For LANs to go "all wireless," they must achieve close technical parity with Ethernet. The wireless LAN industry appears hard at work to make it so.

The first segment of the LAN to break free of cables is the connection between client devices and wireless access points (AP) for obvious mobility reasons. From there, wireless mesh AP-to-AP connections promise enterprises some relief from the labor and expense of physically having to cable every AP to an Ethernet switch port.

Getting WLAN throughput to respectably compete with Ethernet in both these network segments is being addressed by the emerging IEEE 802.11n standard. A number of pre-standard enterprise-class products are available that support throughput well above 100Mbps.

Next on the list of Ethernet attributes for WLANs to match is high availability (HA). HA considerations extend from the radio-frequency (RF) access network all the way to the back-end controller network (in controller-based architectures) and authentication servers.

In the RF segment, most enterprise WLAN vendors have developed fairly sophisticated and automated capabilities for detecting interference and dynamically moving wireless devices to less cluttered channels to keep communications running. Most also balance traffic loads among APs to ensure connection success.

If an AP fails, depending on architecture, a nearby AP increases its power output to fill in the gap or will route around the failure to another AP. A number of vendors, too, have pushed key functions out to the AP so that if there is a controller failure, existing WLAN sessions keep on running.

Still, the RF client-to-AP network is prone to having “sticky” and “frisky” clients. Sticky clients cling to a given AP even when they should roam to one with a stronger signal. Frisky clients do the opposite, detecting multiple signals and ping-ponging back and forth among APs. Both conditions can drop or disrupt sessions. To stabilize the RF environment, the trend is to move WLAN-wide operational decisions out of client devices and into the network infrastructure. At least three vendors – Meru Networks, Extricom and, most recently, Aruba – are using controller-based decision making to help in the HA area.

Meru, for example, has been shipping (but has not yet officially announced) an RF capability called Proactive Spectrum Management (PSM). PSM centrally analyzes the RF environment, taking into account variables such as interference from other Wi-Fi networks and devices, and assigns a “goodness” value to each channel, explains Rachna Ahlawat, VP of strategic marketing. At any point in time, it ensures that all APs operating on a common channel in the company’s Virtual Cell single-channel architecture are tuned to the one with the highest score, she says.

Joanie Wexler is an independent networking technology writer/editor in Silicon Valley.