LAN managers and CIOs can breathe a little easier, now that solid security standards are available for WLANs. This 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. “Now the top problem is making it work robustly and reliably,” says Paul Congdon, chief architect of ProCurve networking products at Hewlett-Packard.
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. 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.
Bob O’Hara, vice president of systems engineering at wireless hardware provider Airespace, 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 it are Chantry Networks, Cisco Systems, and Meru Networks. 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.
