Guide to WLAN Management

Controlling the complexity that WLANs add to network management

By John Cox

Managing an IEEE 802.11 wireless LAN adds complexity to the network management challenges facing administrators.

Wireless LANs use a radio signal instead of a cable to link clients to the network infrastructure of access points and controllers, and that means anyone with an 802.11 wireless adapter can connect to your network. Second, the clients are no longer anchored by a cable to the net: They can and do move anywhere, crossing access points and subnets.

So, wireless LAN management, like wireless LAN security, calls for a more comprehensive and more detailed approach than conventional LAN management. You need tools to monitor and administer the physical devices that form the infrastructure – access points and controllers – but also the wireless clients, which can connect to anywhere in that infrastructure, and the radio spectrum (to the degree that that's possible).

But the basic issue is the same as with wired nets: The more information you have about the WLAN, the better you can ensure availability and connectivity, optimize performance, and support a growing portfolio of services such as voice, video and location.

All WLAN vendors have a management application for their access points and controllers. The capabilities, features, GUIs and overall design of these applications vary widely. Evaluating the specifics of WLAN management products should be a high priority for any WLAN deployment or expansion. Some analysts say that management features will be one of the main differentiators, if not the primary one, between WLAN vendors.

A comprehensive network management application has two main elements. But these might be subdivided into several different applications, some developed by the WLAN vendor, some from third-party software vendors, or licensed from them and integrated by the WLAN vendor.

First, WLAN management should let you centrally configure, monitor and administer the physical devices, as in a wired net. The goal is to centralize and automate chunks of the management challenge, making the WLAN more resilient, reducing the burden of manual intervention, and optimizing the service levels for end-user and application performance.

Many management products have been focused on real-time snapshots of the network, but this kind of data is especially valuable if stored in a data warehouse, where it can be eventually correlated with relevant data from back-end servers for authentication, IP management or services such as VoIP.

Second, WLAN management should collect and analyze real-time data about the radio environment of access points and clients. At a minimum, this means data about:

* Interference from radios in the relevant signal bands, ambient radio noise and rogue wireless devices, all for managing the radio frequencies.

* Channel utilization, number of clients per access point, a full array of 802.11 statistics such as packet errors and drops, quality of service statistics on factors such as jitter and delay to evaluate streaming traffic like voice.

* The users' experience in terms of coverage, signal strength, signal-to-noise ratio, throughput and so on.

This data is essential for maintaining and optimizing the wireless network connection, for locating legitimate clients as well as interferers or threats, for mapping radio coverage patterns, and for alerting administrators to a wide range of real or potential problems, including channel conflicts and dropped connections.

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