Wireless LANs face next challenges

LAN managers and CIOs can breathe a little easier, now that solid security standards are available for wireless LANs (WLANs). Last summer, the IEEE released — and many vendors have already implemented — the 802.11i authentication and encryption standard, bolstered by the WPA2 (Wi-Fi Protected Access 2) interoperability certification from the Wi-Fi Alliance industry group.

Yet, as they deploy broader WLANs as part of the overall corporate network, IT managers will face other issues — for which standards are still in development or have not yet even been started, notes Warren Wilson, an analyst at Summit Strategies Inc. “Now the top problem is making it work robustly and reliably,” says Paul Congdon, chief architect of ProCurve networking products at Hewlett-Packard Co.

These issues fall into four categories: quality of service, WLAN management, roaming, and interoperability with other wireless technologies.

Quality of service

As WLANs are more broadly deployed, traffic management will become an issue. Access points (APs) can typically handle a dozen or so connections at a time, and the burst-traffic nature of data traffic means that most enterprises will handle that traffic easily, especially if their APs can offload traffic to one another during peak demand. “Most users aren’t saturating the bandwidth,” says Harry Simpson, vice-president of sales and marketing at wireless management tools provider Roving Planet Inc.

Bob O’Hara, vice-president of systems engineering at wireless hardware provider Airespace Inc., also sees increasing uptake in the warehousing and hospitality industries leading to potential saturation. “Health care is the exception because they have lots of other applications in use,” he says.

Bandwidth saturation could be problematic for all enterprises in two areas. One is in high-traffic zones, where throngs of users might suddenly appear, such as at hotspots, requiring both prioritization and handoff to other APs. The other is in organizations that deploy VoIP on the WLAN for mobile workers, such as within a corporate campus or to allow follow-me-anywhere IP-based telephony systems that permit both wired and wireless access.

Because 802.11 wireless networks are contention-based, the first packets to arrive get the APs’ attention. For streamed data such as voice, this contention causes dropouts. Fortunately, “wireless VoIP handsets haven’t gotten there yet,” Summit Strategies’ Wilson notes. Roving Planet’s Simpson concurs, adding that voice over wireless is not high on the list of most enterprises’ needs.

Because there has been no QoS standard, VoIP provider SpectraLink has made its own prioritization protocols available to other vendors; among those using them are Chantry Networks Inc., Cisco Systems Inc., and Meru Networks Inc. The IEEE expects to finalize its 802.11e QoS standard in spring 2005. The standard will set four priority levels each for users and applications so that network administrators can prioritize both user classes and application types, such as data, voice and streaming media. It also will standardize power settings and traffic scheduling to help APs optimize radio range and bandwidth usage based on traffic patterns.

Wireless LAN management

Managing a few APs in conference rooms is not hard, but as enterprises start to deploy dozens, updating them with authentication keys, firmware upgrades and policies might become a difficult set IT challenges.

Enterprise-class APs permit remote updating via software tools, accessing the APs’ settings typically through MIBs (management information blocks), which are capability specifications called through SNMP and are widely used for wired routers, gateways and switches. Wireless devices, however, have additional configurations related to managing the radio strength for which there are no standard MIBs.

“The original philosophy (for 802.11) was to put the power in the end nodes,

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