InformationWeek
Defining The Business Value Of Technology
June 7, 1999
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New standards are making wireless networks much easier to set up and use-and they cost less, too
By Logan Harbaugh
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here are a number of reasons why a business might not want to run network wiring to all computers. The computers may be mobile, or the construction of the building may not easily accommodate new wiring, or departments might often need to quickly and easily reconfigure the layout of the office space. Wireless networks are available to address these issues and others.Many existing wireless networks were installed to support special functions, such as in hospitals, stock exchanges, and similar organizations, where the ability to roam around a building is extremely important. The first-generation products were typically proprietary, slow, and expensive.
This is no longer the case--in addition to the OpenAir standard, the Institute of Electrical and Electronics Engineers has defined the 802.11 standard for interoperability. Speeds have gone from less than 1 Mbps to 2 Mbps under the 802.11 standard, and 11-Mbps data rates are available on proprietary products and soon under the 802.11 High Rate standard. Pricing has dropped from more than $500 to less than $300.
OpenAir is a standard agreed to by about 40 vendors who were tired of waiting for the 802.11 standard to be developed. It offers some degree of interoperability between products from different vendors. Although many current installations use OpenAir products, with the ratification of the IEEE standard, it is likely to become much less prevalent.
IEEE 802.11, first defined in 1997, specifies three types of wireless LANs: diffused infrared, direct sequence, and frequency-hopping spread-sequence radio. The radio standards operate at 2.4 GHz and support speeds up to 2 Mbps. Direct-spectrum and frequency-hopping products are not compatible with each other.
The IEEE 802.11 Working Group has completed the first iteration of the 802.11 High Rate specification for 11-Mbps wireless connections, which should provide 10-Mbps throughput, considering the network overhead. While RadioLAN has been offering 11-Mbps wireless products for a year or so, most vendors waited for the high-rate specification to be ratified, and should be shipping products based on it in the near future (some may even ship by the time you read this, though too late to be tested for this review).
The intent of this review was not merely to test wireless products but to verify interoperability between vendors using the same version of the 802.11 protocol. I also wanted to test the new fast-rate products, but none were available. I was able to test the RadioLAN 11 Mbps product, which should be similar to 802.11 fast rate.
I received wireless products from four vendors: Aironet Wireless Communications, Bay Networks (Nortel), Lucent Technologies, and RadioLAN. I received a number of different products, but in order to simplify things, I tested only the wireless PC Cards and access points from each vendor. Other components available from some or all vendors are ISA and PCI cards for standard desktop PCs, 10BaseT to wireless transceivers for devices such as printers and bridges to connect network segments over distances of up to 1,000 feet.
The Aironet, Bay Networks, and Lucent products are IEEE 802.11 2.4-GHz direct-sequence spread-spectrum devices. They support 1- and 2-Mbps data rates, which translate to 700-Kbps to 800-Kbps and 1.5-Mbps to 1.6-Mbps effective throughput. The RadioLAN devices use a 5.8-GHz frequency that supports an 11-Mbps data rate, using a proprietary protocol called 10BaseRadio. It is representative of the new 802.11 fast-rate products. Aironet and Lucent have announced fast-rate products; Aironet says its access point will be firmware upgradable to fast rate, although the PC Cards will have to be replaced, while Lucent's design requires the replacement of the PC Card in the access point, which is still less expensive than buying a new access point.
Is there an advantage to sticking to the standards? Yes. All of the 802.11 direct-sequence spread-spectrum cards were able to connect to any of the access points, as long as the service-set identifier was the same. The three products use different default service-set identifiers, but setting them to a single one is easy. This means that a company could standardize on either direct sequence or frequency hopping and be confident that products from any of the 802.11 vendors would work in its network, just as different Ethernet network interface cards will work on an Ethernet network.
continued...page 2, 3, 4
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