InformationWeek

June 7, 1999

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Wireless Networking

continued...page 2 of 4

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Setup And Installation
Wireless networks require an access point, which connects the wired network to the wireless segment, with a 10BaseT connection and adapters for the computers. Networks that need to cover a large area can be set up easily--it's simply a matter of adding access points and making sure that all of them use the same service-set identifier. You can also establish different subnets using different service-set identifiers.

A survey of the area to be networked may be necessary to verify adequate signal strength in all areas, depending on the building. A large, open area like a warehouse presents relatively little problem. The ranges noted in the features summary are for typical office buildings--in open areas, the range may be doubled. The utilities available for testing signal strength vary from vendor to vendor.

All the products reviewed include a utility to monitor signal strength. This is useful to identify areas with lower signal strength, which can help pinpoint areas that might require an additional access point. Metal-backed insulation, metal walls (such as corrugated metal shed walls), and heavy metal equipment can degrade the radio signal. Such degradation can be addressed by adding access points.

All the 802.11 products support a peer-to-peer mode, which can be used to exchange data between two stations, whether or not they are within range of an access point.

All the products reviewed are no more difficult to set up than a standard Ethernet PC Card and an Ethernet hub, and because there's no need for cabling, they may actually be easier to install.

Management
All of the access points can be managed via a browser, once an IP address is set using the serial management port. The Lucent access points have a default IP address set, which means they can be initialized via a browser rather than requiring a serial connection to config-ure them, and the RadioLAN access points can be configured with an IP address via Ethernet using a utility or a wireless PC Card.

Like standard Ethernet hubs and network interface cards, once installed, the access points and PC Cards don't really require much maintenance. Other than creating subnets to reduce the number of users on a given access point, there is little reason that any ongoing management of the access points and cards would be necessary, other than for upgrades of firmware or the like. All vendors offer some level of network upgradability that can broadcast firmware upgrades to multiple access points.

To test the products, I downloaded large files using one, two, and three portables. All the 802.11 cards sustained speeds of about 1.5 Mbps when a single card was in use. When multiple computers were downloading simultaneously, the bandwidth dropped. With two systems, throughput on both systems dropped to about 700 Kbps. With three systems, it dropped to about 440 Kbps on each system. I had only two of the RadioLAN cards but observed a similar drop when two were running at full bandwidth at once; throughput when two cards were downloading dropped from 10 Mbps to about 5 Mbps.

The drops in throughput would also happen in a wired network, and, in general, heavy downloads are not characteristic of most network use; in most cases, little degradation in network performance would occur, even with up to 100 users. The more important issue is that the quoted data rates are for raw data, including network protocols. The actual throughput is somewhat less.

While I was unable to test the networks with more than a few PC Cards, I used the RadioLAN product at Novell's BrainShare '99 conference a few months ago. With access points positioned all over the convention center, more than 100 users were able to access the network at full Ethernet speeds at all times. I was unable to find anywhere inside the building where I was unable to access the network, and it even worked quite a ways outside, providing access at speeds not noticeably slower than standard Ethernet. This bodes well for the new fast-rate 802.11 products.