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There are two main components in a wireless LAN: access points (APs) and PC Cards that slide into the expansion slots in notebooks. Both components are receiver/transmitters. The AP and PC Cards communicate with one another via the 2.4GHz radio band, which allows indoor mobility reaching 25 to as much as 100 metres from a given access point.
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Early wireless LANs were very expensive to implement and manage, and many were proprietary solutions. Five years ago, a 2Mbps AP could cost as much as AU$5000, and wireless PC Cards as much as AU$1500 each.
The arrival of the 11Mbps 802.11b standard in late 1999 changed everything. Adoption of the standard and the availability of off-the-shelf chip sets quickly brought costs down. In fact, the most expensive access point in our roundup costs AU$3505, and some very capable units now are available for as little as AU$1000. Client PC Cards cost AU$295 to AU$536, which is a lot less than the highest PC Card price in 1998.
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With a wireless LAN, users can access network services from conference rooms, offices, and even public spaces within the building. Wireless LANs are particularly well-suited to places where traditional Ethernet networks are too expensive or too cumbersome to install. And this technology can be used to cover larger areas such as warehouses and college lecture halls where Ethernet cable is impractical. Even better, you can take your entire network with you if you move to a larger space.
Several companies--including D-Link Systems and Linksys--offer low-cost 802.11b wireless systems designed specifically for the home and small-office markets. These systems follow on the heels of the immensely popular Apple AirPort wireless network system, introduced in late 1999.
Seal of Approval
The 802.11b standard was designed by the Institute of Electrical and Electronics Engineers (IEEE) and adopted by the Wireless Ethernet Compatibility Alliance (WECA). WECA tests and certifies products for compliance and interoperability with the 802.11b standard and gives the Wi-Fi label to those that pass the tests.
The heart of any 802.11b device is the radio chip set. Currently, there are only two 802.11b chip set manufacturers: Intersil and Lucent Technologies. When we began our testing, the WECA Web site showed that there were 67 Wi-Fi-certified products from 28 different vendors. During our tests, we found that many of those products use the same technology in different packages. We included them because each vendor claims that its product is unique, thanks to the drivers, installation software, and utilities packaged with the products. 3Com, for example, has additional security and client configuration features not found in the other Symbol Technologies-based products. With so few manufacturers and such stringent compatibility testing, we expected 100 percent interoperability. This expectation was achieved with some minor tweaking.
A Secure Environment
As with all networks, security is a major issue with wireless systems--especially in the business environment. And with the recent availability of wireless packet analysers from companies such as Network Associates and WildPackets, the issue becomes paramount.
All Wi-Fi products support wired equivalent privacy (WEP), a security specification that uses 40-bit encryption to scramble wireless data on the fly. While 128-bit encryption is not currently part of the specification, it is under study and is already supported by several vendors.
WEP is implemented on both the access point and the client side of the connection, and WEP requires the use of shared keys on all access points and clients in the system. To enable WEP, users must enter the security keys manually on each client when installing wireless network cards. This is very time-consuming and can be a major obstacle to wide-scale deployment. The Cisco Aironet 350 is the first solution to address this shortcoming.
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