernet usually works fine on a 50- or 100-foot Category 5e cable, but better safe than sorry.)