How to buy home networking products

July 16, 2008

A network lets you connect multiple PCs and other devices together so that they can share resources such as printers, files or an Internet connection. There are three major types of home networks: Ethernet networks that make connections over special (Category 5) wiring; power-line networks that use existing electric wiring and outlets; and wireless (Wi-Fi) networks based on components that send data over the airwaves using radio frequencies.

A wireless home network offers more convenience than a wired one — there’s no need to install cables, and notebook users can roam untethered. But wired networks are generally more secure and reliable (especially for multimedia streaming), and those that use existing electrical wiring eliminate the expense and hassle of installing new cables. Depending on your requirements for the location and mobility of networked devices, you might consider combining elements of wired and wireless networks; it’s relatively easy if you plan ahead.

Wi-Fi standards

Networks based on the IEEE’s family of 802.11 standards for wireless Ethernet are commonly referred to as Wi-Fi.

Wi-Fi comes in several flavors. The newest and most common are based on Draft 2 of the upcoming 802.11n standard. They are among the fastest wireless products available, with maximum theoretical speeds of up to 300Mbit/sec.; their range of coverage is also dramatically better than that of networks based on the earlier and slower 802.11a, b and g standards described below.

Although the IEEE still hasn’t finalized 802.11n (final ratification is expected later this year), the Wi-Fi Alliance — the industry group that certifies Wi-Fi products for compatibility — last year began a certification program for Draft 2 products to address compatibility issues that had surfaced with earlier products based on the initial draft. Fortunately, most products based on the earlier draft are firmware-upgradable to the more recent draft, but shoppers should strive to find the newer products that the Alliance has certified for 802.11n Draft 2 compatibility.

Unlike previous Wi-Fi standards, 802.11n covers operations on two different frequency bands: 2.4 GHz and 5 GHz. Most products operate only on the 2.4-GHz band, and are backward-compatible with products based on the previous 2.4-GHz Wi-Fi standards, 802.11g and 802.11b. A few recent high-end 802.11n products, however, also support the 5-GHz band, and are also backward-compatible with 802.11a products (which use the 5-GHz band). We’ll discuss the benefits of such "dual-band" products later.

The Wi-Fi Alliance certifies 802.11n products for each of these frequencies; products from different vendors will be able to interoperate at high speed on the frequencies for which they are certified.

Draft-N vs. Pre-N

The 802.11n standard’s superior speed and range derive in part from its use of multipath radio and antenna technology that first appeared a couple of years ago in products (including some labeled "pre-n") based on chips from a single vendor, Airgo Networks. These early products have been largely discontinued; you should avoid them, as they are compatible with 2.4-GHz Draft-n products only at the speeds of older 802.11g products. One way of making sure that you are buying the most current technology is to look for Wi-Fi Alliance certification for 802.11n (draft).

Older and slower standards

Because prices on low-end Draft-n gear have declined dramatically, we don’t recommend buying products based on the older 2.4-GHz 802.11 standards (802.11g and 802.11b) — they’re increasingly hard to find anyway. The 802.11g standard has a theoretical maximum throughput of 54Mbit/sec., and 802.11b has a theoretical maximum off 11Mbit/sec.

You may also see 802.11g gear promising speeds of up to 108Mbit/sec., but such products use proprietary technologies, and you probably won’t achieve those speeds if you mix and match 802.11g products from different vendors.

Note that if all you’re sharing on your network is broadband Internet access, you might not notice any performance boost with faster Wi-Fi gear, since most cable and DSL hookups top out at 6Mbit/sec. Though Wi-Fi connections never approach their theoretical maximum speeds, even 802.11g Wi-Fi networks can keep up with the fastest broadband.

Products based on the 802.11a standard also support theoretical maximum speeds of 54Mbit/sec., but tend to have a slightly shorter range than 802.11g products do. Even so, 802.11a does not interoperate with b/g products because it works on a different radio band (5 GHz), and the standard never took off the way its siblings did. In the end, 802.11a was used primarily in some business environments.

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