Wireless Hacks. 1917 IndustrialStrength Tips and Tools [Electronic resources] نسخه متنی

Hack 3 802.11b: The De Facto Standard

Many people continue to use 802.11b, the
protocol of the Wi-Fi revolution.

Throughout
this book, I mainly discuss 802.11b (also known as
Wi-Fi,
but then, so is 802.11a). It is the de facto wireless networking
standard of the last few years, and for good reason. It offers
excellent range and respectable throughput.
(While the radio can send frames at up to 11
Mbps, protocol overhead puts the data rate at 5 to 6 Mbps, which is
about on par with 10baseT-wired Ethernet.) It operates using DSSS at
2.4 GHz, and automatically selects the best data rate (either 1, 2,
5.5 or 11 Mbps), depending on available signal strength. Its greatest
advantage at this point is its ubiquity: millions of 802.11b devices
have shipped, and the cost of client and access point gear is not
only phenomenally low, but also ships embedded in many laptop and
handheld devices. Since it can move data at rates much faster than
the average Internet connection, it is widely regarded as
"good enough" for general use.

Pros

Near universal ubiquity in standard consumer devices, add-on cards,
and APs.

Extreme popularity and pressure from 802.11a/g has led to massively
discounted hardware. Cards less than $40 and APs less than $100 are
common as of this writing.

802.11b "hot spots" are available
at many coffee shops, restaurants, public parks, libraries, and
airports, further increasing its popularity.

With many people using and experimenting with it, 802.11b is arguably
the most hackable (and customizable) wireless protocol on the planet.

Cons

The 11 Mbps data rate of 802.11b will never get any faster, and is
already surpassed by 802.11a and 802.11g.

802.11b's
channel scheme allows only for three
nonoverlapping channels, making for considerable contention in the
2.4 GHz ISM band.

Standard 802.11b
security features have been revealed
to be less than effective. See [Hack #87] and all of Chapter 7 for details.

Recommendation

While it is impossible to forecast the fickle weather patterns of the
consumer marketplace, it is very likely that 802.11b has at least a
few years left in it. Millions of devices have shipped, making it the
most popular wireless networking protocol on the planet. Ironically,
it will probably get a life extension from its competitor 802.11g, as
the newer 802.11g equipment will work with existing 802.11b access
points. This makes upgrades less of an immediate issue, and if
there's anything that network administrators hate,
it's upgrading the critical network devices.

Considering that average Internet speeds are still much slower than
802.11b, it is likely that 802.11b will be used as a mechanism for
providing Internet access for some time yet. Backbone links and
corporate networks may have an immediate need for the increased
bandwidth of 802.11a and 802.11g, but for the average Internet user,
802.11b provides sufficient speed and a very simple mechanism for
accessing networks. Even after three years of explosive growth,
802.11b continues to enjoy a lively general acceptance.