Network issues

By Andrew Garcia  |  Posted 2005-10-31 Print this article Print

The numbers we present here reflect performance in a wireless network configured without encryption. Administrators should expect increased delays with security enabled, and these numbers may vary depending on the type of security selected.

The 802.1x protocol that provides strong port-based authentication to the WPA and WPA2 WLAN security specifications may add significant delay when a client initiates a roam between access points. In a worst-case scenario, the wireless client device must re-authenticate to the RADIUS server for each handoff.

The IEEE 802.11i security standard, ratified last year, includes a few optional parameters to help speed roaming in a secured environment. Implementers should check with their wireless vendor as to whether preauthentication to neighboring access points or proactive key caching is supported.

Many wireless switch vendors also include proprietary features to help load balance the wireless network and ensure QOS for users, particularly voice clients.

For example, Meru Networks Inc.s WLAN System works to remove the burden of roaming from the client devices almost entirely. Using a single MAC (media access control) address and one radio channel for an entire wireless network, roaming decisions are instead initiated by the central switch. Client devices view the entire network as a single radio cell, which minimizes delay in handoffs because the client does not need to reassociate and reauthenticate.

Technical Analyst Andrew Garcia can be reached at

Check out eWEEK.coms for the latest news, views and analysis on voice over IP and telephony.

Andrew cut his teeth as a systems administrator at the University of California, learning the ins and outs of server migration, Windows desktop management, Unix and Novell administration. After a tour of duty as a team leader for PC Magazine's Labs, Andrew turned to system integration - providing network, server, and desktop consulting services for small businesses throughout the Bay Area. With eWEEK Labs since 2003, Andrew concentrates on wireless networking technologies while moonlighting with Microsoft Windows, mobile devices and management, and unified communications. He produces product reviews, technology analysis and opinion pieces for, eWEEK magazine, and the Labs' Release Notes blog. Follow Andrew on Twitter at andrewrgarcia, or reach him by email at

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