2. 802.11n and 802.11g Wireless (Wi-Fi) Networking
One way to build a network without switches,
cables, connectors, drills, swearing, tools, or outside contractors is
to go wireless. Blocks of radio frequencies in the 2.4GHz and 5GHz
bands are reserved for close-range data communications, and
standardized products from cordless telephones to computer networking
devices take advantage of this. Prices have fallen to the point that
wireless connectivity is competitive with wired networks, even before
the installation cost savings are factored in.
There are two common types of wireless equipment, titled 802.11g (or Wireless-G) and 802.11n (or Wireless-N) after the industry standard documents on which they’re based.
Tip
If your network is small and/or temporary,
you can run network cables along walls and desks. Otherwise, you
probably should keep them out of the way and protect them from
accidental damage by installing them within the walls of your home or
office. If you use in-wall wiring, the work should be done by someone
with professional-level skills.
802.11g equipment operates at up to 54Mbps
and is compatible with older 802.11b (11Mbps) equipment. Some
manufacturers offer Wireless-G equipment that operates at up to
108Mbps, but you get this speed boost only if you buy all your
equipment from the same manufacturer (and even then, you need to read
the packaging carefully to see if the double-speed function will work
with the particular parts you’re buying). Wireless-G can transmit data
about 100 feet indoors and up to 300 feet outdoors—at most. And at
these longer distances, lower signal strengths will result in data
errors, so the equipment will switch down to lower data speeds.
The newer standard for wireless networking is
802.11n (Wireless-N). It offers higher speeds—up to 150Mbps—and greater
range than Wireless-G. Here’s the skinny on Wireless-N:
Note
Some additional terminology: Wi-Fi
is an industry term that doesn’t mean anything in particular, but it’s
kind of catchy. It’s used to refer to any variant of 802.11 wireless
networking. Wireless local area networks are often called WLANs.
• Wireless-N, -G
and -B equipment is compatible, and can be used together on the same
network. That is, a -G network adapter in a computer can talk with a -N
router, and vice versa. However, they’ll communicate with each other at
the lower -G speed. Older -B equipment can be used, too, but again, at
the lower -B speed.
• Furthermore, having -G or -B
equipment on the network can drag down the speed as much as 25%, even
for -N devices talking to -N, if the older devices are transmitting at
the same time.
• Wireless-N signals should travel
about twice as far as Wireless-G: about 200 feet indoors, and about 600
feet outdoors. However, this applies only when an -N device is talking
to another -N device. Getting a Wireless-N router won’t improve
reception for a distant Wireless-G or -B device.
• Wireless-N can operate in the 2.4GHz
frequency band and the 5GHz band. Only “dual-radio” routers can operate
at both frequencies at once, however. Single-radio routers have to
switch back and forth, slowing performance if both frequencies are used
at the same time. The 5GHz band tends to work better than 2.4GHz at
shorter distances. At 5GHz, the signal can’t travel as far, but there
tends to be less interference from neighboring networks, cordless
phones, and so on.
Whichever version you use, Wi-Fi networking products typically have the following features:
• An actual throughput up to about half the advertised speed.
• Available for both desktop and laptop computers, in PCI, PCMCIA (PC Card), and USB formats.
• A cost of $25–$70 per adapter.
• The ability to be bridged to a wired
LAN through a device called an access point, router, bridge, or base
unit, costing $20 and up. (That’s not a typo: $20, if you catch a good
sale. $40 to $150 is more typical without a sale.)
• Usually don’t work well between floors of a multistory building.
Figure 2
shows a typical family of wireless products: a wireless access point
(Ethernet bridge), a wireless router that can also share a DSL or
Internet connection, an internal wireless network adapter for desktop
computers, and a PCMCIA adapter for laptops.
Figure 2.
Typical wireless networking equipment. Clockwise from upper left:
access point, router with Internet Connection Sharing capability, PCI
adapter, PCMCIA adapter. (Photo used by permission of D-Link.)
