A Field Guide to Wireless LANs for Administrators and Power Users

2017-07-07 02:10:07

The standards that define WLANs will continue to evolve, at least in that new PHYs will be defined that provide for progressively higher speeds. As this book is going to press, the first mentions of the new IEEE 802.11n TG are being seen in the trade press.^[1] As we have seen, additional capabilities such as improved security or QoS are also being added, and new PHYs are being defined that extend the reach of WLANs into more regulatory domains. The target deployment, however, will remain local (as far as the IEEE 802.11 WG is concerned), but end users will not be intentionally constrained in their ability to creatively deploy WLAN technology in legally permissible ways.

^[1] These mentions are a bit early, since TGn will not formally exist until September 2003, and the work of TGn in defining a new high-speed PHY (perhaps as fast as 250 Mbps) will take on the order of two years. At this point, it would be irresponsible to do more than mention the imminent existence of TGn, since they have not even been formally chartered, and so there is no proposed standard on the table. Almost anything written about TGn in 2003 would be highly speculative.

"LAN" is a term that has a surprisingly confusing meaning. It used to be the case that LAN was primarily defined by the "LA" portion of the acronym (i.e., local area), but certain applications of Ethernet allow operation over distances on the order of a few kilometers, stretching the meaning of the term "local." The same is true in WLANs, in that they typically are a "local area" network, covering on the order of 300 feet, but some people have found ways to extend their reach over distances that don't seem to be local (i.e., 10 miles, with special antennas…).

I would not bother to mention this, except that I had someone ask me this very question at an IEEE 802.11 meeting. The answer is that all LAN technology was originally designed for applicability in a certain domain, but that original intent does not limit the creativity of vendors or customers in deploying the products in a way that is not consistent with the term "local." The products are still based on standards, and if the standards have multiple domains of application, that is probably a good thing, as long as the cost of products is not unduly driven up by the additional capabilities that the equipment and/or the standard is able to support.

This book has focused on IEEE 802.11-based devices, and while these are very popular, they are not the only class of wireless devices. In the late 1990s, another wireless technology was being developed that many people mistakenly perceived to be competitive with IEEE 802.11b. One reason for the implied competition was that both of these technologies used the 2.4 GHz ISM band. The name of this technology was, and is, Bluetooth^®. It is still in existence…primarily because it has applications to which it is uniquely suited, and for which IEEE 802.11 is not suited.

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