The company also says the new firmware release, ArubaOS 18.104.22.168, has features that speed recovery from network failures and maintain client application sessions for real-time applications, such as Microsoft Lync, videoconferencing, and others.
In both cases, the changes are intended to make the enterprise WLAN more adaptable to changing spectrum conditions as the number of Wi-Fi clients soar, with smartphones and tablets. It's part of major trend by WLAN vendors over the past 18 months to focus on WLAN features for improving RF spectrum management, signal quality and connectivity resilience.
The first set of changes is to Aruba's Adaptive Radio Management (ARM) software, an application that optimizes a battery of radio frequency features for enterprise wireless LANs.
What Aruba noticed, according to Ozer Dondurmacioglu, director of product marketing for the Sunnyvale, Calif., WLAN vendor, was an opportunity to mitigate a potential performance problem. If a Wi-Fi access point doesn't receive an acknowledgement from a client, it tries again to send the packets. But the access point picks a lower transmit rate for those retry packets, to make it more likely that they'll get through.
"The second try [therefore] takes up more airtime," Dondurmacioglu says. If this happens to, say 10 to 15 percent of the packets in an area with a lot of mobile Wi-Fi clients, "it can downgrade the total overall throughput for the access point and its associated clients," he says.
The software update counters this default behavior, and works to maintain higher retransmit rates and the overall throughput for the access point.
A second change is an improved ARM algorithm that can distinguish between different types of 802.11n client radios, so they can be grouped together and given a fair share of the available airtime. For example, laptops might have high-performance 11n radios that support two or three data streams, with a potential data rate of 450Mbps, while 11n-equipped tablets have a radio with only one data stream, and a data rate of 65Mbps.
By grouping slower with slower and faster with faster, the latest ArubaOS firmware prevents slower clients from bogging down the faster ones. In turn, the faster clients spend less time on the radio link, freeing it up for reuse.